2020-08-07 08:41:08

by Jürgen Groß

[permalink] [raw]
Subject: [PATCH v3 0/7] Remove 32-bit Xen PV guest support

The long term plan has been to replace Xen PV guests by PVH. The first
victim of that plan are now 32-bit PV guests, as those are used only
rather seldom these days. Xen on x86 requires 64-bit support and with
Grub2 now supporting PVH officially since version 2.04 there is no
need to keep 32-bit PV guest support alive in the Linux kernel.
Additionally Meltdown mitigation is not available in the kernel running
as 32-bit PV guest, so dropping this mode makes sense from security
point of view, too.

Changes in V3:
- addressed comments to V2
- split patch 1 into 2 patches
- new patches 3 and 7

Changes in V2:
- rebase to 5.8 kernel
- addressed comments to V1
- new patches 3 and 4

Juergen Gross (7):
x86/xen: remove 32-bit Xen PV guest support
x86/xen: eliminate xen-asm_64.S
x86/xen: drop tests for highmem in pv code
x86/paravirt: remove 32-bit support from PARAVIRT_XXL
x86/paravirt: cleanup paravirt macros
x86/paravirt: use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT
x86/entry/32: revert "Fix XEN_PV build dependency"

arch/x86/entry/entry_32.S | 109 +----
arch/x86/entry/entry_64.S | 4 +-
arch/x86/entry/vdso/vdso32/note.S | 30 --
arch/x86/entry/vdso/vdso32/vclock_gettime.c | 1 +
arch/x86/include/asm/fixmap.h | 2 +-
arch/x86/include/asm/idtentry.h | 4 +-
arch/x86/include/asm/paravirt.h | 107 +----
arch/x86/include/asm/paravirt_types.h | 21 -
arch/x86/include/asm/pgtable-3level_types.h | 5 -
arch/x86/include/asm/proto.h | 2 +-
arch/x86/include/asm/required-features.h | 2 +-
arch/x86/include/asm/segment.h | 6 +-
arch/x86/kernel/cpu/common.c | 8 -
arch/x86/kernel/head_32.S | 31 --
arch/x86/kernel/kprobes/core.c | 1 -
arch/x86/kernel/kprobes/opt.c | 1 -
arch/x86/kernel/paravirt.c | 18 -
arch/x86/kernel/paravirt_patch.c | 17 -
arch/x86/xen/Kconfig | 3 +-
arch/x86/xen/Makefile | 3 +-
arch/x86/xen/apic.c | 17 -
arch/x86/xen/enlighten_pv.c | 78 +---
arch/x86/xen/mmu_pv.c | 488 ++++----------------
arch/x86/xen/p2m.c | 6 +-
arch/x86/xen/setup.c | 36 +-
arch/x86/xen/smp_pv.c | 18 -
arch/x86/xen/vdso.h | 6 -
arch/x86/xen/xen-asm.S | 193 +++++++-
arch/x86/xen/xen-asm_32.S | 185 --------
arch/x86/xen/xen-asm_64.S | 192 --------
arch/x86/xen/xen-head.S | 6 -
drivers/xen/Kconfig | 4 +-
32 files changed, 305 insertions(+), 1299 deletions(-)
delete mode 100644 arch/x86/xen/vdso.h
delete mode 100644 arch/x86/xen/xen-asm_32.S
delete mode 100644 arch/x86/xen/xen-asm_64.S

--
2.26.2


2020-08-07 08:41:34

by Jürgen Groß

[permalink] [raw]
Subject: [PATCH v3 6/7] x86/paravirt: use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT

There are some code parts using CONFIG_PARAVIRT for Xen pvops related
issues instead of the more stringent CONFIG_PARAVIRT_XXL.

Signed-off-by: Juergen Gross <[email protected]>
---
arch/x86/entry/entry_64.S | 4 ++--
arch/x86/include/asm/fixmap.h | 2 +-
arch/x86/include/asm/required-features.h | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 70dea9337816..26fc9b42fadc 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -46,13 +46,13 @@
.code64
.section .entry.text, "ax"

-#ifdef CONFIG_PARAVIRT
+#ifdef CONFIG_PARAVIRT_XXL
SYM_CODE_START(native_usergs_sysret64)
UNWIND_HINT_EMPTY
swapgs
sysretq
SYM_CODE_END(native_usergs_sysret64)
-#endif /* CONFIG_PARAVIRT */
+#endif /* CONFIG_PARAVIRT_XXL */

/*
* 64-bit SYSCALL instruction entry. Up to 6 arguments in registers.
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index b9527a54db99..f1422ada4ffe 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -99,7 +99,7 @@ enum fixed_addresses {
FIX_PCIE_MCFG,
#endif
#endif
-#ifdef CONFIG_PARAVIRT
+#ifdef CONFIG_PARAVIRT_XXL
FIX_PARAVIRT_BOOTMAP,
#endif
#ifdef CONFIG_X86_INTEL_MID
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index 6847d85400a8..3ff0d48469f2 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -54,7 +54,7 @@
#endif

#ifdef CONFIG_X86_64
-#ifdef CONFIG_PARAVIRT
+#ifdef CONFIG_PARAVIRT_XXL
/* Paravirtualized systems may not have PSE or PGE available */
#define NEED_PSE 0
#define NEED_PGE 0
--
2.26.2

2020-08-07 08:41:53

by Jürgen Groß

[permalink] [raw]
Subject: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

The last 32-bit user of stuff under CONFIG_PARAVIRT_XXL is gone.

Remove 32-bit specific parts.

Signed-off-by: Juergen Gross <[email protected]>
---
arch/x86/entry/vdso/vdso32/vclock_gettime.c | 1 +
arch/x86/include/asm/paravirt.h | 92 +++------------------
arch/x86/include/asm/paravirt_types.h | 21 -----
arch/x86/include/asm/pgtable-3level_types.h | 5 --
arch/x86/include/asm/segment.h | 4 -
arch/x86/kernel/cpu/common.c | 8 --
arch/x86/kernel/kprobes/core.c | 1 -
arch/x86/kernel/kprobes/opt.c | 1 -
arch/x86/kernel/paravirt.c | 18 ----
arch/x86/kernel/paravirt_patch.c | 17 ----
arch/x86/xen/enlighten_pv.c | 6 --
11 files changed, 13 insertions(+), 161 deletions(-)

diff --git a/arch/x86/entry/vdso/vdso32/vclock_gettime.c b/arch/x86/entry/vdso/vdso32/vclock_gettime.c
index 84a4a73f77f7..283ed9d00426 100644
--- a/arch/x86/entry/vdso/vdso32/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vdso32/vclock_gettime.c
@@ -14,6 +14,7 @@
#undef CONFIG_ILLEGAL_POINTER_VALUE
#undef CONFIG_SPARSEMEM_VMEMMAP
#undef CONFIG_NR_CPUS
+#undef CONFIG_PARAVIRT_XXL

#define CONFIG_X86_32 1
#define CONFIG_PGTABLE_LEVELS 2
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 3d2afecde50c..dedc89a07826 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -160,8 +160,6 @@ static inline void wbinvd(void)
PVOP_VCALL0(cpu.wbinvd);
}

-#define get_kernel_rpl() (pv_info.kernel_rpl)
-
static inline u64 paravirt_read_msr(unsigned msr)
{
return PVOP_CALL1(u64, cpu.read_msr, msr);
@@ -277,12 +275,10 @@ static inline void load_TLS(struct thread_struct *t, unsigned cpu)
PVOP_VCALL2(cpu.load_tls, t, cpu);
}

-#ifdef CONFIG_X86_64
static inline void load_gs_index(unsigned int gs)
{
PVOP_VCALL1(cpu.load_gs_index, gs);
}
-#endif

static inline void write_ldt_entry(struct desc_struct *dt, int entry,
const void *desc)
@@ -377,10 +373,7 @@ static inline pte_t __pte(pteval_t val)
{
pteval_t ret;

- if (sizeof(pteval_t) > sizeof(long))
- ret = PVOP_CALLEE2(pteval_t, mmu.make_pte, val, (u64)val >> 32);
- else
- ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
+ ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);

return (pte_t) { .pte = ret };
}
@@ -389,11 +382,7 @@ static inline pteval_t pte_val(pte_t pte)
{
pteval_t ret;

- if (sizeof(pteval_t) > sizeof(long))
- ret = PVOP_CALLEE2(pteval_t, mmu.pte_val,
- pte.pte, (u64)pte.pte >> 32);
- else
- ret = PVOP_CALLEE1(pteval_t, mmu.pte_val, pte.pte);
+ ret = PVOP_CALLEE1(pteval_t, mmu.pte_val, pte.pte);

return ret;
}
@@ -402,10 +391,7 @@ static inline pgd_t __pgd(pgdval_t val)
{
pgdval_t ret;

- if (sizeof(pgdval_t) > sizeof(long))
- ret = PVOP_CALLEE2(pgdval_t, mmu.make_pgd, val, (u64)val >> 32);
- else
- ret = PVOP_CALLEE1(pgdval_t, mmu.make_pgd, val);
+ ret = PVOP_CALLEE1(pgdval_t, mmu.make_pgd, val);

return (pgd_t) { ret };
}
@@ -414,11 +400,7 @@ static inline pgdval_t pgd_val(pgd_t pgd)
{
pgdval_t ret;

- if (sizeof(pgdval_t) > sizeof(long))
- ret = PVOP_CALLEE2(pgdval_t, mmu.pgd_val,
- pgd.pgd, (u64)pgd.pgd >> 32);
- else
- ret = PVOP_CALLEE1(pgdval_t, mmu.pgd_val, pgd.pgd);
+ ret = PVOP_CALLEE1(pgdval_t, mmu.pgd_val, pgd.pgd);

return ret;
}
@@ -438,51 +420,32 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned
pte_t *ptep, pte_t old_pte, pte_t pte)
{

- if (sizeof(pteval_t) > sizeof(long))
- /* 5 arg words */
- pv_ops.mmu.ptep_modify_prot_commit(vma, addr, ptep, pte);
- else
- PVOP_VCALL4(mmu.ptep_modify_prot_commit,
- vma, addr, ptep, pte.pte);
+ PVOP_VCALL4(mmu.ptep_modify_prot_commit, vma, addr, ptep, pte.pte);
}

static inline void set_pte(pte_t *ptep, pte_t pte)
{
- if (sizeof(pteval_t) > sizeof(long))
- PVOP_VCALL3(mmu.set_pte, ptep, pte.pte, (u64)pte.pte >> 32);
- else
- PVOP_VCALL2(mmu.set_pte, ptep, pte.pte);
+ PVOP_VCALL2(mmu.set_pte, ptep, pte.pte);
}

static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
- if (sizeof(pteval_t) > sizeof(long))
- /* 5 arg words */
- pv_ops.mmu.set_pte_at(mm, addr, ptep, pte);
- else
- PVOP_VCALL4(mmu.set_pte_at, mm, addr, ptep, pte.pte);
+ PVOP_VCALL4(mmu.set_pte_at, mm, addr, ptep, pte.pte);
}

static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
{
pmdval_t val = native_pmd_val(pmd);

- if (sizeof(pmdval_t) > sizeof(long))
- PVOP_VCALL3(mmu.set_pmd, pmdp, val, (u64)val >> 32);
- else
- PVOP_VCALL2(mmu.set_pmd, pmdp, val);
+ PVOP_VCALL2(mmu.set_pmd, pmdp, val);
}

-#if CONFIG_PGTABLE_LEVELS >= 3
static inline pmd_t __pmd(pmdval_t val)
{
pmdval_t ret;

- if (sizeof(pmdval_t) > sizeof(long))
- ret = PVOP_CALLEE2(pmdval_t, mmu.make_pmd, val, (u64)val >> 32);
- else
- ret = PVOP_CALLEE1(pmdval_t, mmu.make_pmd, val);
+ ret = PVOP_CALLEE1(pmdval_t, mmu.make_pmd, val);

return (pmd_t) { ret };
}
@@ -491,11 +454,7 @@ static inline pmdval_t pmd_val(pmd_t pmd)
{
pmdval_t ret;

- if (sizeof(pmdval_t) > sizeof(long))
- ret = PVOP_CALLEE2(pmdval_t, mmu.pmd_val,
- pmd.pmd, (u64)pmd.pmd >> 32);
- else
- ret = PVOP_CALLEE1(pmdval_t, mmu.pmd_val, pmd.pmd);
+ ret = PVOP_CALLEE1(pmdval_t, mmu.pmd_val, pmd.pmd);

return ret;
}
@@ -504,12 +463,9 @@ static inline void set_pud(pud_t *pudp, pud_t pud)
{
pudval_t val = native_pud_val(pud);

- if (sizeof(pudval_t) > sizeof(long))
- PVOP_VCALL3(mmu.set_pud, pudp, val, (u64)val >> 32);
- else
- PVOP_VCALL2(mmu.set_pud, pudp, val);
+ PVOP_VCALL2(mmu.set_pud, pudp, val);
}
-#if CONFIG_PGTABLE_LEVELS >= 4
+
static inline pud_t __pud(pudval_t val)
{
pudval_t ret;
@@ -574,29 +530,6 @@ static inline void p4d_clear(p4d_t *p4dp)
set_p4d(p4dp, __p4d(0));
}

-#endif /* CONFIG_PGTABLE_LEVELS == 4 */
-
-#endif /* CONFIG_PGTABLE_LEVELS >= 3 */
-
-#ifdef CONFIG_X86_PAE
-/* Special-case pte-setting operations for PAE, which can't update a
- 64-bit pte atomically */
-static inline void set_pte_atomic(pte_t *ptep, pte_t pte)
-{
- PVOP_VCALL3(mmu.set_pte_atomic, ptep, pte.pte, pte.pte >> 32);
-}
-
-static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep)
-{
- PVOP_VCALL3(mmu.pte_clear, mm, addr, ptep);
-}
-
-static inline void pmd_clear(pmd_t *pmdp)
-{
- PVOP_VCALL1(mmu.pmd_clear, pmdp);
-}
-#else /* !CONFIG_X86_PAE */
static inline void set_pte_atomic(pte_t *ptep, pte_t pte)
{
set_pte(ptep, pte);
@@ -612,7 +545,6 @@ static inline void pmd_clear(pmd_t *pmdp)
{
set_pmd(pmdp, __pmd(0));
}
-#endif /* CONFIG_X86_PAE */

#define __HAVE_ARCH_START_CONTEXT_SWITCH
static inline void arch_start_context_switch(struct task_struct *prev)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 8dfcb2508e6d..f27c3febaa6e 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -68,12 +68,7 @@ struct paravirt_callee_save {
/* general info */
struct pv_info {
#ifdef CONFIG_PARAVIRT_XXL
- unsigned int kernel_rpl;
- int shared_kernel_pmd;
-
-#ifdef CONFIG_X86_64
u16 extra_user_64bit_cs; /* __USER_CS if none */
-#endif
#endif

const char *name;
@@ -126,9 +121,7 @@ struct pv_cpu_ops {
void (*set_ldt)(const void *desc, unsigned entries);
unsigned long (*store_tr)(void);
void (*load_tls)(struct thread_struct *t, unsigned int cpu);
-#ifdef CONFIG_X86_64
void (*load_gs_index)(unsigned int idx);
-#endif
void (*write_ldt_entry)(struct desc_struct *ldt, int entrynum,
const void *desc);
void (*write_gdt_entry)(struct desc_struct *,
@@ -264,21 +257,11 @@ struct pv_mmu_ops {
struct paravirt_callee_save pgd_val;
struct paravirt_callee_save make_pgd;

-#if CONFIG_PGTABLE_LEVELS >= 3
-#ifdef CONFIG_X86_PAE
- void (*set_pte_atomic)(pte_t *ptep, pte_t pteval);
- void (*pte_clear)(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep);
- void (*pmd_clear)(pmd_t *pmdp);
-
-#endif /* CONFIG_X86_PAE */
-
void (*set_pud)(pud_t *pudp, pud_t pudval);

struct paravirt_callee_save pmd_val;
struct paravirt_callee_save make_pmd;

-#if CONFIG_PGTABLE_LEVELS >= 4
struct paravirt_callee_save pud_val;
struct paravirt_callee_save make_pud;

@@ -291,10 +274,6 @@ struct pv_mmu_ops {
void (*set_pgd)(pgd_t *pgdp, pgd_t pgdval);
#endif /* CONFIG_PGTABLE_LEVELS >= 5 */

-#endif /* CONFIG_PGTABLE_LEVELS >= 4 */
-
-#endif /* CONFIG_PGTABLE_LEVELS >= 3 */
-
struct pv_lazy_ops lazy_mode;

/* dom0 ops */
diff --git a/arch/x86/include/asm/pgtable-3level_types.h b/arch/x86/include/asm/pgtable-3level_types.h
index 80fbb4a9ed87..56baf43befb4 100644
--- a/arch/x86/include/asm/pgtable-3level_types.h
+++ b/arch/x86/include/asm/pgtable-3level_types.h
@@ -20,12 +20,7 @@ typedef union {
} pte_t;
#endif /* !__ASSEMBLY__ */

-#ifdef CONFIG_PARAVIRT_XXL
-#define SHARED_KERNEL_PMD ((!static_cpu_has(X86_FEATURE_PTI) && \
- (pv_info.shared_kernel_pmd)))
-#else
#define SHARED_KERNEL_PMD (!static_cpu_has(X86_FEATURE_PTI))
-#endif

#define ARCH_PAGE_TABLE_SYNC_MASK (SHARED_KERNEL_PMD ? 0 : PGTBL_PMD_MODIFIED)

diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 9646c300f128..517920928989 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -222,10 +222,6 @@

#endif

-#ifndef CONFIG_PARAVIRT_XXL
-# define get_kernel_rpl() 0
-#endif
-
#define IDT_ENTRIES 256
#define NUM_EXCEPTION_VECTORS 32

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 965474d78cef..ca89cea31e81 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1412,15 +1412,7 @@ static void generic_identify(struct cpuinfo_x86 *c)
* ESPFIX issue, we can change this.
*/
#ifdef CONFIG_X86_32
-# ifdef CONFIG_PARAVIRT_XXL
- do {
- extern void native_iret(void);
- if (pv_ops.cpu.iret == native_iret)
- set_cpu_bug(c, X86_BUG_ESPFIX);
- } while (0);
-# else
set_cpu_bug(c, X86_BUG_ESPFIX);
-# endif
#endif
}

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index fdadc37d72af..2ca10b770cff 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -793,7 +793,6 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
/* fixup registers */
regs->cs = __KERNEL_CS;
#ifdef CONFIG_X86_32
- regs->cs |= get_kernel_rpl();
regs->gs = 0;
#endif
/* We use pt_regs->sp for return address holder. */
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 40f380461e6d..b8dd113a1284 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -181,7 +181,6 @@ optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
/* Save skipped registers */
regs->cs = __KERNEL_CS;
#ifdef CONFIG_X86_32
- regs->cs |= get_kernel_rpl();
regs->gs = 0;
#endif
regs->ip = (unsigned long)op->kp.addr + INT3_INSN_SIZE;
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index de2138ba38e5..e56a144c13b3 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -263,13 +263,8 @@ enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
struct pv_info pv_info = {
.name = "bare hardware",
#ifdef CONFIG_PARAVIRT_XXL
- .kernel_rpl = 0,
- .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
-
-#ifdef CONFIG_X86_64
.extra_user_64bit_cs = __USER_CS,
#endif
-#endif
};

/* 64-bit pagetable entries */
@@ -305,9 +300,7 @@ struct paravirt_patch_template pv_ops = {
.cpu.load_idt = native_load_idt,
.cpu.store_tr = native_store_tr,
.cpu.load_tls = native_load_tls,
-#ifdef CONFIG_X86_64
.cpu.load_gs_index = native_load_gs_index,
-#endif
.cpu.write_ldt_entry = native_write_ldt_entry,
.cpu.write_gdt_entry = native_write_gdt_entry,
.cpu.write_idt_entry = native_write_idt_entry,
@@ -317,9 +310,7 @@ struct paravirt_patch_template pv_ops = {

.cpu.load_sp0 = native_load_sp0,

-#ifdef CONFIG_X86_64
.cpu.usergs_sysret64 = native_usergs_sysret64,
-#endif
.cpu.iret = native_iret,
.cpu.swapgs = native_swapgs,

@@ -375,18 +366,11 @@ struct paravirt_patch_template pv_ops = {
.mmu.ptep_modify_prot_start = __ptep_modify_prot_start,
.mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit,

-#if CONFIG_PGTABLE_LEVELS >= 3
-#ifdef CONFIG_X86_PAE
- .mmu.set_pte_atomic = native_set_pte_atomic,
- .mmu.pte_clear = native_pte_clear,
- .mmu.pmd_clear = native_pmd_clear,
-#endif
.mmu.set_pud = native_set_pud,

.mmu.pmd_val = PTE_IDENT,
.mmu.make_pmd = PTE_IDENT,

-#if CONFIG_PGTABLE_LEVELS >= 4
.mmu.pud_val = PTE_IDENT,
.mmu.make_pud = PTE_IDENT,

@@ -398,8 +382,6 @@ struct paravirt_patch_template pv_ops = {

.mmu.set_pgd = native_set_pgd,
#endif /* CONFIG_PGTABLE_LEVELS >= 5 */
-#endif /* CONFIG_PGTABLE_LEVELS >= 4 */
-#endif /* CONFIG_PGTABLE_LEVELS >= 3 */

.mmu.pte_val = PTE_IDENT,
.mmu.pgd_val = PTE_IDENT,
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index 3eff63c090d2..ace6e334cb39 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -26,14 +26,10 @@ struct patch_xxl {
const unsigned char mmu_read_cr3[3];
const unsigned char mmu_write_cr3[3];
const unsigned char irq_restore_fl[2];
-# ifdef CONFIG_X86_64
const unsigned char cpu_wbinvd[2];
const unsigned char cpu_usergs_sysret64[6];
const unsigned char cpu_swapgs[3];
const unsigned char mov64[3];
-# else
- const unsigned char cpu_iret[1];
-# endif
};

static const struct patch_xxl patch_data_xxl = {
@@ -42,7 +38,6 @@ static const struct patch_xxl patch_data_xxl = {
.irq_save_fl = { 0x9c, 0x58 }, // pushf; pop %[re]ax
.mmu_read_cr2 = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
.mmu_read_cr3 = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
-# ifdef CONFIG_X86_64
.mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
.irq_restore_fl = { 0x57, 0x9d }, // push %rdi; popfq
.cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
@@ -50,19 +45,11 @@ static const struct patch_xxl patch_data_xxl = {
0x48, 0x0f, 0x07 }, // swapgs; sysretq
.cpu_swapgs = { 0x0f, 0x01, 0xf8 }, // swapgs
.mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
-# else
- .mmu_write_cr3 = { 0x0f, 0x22, 0xd8 }, // mov %eax, %cr3
- .irq_restore_fl = { 0x50, 0x9d }, // push %eax; popf
- .cpu_iret = { 0xcf }, // iret
-# endif
};

unsigned int paravirt_patch_ident_64(void *insn_buff, unsigned int len)
{
-#ifdef CONFIG_X86_64
return PATCH(xxl, mov64, insn_buff, len);
-#endif
- return 0;
}
# endif /* CONFIG_PARAVIRT_XXL */

@@ -98,13 +85,9 @@ unsigned int native_patch(u8 type, void *insn_buff, unsigned long addr,
PATCH_CASE(mmu, read_cr3, xxl, insn_buff, len);
PATCH_CASE(mmu, write_cr3, xxl, insn_buff, len);

-# ifdef CONFIG_X86_64
PATCH_CASE(cpu, usergs_sysret64, xxl, insn_buff, len);
PATCH_CASE(cpu, swapgs, xxl, insn_buff, len);
PATCH_CASE(cpu, wbinvd, xxl, insn_buff, len);
-# else
- PATCH_CASE(cpu, iret, xxl, insn_buff, len);
-# endif
#endif

#ifdef CONFIG_PARAVIRT_SPINLOCKS
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 9fec952f84f3..b84d3d47082b 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1017,8 +1017,6 @@ void __init xen_setup_vcpu_info_placement(void)
}

static const struct pv_info xen_info __initconst = {
- .shared_kernel_pmd = 0,
-
.extra_user_64bit_cs = FLAT_USER_CS64,
.name = "Xen",
};
@@ -1317,10 +1315,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
xen_start_info->nr_pages);
xen_reserve_special_pages();

- /* keep using Xen gdt for now; no urgent need to change it */
-
- pv_info.kernel_rpl = 0;
-
/* set the limit of our address space */
xen_reserve_top();

--
2.26.2

2020-08-07 08:41:57

by Jürgen Groß

[permalink] [raw]
Subject: [PATCH v3 1/7] x86/xen: remove 32-bit Xen PV guest support

Xen is requiring 64-bit machines today and since Xen 4.14 it can be
built without 32-bit PV guest support. There is no need to carry the
burden of 32-bit PV guest support in the kernel any longer, as new
guests can be either HVM or PVH, or they can use a 64 bit kernel.

Remove the 32-bit Xen PV support from the kernel.

Signed-off-by: Juergen Gross <[email protected]>
---
arch/x86/entry/entry_32.S | 109 +--------
arch/x86/entry/vdso/vdso32/note.S | 30 ---
arch/x86/include/asm/proto.h | 2 +-
arch/x86/include/asm/segment.h | 2 +-
arch/x86/kernel/head_32.S | 31 ---
arch/x86/xen/Kconfig | 3 +-
arch/x86/xen/apic.c | 17 --
arch/x86/xen/enlighten_pv.c | 63 +-----
arch/x86/xen/mmu_pv.c | 352 ++++--------------------------
arch/x86/xen/p2m.c | 6 +-
arch/x86/xen/setup.c | 36 +--
arch/x86/xen/smp_pv.c | 18 --
arch/x86/xen/vdso.h | 6 -
arch/x86/xen/xen-asm.S | 14 --
arch/x86/xen/xen-asm_32.S | 185 ----------------
arch/x86/xen/xen-head.S | 6 -
drivers/xen/Kconfig | 4 +-
17 files changed, 51 insertions(+), 833 deletions(-)
delete mode 100644 arch/x86/xen/vdso.h
delete mode 100644 arch/x86/xen/xen-asm_32.S

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 29b7d52143e9..df8c017e6161 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -449,8 +449,6 @@

.macro SWITCH_TO_KERNEL_STACK

- ALTERNATIVE "", "jmp .Lend_\@", X86_FEATURE_XENPV
-
BUG_IF_WRONG_CR3

SWITCH_TO_KERNEL_CR3 scratch_reg=%eax
@@ -599,8 +597,6 @@
*/
.macro SWITCH_TO_ENTRY_STACK

- ALTERNATIVE "", "jmp .Lend_\@", X86_FEATURE_XENPV
-
/* Bytes to copy */
movl $PTREGS_SIZE, %ecx

@@ -872,17 +868,6 @@ SYM_ENTRY(__begin_SYSENTER_singlestep_region, SYM_L_GLOBAL, SYM_A_NONE)
* will ignore all of the single-step traps generated in this range.
*/

-#ifdef CONFIG_XEN_PV
-/*
- * Xen doesn't set %esp to be precisely what the normal SYSENTER
- * entry point expects, so fix it up before using the normal path.
- */
-SYM_CODE_START(xen_sysenter_target)
- addl $5*4, %esp /* remove xen-provided frame */
- jmp .Lsysenter_past_esp
-SYM_CODE_END(xen_sysenter_target)
-#endif
-
/*
* 32-bit SYSENTER entry.
*
@@ -965,9 +950,8 @@ SYM_FUNC_START(entry_SYSENTER_32)

movl %esp, %eax
call do_SYSENTER_32
- /* XEN PV guests always use IRET path */
- ALTERNATIVE "testl %eax, %eax; jz .Lsyscall_32_done", \
- "jmp .Lsyscall_32_done", X86_FEATURE_XENPV
+ testl %eax, %eax
+ jz .Lsyscall_32_done

STACKLEAK_ERASE

@@ -1165,95 +1149,6 @@ SYM_FUNC_END(entry_INT80_32)
#endif
.endm

-#ifdef CONFIG_PARAVIRT
-SYM_CODE_START(native_iret)
- iret
- _ASM_EXTABLE(native_iret, asm_iret_error)
-SYM_CODE_END(native_iret)
-#endif
-
-#ifdef CONFIG_XEN_PV
-/*
- * See comment in entry_64.S for further explanation
- *
- * Note: This is not an actual IDT entry point. It's a XEN specific entry
- * point and therefore named to match the 64-bit trampoline counterpart.
- */
-SYM_FUNC_START(xen_asm_exc_xen_hypervisor_callback)
- /*
- * Check to see if we got the event in the critical
- * region in xen_iret_direct, after we've reenabled
- * events and checked for pending events. This simulates
- * iret instruction's behaviour where it delivers a
- * pending interrupt when enabling interrupts:
- */
- cmpl $xen_iret_start_crit, (%esp)
- jb 1f
- cmpl $xen_iret_end_crit, (%esp)
- jae 1f
- call xen_iret_crit_fixup
-1:
- pushl $-1 /* orig_ax = -1 => not a system call */
- SAVE_ALL
- ENCODE_FRAME_POINTER
-
- mov %esp, %eax
- call xen_pv_evtchn_do_upcall
- jmp handle_exception_return
-SYM_FUNC_END(xen_asm_exc_xen_hypervisor_callback)
-
-/*
- * Hypervisor uses this for application faults while it executes.
- * We get here for two reasons:
- * 1. Fault while reloading DS, ES, FS or GS
- * 2. Fault while executing IRET
- * Category 1 we fix up by reattempting the load, and zeroing the segment
- * register if the load fails.
- * Category 2 we fix up by jumping to do_iret_error. We cannot use the
- * normal Linux return path in this case because if we use the IRET hypercall
- * to pop the stack frame we end up in an infinite loop of failsafe callbacks.
- * We distinguish between categories by maintaining a status value in EAX.
- */
-SYM_FUNC_START(xen_failsafe_callback)
- pushl %eax
- movl $1, %eax
-1: mov 4(%esp), %ds
-2: mov 8(%esp), %es
-3: mov 12(%esp), %fs
-4: mov 16(%esp), %gs
- /* EAX == 0 => Category 1 (Bad segment)
- EAX != 0 => Category 2 (Bad IRET) */
- testl %eax, %eax
- popl %eax
- lea 16(%esp), %esp
- jz 5f
- jmp asm_iret_error
-5: pushl $-1 /* orig_ax = -1 => not a system call */
- SAVE_ALL
- ENCODE_FRAME_POINTER
- jmp handle_exception_return
-
-.section .fixup, "ax"
-6: xorl %eax, %eax
- movl %eax, 4(%esp)
- jmp 1b
-7: xorl %eax, %eax
- movl %eax, 8(%esp)
- jmp 2b
-8: xorl %eax, %eax
- movl %eax, 12(%esp)
- jmp 3b
-9: xorl %eax, %eax
- movl %eax, 16(%esp)
- jmp 4b
-.previous
- _ASM_EXTABLE(1b, 6b)
- _ASM_EXTABLE(2b, 7b)
- _ASM_EXTABLE(3b, 8b)
- _ASM_EXTABLE(4b, 9b)
-SYM_FUNC_END(xen_failsafe_callback)
-#endif /* CONFIG_XEN_PV */
-
SYM_CODE_START_LOCAL_NOALIGN(handle_exception)
/* the function address is in %gs's slot on the stack */
SAVE_ALL switch_stacks=1 skip_gs=1 unwind_espfix=1
diff --git a/arch/x86/entry/vdso/vdso32/note.S b/arch/x86/entry/vdso/vdso32/note.S
index e78047d119f6..2cbd39939dc6 100644
--- a/arch/x86/entry/vdso/vdso32/note.S
+++ b/arch/x86/entry/vdso/vdso32/note.S
@@ -16,33 +16,3 @@ ELFNOTE_START(Linux, 0, "a")
ELFNOTE_END

BUILD_SALT
-
-#ifdef CONFIG_XEN
-/*
- * Add a special note telling glibc's dynamic linker a fake hardware
- * flavor that it will use to choose the search path for libraries in the
- * same way it uses real hardware capabilities like "mmx".
- * We supply "nosegneg" as the fake capability, to indicate that we
- * do not like negative offsets in instructions using segment overrides,
- * since we implement those inefficiently. This makes it possible to
- * install libraries optimized to avoid those access patterns in someplace
- * like /lib/i686/tls/nosegneg. Note that an /etc/ld.so.conf.d/file
- * corresponding to the bits here is needed to make ldconfig work right.
- * It should contain:
- * hwcap 1 nosegneg
- * to match the mapping of bit to name that we give here.
- *
- * At runtime, the fake hardware feature will be considered to be present
- * if its bit is set in the mask word. So, we start with the mask 0, and
- * at boot time we set VDSO_NOTE_NONEGSEG_BIT if running under Xen.
- */
-
-#include "../../xen/vdso.h" /* Defines VDSO_NOTE_NONEGSEG_BIT. */
-
-ELFNOTE_START(GNU, 2, "a")
- .long 1 /* ncaps */
-VDSO32_NOTE_MASK: /* Symbol used by arch/x86/xen/setup.c */
- .long 0 /* mask */
- .byte VDSO_NOTE_NONEGSEG_BIT; .asciz "nosegneg" /* bit, name */
-ELFNOTE_END
-#endif
diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h
index 6e81788a30c1..28996fe19301 100644
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -25,7 +25,7 @@ void entry_SYSENTER_compat(void);
void __end_entry_SYSENTER_compat(void);
void entry_SYSCALL_compat(void);
void entry_INT80_compat(void);
-#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
+#ifdef CONFIG_XEN_PV
void xen_entry_INT80_compat(void);
#endif
#endif
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 6669164abadc..9646c300f128 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -301,7 +301,7 @@ static inline void vdso_read_cpunode(unsigned *cpu, unsigned *node)
extern const char early_idt_handler_array[NUM_EXCEPTION_VECTORS][EARLY_IDT_HANDLER_SIZE];
extern void early_ignore_irq(void);

-#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
+#ifdef CONFIG_XEN_PV
extern const char xen_early_idt_handler_array[NUM_EXCEPTION_VECTORS][XEN_EARLY_IDT_HANDLER_SIZE];
#endif

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index f66a6b90f954..7ed84c282233 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -134,38 +134,7 @@ SYM_CODE_START(startup_32)
movl %eax,pa(initial_page_table+0xffc)
#endif

-#ifdef CONFIG_PARAVIRT
- /* This is can only trip for a broken bootloader... */
- cmpw $0x207, pa(boot_params + BP_version)
- jb .Ldefault_entry
-
- /* Paravirt-compatible boot parameters. Look to see what architecture
- we're booting under. */
- movl pa(boot_params + BP_hardware_subarch), %eax
- cmpl $num_subarch_entries, %eax
- jae .Lbad_subarch
-
- movl pa(subarch_entries)(,%eax,4), %eax
- subl $__PAGE_OFFSET, %eax
- jmp *%eax
-
-.Lbad_subarch:
-SYM_INNER_LABEL_ALIGN(xen_entry, SYM_L_WEAK)
- /* Unknown implementation; there's really
- nothing we can do at this point. */
- ud2a
-
- __INITDATA
-
-subarch_entries:
- .long .Ldefault_entry /* normal x86/PC */
- .long xen_entry /* Xen hypervisor */
- .long .Ldefault_entry /* Moorestown MID */
-num_subarch_entries = (. - subarch_entries) / 4
-.previous
-#else
jmp .Ldefault_entry
-#endif /* CONFIG_PARAVIRT */
SYM_CODE_END(startup_32)

#ifdef CONFIG_HOTPLUG_CPU
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 1aded63a95cb..218acbd5c7a0 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -19,6 +19,7 @@ config XEN_PV
bool "Xen PV guest support"
default y
depends on XEN
+ depends on X86_64
select PARAVIRT_XXL
select XEN_HAVE_PVMMU
select XEN_HAVE_VPMU
@@ -50,7 +51,7 @@ config XEN_PVHVM_SMP

config XEN_512GB
bool "Limit Xen pv-domain memory to 512GB"
- depends on XEN_PV && X86_64
+ depends on XEN_PV
default y
help
Limit paravirtualized user domains to 512GB of RAM.
diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c
index 5e53bfbe5823..ea6e9c54da9d 100644
--- a/arch/x86/xen/apic.c
+++ b/arch/x86/xen/apic.c
@@ -58,10 +58,6 @@ static u32 xen_apic_read(u32 reg)

if (reg == APIC_LVR)
return 0x14;
-#ifdef CONFIG_X86_32
- if (reg == APIC_LDR)
- return SET_APIC_LOGICAL_ID(1UL << smp_processor_id());
-#endif
if (reg != APIC_ID)
return 0;

@@ -127,14 +123,6 @@ static int xen_phys_pkg_id(int initial_apic_id, int index_msb)
return initial_apic_id >> index_msb;
}

-#ifdef CONFIG_X86_32
-static int xen_x86_32_early_logical_apicid(int cpu)
-{
- /* Match with APIC_LDR read. Otherwise setup_local_APIC complains. */
- return 1 << cpu;
-}
-#endif
-
static void xen_noop(void)
{
}
@@ -197,11 +185,6 @@ static struct apic xen_pv_apic = {
.icr_write = xen_apic_icr_write,
.wait_icr_idle = xen_noop,
.safe_wait_icr_idle = xen_safe_apic_wait_icr_idle,
-
-#ifdef CONFIG_X86_32
- /* generic_processor_info and setup_local_APIC. */
- .x86_32_early_logical_apicid = xen_x86_32_early_logical_apicid,
-#endif
};

static void __init xen_apic_check(void)
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 2aab43a13a8c..7d90b3da8bb4 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -119,14 +119,6 @@ static void __init xen_banner(void)
printk(KERN_INFO "Xen version: %d.%d%s%s\n",
version >> 16, version & 0xffff, extra.extraversion,
xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
-
-#ifdef CONFIG_X86_32
- pr_warn("WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!\n"
- "Support for running as 32-bit PV-guest under Xen will soon be removed\n"
- "from the Linux kernel!\n"
- "Please use either a 64-bit kernel or switch to HVM or PVH mode!\n"
- "WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!\n");
-#endif
}

static void __init xen_pv_init_platform(void)
@@ -538,30 +530,12 @@ static void load_TLS_descriptor(struct thread_struct *t,
static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
{
/*
- * XXX sleazy hack: If we're being called in a lazy-cpu zone
- * and lazy gs handling is enabled, it means we're in a
- * context switch, and %gs has just been saved. This means we
- * can zero it out to prevent faults on exit from the
- * hypervisor if the next process has no %gs. Either way, it
- * has been saved, and the new value will get loaded properly.
- * This will go away as soon as Xen has been modified to not
- * save/restore %gs for normal hypercalls.
- *
- * On x86_64, this hack is not used for %gs, because gs points
- * to KERNEL_GS_BASE (and uses it for PDA references), so we
- * must not zero %gs on x86_64
- *
- * For x86_64, we need to zero %fs, otherwise we may get an
+ * In lazy mode we need to zero %fs, otherwise we may get an
* exception between the new %fs descriptor being loaded and
* %fs being effectively cleared at __switch_to().
*/
- if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
-#ifdef CONFIG_X86_32
- lazy_load_gs(0);
-#else
+ if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU)
loadsegment(fs, 0);
-#endif
- }

xen_mc_batch();

@@ -572,13 +546,11 @@ static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
xen_mc_issue(PARAVIRT_LAZY_CPU);
}

-#ifdef CONFIG_X86_64
static void xen_load_gs_index(unsigned int idx)
{
if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
BUG();
}
-#endif

static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
const void *ptr)
@@ -597,7 +569,6 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
preempt_enable();
}

-#ifdef CONFIG_X86_64
void noist_exc_debug(struct pt_regs *regs);

DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
@@ -697,7 +668,6 @@ static bool __ref get_trap_addr(void **addr, unsigned int ist)

return true;
}
-#endif

static int cvt_gate_to_trap(int vector, const gate_desc *val,
struct trap_info *info)
@@ -710,10 +680,8 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val,
info->vector = vector;

addr = gate_offset(val);
-#ifdef CONFIG_X86_64
if (!get_trap_addr((void **)&addr, val->bits.ist))
return 0;
-#endif /* CONFIG_X86_64 */
info->address = addr;

info->cs = gate_segment(val);
@@ -958,15 +926,12 @@ static u64 xen_read_msr_safe(unsigned int msr, int *err)
static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
{
int ret;
-#ifdef CONFIG_X86_64
unsigned int which;
u64 base;
-#endif

ret = 0;

switch (msr) {
-#ifdef CONFIG_X86_64
case MSR_FS_BASE: which = SEGBASE_FS; goto set;
case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set;
case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set;
@@ -976,7 +941,6 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
if (HYPERVISOR_set_segment_base(which, base) != 0)
ret = -EIO;
break;
-#endif

case MSR_STAR:
case MSR_CSTAR:
@@ -1058,9 +1022,7 @@ void __init xen_setup_vcpu_info_placement(void)
static const struct pv_info xen_info __initconst = {
.shared_kernel_pmd = 0,

-#ifdef CONFIG_X86_64
.extra_user_64bit_cs = FLAT_USER_CS64,
-#endif
.name = "Xen",
};

@@ -1086,18 +1048,14 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
.read_pmc = xen_read_pmc,

.iret = xen_iret,
-#ifdef CONFIG_X86_64
.usergs_sysret64 = xen_sysret64,
-#endif

.load_tr_desc = paravirt_nop,
.set_ldt = xen_set_ldt,
.load_gdt = xen_load_gdt,
.load_idt = xen_load_idt,
.load_tls = xen_load_tls,
-#ifdef CONFIG_X86_64
.load_gs_index = xen_load_gs_index,
-#endif

.alloc_ldt = xen_alloc_ldt,
.free_ldt = xen_free_ldt,
@@ -1364,13 +1322,8 @@ asmlinkage __visible void __init xen_start_kernel(void)

/* keep using Xen gdt for now; no urgent need to change it */

-#ifdef CONFIG_X86_32
- pv_info.kernel_rpl = 1;
- if (xen_feature(XENFEAT_supervisor_mode_kernel))
- pv_info.kernel_rpl = 0;
-#else
pv_info.kernel_rpl = 0;
-#endif
+
/* set the limit of our address space */
xen_reserve_top();

@@ -1384,12 +1337,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
if (rc != 0)
xen_raw_printk("physdev_op failed %d\n", rc);

-#ifdef CONFIG_X86_32
- /* set up basic CPUID stuff */
- cpu_detect(&new_cpu_data);
- set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
- new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
-#endif

if (xen_start_info->mod_start) {
if (xen_start_info->flags & SIF_MOD_START_PFN)
@@ -1458,12 +1405,8 @@ asmlinkage __visible void __init xen_start_kernel(void)
xen_efi_init(&boot_params);

/* Start the world */
-#ifdef CONFIG_X86_32
- i386_start_kernel();
-#else
cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
x86_64_start_reservations((char *)__pa_symbol(&boot_params));
-#endif
}

static int xen_cpu_up_prepare_pv(unsigned int cpu)
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index a58d9c69807a..1f9500d0b839 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -86,19 +86,8 @@
#include "mmu.h"
#include "debugfs.h"

-#ifdef CONFIG_X86_32
-/*
- * Identity map, in addition to plain kernel map. This needs to be
- * large enough to allocate page table pages to allocate the rest.
- * Each page can map 2MB.
- */
-#define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
-static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
-#endif
-#ifdef CONFIG_X86_64
/* l3 pud for userspace vsyscall mapping */
static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
-#endif /* CONFIG_X86_64 */

/*
* Protects atomic reservation decrease/increase against concurrent increases.
@@ -280,10 +269,7 @@ static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
if (!xen_batched_set_pte(ptep, pteval)) {
/*
* Could call native_set_pte() here and trap and
- * emulate the PTE write but with 32-bit guests this
- * needs two traps (one for each of the two 32-bit
- * words in the PTE) so do one hypercall directly
- * instead.
+ * emulate the PTE write, but a hypercall is much cheaper.
*/
struct mmu_update u;

@@ -439,26 +425,6 @@ static void xen_set_pud(pud_t *ptr, pud_t val)
xen_set_pud_hyper(ptr, val);
}

-#ifdef CONFIG_X86_PAE
-static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
-{
- trace_xen_mmu_set_pte_atomic(ptep, pte);
- __xen_set_pte(ptep, pte);
-}
-
-static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
-{
- trace_xen_mmu_pte_clear(mm, addr, ptep);
- __xen_set_pte(ptep, native_make_pte(0));
-}
-
-static void xen_pmd_clear(pmd_t *pmdp)
-{
- trace_xen_mmu_pmd_clear(pmdp);
- set_pmd(pmdp, __pmd(0));
-}
-#endif /* CONFIG_X86_PAE */
-
__visible pmd_t xen_make_pmd(pmdval_t pmd)
{
pmd = pte_pfn_to_mfn(pmd);
@@ -466,7 +432,6 @@ __visible pmd_t xen_make_pmd(pmdval_t pmd)
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);

-#ifdef CONFIG_X86_64
__visible pudval_t xen_pud_val(pud_t pud)
{
return pte_mfn_to_pfn(pud.pud);
@@ -571,7 +536,6 @@ __visible p4d_t xen_make_p4d(p4dval_t p4d)
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_p4d);
#endif /* CONFIG_PGTABLE_LEVELS >= 5 */
-#endif /* CONFIG_X86_64 */

static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
@@ -636,11 +600,8 @@ static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
* will be STACK_TOP_MAX, but at boot we need to pin up to
* FIXADDR_TOP.
*
- * For 32-bit the important bit is that we don't pin beyond there,
- * because then we start getting into Xen's ptes.
- *
- * For 64-bit, we must skip the Xen hole in the middle of the address
- * space, just after the big x86-64 virtual hole.
+ * We must skip the Xen hole in the middle of the address space, just after
+ * the big x86-64 virtual hole.
*/
static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
int (*func)(struct mm_struct *mm, struct page *,
@@ -654,14 +615,12 @@ static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
limit--;
BUG_ON(limit >= FIXADDR_TOP);

-#ifdef CONFIG_X86_64
/*
* 64-bit has a great big hole in the middle of the address
* space, which contains the Xen mappings.
*/
hole_low = pgd_index(GUARD_HOLE_BASE_ADDR);
hole_high = pgd_index(GUARD_HOLE_END_ADDR);
-#endif

nr = pgd_index(limit) + 1;
for (i = 0; i < nr; i++) {
@@ -787,6 +746,8 @@ static int xen_pin_page(struct mm_struct *mm, struct page *page,
read-only, and can be pinned. */
static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
{
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
trace_xen_mmu_pgd_pin(mm, pgd);

xen_mc_batch();
@@ -800,26 +761,14 @@ static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
xen_mc_batch();
}

-#ifdef CONFIG_X86_64
- {
- pgd_t *user_pgd = xen_get_user_pgd(pgd);
+ xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));

- xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
-
- if (user_pgd) {
- xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
- xen_do_pin(MMUEXT_PIN_L4_TABLE,
- PFN_DOWN(__pa(user_pgd)));
- }
+ if (user_pgd) {
+ xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
+ xen_do_pin(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa(user_pgd)));
}
-#else /* CONFIG_X86_32 */
-#ifdef CONFIG_X86_PAE
- /* Need to make sure unshared kernel PMD is pinnable */
- xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
- PT_PMD);
-#endif
- xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
-#endif /* CONFIG_X86_64 */
+
xen_mc_issue(0);
}

@@ -870,9 +819,7 @@ static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
static void __init xen_after_bootmem(void)
{
static_branch_enable(&xen_struct_pages_ready);
-#ifdef CONFIG_X86_64
SetPagePinned(virt_to_page(level3_user_vsyscall));
-#endif
xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
}

@@ -919,29 +866,19 @@ static int xen_unpin_page(struct mm_struct *mm, struct page *page,
/* Release a pagetables pages back as normal RW */
static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
{
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
trace_xen_mmu_pgd_unpin(mm, pgd);

xen_mc_batch();

xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));

-#ifdef CONFIG_X86_64
- {
- pgd_t *user_pgd = xen_get_user_pgd(pgd);
-
- if (user_pgd) {
- xen_do_pin(MMUEXT_UNPIN_TABLE,
- PFN_DOWN(__pa(user_pgd)));
- xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
- }
+ if (user_pgd) {
+ xen_do_pin(MMUEXT_UNPIN_TABLE,
+ PFN_DOWN(__pa(user_pgd)));
+ xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
}
-#endif
-
-#ifdef CONFIG_X86_PAE
- /* Need to make sure unshared kernel PMD is unpinned */
- xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
- PT_PMD);
-#endif

__xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);

@@ -1089,7 +1026,6 @@ static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
BUG();
}

-#ifdef CONFIG_X86_64
static void __init xen_cleanhighmap(unsigned long vaddr,
unsigned long vaddr_end)
{
@@ -1273,17 +1209,15 @@ static void __init xen_pagetable_cleanhighmap(void)
xen_cleanhighmap(addr, roundup(addr + size, PMD_SIZE * 2));
xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
}
-#endif

static void __init xen_pagetable_p2m_setup(void)
{
xen_vmalloc_p2m_tree();

-#ifdef CONFIG_X86_64
xen_pagetable_p2m_free();

xen_pagetable_cleanhighmap();
-#endif
+
/* And revector! Bye bye old array */
xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
}
@@ -1420,6 +1354,8 @@ static void __xen_write_cr3(bool kernel, unsigned long cr3)
}
static void xen_write_cr3(unsigned long cr3)
{
+ pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
+
BUG_ON(preemptible());

xen_mc_batch(); /* disables interrupts */
@@ -1430,20 +1366,14 @@ static void xen_write_cr3(unsigned long cr3)

__xen_write_cr3(true, cr3);

-#ifdef CONFIG_X86_64
- {
- pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
- if (user_pgd)
- __xen_write_cr3(false, __pa(user_pgd));
- else
- __xen_write_cr3(false, 0);
- }
-#endif
+ if (user_pgd)
+ __xen_write_cr3(false, __pa(user_pgd));
+ else
+ __xen_write_cr3(false, 0);

xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
}

-#ifdef CONFIG_X86_64
/*
* At the start of the day - when Xen launches a guest, it has already
* built pagetables for the guest. We diligently look over them
@@ -1478,49 +1408,39 @@ static void __init xen_write_cr3_init(unsigned long cr3)

xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
}
-#endif

static int xen_pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd = mm->pgd;
- int ret = 0;
+ struct page *page = virt_to_page(pgd);
+ pgd_t *user_pgd;
+ int ret = -ENOMEM;

BUG_ON(PagePinned(virt_to_page(pgd)));
+ BUG_ON(page->private != 0);

-#ifdef CONFIG_X86_64
- {
- struct page *page = virt_to_page(pgd);
- pgd_t *user_pgd;
-
- BUG_ON(page->private != 0);
-
- ret = -ENOMEM;
-
- user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
- page->private = (unsigned long)user_pgd;
+ user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+ page->private = (unsigned long)user_pgd;

- if (user_pgd != NULL) {
+ if (user_pgd != NULL) {
#ifdef CONFIG_X86_VSYSCALL_EMULATION
- user_pgd[pgd_index(VSYSCALL_ADDR)] =
- __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
+ user_pgd[pgd_index(VSYSCALL_ADDR)] =
+ __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
#endif
- ret = 0;
- }
-
- BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
+ ret = 0;
}
-#endif
+
+ BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
+
return ret;
}

static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
-#ifdef CONFIG_X86_64
pgd_t *user_pgd = xen_get_user_pgd(pgd);

if (user_pgd)
free_page((unsigned long)user_pgd);
-#endif
}

/*
@@ -1539,7 +1459,6 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
*/
__visible pte_t xen_make_pte_init(pteval_t pte)
{
-#ifdef CONFIG_X86_64
unsigned long pfn;

/*
@@ -1553,7 +1472,7 @@ __visible pte_t xen_make_pte_init(pteval_t pte)
pfn >= xen_start_info->first_p2m_pfn &&
pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
pte &= ~_PAGE_RW;
-#endif
+
pte = pte_pfn_to_mfn(pte);
return native_make_pte(pte);
}
@@ -1561,13 +1480,6 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);

static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
{
-#ifdef CONFIG_X86_32
- /* If there's an existing pte, then don't allow _PAGE_RW to be set */
- if (pte_mfn(pte) != INVALID_P2M_ENTRY
- && pte_val_ma(*ptep) & _PAGE_PRESENT)
- pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
- pte_val_ma(pte));
-#endif
__xen_set_pte(ptep, pte);
}

@@ -1702,7 +1614,6 @@ static void xen_release_pmd(unsigned long pfn)
xen_release_ptpage(pfn, PT_PMD);
}

-#ifdef CONFIG_X86_64
static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
{
xen_alloc_ptpage(mm, pfn, PT_PUD);
@@ -1712,19 +1623,9 @@ static void xen_release_pud(unsigned long pfn)
{
xen_release_ptpage(pfn, PT_PUD);
}
-#endif

void __init xen_reserve_top(void)
{
-#ifdef CONFIG_X86_32
- unsigned long top = HYPERVISOR_VIRT_START;
- struct xen_platform_parameters pp;
-
- if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
- top = pp.virt_start;
-
- reserve_top_address(-top);
-#endif /* CONFIG_X86_32 */
}

/*
@@ -1733,11 +1634,7 @@ void __init xen_reserve_top(void)
*/
static void * __init __ka(phys_addr_t paddr)
{
-#ifdef CONFIG_X86_64
return (void *)(paddr + __START_KERNEL_map);
-#else
- return __va(paddr);
-#endif
}

/* Convert a machine address to physical address */
@@ -1771,56 +1668,7 @@ static void __init set_page_prot(void *addr, pgprot_t prot)
{
return set_page_prot_flags(addr, prot, UVMF_NONE);
}
-#ifdef CONFIG_X86_32
-static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
-{
- unsigned pmdidx, pteidx;
- unsigned ident_pte;
- unsigned long pfn;
-
- level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
- PAGE_SIZE);

- ident_pte = 0;
- pfn = 0;
- for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
- pte_t *pte_page;
-
- /* Reuse or allocate a page of ptes */
- if (pmd_present(pmd[pmdidx]))
- pte_page = m2v(pmd[pmdidx].pmd);
- else {
- /* Check for free pte pages */
- if (ident_pte == LEVEL1_IDENT_ENTRIES)
- break;
-
- pte_page = &level1_ident_pgt[ident_pte];
- ident_pte += PTRS_PER_PTE;
-
- pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
- }
-
- /* Install mappings */
- for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
- pte_t pte;
-
- if (pfn > max_pfn_mapped)
- max_pfn_mapped = pfn;
-
- if (!pte_none(pte_page[pteidx]))
- continue;
-
- pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
- pte_page[pteidx] = pte;
- }
- }
-
- for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
- set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
-
- set_page_prot(pmd, PAGE_KERNEL_RO);
-}
-#endif
void __init xen_setup_machphys_mapping(void)
{
struct xen_machphys_mapping mapping;
@@ -1831,13 +1679,8 @@ void __init xen_setup_machphys_mapping(void)
} else {
machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
}
-#ifdef CONFIG_X86_32
- WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
- < machine_to_phys_mapping);
-#endif
}

-#ifdef CONFIG_X86_64
static void __init convert_pfn_mfn(void *v)
{
pte_t *pte = v;
@@ -2168,105 +2011,6 @@ void __init xen_relocate_p2m(void)
xen_start_info->nr_p2m_frames = n_frames;
}

-#else /* !CONFIG_X86_64 */
-static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
-static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
-RESERVE_BRK(fixup_kernel_pmd, PAGE_SIZE);
-RESERVE_BRK(fixup_kernel_pte, PAGE_SIZE);
-
-static void __init xen_write_cr3_init(unsigned long cr3)
-{
- unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
-
- BUG_ON(read_cr3_pa() != __pa(initial_page_table));
- BUG_ON(cr3 != __pa(swapper_pg_dir));
-
- /*
- * We are switching to swapper_pg_dir for the first time (from
- * initial_page_table) and therefore need to mark that page
- * read-only and then pin it.
- *
- * Xen disallows sharing of kernel PMDs for PAE
- * guests. Therefore we must copy the kernel PMD from
- * initial_page_table into a new kernel PMD to be used in
- * swapper_pg_dir.
- */
- swapper_kernel_pmd =
- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
- copy_page(swapper_kernel_pmd, initial_kernel_pmd);
- swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
- __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
- set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
-
- set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
- xen_write_cr3(cr3);
- pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
-
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
- PFN_DOWN(__pa(initial_page_table)));
- set_page_prot(initial_page_table, PAGE_KERNEL);
- set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
-
- pv_ops.mmu.write_cr3 = &xen_write_cr3;
-}
-
-/*
- * For 32 bit domains xen_start_info->pt_base is the pgd address which might be
- * not the first page table in the page table pool.
- * Iterate through the initial page tables to find the real page table base.
- */
-static phys_addr_t __init xen_find_pt_base(pmd_t *pmd)
-{
- phys_addr_t pt_base, paddr;
- unsigned pmdidx;
-
- pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
-
- for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
- if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
- paddr = m2p(pmd[pmdidx].pmd);
- pt_base = min(pt_base, paddr);
- }
-
- return pt_base;
-}
-
-void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
-{
- pmd_t *kernel_pmd;
-
- kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
-
- xen_pt_base = xen_find_pt_base(kernel_pmd);
- xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
-
- initial_kernel_pmd =
- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
-
- max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
-
- copy_page(initial_kernel_pmd, kernel_pmd);
-
- xen_map_identity_early(initial_kernel_pmd, max_pfn);
-
- copy_page(initial_page_table, pgd);
- initial_page_table[KERNEL_PGD_BOUNDARY] =
- __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
-
- set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
- set_page_prot(initial_page_table, PAGE_KERNEL_RO);
- set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
-
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
-
- pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
- PFN_DOWN(__pa(initial_page_table)));
- xen_write_cr3(__pa(initial_page_table));
-
- memblock_reserve(xen_pt_base, xen_pt_size);
-}
-#endif /* CONFIG_X86_64 */
-
void __init xen_reserve_special_pages(void)
{
phys_addr_t paddr;
@@ -2300,12 +2044,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)

switch (idx) {
case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
-#ifdef CONFIG_X86_32
- case FIX_WP_TEST:
-# ifdef CONFIG_HIGHMEM
- case FIX_KMAP_BEGIN ... FIX_KMAP_END:
-# endif
-#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
case VSYSCALL_PAGE:
#endif
/* All local page mappings */
@@ -2357,9 +2096,7 @@ static void __init xen_post_allocator_init(void)
pv_ops.mmu.set_pte = xen_set_pte;
pv_ops.mmu.set_pmd = xen_set_pmd;
pv_ops.mmu.set_pud = xen_set_pud;
-#ifdef CONFIG_X86_64
pv_ops.mmu.set_p4d = xen_set_p4d;
-#endif

/* This will work as long as patching hasn't happened yet
(which it hasn't) */
@@ -2367,15 +2104,11 @@ static void __init xen_post_allocator_init(void)
pv_ops.mmu.alloc_pmd = xen_alloc_pmd;
pv_ops.mmu.release_pte = xen_release_pte;
pv_ops.mmu.release_pmd = xen_release_pmd;
-#ifdef CONFIG_X86_64
pv_ops.mmu.alloc_pud = xen_alloc_pud;
pv_ops.mmu.release_pud = xen_release_pud;
-#endif
pv_ops.mmu.make_pte = PV_CALLEE_SAVE(xen_make_pte);

-#ifdef CONFIG_X86_64
pv_ops.mmu.write_cr3 = &xen_write_cr3;
-#endif
}

static void xen_leave_lazy_mmu(void)
@@ -2420,17 +2153,11 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
.make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),

-#ifdef CONFIG_X86_PAE
- .set_pte_atomic = xen_set_pte_atomic,
- .pte_clear = xen_pte_clear,
- .pmd_clear = xen_pmd_clear,
-#endif /* CONFIG_X86_PAE */
.set_pud = xen_set_pud_hyper,

.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),

-#ifdef CONFIG_X86_64
.pud_val = PV_CALLEE_SAVE(xen_pud_val),
.make_pud = PV_CALLEE_SAVE(xen_make_pud),
.set_p4d = xen_set_p4d_hyper,
@@ -2442,7 +2169,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
.p4d_val = PV_CALLEE_SAVE(xen_p4d_val),
.make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
#endif
-#endif /* CONFIG_X86_64 */

.activate_mm = xen_activate_mm,
.dup_mmap = xen_dup_mmap,
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 0acba2c712ab..be4151f42611 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -379,12 +379,8 @@ static void __init xen_rebuild_p2m_list(unsigned long *p2m)

if (type == P2M_TYPE_PFN || i < chunk) {
/* Use initial p2m page contents. */
-#ifdef CONFIG_X86_64
mfns = alloc_p2m_page();
copy_page(mfns, xen_p2m_addr + pfn);
-#else
- mfns = xen_p2m_addr + pfn;
-#endif
ptep = populate_extra_pte((unsigned long)(p2m + pfn));
set_pte(ptep,
pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
@@ -467,7 +463,7 @@ EXPORT_SYMBOL_GPL(get_phys_to_machine);
* Allocate new pmd(s). It is checked whether the old pmd is still in place.
* If not, nothing is changed. This is okay as the only reason for allocating
* a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
- * pmd. In case of PAE/x86-32 there are multiple pmds to allocate!
+ * pmd.
*/
static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
{
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 3566e37241d7..7eab14d56369 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -32,7 +32,6 @@
#include <xen/features.h>
#include <xen/hvc-console.h>
#include "xen-ops.h"
-#include "vdso.h"
#include "mmu.h"

#define GB(x) ((uint64_t)(x) * 1024 * 1024 * 1024)
@@ -545,13 +544,10 @@ static unsigned long __init xen_get_pages_limit(void)
{
unsigned long limit;

-#ifdef CONFIG_X86_32
- limit = GB(64) / PAGE_SIZE;
-#else
limit = MAXMEM / PAGE_SIZE;
if (!xen_initial_domain() && xen_512gb_limit)
limit = GB(512) / PAGE_SIZE;
-#endif
+
return limit;
}

@@ -722,17 +718,8 @@ static void __init xen_reserve_xen_mfnlist(void)
if (!xen_is_e820_reserved(start, size))
return;

-#ifdef CONFIG_X86_32
- /*
- * Relocating the p2m on 32 bit system to an arbitrary virtual address
- * is not supported, so just give up.
- */
- xen_raw_console_write("Xen hypervisor allocated p2m list conflicts with E820 map\n");
- BUG();
-#else
xen_relocate_p2m();
memblock_free(start, size);
-#endif
}

/**
@@ -921,20 +908,6 @@ char * __init xen_memory_setup(void)
return "Xen";
}

-/*
- * Set the bit indicating "nosegneg" library variants should be used.
- * We only need to bother in pure 32-bit mode; compat 32-bit processes
- * can have un-truncated segments, so wrapping around is allowed.
- */
-static void __init fiddle_vdso(void)
-{
-#ifdef CONFIG_X86_32
- u32 *mask = vdso_image_32.data +
- vdso_image_32.sym_VDSO32_NOTE_MASK;
- *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
-#endif
-}
-
static int register_callback(unsigned type, const void *func)
{
struct callback_register callback = {
@@ -951,11 +924,7 @@ void xen_enable_sysenter(void)
int ret;
unsigned sysenter_feature;

-#ifdef CONFIG_X86_32
- sysenter_feature = X86_FEATURE_SEP;
-#else
sysenter_feature = X86_FEATURE_SYSENTER32;
-#endif

if (!boot_cpu_has(sysenter_feature))
return;
@@ -967,7 +936,6 @@ void xen_enable_sysenter(void)

void xen_enable_syscall(void)
{
-#ifdef CONFIG_X86_64
int ret;

ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
@@ -983,7 +951,6 @@ void xen_enable_syscall(void)
if (ret != 0)
setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
}
-#endif /* CONFIG_X86_64 */
}

static void __init xen_pvmmu_arch_setup(void)
@@ -1024,7 +991,6 @@ void __init xen_arch_setup(void)
disable_cpuidle();
disable_cpufreq();
WARN_ON(xen_set_default_idle());
- fiddle_vdso();
#ifdef CONFIG_NUMA
numa_off = 1;
#endif
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index 9ea598dcc132..3a70cb1e9550 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -210,15 +210,6 @@ static void __init xen_pv_smp_prepare_boot_cpu(void)
* sure the old memory can be recycled. */
make_lowmem_page_readwrite(xen_initial_gdt);

-#ifdef CONFIG_X86_32
- /*
- * Xen starts us with XEN_FLAT_RING1_DS, but linux code
- * expects __USER_DS
- */
- loadsegment(ds, __USER_DS);
- loadsegment(es, __USER_DS);
-#endif
-
xen_filter_cpu_maps();
xen_setup_vcpu_info_placement();

@@ -299,10 +290,6 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)

gdt = get_cpu_gdt_rw(cpu);

-#ifdef CONFIG_X86_32
- ctxt->user_regs.fs = __KERNEL_PERCPU;
- ctxt->user_regs.gs = __KERNEL_STACK_CANARY;
-#endif
memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));

/*
@@ -340,12 +327,7 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
ctxt->kernel_ss = __KERNEL_DS;
ctxt->kernel_sp = task_top_of_stack(idle);

-#ifdef CONFIG_X86_32
- ctxt->event_callback_cs = __KERNEL_CS;
- ctxt->failsafe_callback_cs = __KERNEL_CS;
-#else
ctxt->gs_base_kernel = per_cpu_offset(cpu);
-#endif
ctxt->event_callback_eip =
(unsigned long)xen_asm_exc_xen_hypervisor_callback;
ctxt->failsafe_callback_eip =
diff --git a/arch/x86/xen/vdso.h b/arch/x86/xen/vdso.h
deleted file mode 100644
index 873c54c488fe..000000000000
--- a/arch/x86/xen/vdso.h
+++ /dev/null
@@ -1,6 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-/* Bit used for the pseudo-hwcap for non-negative segments. We use
- bit 1 to avoid bugs in some versions of glibc when bit 0 is
- used; the choice is otherwise arbitrary. */
-#define VDSO_NOTE_NONEGSEG_BIT 1
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 508fe204520b..c59d077510bf 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -76,11 +76,7 @@ SYM_FUNC_END(xen_save_fl_direct)
*/
SYM_FUNC_START(xen_restore_fl_direct)
FRAME_BEGIN
-#ifdef CONFIG_X86_64
testw $X86_EFLAGS_IF, %di
-#else
- testb $X86_EFLAGS_IF>>8, %ah
-#endif
setz PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
/*
* Preempt here doesn't matter because that will deal with any
@@ -104,15 +100,6 @@ SYM_FUNC_END(xen_restore_fl_direct)
*/
SYM_FUNC_START(check_events)
FRAME_BEGIN
-#ifdef CONFIG_X86_32
- push %eax
- push %ecx
- push %edx
- call xen_force_evtchn_callback
- pop %edx
- pop %ecx
- pop %eax
-#else
push %rax
push %rcx
push %rdx
@@ -132,7 +119,6 @@ SYM_FUNC_START(check_events)
pop %rdx
pop %rcx
pop %rax
-#endif
FRAME_END
ret
SYM_FUNC_END(check_events)
diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S
deleted file mode 100644
index 4757cec33abe..000000000000
--- a/arch/x86/xen/xen-asm_32.S
+++ /dev/null
@@ -1,185 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Asm versions of Xen pv-ops, suitable for direct use.
- *
- * We only bother with direct forms (ie, vcpu in pda) of the
- * operations here; the indirect forms are better handled in C.
- */
-
-#include <asm/thread_info.h>
-#include <asm/processor-flags.h>
-#include <asm/segment.h>
-#include <asm/asm.h>
-
-#include <xen/interface/xen.h>
-
-#include <linux/linkage.h>
-
-/* Pseudo-flag used for virtual NMI, which we don't implement yet */
-#define XEN_EFLAGS_NMI 0x80000000
-
-/*
- * This is run where a normal iret would be run, with the same stack setup:
- * 8: eflags
- * 4: cs
- * esp-> 0: eip
- *
- * This attempts to make sure that any pending events are dealt with
- * on return to usermode, but there is a small window in which an
- * event can happen just before entering usermode. If the nested
- * interrupt ends up setting one of the TIF_WORK_MASK pending work
- * flags, they will not be tested again before returning to
- * usermode. This means that a process can end up with pending work,
- * which will be unprocessed until the process enters and leaves the
- * kernel again, which could be an unbounded amount of time. This
- * means that a pending signal or reschedule event could be
- * indefinitely delayed.
- *
- * The fix is to notice a nested interrupt in the critical window, and
- * if one occurs, then fold the nested interrupt into the current
- * interrupt stack frame, and re-process it iteratively rather than
- * recursively. This means that it will exit via the normal path, and
- * all pending work will be dealt with appropriately.
- *
- * Because the nested interrupt handler needs to deal with the current
- * stack state in whatever form its in, we keep things simple by only
- * using a single register which is pushed/popped on the stack.
- */
-
-.macro POP_FS
-1:
- popw %fs
-.pushsection .fixup, "ax"
-2: movw $0, (%esp)
- jmp 1b
-.popsection
- _ASM_EXTABLE(1b,2b)
-.endm
-
-SYM_CODE_START(xen_iret)
- /* test eflags for special cases */
- testl $(X86_EFLAGS_VM | XEN_EFLAGS_NMI), 8(%esp)
- jnz hyper_iret
-
- push %eax
- ESP_OFFSET=4 # bytes pushed onto stack
-
- /* Store vcpu_info pointer for easy access */
-#ifdef CONFIG_SMP
- pushw %fs
- movl $(__KERNEL_PERCPU), %eax
- movl %eax, %fs
- movl %fs:xen_vcpu, %eax
- POP_FS
-#else
- movl %ss:xen_vcpu, %eax
-#endif
-
- /* check IF state we're restoring */
- testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp)
-
- /*
- * Maybe enable events. Once this happens we could get a
- * recursive event, so the critical region starts immediately
- * afterwards. However, if that happens we don't end up
- * resuming the code, so we don't have to be worried about
- * being preempted to another CPU.
- */
- setz %ss:XEN_vcpu_info_mask(%eax)
-xen_iret_start_crit:
-
- /* check for unmasked and pending */
- cmpw $0x0001, %ss:XEN_vcpu_info_pending(%eax)
-
- /*
- * If there's something pending, mask events again so we can
- * jump back into exc_xen_hypervisor_callback. Otherwise do not
- * touch XEN_vcpu_info_mask.
- */
- jne 1f
- movb $1, %ss:XEN_vcpu_info_mask(%eax)
-
-1: popl %eax
-
- /*
- * From this point on the registers are restored and the stack
- * updated, so we don't need to worry about it if we're
- * preempted
- */
-iret_restore_end:
-
- /*
- * Jump to hypervisor_callback after fixing up the stack.
- * Events are masked, so jumping out of the critical region is
- * OK.
- */
- je xen_asm_exc_xen_hypervisor_callback
-
-1: iret
-xen_iret_end_crit:
- _ASM_EXTABLE(1b, asm_iret_error)
-
-hyper_iret:
- /* put this out of line since its very rarely used */
- jmp hypercall_page + __HYPERVISOR_iret * 32
-SYM_CODE_END(xen_iret)
-
- .globl xen_iret_start_crit, xen_iret_end_crit
-
-/*
- * This is called by xen_asm_exc_xen_hypervisor_callback in entry_32.S when it sees
- * that the EIP at the time of interrupt was between
- * xen_iret_start_crit and xen_iret_end_crit.
- *
- * The stack format at this point is:
- * ----------------
- * ss : (ss/esp may be present if we came from usermode)
- * esp :
- * eflags } outer exception info
- * cs }
- * eip }
- * ----------------
- * eax : outer eax if it hasn't been restored
- * ----------------
- * eflags }
- * cs } nested exception info
- * eip }
- * return address : (into xen_asm_exc_xen_hypervisor_callback)
- *
- * In order to deliver the nested exception properly, we need to discard the
- * nested exception frame such that when we handle the exception, we do it
- * in the context of the outer exception rather than starting a new one.
- *
- * The only caveat is that if the outer eax hasn't been restored yet (i.e.
- * it's still on stack), we need to restore its value here.
-*/
-.pushsection .noinstr.text, "ax"
-SYM_CODE_START(xen_iret_crit_fixup)
- /*
- * Paranoia: Make sure we're really coming from kernel space.
- * One could imagine a case where userspace jumps into the
- * critical range address, but just before the CPU delivers a
- * PF, it decides to deliver an interrupt instead. Unlikely?
- * Definitely. Easy to avoid? Yes.
- */
- testb $2, 2*4(%esp) /* nested CS */
- jnz 2f
-
- /*
- * If eip is before iret_restore_end then stack
- * hasn't been restored yet.
- */
- cmpl $iret_restore_end, 1*4(%esp)
- jae 1f
-
- movl 4*4(%esp), %eax /* load outer EAX */
- ret $4*4 /* discard nested EIP, CS, and EFLAGS as
- * well as the just restored EAX */
-
-1:
- ret $3*4 /* discard nested EIP, CS, and EFLAGS */
-
-2:
- ret
-SYM_CODE_END(xen_iret_crit_fixup)
-.popsection
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index 1ba601df3a37..2d7c8f34f56c 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -35,13 +35,8 @@ SYM_CODE_START(startup_xen)
rep __ASM_SIZE(stos)

mov %_ASM_SI, xen_start_info
-#ifdef CONFIG_X86_64
mov initial_stack(%rip), %rsp
-#else
- mov initial_stack, %esp
-#endif

-#ifdef CONFIG_X86_64
/* Set up %gs.
*
* The base of %gs always points to fixed_percpu_data. If the
@@ -53,7 +48,6 @@ SYM_CODE_START(startup_xen)
movq $INIT_PER_CPU_VAR(fixed_percpu_data),%rax
cdq
wrmsr
-#endif

call xen_start_kernel
SYM_CODE_END(startup_xen)
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 1d339ef92422..ea6c1e7e3e42 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -52,9 +52,7 @@ config XEN_BALLOON_MEMORY_HOTPLUG

config XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
int "Hotplugged memory limit (in GiB) for a PV guest"
- default 512 if X86_64
- default 4 if X86_32
- range 0 64 if X86_32
+ default 512
depends on XEN_HAVE_PVMMU
depends on XEN_BALLOON_MEMORY_HOTPLUG
help
--
2.26.2

2020-08-07 09:41:21

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

On Fri, Aug 07, 2020 at 10:38:23AM +0200, Juergen Gross wrote:

> -# else
> - const unsigned char cpu_iret[1];
> -# endif
> };
>
> static const struct patch_xxl patch_data_xxl = {
> @@ -42,7 +38,6 @@ static const struct patch_xxl patch_data_xxl = {
> .irq_save_fl = { 0x9c, 0x58 }, // pushf; pop %[re]ax
> .mmu_read_cr2 = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
> .mmu_read_cr3 = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
> -# ifdef CONFIG_X86_64
> .mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
> .irq_restore_fl = { 0x57, 0x9d }, // push %rdi; popfq
> .cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
> @@ -50,19 +45,11 @@ static const struct patch_xxl patch_data_xxl = {
> 0x48, 0x0f, 0x07 }, // swapgs; sysretq
> .cpu_swapgs = { 0x0f, 0x01, 0xf8 }, // swapgs
> .mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
> -# else
> - .mmu_write_cr3 = { 0x0f, 0x22, 0xd8 }, // mov %eax, %cr3
> - .irq_restore_fl = { 0x50, 0x9d }, // push %eax; popf
> - .cpu_iret = { 0xcf }, // iret
> -# endif

I was looking at x86_64 paravirt the other day and found we actually
have pv_ops.cpu.iret users there..

So we want to change the above to also patch iret on x86_64 or do we
need to fix x86_64 to not have pv-iret?

2020-08-07 10:04:44

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

On 07.08.20 11:39, [email protected] wrote:
> On Fri, Aug 07, 2020 at 10:38:23AM +0200, Juergen Gross wrote:
>
>> -# else
>> - const unsigned char cpu_iret[1];
>> -# endif
>> };
>>
>> static const struct patch_xxl patch_data_xxl = {
>> @@ -42,7 +38,6 @@ static const struct patch_xxl patch_data_xxl = {
>> .irq_save_fl = { 0x9c, 0x58 }, // pushf; pop %[re]ax
>> .mmu_read_cr2 = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
>> .mmu_read_cr3 = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
>> -# ifdef CONFIG_X86_64
>> .mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
>> .irq_restore_fl = { 0x57, 0x9d }, // push %rdi; popfq
>> .cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
>> @@ -50,19 +45,11 @@ static const struct patch_xxl patch_data_xxl = {
>> 0x48, 0x0f, 0x07 }, // swapgs; sysretq
>> .cpu_swapgs = { 0x0f, 0x01, 0xf8 }, // swapgs
>> .mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
>> -# else
>> - .mmu_write_cr3 = { 0x0f, 0x22, 0xd8 }, // mov %eax, %cr3
>> - .irq_restore_fl = { 0x50, 0x9d }, // push %eax; popf
>> - .cpu_iret = { 0xcf }, // iret
>> -# endif
>
> I was looking at x86_64 paravirt the other day and found we actually
> have pv_ops.cpu.iret users there..

On x86_64 we have (without PARAVIRT_XXL):

#define INTERRUPT_RETURN jmp native_iret

and with PARAVIRT_XXL this is basically a jmp *pv_ops.cpu.iret which
will then be patched to either jmp native_iret or jmp xen_iret.

On x86_32 INTERRUPT_RETURN was just "iret" for the non-paravirt case.
This is the reason for above dropping of the static patch data.

> So we want to change the above to also patch iret on x86_64 or do we
> need to fix x86_64 to not have pv-iret?

We want it to stay how it is. This will let both variants (PARVIRT y/n)
continue to work.


Juergen

2020-08-07 10:23:18

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

On Fri, Aug 07, 2020 at 12:02:59PM +0200, J?rgen Gro? wrote:
> On 07.08.20 11:39, [email protected] wrote:
> > On Fri, Aug 07, 2020 at 10:38:23AM +0200, Juergen Gross wrote:
> >
> > > -# else
> > > - const unsigned char cpu_iret[1];
> > > -# endif
> > > };
> > > static const struct patch_xxl patch_data_xxl = {
> > > @@ -42,7 +38,6 @@ static const struct patch_xxl patch_data_xxl = {
> > > .irq_save_fl = { 0x9c, 0x58 }, // pushf; pop %[re]ax
> > > .mmu_read_cr2 = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
> > > .mmu_read_cr3 = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
> > > -# ifdef CONFIG_X86_64
> > > .mmu_write_cr3 = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
> > > .irq_restore_fl = { 0x57, 0x9d }, // push %rdi; popfq
> > > .cpu_wbinvd = { 0x0f, 0x09 }, // wbinvd
> > > @@ -50,19 +45,11 @@ static const struct patch_xxl patch_data_xxl = {
> > > 0x48, 0x0f, 0x07 }, // swapgs; sysretq
> > > .cpu_swapgs = { 0x0f, 0x01, 0xf8 }, // swapgs
> > > .mov64 = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
> > > -# else
> > > - .mmu_write_cr3 = { 0x0f, 0x22, 0xd8 }, // mov %eax, %cr3
> > > - .irq_restore_fl = { 0x50, 0x9d }, // push %eax; popf
> > > - .cpu_iret = { 0xcf }, // iret
> > > -# endif
> >
> > I was looking at x86_64 paravirt the other day and found we actually
> > have pv_ops.cpu.iret users there..
>
> On x86_64 we have (without PARAVIRT_XXL):
>
> #define INTERRUPT_RETURN jmp native_iret
>
> and with PARAVIRT_XXL this is basically a jmp *pv_ops.cpu.iret which
> will then be patched to either jmp native_iret or jmp xen_iret.

Ah, okay. Clearly I didn't look hard enough. Thanks!

2020-08-09 02:07:20

by Boris Ostrovsky

[permalink] [raw]
Subject: Re: [PATCH v3 1/7] x86/xen: remove 32-bit Xen PV guest support

On 8/7/20 4:38 AM, Juergen Gross wrote:
>
> void __init xen_reserve_top(void)
> {
> -#ifdef CONFIG_X86_32
> - unsigned long top = HYPERVISOR_VIRT_START;
> - struct xen_platform_parameters pp;
> -
> - if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
> - top = pp.virt_start;
> -
> - reserve_top_address(-top);
> -#endif /* CONFIG_X86_32 */
> }
>


We should be able now to get rid of xen_reserve_top() altogether.


Other than that


Reviewed-by: Boris Ostrovsky <[email protected]>


-boris


2020-08-09 02:37:10

by Boris Ostrovsky

[permalink] [raw]
Subject: Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

On 8/7/20 4:38 AM, Juergen Gross wrote:
> @@ -377,10 +373,7 @@ static inline pte_t __pte(pteval_t val)
> {
> pteval_t ret;
>
> - if (sizeof(pteval_t) > sizeof(long))
> - ret = PVOP_CALLEE2(pteval_t, mmu.make_pte, val, (u64)val >> 32);
> - else
> - ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
> + ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
>
> return (pte_t) { .pte = ret };


Can this now simply return (pte_t) ret?


-boris



2020-08-10 04:40:35

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH v3 1/7] x86/xen: remove 32-bit Xen PV guest support

On 09.08.20 04:01, Boris Ostrovsky wrote:
> On 8/7/20 4:38 AM, Juergen Gross wrote:
>>
>> void __init xen_reserve_top(void)
>> {
>> -#ifdef CONFIG_X86_32
>> - unsigned long top = HYPERVISOR_VIRT_START;
>> - struct xen_platform_parameters pp;
>> -
>> - if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
>> - top = pp.virt_start;
>> -
>> - reserve_top_address(-top);
>> -#endif /* CONFIG_X86_32 */
>> }
>>
>
>
> We should be able now to get rid of xen_reserve_top() altogether.

Oh, yes.

>
>
> Other than that
>
>
> Reviewed-by: Boris Ostrovsky <[email protected]>

Thanks,

Juergen

2020-08-10 04:43:38

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

On 09.08.20 04:34, Boris Ostrovsky wrote:
> On 8/7/20 4:38 AM, Juergen Gross wrote:
>> @@ -377,10 +373,7 @@ static inline pte_t __pte(pteval_t val)
>> {
>> pteval_t ret;
>>
>> - if (sizeof(pteval_t) > sizeof(long))
>> - ret = PVOP_CALLEE2(pteval_t, mmu.make_pte, val, (u64)val >> 32);
>> - else
>> - ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
>> + ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
>>
>> return (pte_t) { .pte = ret };
>
>
> Can this now simply return (pte_t) ret?

I don't think so, but I can turn it into

return native_make_pte(PVOP_CALLEE1(...));


Juergen

2020-08-10 16:55:46

by Boris Ostrovsky

[permalink] [raw]
Subject: Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

On 8/10/20 12:39 AM, Jürgen Groß wrote:
> On 09.08.20 04:34, Boris Ostrovsky wrote:
>> On 8/7/20 4:38 AM, Juergen Gross wrote:
>>> @@ -377,10 +373,7 @@ static inline pte_t __pte(pteval_t val)
>>>   {
>>>       pteval_t ret;
>>>   -    if (sizeof(pteval_t) > sizeof(long))
>>> -        ret = PVOP_CALLEE2(pteval_t, mmu.make_pte, val, (u64)val >>
>>> 32);
>>> -    else
>>> -        ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
>>> +    ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
>>>         return (pte_t) { .pte = ret };
>>
>>
>> Can this now simply return (pte_t) ret?
>
> I don't think so, but I can turn it into
>
>   return native_make_pte(PVOP_CALLEE1(...));


I thought that since now this is only built for 64-bit we don't have to
worry about different pte_t definitions and can do what we do for
example, for __pgd()?


-boris


2020-08-10 18:44:02

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

On 10.08.20 18:53, Boris Ostrovsky wrote:
> On 8/10/20 12:39 AM, Jürgen Groß wrote:
>> On 09.08.20 04:34, Boris Ostrovsky wrote:
>>> On 8/7/20 4:38 AM, Juergen Gross wrote:
>>>> @@ -377,10 +373,7 @@ static inline pte_t __pte(pteval_t val)
>>>>   {
>>>>       pteval_t ret;
>>>>   -    if (sizeof(pteval_t) > sizeof(long))
>>>> -        ret = PVOP_CALLEE2(pteval_t, mmu.make_pte, val, (u64)val >>
>>>> 32);
>>>> -    else
>>>> -        ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
>>>> +    ret = PVOP_CALLEE1(pteval_t, mmu.make_pte, val);
>>>>         return (pte_t) { .pte = ret };
>>>
>>>
>>> Can this now simply return (pte_t) ret?
>>
>> I don't think so, but I can turn it into
>>
>>   return native_make_pte(PVOP_CALLEE1(...));
>
>
> I thought that since now this is only built for 64-bit we don't have to
> worry about different pte_t definitions and can do what we do for
> example, for __pgd()?

Yes, I did that:

return (pte_t) { ret };


Juergen