Those structs will be used to read/write the smram state image.
Also document the differences between KVM's SMRAM layout and SMRAM
layout that is used by real Intel/AMD cpus.
Signed-off-by: Maxim Levitsky <[email protected]>
---
arch/x86/kvm/emulate.c | 6 +
arch/x86/kvm/kvm_emulate.h | 218 +++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 1 +
3 files changed, 225 insertions(+)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 18551611cb13af..55d9328e6074a2 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -5864,3 +5864,9 @@ bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt)
return true;
}
+
+void __init kvm_emulator_init(void)
+{
+ __check_smram32_offsets();
+ __check_smram64_offsets();
+}
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index 89246446d6aa9d..dd0ae61e44a116 100644
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -13,6 +13,7 @@
#define _ASM_X86_KVM_X86_EMULATE_H
#include <asm/desc_defs.h>
+#include <linux/build_bug.h>
#include "fpu.h"
struct x86_emulate_ctxt;
@@ -503,6 +504,223 @@ enum x86_intercept {
nr_x86_intercepts
};
+
+/* 32 bit KVM's emulated SMM layout. Loosely based on Intel's layout */
+
+struct kvm_smm_seg_state_32 {
+ u32 flags;
+ u32 limit;
+ u32 base;
+} __packed;
+
+struct kvm_smram_state_32 {
+ u32 reserved1[62];
+ u32 smbase;
+ u32 smm_revision;
+ u32 reserved2[5];
+ u32 cr4; /* CR4 is not present in Intel/AMD SMRAM image */
+ u32 reserved3[5];
+
+ /*
+ * Segment state is not present/documented in the Intel/AMD SMRAM image
+ * Instead this area on Intel/AMD contains IO/HLT restart flags.
+ */
+ struct kvm_smm_seg_state_32 ds;
+ struct kvm_smm_seg_state_32 fs;
+ struct kvm_smm_seg_state_32 gs;
+ struct kvm_smm_seg_state_32 idtr; /* IDTR has only base and limit */
+ struct kvm_smm_seg_state_32 tr;
+ u32 reserved;
+ struct kvm_smm_seg_state_32 gdtr; /* GDTR has only base and limit */
+ struct kvm_smm_seg_state_32 ldtr;
+ struct kvm_smm_seg_state_32 es;
+ struct kvm_smm_seg_state_32 cs;
+ struct kvm_smm_seg_state_32 ss;
+
+ u32 es_sel;
+ u32 cs_sel;
+ u32 ss_sel;
+ u32 ds_sel;
+ u32 fs_sel;
+ u32 gs_sel;
+ u32 ldtr_sel;
+ u32 tr_sel;
+
+ u32 dr7;
+ u32 dr6;
+ u32 gprs[8]; /* GPRS in the "natural" X86 order (EAX/ECX/EDX.../EDI) */
+ u32 eip;
+ u32 eflags;
+ u32 cr3;
+ u32 cr0;
+} __packed;
+
+
+static inline void __check_smram32_offsets(void)
+{
+#define __CHECK_SMRAM32_OFFSET(field, offset) \
+ ASSERT_STRUCT_OFFSET(struct kvm_smram_state_32, field, offset - 0xFE00)
+
+ __CHECK_SMRAM32_OFFSET(reserved1, 0xFE00);
+ __CHECK_SMRAM32_OFFSET(smbase, 0xFEF8);
+ __CHECK_SMRAM32_OFFSET(smm_revision, 0xFEFC);
+ __CHECK_SMRAM32_OFFSET(reserved2, 0xFF00);
+ __CHECK_SMRAM32_OFFSET(cr4, 0xFF14);
+ __CHECK_SMRAM32_OFFSET(reserved3, 0xFF18);
+ __CHECK_SMRAM32_OFFSET(ds, 0xFF2C);
+ __CHECK_SMRAM32_OFFSET(fs, 0xFF38);
+ __CHECK_SMRAM32_OFFSET(gs, 0xFF44);
+ __CHECK_SMRAM32_OFFSET(idtr, 0xFF50);
+ __CHECK_SMRAM32_OFFSET(tr, 0xFF5C);
+ __CHECK_SMRAM32_OFFSET(gdtr, 0xFF6C);
+ __CHECK_SMRAM32_OFFSET(ldtr, 0xFF78);
+ __CHECK_SMRAM32_OFFSET(es, 0xFF84);
+ __CHECK_SMRAM32_OFFSET(cs, 0xFF90);
+ __CHECK_SMRAM32_OFFSET(ss, 0xFF9C);
+ __CHECK_SMRAM32_OFFSET(es_sel, 0xFFA8);
+ __CHECK_SMRAM32_OFFSET(cs_sel, 0xFFAC);
+ __CHECK_SMRAM32_OFFSET(ss_sel, 0xFFB0);
+ __CHECK_SMRAM32_OFFSET(ds_sel, 0xFFB4);
+ __CHECK_SMRAM32_OFFSET(fs_sel, 0xFFB8);
+ __CHECK_SMRAM32_OFFSET(gs_sel, 0xFFBC);
+ __CHECK_SMRAM32_OFFSET(ldtr_sel, 0xFFC0);
+ __CHECK_SMRAM32_OFFSET(tr_sel, 0xFFC4);
+ __CHECK_SMRAM32_OFFSET(dr7, 0xFFC8);
+ __CHECK_SMRAM32_OFFSET(dr6, 0xFFCC);
+ __CHECK_SMRAM32_OFFSET(gprs, 0xFFD0);
+ __CHECK_SMRAM32_OFFSET(eip, 0xFFF0);
+ __CHECK_SMRAM32_OFFSET(eflags, 0xFFF4);
+ __CHECK_SMRAM32_OFFSET(cr3, 0xFFF8);
+ __CHECK_SMRAM32_OFFSET(cr0, 0xFFFC);
+#undef __CHECK_SMRAM32_OFFSET
+}
+
+
+/* 64 bit KVM's emulated SMM layout. Based on AMD64 layout */
+
+struct kvm_smm_seg_state_64 {
+ u16 selector;
+ u16 attributes;
+ u32 limit;
+ u64 base;
+};
+
+struct kvm_smram_state_64 {
+
+ struct kvm_smm_seg_state_64 es;
+ struct kvm_smm_seg_state_64 cs;
+ struct kvm_smm_seg_state_64 ss;
+ struct kvm_smm_seg_state_64 ds;
+ struct kvm_smm_seg_state_64 fs;
+ struct kvm_smm_seg_state_64 gs;
+ struct kvm_smm_seg_state_64 gdtr; /* GDTR has only base and limit*/
+ struct kvm_smm_seg_state_64 ldtr;
+ struct kvm_smm_seg_state_64 idtr; /* IDTR has only base and limit*/
+ struct kvm_smm_seg_state_64 tr;
+
+ /* I/O restart and auto halt restart are not implemented by KVM */
+ u64 io_restart_rip;
+ u64 io_restart_rcx;
+ u64 io_restart_rsi;
+ u64 io_restart_rdi;
+ u32 io_restart_dword;
+ u32 reserved1;
+ u8 io_inst_restart;
+ u8 auto_hlt_restart;
+ u8 reserved2[6];
+
+ u64 efer;
+
+ /*
+ * Two fields below are implemented on AMD only, to store
+ * SVM guest vmcb address if the #SMI was received while in the guest mode.
+ */
+ u64 svm_guest_flag;
+ u64 svm_guest_vmcb_gpa;
+ u64 svm_guest_virtual_int; /* unknown purpose, not implemented */
+
+ u32 reserved3[3];
+ u32 smm_revison;
+ u32 smbase;
+ u32 reserved4[5];
+
+ /* ssp and svm_* fields below are not implemented by KVM */
+ u64 ssp;
+ u64 svm_guest_pat;
+ u64 svm_host_efer;
+ u64 svm_host_cr4;
+ u64 svm_host_cr3;
+ u64 svm_host_cr0;
+
+ u64 cr4;
+ u64 cr3;
+ u64 cr0;
+ u64 dr7;
+ u64 dr6;
+ u64 rflags;
+ u64 rip;
+ u64 gprs[16]; /* GPRS in a reversed "natural" X86 order (R15/R14/../RCX/RAX.) */
+};
+
+
+static inline void __check_smram64_offsets(void)
+{
+#define __CHECK_SMRAM64_OFFSET(field, offset) \
+ ASSERT_STRUCT_OFFSET(struct kvm_smram_state_64, field, offset - 0xFE00)
+
+ __CHECK_SMRAM64_OFFSET(es, 0xFE00);
+ __CHECK_SMRAM64_OFFSET(cs, 0xFE10);
+ __CHECK_SMRAM64_OFFSET(ss, 0xFE20);
+ __CHECK_SMRAM64_OFFSET(ds, 0xFE30);
+ __CHECK_SMRAM64_OFFSET(fs, 0xFE40);
+ __CHECK_SMRAM64_OFFSET(gs, 0xFE50);
+ __CHECK_SMRAM64_OFFSET(gdtr, 0xFE60);
+ __CHECK_SMRAM64_OFFSET(ldtr, 0xFE70);
+ __CHECK_SMRAM64_OFFSET(idtr, 0xFE80);
+ __CHECK_SMRAM64_OFFSET(tr, 0xFE90);
+ __CHECK_SMRAM64_OFFSET(io_restart_rip, 0xFEA0);
+ __CHECK_SMRAM64_OFFSET(io_restart_rcx, 0xFEA8);
+ __CHECK_SMRAM64_OFFSET(io_restart_rsi, 0xFEB0);
+ __CHECK_SMRAM64_OFFSET(io_restart_rdi, 0xFEB8);
+ __CHECK_SMRAM64_OFFSET(io_restart_dword, 0xFEC0);
+ __CHECK_SMRAM64_OFFSET(reserved1, 0xFEC4);
+ __CHECK_SMRAM64_OFFSET(io_inst_restart, 0xFEC8);
+ __CHECK_SMRAM64_OFFSET(auto_hlt_restart, 0xFEC9);
+ __CHECK_SMRAM64_OFFSET(reserved2, 0xFECA);
+ __CHECK_SMRAM64_OFFSET(efer, 0xFED0);
+ __CHECK_SMRAM64_OFFSET(svm_guest_flag, 0xFED8);
+ __CHECK_SMRAM64_OFFSET(svm_guest_vmcb_gpa, 0xFEE0);
+ __CHECK_SMRAM64_OFFSET(svm_guest_virtual_int, 0xFEE8);
+ __CHECK_SMRAM64_OFFSET(reserved3, 0xFEF0);
+ __CHECK_SMRAM64_OFFSET(smm_revison, 0xFEFC);
+ __CHECK_SMRAM64_OFFSET(smbase, 0xFF00);
+ __CHECK_SMRAM64_OFFSET(reserved4, 0xFF04);
+ __CHECK_SMRAM64_OFFSET(ssp, 0xFF18);
+ __CHECK_SMRAM64_OFFSET(svm_guest_pat, 0xFF20);
+ __CHECK_SMRAM64_OFFSET(svm_host_efer, 0xFF28);
+ __CHECK_SMRAM64_OFFSET(svm_host_cr4, 0xFF30);
+ __CHECK_SMRAM64_OFFSET(svm_host_cr3, 0xFF38);
+ __CHECK_SMRAM64_OFFSET(svm_host_cr0, 0xFF40);
+ __CHECK_SMRAM64_OFFSET(cr4, 0xFF48);
+ __CHECK_SMRAM64_OFFSET(cr3, 0xFF50);
+ __CHECK_SMRAM64_OFFSET(cr0, 0xFF58);
+ __CHECK_SMRAM64_OFFSET(dr7, 0xFF60);
+ __CHECK_SMRAM64_OFFSET(dr6, 0xFF68);
+ __CHECK_SMRAM64_OFFSET(rflags, 0xFF70);
+ __CHECK_SMRAM64_OFFSET(rip, 0xFF78);
+ __CHECK_SMRAM64_OFFSET(gprs, 0xFF80);
+#undef __CHECK_SMRAM64_OFFSET
+}
+
+union kvm_smram {
+ struct kvm_smram_state_64 smram64;
+ struct kvm_smram_state_32 smram32;
+ u8 bytes[512];
+};
+
+void __init kvm_emulator_init(void);
+
+
/* Host execution mode. */
#if defined(CONFIG_X86_32)
#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 33560bfa0cac6e..bea7e5015d592e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13355,6 +13355,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_msr_protocol_exit);
static int __init kvm_x86_init(void)
{
kvm_mmu_x86_module_init();
+ kvm_emulator_init();
return 0;
}
module_init(kvm_x86_init);
--
2.26.3
On Wed, Aug 03, 2022, Maxim Levitsky wrote:
> Those structs will be used to read/write the smram state image.
>
> Also document the differences between KVM's SMRAM layout and SMRAM
> layout that is used by real Intel/AMD cpus.
>
> Signed-off-by: Maxim Levitsky <[email protected]>
> ---
> arch/x86/kvm/emulate.c | 6 +
> arch/x86/kvm/kvm_emulate.h | 218 +++++++++++++++++++++++++++++++++++++
> arch/x86/kvm/x86.c | 1 +
> 3 files changed, 225 insertions(+)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 18551611cb13af..55d9328e6074a2 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -5864,3 +5864,9 @@ bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt)
>
> return true;
> }
> +
> +void __init kvm_emulator_init(void)
> +{
> + __check_smram32_offsets();
> + __check_smram64_offsets();
> +}
...
> +static inline void __check_smram64_offsets(void)
Why double underscores? Same question for the macros.
> +{
> +#define __CHECK_SMRAM64_OFFSET(field, offset) \
> + ASSERT_STRUCT_OFFSET(struct kvm_smram_state_64, field, offset - 0xFE00)
> +
> + __CHECK_SMRAM64_OFFSET(es, 0xFE00);
> + __CHECK_SMRAM64_OFFSET(cs, 0xFE10);
> + __CHECK_SMRAM64_OFFSET(ss, 0xFE20);
> + __CHECK_SMRAM64_OFFSET(ds, 0xFE30);
> + __CHECK_SMRAM64_OFFSET(fs, 0xFE40);
> + __CHECK_SMRAM64_OFFSET(gs, 0xFE50);
> + __CHECK_SMRAM64_OFFSET(gdtr, 0xFE60);
> + __CHECK_SMRAM64_OFFSET(ldtr, 0xFE70);
> + __CHECK_SMRAM64_OFFSET(idtr, 0xFE80);
> + __CHECK_SMRAM64_OFFSET(tr, 0xFE90);
> + __CHECK_SMRAM64_OFFSET(io_restart_rip, 0xFEA0);
> + __CHECK_SMRAM64_OFFSET(io_restart_rcx, 0xFEA8);
> + __CHECK_SMRAM64_OFFSET(io_restart_rsi, 0xFEB0);
> + __CHECK_SMRAM64_OFFSET(io_restart_rdi, 0xFEB8);
> + __CHECK_SMRAM64_OFFSET(io_restart_dword, 0xFEC0);
> + __CHECK_SMRAM64_OFFSET(reserved1, 0xFEC4);
> + __CHECK_SMRAM64_OFFSET(io_inst_restart, 0xFEC8);
> + __CHECK_SMRAM64_OFFSET(auto_hlt_restart, 0xFEC9);
> + __CHECK_SMRAM64_OFFSET(reserved2, 0xFECA);
> + __CHECK_SMRAM64_OFFSET(efer, 0xFED0);
> + __CHECK_SMRAM64_OFFSET(svm_guest_flag, 0xFED8);
> + __CHECK_SMRAM64_OFFSET(svm_guest_vmcb_gpa, 0xFEE0);
> + __CHECK_SMRAM64_OFFSET(svm_guest_virtual_int, 0xFEE8);
> + __CHECK_SMRAM64_OFFSET(reserved3, 0xFEF0);
> + __CHECK_SMRAM64_OFFSET(smm_revison, 0xFEFC);
> + __CHECK_SMRAM64_OFFSET(smbase, 0xFF00);
> + __CHECK_SMRAM64_OFFSET(reserved4, 0xFF04);
> + __CHECK_SMRAM64_OFFSET(ssp, 0xFF18);
> + __CHECK_SMRAM64_OFFSET(svm_guest_pat, 0xFF20);
> + __CHECK_SMRAM64_OFFSET(svm_host_efer, 0xFF28);
> + __CHECK_SMRAM64_OFFSET(svm_host_cr4, 0xFF30);
> + __CHECK_SMRAM64_OFFSET(svm_host_cr3, 0xFF38);
> + __CHECK_SMRAM64_OFFSET(svm_host_cr0, 0xFF40);
> + __CHECK_SMRAM64_OFFSET(cr4, 0xFF48);
> + __CHECK_SMRAM64_OFFSET(cr3, 0xFF50);
> + __CHECK_SMRAM64_OFFSET(cr0, 0xFF58);
> + __CHECK_SMRAM64_OFFSET(dr7, 0xFF60);
> + __CHECK_SMRAM64_OFFSET(dr6, 0xFF68);
> + __CHECK_SMRAM64_OFFSET(rflags, 0xFF70);
> + __CHECK_SMRAM64_OFFSET(rip, 0xFF78);
> + __CHECK_SMRAM64_OFFSET(gprs, 0xFF80);
> +#undef __CHECK_SMRAM64_OFFSET
> +}
> +
> +union kvm_smram {
> + struct kvm_smram_state_64 smram64;
> + struct kvm_smram_state_32 smram32;
> + u8 bytes[512];
> +};
> +
> +void __init kvm_emulator_init(void);
> +
> +
Unnecessary newline.
> /* Host execution mode. */
> #if defined(CONFIG_X86_32)
> #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 33560bfa0cac6e..bea7e5015d592e 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -13355,6 +13355,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmgexit_msr_protocol_exit);
> static int __init kvm_x86_init(void)
> {
> kvm_mmu_x86_module_init();
> + kvm_emulator_init();
Please don't add an init call that is nop at runtime, e.g. I was _really_ curious
what initialization needed to be done in the emulator. And it makes it look like
kvm_x86_exit() forgot to call kvm_emulator_exit().
em_rsm() already ends up with
BUILD_BUG_ON(sizeof(smram) != 512);
just put all the assertions there.
> return 0;
> }
> module_init(kvm_x86_init);
> --
> 2.26.3
>