This introduces a level of indirection for the debug registers. Instead
of using the sys_regs[] directly we store registers in a structure in
the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
guest context.
This also entails updating the sys_regs code to access this new
structure. New access function have been added for each set of debug
registers. The generic functions are still used for the few registers
stored in the main context.
New access function pointers have been added to the sys_reg_desc
structure to support the GET/SET_ONE_REG ioctl operations.
Signed-off-by: Alex Bennée <[email protected]>
---
v6:
- fix up some ws issues
- correct clobber info
- re-word commentary in kvm_host.h
- fix endian access issues for aarch32 fields
- revert all KVM_GET/SET_ONE_REG to 64bit (also see ABI update)
v7
- new fn kvm_arm_reset_debug_ptr(), stubbed for arm
- split trap fns into bcr,bvr,bcr,wvr and wxvr
- add set/get fns to sys_regs_desc
- reg_to_dbg/dbg_to_reg helpers for 32bit support
---
arch/arm/include/asm/kvm_host.h | 2 +-
arch/arm/kvm/arm.c | 2 +
arch/arm64/include/asm/kvm_asm.h | 24 ++--
arch/arm64/include/asm/kvm_host.h | 17 ++-
arch/arm64/kernel/asm-offsets.c | 6 +
arch/arm64/kvm/debug.c | 9 ++
arch/arm64/kvm/hyp.S | 24 ++--
arch/arm64/kvm/sys_regs.c | 281 ++++++++++++++++++++++++++++++++++----
arch/arm64/kvm/sys_regs.h | 6 +
9 files changed, 321 insertions(+), 50 deletions(-)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 746c0c69..f42759b 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -239,5 +239,5 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
static inline void kvm_arm_init_debug(void) {}
static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
-
+static inline void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) {}
#endif /* __ARM_KVM_HOST_H__ */
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index af60e6f..525473f 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -279,6 +279,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
/* Set up the timer */
kvm_timer_vcpu_init(vcpu);
+ kvm_arm_reset_debug_ptr(vcpu);
+
return 0;
}
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index d6b507e..e997404 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -46,24 +46,16 @@
#define CNTKCTL_EL1 20 /* Timer Control Register (EL1) */
#define PAR_EL1 21 /* Physical Address Register */
#define MDSCR_EL1 22 /* Monitor Debug System Control Register */
-#define DBGBCR0_EL1 23 /* Debug Breakpoint Control Registers (0-15) */
-#define DBGBCR15_EL1 38
-#define DBGBVR0_EL1 39 /* Debug Breakpoint Value Registers (0-15) */
-#define DBGBVR15_EL1 54
-#define DBGWCR0_EL1 55 /* Debug Watchpoint Control Registers (0-15) */
-#define DBGWCR15_EL1 70
-#define DBGWVR0_EL1 71 /* Debug Watchpoint Value Registers (0-15) */
-#define DBGWVR15_EL1 86
-#define MDCCINT_EL1 87 /* Monitor Debug Comms Channel Interrupt Enable Reg */
+#define MDCCINT_EL1 23 /* Monitor Debug Comms Channel Interrupt Enable Reg */
/* 32bit specific registers. Keep them at the end of the range */
-#define DACR32_EL2 88 /* Domain Access Control Register */
-#define IFSR32_EL2 89 /* Instruction Fault Status Register */
-#define FPEXC32_EL2 90 /* Floating-Point Exception Control Register */
-#define DBGVCR32_EL2 91 /* Debug Vector Catch Register */
-#define TEECR32_EL1 92 /* ThumbEE Configuration Register */
-#define TEEHBR32_EL1 93 /* ThumbEE Handler Base Register */
-#define NR_SYS_REGS 94
+#define DACR32_EL2 24 /* Domain Access Control Register */
+#define IFSR32_EL2 25 /* Instruction Fault Status Register */
+#define FPEXC32_EL2 26 /* Floating-Point Exception Control Register */
+#define DBGVCR32_EL2 27 /* Debug Vector Catch Register */
+#define TEECR32_EL1 28 /* ThumbEE Configuration Register */
+#define TEEHBR32_EL1 29 /* ThumbEE Handler Base Register */
+#define NR_SYS_REGS 30
/* 32bit mapping */
#define c0_MPIDR (MPIDR_EL1 * 2) /* MultiProcessor ID Register */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e2db6a6..461d288 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -108,11 +108,25 @@ struct kvm_vcpu_arch {
/* Exception Information */
struct kvm_vcpu_fault_info fault;
- /* Debug state */
+ /* Guest debug state */
u64 debug_flags;
+ /*
+ * We maintain more than a single set of debug registers to support
+ * debugging the guest from the host and to maintain separate host and
+ * guest state during world switches. vcpu_debug_state are the debug
+ * registers of the vcpu as the guest sees them. host_debug_state are
+ * the host registers which are saved and restored during world switches.
+ *
+ * debug_ptr points to the set of debug registers that should be loaded
+ * onto the hardware when running the guest.
+ */
+ struct kvm_guest_debug_arch *debug_ptr;
+ struct kvm_guest_debug_arch vcpu_debug_state;
+
/* Pointer to host CPU context */
kvm_cpu_context_t *host_cpu_context;
+ struct kvm_guest_debug_arch host_debug_state;
/* VGIC state */
struct vgic_cpu vgic_cpu;
@@ -265,5 +279,6 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
void kvm_arm_init_debug(void);
void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
void kvm_arm_clear_debug(struct kvm_vcpu *vcpu);
+void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu);
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index dfb25a2..1a8e97c 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -116,10 +116,16 @@ int main(void)
DEFINE(VCPU_FAR_EL2, offsetof(struct kvm_vcpu, arch.fault.far_el2));
DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags));
+ DEFINE(VCPU_DEBUG_PTR, offsetof(struct kvm_vcpu, arch.debug_ptr));
+ DEFINE(DEBUG_BCR, offsetof(struct kvm_guest_debug_arch, dbg_bcr));
+ DEFINE(DEBUG_BVR, offsetof(struct kvm_guest_debug_arch, dbg_bvr));
+ DEFINE(DEBUG_WCR, offsetof(struct kvm_guest_debug_arch, dbg_wcr));
+ DEFINE(DEBUG_WVR, offsetof(struct kvm_guest_debug_arch, dbg_wvr));
DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2));
DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2));
DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines));
DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context));
+ DEFINE(VCPU_HOST_DEBUG_STATE, offsetof(struct kvm_vcpu, arch.host_debug_state));
DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl));
DEFINE(VCPU_TIMER_CNTV_CVAL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_cval));
DEFINE(KVM_TIMER_CNTVOFF, offsetof(struct kvm, arch.timer.cntvoff));
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index d439eb8..ffefb97 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -67,6 +67,15 @@ void kvm_arm_init_debug(void)
}
/**
+ * kvm_arm_reset_debug_ptr - set the debug registers to be the guests
+ */
+
+void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
+{
+ vcpu->arch.debug_ptr = &vcpu->arch.vcpu_debug_state;
+}
+
+/**
* kvm_arm_setup_debug - set up debug related stuff
*
* @vcpu: the vcpu pointer
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 77c08df..f56e93f 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -600,6 +600,7 @@ __restore_sysregs:
/* Save debug state */
__save_debug:
// x2: ptr to CPU context
+ // x3: ptr to debug reg struct
// x4/x5/x6-22/x24-26: trashed
mrs x26, id_aa64dfr0_el1
@@ -610,15 +611,15 @@ __save_debug:
sub w25, w26, w25 // How many WPs to skip
mov x5, x24
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
+ add x4, x3, #DEBUG_BCR
save_debug dbgbcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
+ add x4, x3, #DEBUG_BVR
save_debug dbgbvr
mov x5, x25
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
+ add x4, x3, #DEBUG_WCR
save_debug dbgwcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
+ add x4, x3, #DEBUG_WVR
save_debug dbgwvr
mrs x21, mdccint_el1
@@ -628,6 +629,7 @@ __save_debug:
/* Restore debug state */
__restore_debug:
// x2: ptr to CPU context
+ // x3: ptr to debug reg struct
// x4/x5/x6-22/x24-26: trashed
mrs x26, id_aa64dfr0_el1
@@ -638,15 +640,15 @@ __restore_debug:
sub w25, w26, w25 // How many WPs to skip
mov x5, x24
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
+ add x4, x3, #DEBUG_BCR
restore_debug dbgbcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
+ add x4, x3, #DEBUG_BVR
restore_debug dbgbvr
mov x5, x25
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
+ add x4, x3, #DEBUG_WCR
restore_debug dbgwcr
- add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
+ add x4, x3, #DEBUG_WVR
restore_debug dbgwvr
ldr x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
@@ -686,6 +688,7 @@ ENTRY(__kvm_vcpu_run)
bl __save_sysregs
compute_debug_state 1f
+ add x3, x0, #VCPU_HOST_DEBUG_STATE
bl __save_debug
1:
activate_traps
@@ -701,6 +704,8 @@ ENTRY(__kvm_vcpu_run)
bl __restore_fpsimd
skip_debug_state x3, 1f
+ ldr x3, [x0, #VCPU_DEBUG_PTR]
+ kern_hyp_va x3
bl __restore_debug
1:
restore_guest_32bit_state
@@ -721,6 +726,8 @@ __kvm_vcpu_return:
bl __save_sysregs
skip_debug_state x3, 1f
+ ldr x3, [x0, #VCPU_DEBUG_PTR]
+ kern_hyp_va x3
bl __save_debug
1:
save_guest_32bit_state
@@ -743,6 +750,7 @@ __kvm_vcpu_return:
// already been saved. Note that we nuke the whole 64bit word.
// If we ever add more flags, we'll have to be more careful...
str xzr, [x0, #VCPU_DEBUG_FLAGS]
+ add x3, x0, #VCPU_HOST_DEBUG_STATE
bl __restore_debug
1:
restore_host_regs
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c370b40..3267b96 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -173,14 +173,14 @@ static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu,
/*
* We want to avoid world-switching all the DBG registers all the
* time:
- *
+ *
* - If we've touched any debug register, it is likely that we're
* going to touch more of them. It then makes sense to disable the
* traps and start doing the save/restore dance
* - If debug is active (DBG_MDSCR_KDE or DBG_MDSCR_MDE set), it is
* then mandatory to save/restore the registers, as the guest
* depends on them.
- *
+ *
* For this, we use a DIRTY bit, indicating the guest has modified the
* debug registers, used as follow:
*
@@ -211,6 +211,187 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
return true;
}
+/*
+ * reg_to_dbg/dbg_to_reg - simple masking for 32bit access
+ */
+static inline unsigned long reg_to_dbg(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p)
+{
+ unsigned long val = *vcpu_reg(vcpu, p->Rt);
+ vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
+ if (p->is_32bit)
+ val &= 0xffffffffUL;
+
+ return val;
+}
+
+static inline void dbg_to_reg(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p, unsigned long val)
+{
+ if (p->is_32bit)
+ val &= 0xffffffffUL;
+ *vcpu_reg(vcpu, p->Rt) = val;
+}
+
+static inline bool trap_bvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ if (p->is_write) {
+ vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] =
+ reg_to_dbg(vcpu, p);
+ } else {
+ dbg_to_reg(vcpu, p,
+ vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg]);
+ }
+
+ return true;
+}
+
+static int set_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_bvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] = rd->val;
+}
+
+static inline bool trap_bcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ if (p->is_write) {
+ vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg] =
+ reg_to_dbg(vcpu, p);
+ } else {
+ dbg_to_reg(vcpu, p,
+ vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg]);
+ }
+
+ return true;
+}
+
+static int set_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_bcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg] = rd->val;
+}
+
+static inline bool trap_wvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ if (p->is_write) {
+ vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg] =
+ reg_to_dbg(vcpu, p);
+ } else {
+ dbg_to_reg(vcpu, p,
+ vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg]);
+ }
+
+ return true;
+}
+
+static int set_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_wvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg] = rd->val;
+}
+
+static inline bool trap_wcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ if (p->is_write) {
+ vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg] =
+ reg_to_dbg(vcpu, p);
+ } else {
+ dbg_to_reg(vcpu, p,
+ vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg]);
+ }
+
+ trace_trap_reg(__func__, rd->reg, p->is_write,
+ vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg]);
+
+ return true;
+}
+
+static int set_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static inline void reset_wcr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg] = rd->val;
+}
+
static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 amair;
@@ -240,16 +421,16 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
#define DBG_BCR_BVR_WCR_WVR_EL1(n) \
/* DBGBVRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b100), \
- trap_debug_regs, reset_val, (DBGBVR0_EL1 + (n)), 0 }, \
+ trap_bvr, reset_bvr, n, 0, get_bvr, set_bvr }, \
/* DBGBCRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b101), \
- trap_debug_regs, reset_val, (DBGBCR0_EL1 + (n)), 0 }, \
+ trap_bcr, reset_bcr, n, 0, get_bcr, set_bcr }, \
/* DBGWVRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b110), \
- trap_debug_regs, reset_val, (DBGWVR0_EL1 + (n)), 0 }, \
+ trap_wvr, reset_wvr, n, 0, get_wvr, set_wvr }, \
/* DBGWCRn_EL1 */ \
{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b111), \
- trap_debug_regs, reset_val, (DBGWCR0_EL1 + (n)), 0 }
+ trap_wcr, reset_wcr, n, 0, get_wcr, set_wcr }
/*
* Architected system registers.
@@ -516,28 +697,51 @@ static bool trap_debug32(struct kvm_vcpu *vcpu,
return true;
}
-#define DBG_BCR_BVR_WCR_WVR(n) \
- /* DBGBVRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_debug32, \
- NULL, (cp14_DBGBVR0 + (n) * 2) }, \
- /* DBGBCRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_debug32, \
- NULL, (cp14_DBGBCR0 + (n) * 2) }, \
- /* DBGWVRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_debug32, \
- NULL, (cp14_DBGWVR0 + (n) * 2) }, \
- /* DBGWCRn */ \
- { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_debug32, \
- NULL, (cp14_DBGWCR0 + (n) * 2) }
-
-#define DBGBXVR(n) \
- { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_debug32, \
- NULL, cp14_DBGBXVR0 + n * 2 }
+/* AArch32 debug register mappings
+ *
+ * AArch32 DBGBVRn is mapped to DBGBVRn_EL1[31:0]
+ * AArch32 DBGBXVRn is mapped to DBGBVRn_EL1[63:32]
+ *
+ * All control registers and watchpoint value registers are mapped to
+ * the lower 32 bits of their AArch64 equivalents. We share the trap
+ * handlers with the above AArch64 code which checks what mode the
+ * system is in.
+ */
+
+static inline bool trap_xvr(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *p,
+ const struct sys_reg_desc *rd)
+{
+ if (p->is_write) {
+ u64 val = vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
+ val &= 0xffffffffUL;
+ val |= reg_to_dbg(vcpu, p) << 32;
+ vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] = val;
+ } else {
+ dbg_to_reg(vcpu, p,
+ vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] >> 32);
+ }
+
+ return true;
+}
+
+#define DBG_BCR_BVR_WCR_WVR(n) \
+ /* DBGBVRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_bvr, NULL, n }, \
+ /* DBGBCRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_bcr, NULL, n }, \
+ /* DBGWVRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_wvr, NULL, n }, \
+ /* DBGWCRn */ \
+ { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_wcr, NULL, n }
+
+#define DBGBXVR(n) \
+ { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_xvr, NULL, n }
/*
* Trapped cp14 registers. We generally ignore most of the external
* debug, on the principle that they don't really make sense to a
- * guest. Revisit this one day, whould this principle change.
+ * guest. Revisit this one day, would this principle change.
*/
static const struct sys_reg_desc cp14_regs[] = {
/* DBGIDR */
@@ -1288,6 +1492,29 @@ static int demux_c15_set(u64 id, void __user *uaddr)
}
}
+/*
+ * Access functions for vcpu_debug_state.
+ */
+#if 0
+static int debug_set64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
+ if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+
+static int debug_get64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
+ if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
+ return -EFAULT;
+ return 0;
+}
+#endif
+
int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct sys_reg_desc *r;
@@ -1303,6 +1530,9 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
if (!r)
return get_invariant_sys_reg(reg->id, uaddr);
+ if (r->get)
+ return (r->get)(vcpu, r, reg, uaddr);
+
return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
}
@@ -1321,6 +1551,9 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
if (!r)
return set_invariant_sys_reg(reg->id, uaddr);
+ if (r->set)
+ return (r->set)(vcpu, r, reg, uaddr);
+
return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
}
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index d411e25..9265e7d 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -55,6 +55,12 @@ struct sys_reg_desc {
/* Value (usually reset value) */
u64 val;
+
+ /* Get/Set functions, fallback if NULL */
+ int (*get)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr);
+ int (*set)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr);
};
static inline void print_sys_reg_instr(const struct sys_reg_params *p)
--
2.4.5
On Wed, Jul 01, 2015 at 07:29:00PM +0100, Alex Benn?e wrote:
> This introduces a level of indirection for the debug registers. Instead
> of using the sys_regs[] directly we store registers in a structure in
> the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
> guest context.
>
> This also entails updating the sys_regs code to access this new
> structure. New access function have been added for each set of debug
> registers. The generic functions are still used for the few registers
> stored in the main context.
>
> New access function pointers have been added to the sys_reg_desc
> structure to support the GET/SET_ONE_REG ioctl operations.
Why is this needed?
>
> Signed-off-by: Alex Benn?e <[email protected]>
>
> ---
> v6:
> - fix up some ws issues
> - correct clobber info
> - re-word commentary in kvm_host.h
> - fix endian access issues for aarch32 fields
> - revert all KVM_GET/SET_ONE_REG to 64bit (also see ABI update)
> v7
> - new fn kvm_arm_reset_debug_ptr(), stubbed for arm
> - split trap fns into bcr,bvr,bcr,wvr and wxvr
> - add set/get fns to sys_regs_desc
> - reg_to_dbg/dbg_to_reg helpers for 32bit support
> ---
> arch/arm/include/asm/kvm_host.h | 2 +-
> arch/arm/kvm/arm.c | 2 +
> arch/arm64/include/asm/kvm_asm.h | 24 ++--
> arch/arm64/include/asm/kvm_host.h | 17 ++-
> arch/arm64/kernel/asm-offsets.c | 6 +
> arch/arm64/kvm/debug.c | 9 ++
> arch/arm64/kvm/hyp.S | 24 ++--
> arch/arm64/kvm/sys_regs.c | 281 ++++++++++++++++++++++++++++++++++----
> arch/arm64/kvm/sys_regs.h | 6 +
> 9 files changed, 321 insertions(+), 50 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 746c0c69..f42759b 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -239,5 +239,5 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
> static inline void kvm_arm_init_debug(void) {}
> static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
> static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
> -
> +static inline void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) {}
seems like a strange decision to nuke the whitespace for adding this
function ;)
> #endif /* __ARM_KVM_HOST_H__ */
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index af60e6f..525473f 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -279,6 +279,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
> /* Set up the timer */
> kvm_timer_vcpu_init(vcpu);
>
> + kvm_arm_reset_debug_ptr(vcpu);
> +
> return 0;
> }
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index d6b507e..e997404 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -46,24 +46,16 @@
> #define CNTKCTL_EL1 20 /* Timer Control Register (EL1) */
> #define PAR_EL1 21 /* Physical Address Register */
> #define MDSCR_EL1 22 /* Monitor Debug System Control Register */
> -#define DBGBCR0_EL1 23 /* Debug Breakpoint Control Registers (0-15) */
> -#define DBGBCR15_EL1 38
> -#define DBGBVR0_EL1 39 /* Debug Breakpoint Value Registers (0-15) */
> -#define DBGBVR15_EL1 54
> -#define DBGWCR0_EL1 55 /* Debug Watchpoint Control Registers (0-15) */
> -#define DBGWCR15_EL1 70
> -#define DBGWVR0_EL1 71 /* Debug Watchpoint Value Registers (0-15) */
> -#define DBGWVR15_EL1 86
> -#define MDCCINT_EL1 87 /* Monitor Debug Comms Channel Interrupt Enable Reg */
> +#define MDCCINT_EL1 23 /* Monitor Debug Comms Channel Interrupt Enable Reg */
>
> /* 32bit specific registers. Keep them at the end of the range */
> -#define DACR32_EL2 88 /* Domain Access Control Register */
> -#define IFSR32_EL2 89 /* Instruction Fault Status Register */
> -#define FPEXC32_EL2 90 /* Floating-Point Exception Control Register */
> -#define DBGVCR32_EL2 91 /* Debug Vector Catch Register */
> -#define TEECR32_EL1 92 /* ThumbEE Configuration Register */
> -#define TEEHBR32_EL1 93 /* ThumbEE Handler Base Register */
> -#define NR_SYS_REGS 94
> +#define DACR32_EL2 24 /* Domain Access Control Register */
> +#define IFSR32_EL2 25 /* Instruction Fault Status Register */
> +#define FPEXC32_EL2 26 /* Floating-Point Exception Control Register */
> +#define DBGVCR32_EL2 27 /* Debug Vector Catch Register */
> +#define TEECR32_EL1 28 /* ThumbEE Configuration Register */
> +#define TEEHBR32_EL1 29 /* ThumbEE Handler Base Register */
> +#define NR_SYS_REGS 30
>
> /* 32bit mapping */
> #define c0_MPIDR (MPIDR_EL1 * 2) /* MultiProcessor ID Register */
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index e2db6a6..461d288 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -108,11 +108,25 @@ struct kvm_vcpu_arch {
> /* Exception Information */
> struct kvm_vcpu_fault_info fault;
>
> - /* Debug state */
> + /* Guest debug state */
> u64 debug_flags;
>
> + /*
> + * We maintain more than a single set of debug registers to support
> + * debugging the guest from the host and to maintain separate host and
> + * guest state during world switches. vcpu_debug_state are the debug
> + * registers of the vcpu as the guest sees them. host_debug_state are
> + * the host registers which are saved and restored during world switches.
> + *
> + * debug_ptr points to the set of debug registers that should be loaded
> + * onto the hardware when running the guest.
> + */
> + struct kvm_guest_debug_arch *debug_ptr;
> + struct kvm_guest_debug_arch vcpu_debug_state;
> +
> /* Pointer to host CPU context */
> kvm_cpu_context_t *host_cpu_context;
> + struct kvm_guest_debug_arch host_debug_state;
>
> /* VGIC state */
> struct vgic_cpu vgic_cpu;
> @@ -265,5 +279,6 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
> void kvm_arm_init_debug(void);
> void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
> void kvm_arm_clear_debug(struct kvm_vcpu *vcpu);
> +void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu);
>
> #endif /* __ARM64_KVM_HOST_H__ */
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index dfb25a2..1a8e97c 100644
> --- a/arch/arm64/kernel/asm-offsets.c
> +++ b/arch/arm64/kernel/asm-offsets.c
> @@ -116,10 +116,16 @@ int main(void)
> DEFINE(VCPU_FAR_EL2, offsetof(struct kvm_vcpu, arch.fault.far_el2));
> DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
> DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags));
> + DEFINE(VCPU_DEBUG_PTR, offsetof(struct kvm_vcpu, arch.debug_ptr));
> + DEFINE(DEBUG_BCR, offsetof(struct kvm_guest_debug_arch, dbg_bcr));
> + DEFINE(DEBUG_BVR, offsetof(struct kvm_guest_debug_arch, dbg_bvr));
> + DEFINE(DEBUG_WCR, offsetof(struct kvm_guest_debug_arch, dbg_wcr));
> + DEFINE(DEBUG_WVR, offsetof(struct kvm_guest_debug_arch, dbg_wvr));
> DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2));
> DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2));
> DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines));
> DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context));
> + DEFINE(VCPU_HOST_DEBUG_STATE, offsetof(struct kvm_vcpu, arch.host_debug_state));
> DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl));
> DEFINE(VCPU_TIMER_CNTV_CVAL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_cval));
> DEFINE(KVM_TIMER_CNTVOFF, offsetof(struct kvm, arch.timer.cntvoff));
> diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
> index d439eb8..ffefb97 100644
> --- a/arch/arm64/kvm/debug.c
> +++ b/arch/arm64/kvm/debug.c
> @@ -67,6 +67,15 @@ void kvm_arm_init_debug(void)
> }
>
> /**
> + * kvm_arm_reset_debug_ptr - set the debug registers to be the guests
nit: guest's, but I actually prefer:
kvm_arm_reset_debug_ptr - reset the debug ptr to point to the vcpu state
> + */
> +
> +void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
> +{
> + vcpu->arch.debug_ptr = &vcpu->arch.vcpu_debug_state;
> +}
> +
> +/**
> * kvm_arm_setup_debug - set up debug related stuff
> *
> * @vcpu: the vcpu pointer
> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
> index 77c08df..f56e93f 100644
> --- a/arch/arm64/kvm/hyp.S
> +++ b/arch/arm64/kvm/hyp.S
> @@ -600,6 +600,7 @@ __restore_sysregs:
> /* Save debug state */
> __save_debug:
> // x2: ptr to CPU context
> + // x3: ptr to debug reg struct
> // x4/x5/x6-22/x24-26: trashed
>
> mrs x26, id_aa64dfr0_el1
> @@ -610,15 +611,15 @@ __save_debug:
> sub w25, w26, w25 // How many WPs to skip
>
> mov x5, x24
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> + add x4, x3, #DEBUG_BCR
> save_debug dbgbcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> + add x4, x3, #DEBUG_BVR
> save_debug dbgbvr
>
> mov x5, x25
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> + add x4, x3, #DEBUG_WCR
> save_debug dbgwcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> + add x4, x3, #DEBUG_WVR
> save_debug dbgwvr
>
> mrs x21, mdccint_el1
> @@ -628,6 +629,7 @@ __save_debug:
> /* Restore debug state */
> __restore_debug:
> // x2: ptr to CPU context
> + // x3: ptr to debug reg struct
> // x4/x5/x6-22/x24-26: trashed
>
> mrs x26, id_aa64dfr0_el1
> @@ -638,15 +640,15 @@ __restore_debug:
> sub w25, w26, w25 // How many WPs to skip
>
> mov x5, x24
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> + add x4, x3, #DEBUG_BCR
> restore_debug dbgbcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> + add x4, x3, #DEBUG_BVR
> restore_debug dbgbvr
>
> mov x5, x25
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> + add x4, x3, #DEBUG_WCR
> restore_debug dbgwcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> + add x4, x3, #DEBUG_WVR
> restore_debug dbgwvr
>
> ldr x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
> @@ -686,6 +688,7 @@ ENTRY(__kvm_vcpu_run)
> bl __save_sysregs
>
> compute_debug_state 1f
> + add x3, x0, #VCPU_HOST_DEBUG_STATE
> bl __save_debug
> 1:
> activate_traps
> @@ -701,6 +704,8 @@ ENTRY(__kvm_vcpu_run)
> bl __restore_fpsimd
>
> skip_debug_state x3, 1f
> + ldr x3, [x0, #VCPU_DEBUG_PTR]
> + kern_hyp_va x3
> bl __restore_debug
> 1:
> restore_guest_32bit_state
> @@ -721,6 +726,8 @@ __kvm_vcpu_return:
> bl __save_sysregs
>
> skip_debug_state x3, 1f
> + ldr x3, [x0, #VCPU_DEBUG_PTR]
> + kern_hyp_va x3
> bl __save_debug
> 1:
> save_guest_32bit_state
> @@ -743,6 +750,7 @@ __kvm_vcpu_return:
> // already been saved. Note that we nuke the whole 64bit word.
> // If we ever add more flags, we'll have to be more careful...
> str xzr, [x0, #VCPU_DEBUG_FLAGS]
> + add x3, x0, #VCPU_HOST_DEBUG_STATE
> bl __restore_debug
> 1:
> restore_host_regs
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index c370b40..3267b96 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -173,14 +173,14 @@ static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu,
> /*
> * We want to avoid world-switching all the DBG registers all the
> * time:
> - *
> + *
> * - If we've touched any debug register, it is likely that we're
> * going to touch more of them. It then makes sense to disable the
> * traps and start doing the save/restore dance
> * - If debug is active (DBG_MDSCR_KDE or DBG_MDSCR_MDE set), it is
> * then mandatory to save/restore the registers, as the guest
> * depends on them.
> - *
> + *
stray whitespace changes?
> * For this, we use a DIRTY bit, indicating the guest has modified the
> * debug registers, used as follow:
> *
> @@ -211,6 +211,187 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +/*
> + * reg_to_dbg/dbg_to_reg - simple masking for 32bit access
> + */
> +static inline unsigned long reg_to_dbg(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p)
> +{
> + unsigned long val = *vcpu_reg(vcpu, p->Rt);
> + vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
> + if (p->is_32bit)
> + val &= 0xffffffffUL;
> +
> + return val;
> +}
> +
> +static inline void dbg_to_reg(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p, unsigned long val)
> +{
> + if (p->is_32bit)
> + val &= 0xffffffffUL;
> + *vcpu_reg(vcpu, p->Rt) = val;
> +}
> +
> +static inline bool trap_bvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg]);
> + }
> +
> + return true;
> +}
> +
> +static int set_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_bvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] = rd->val;
> +}
> +
> +static inline bool trap_bcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg]);
> + }
> +
> + return true;
> +}
> +
> +static int set_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_bcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg] = rd->val;
> +}
> +
> +static inline bool trap_wvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg]);
> + }
> +
> + return true;
> +}
> +
> +static int set_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_wvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg] = rd->val;
> +}
> +
> +static inline bool trap_wcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg]);
> + }
> +
> + trace_trap_reg(__func__, rd->reg, p->is_write,
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg]);
> +
> + return true;
> +}
> +
> +static int set_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_wcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg] = rd->val;
> +}
> +
> static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 amair;
> @@ -240,16 +421,16 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> #define DBG_BCR_BVR_WCR_WVR_EL1(n) \
> /* DBGBVRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b100), \
> - trap_debug_regs, reset_val, (DBGBVR0_EL1 + (n)), 0 }, \
> + trap_bvr, reset_bvr, n, 0, get_bvr, set_bvr }, \
> /* DBGBCRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b101), \
> - trap_debug_regs, reset_val, (DBGBCR0_EL1 + (n)), 0 }, \
> + trap_bcr, reset_bcr, n, 0, get_bcr, set_bcr }, \
> /* DBGWVRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b110), \
> - trap_debug_regs, reset_val, (DBGWVR0_EL1 + (n)), 0 }, \
> + trap_wvr, reset_wvr, n, 0, get_wvr, set_wvr }, \
> /* DBGWCRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b111), \
> - trap_debug_regs, reset_val, (DBGWCR0_EL1 + (n)), 0 }
> + trap_wcr, reset_wcr, n, 0, get_wcr, set_wcr }
>
> /*
> * Architected system registers.
> @@ -516,28 +697,51 @@ static bool trap_debug32(struct kvm_vcpu *vcpu,
> return true;
> }
>
> -#define DBG_BCR_BVR_WCR_WVR(n) \
> - /* DBGBVRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_debug32, \
> - NULL, (cp14_DBGBVR0 + (n) * 2) }, \
> - /* DBGBCRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_debug32, \
> - NULL, (cp14_DBGBCR0 + (n) * 2) }, \
> - /* DBGWVRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_debug32, \
> - NULL, (cp14_DBGWVR0 + (n) * 2) }, \
> - /* DBGWCRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_debug32, \
> - NULL, (cp14_DBGWCR0 + (n) * 2) }
> -
> -#define DBGBXVR(n) \
> - { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_debug32, \
> - NULL, cp14_DBGBXVR0 + n * 2 }
> +/* AArch32 debug register mappings
> + *
> + * AArch32 DBGBVRn is mapped to DBGBVRn_EL1[31:0]
> + * AArch32 DBGBXVRn is mapped to DBGBVRn_EL1[63:32]
> + *
> + * All control registers and watchpoint value registers are mapped to
> + * the lower 32 bits of their AArch64 equivalents. We share the trap
> + * handlers with the above AArch64 code which checks what mode the
> + * system is in.
> + */
> +
> +static inline bool trap_xvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + u64 val = vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
> + val &= 0xffffffffUL;
> + val |= reg_to_dbg(vcpu, p) << 32;
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] = val;
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] >> 32);
> + }
> +
> + return true;
> +}
> +
> +#define DBG_BCR_BVR_WCR_WVR(n) \
> + /* DBGBVRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_bvr, NULL, n }, \
> + /* DBGBCRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_bcr, NULL, n }, \
> + /* DBGWVRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_wvr, NULL, n }, \
> + /* DBGWCRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_wcr, NULL, n }
> +
> +#define DBGBXVR(n) \
> + { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_xvr, NULL, n }
>
> /*
> * Trapped cp14 registers. We generally ignore most of the external
> * debug, on the principle that they don't really make sense to a
> - * guest. Revisit this one day, whould this principle change.
> + * guest. Revisit this one day, would this principle change.
> */
> static const struct sys_reg_desc cp14_regs[] = {
> /* DBGIDR */
> @@ -1288,6 +1492,29 @@ static int demux_c15_set(u64 id, void __user *uaddr)
> }
> }
>
> +/*
> + * Access functions for vcpu_debug_state.
> + */
> +#if 0
> +static int debug_set64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int debug_get64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +#endif
> +
what is this ifdef'ed block of code doing here?
> int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> {
> const struct sys_reg_desc *r;
> @@ -1303,6 +1530,9 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
> if (!r)
> return get_invariant_sys_reg(reg->id, uaddr);
>
> + if (r->get)
> + return (r->get)(vcpu, r, reg, uaddr);
> +
> return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
> }
>
> @@ -1321,6 +1551,9 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
> if (!r)
> return set_invariant_sys_reg(reg->id, uaddr);
>
> + if (r->set)
> + return (r->set)(vcpu, r, reg, uaddr);
> +
> return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
> }
>
> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> index d411e25..9265e7d 100644
> --- a/arch/arm64/kvm/sys_regs.h
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -55,6 +55,12 @@ struct sys_reg_desc {
>
> /* Value (usually reset value) */
> u64 val;
> +
> + /* Get/Set functions, fallback if NULL */
Is this only meant for usersapce access or when should one use these?
> + int (*get)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr);
> + int (*set)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr);
> };
>
> static inline void print_sys_reg_instr(const struct sys_reg_params *p)
> --
> 2.4.5
>
Christoffer Dall <[email protected]> writes:
> On Wed, Jul 01, 2015 at 07:29:00PM +0100, Alex Bennée wrote:
>> This introduces a level of indirection for the debug registers. Instead
>> of using the sys_regs[] directly we store registers in a structure in
>> the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
>> guest context.
>>
>> This also entails updating the sys_regs code to access this new
>> structure. New access function have been added for each set of debug
>> registers. The generic functions are still used for the few registers
>> stored in the main context.
>>
>> New access function pointers have been added to the sys_reg_desc
>> structure to support the GET/SET_ONE_REG ioctl operations.
>
> Why is this needed?
Previously I had a hacky:
if (r->access == trap_debug64)
return debug_get64(vcpu, r, reg, uaddr);
Which used the same offset information. Now we have a cleaner:
if (r->set)
return (r->set)(vcpu, r, reg, uaddr);
Which accesses the structure directly, as the trap functions do:
__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
return -EFAULT;
return 0;
<snip>
>> +#if 0
>> +static int debug_set64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr)
>> +{
>> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
>> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
>> + return -EFAULT;
>> + return 0;
>> +}
>> +
>> +static int debug_get64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr)
>> +{
>> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
>> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
>> + return -EFAULT;
>> + return 0;
>> +}
>> +#endif
>> +
>
> what is this ifdef'ed block of code doing here?
Oops. Yeah looks like I missed removing that after I finished the
re-factor. These where the old get/set functions I used.
>
>> int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
>> {
>> const struct sys_reg_desc *r;
>> @@ -1303,6 +1530,9 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
>> if (!r)
>> return get_invariant_sys_reg(reg->id, uaddr);
>>
>> + if (r->get)
>> + return (r->get)(vcpu, r, reg, uaddr);
>> +
>> return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
>> }
>>
>> @@ -1321,6 +1551,9 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
>> if (!r)
>> return set_invariant_sys_reg(reg->id, uaddr);
>>
>> + if (r->set)
>> + return (r->set)(vcpu, r, reg, uaddr);
>> +
>> return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
>> }
>>
>> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
>> index d411e25..9265e7d 100644
>> --- a/arch/arm64/kvm/sys_regs.h
>> +++ b/arch/arm64/kvm/sys_regs.h
>> @@ -55,6 +55,12 @@ struct sys_reg_desc {
>>
>> /* Value (usually reset value) */
>> u64 val;
>> +
>> + /* Get/Set functions, fallback if NULL */
>
> Is this only meant for usersapce access or when should one use these?
Yes for GET/SET
>
>> + int (*get)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr);
>> + int (*set)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>> + const struct kvm_one_reg *reg, void __user *uaddr);
>> };
>>
>> static inline void print_sys_reg_instr(const struct sys_reg_params *p)
>> --
>> 2.4.5
>>
--
Alex Bennée
On Wed, Jul 01, 2015 at 07:29:00PM +0100, Alex Benn?e wrote:
> This introduces a level of indirection for the debug registers. Instead
> of using the sys_regs[] directly we store registers in a structure in
> the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
> guest context.
>
> This also entails updating the sys_regs code to access this new
> structure. New access function have been added for each set of debug
> registers. The generic functions are still used for the few registers
> stored in the main context.
>
> New access function pointers have been added to the sys_reg_desc
> structure to support the GET/SET_ONE_REG ioctl operations.
>
> Signed-off-by: Alex Benn?e <[email protected]>
>
> ---
> v6:
> - fix up some ws issues
> - correct clobber info
> - re-word commentary in kvm_host.h
> - fix endian access issues for aarch32 fields
> - revert all KVM_GET/SET_ONE_REG to 64bit (also see ABI update)
> v7
> - new fn kvm_arm_reset_debug_ptr(), stubbed for arm
> - split trap fns into bcr,bvr,bcr,wvr and wxvr
> - add set/get fns to sys_regs_desc
> - reg_to_dbg/dbg_to_reg helpers for 32bit support
> ---
> arch/arm/include/asm/kvm_host.h | 2 +-
> arch/arm/kvm/arm.c | 2 +
> arch/arm64/include/asm/kvm_asm.h | 24 ++--
> arch/arm64/include/asm/kvm_host.h | 17 ++-
> arch/arm64/kernel/asm-offsets.c | 6 +
> arch/arm64/kvm/debug.c | 9 ++
> arch/arm64/kvm/hyp.S | 24 ++--
> arch/arm64/kvm/sys_regs.c | 281 ++++++++++++++++++++++++++++++++++----
> arch/arm64/kvm/sys_regs.h | 6 +
> 9 files changed, 321 insertions(+), 50 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 746c0c69..f42759b 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -239,5 +239,5 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
> static inline void kvm_arm_init_debug(void) {}
> static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
> static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
> -
> +static inline void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) {}
> #endif /* __ARM_KVM_HOST_H__ */
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index af60e6f..525473f 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -279,6 +279,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
> /* Set up the timer */
> kvm_timer_vcpu_init(vcpu);
>
> + kvm_arm_reset_debug_ptr(vcpu);
> +
> return 0;
> }
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index d6b507e..e997404 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -46,24 +46,16 @@
> #define CNTKCTL_EL1 20 /* Timer Control Register (EL1) */
> #define PAR_EL1 21 /* Physical Address Register */
> #define MDSCR_EL1 22 /* Monitor Debug System Control Register */
> -#define DBGBCR0_EL1 23 /* Debug Breakpoint Control Registers (0-15) */
> -#define DBGBCR15_EL1 38
> -#define DBGBVR0_EL1 39 /* Debug Breakpoint Value Registers (0-15) */
> -#define DBGBVR15_EL1 54
> -#define DBGWCR0_EL1 55 /* Debug Watchpoint Control Registers (0-15) */
> -#define DBGWCR15_EL1 70
> -#define DBGWVR0_EL1 71 /* Debug Watchpoint Value Registers (0-15) */
> -#define DBGWVR15_EL1 86
> -#define MDCCINT_EL1 87 /* Monitor Debug Comms Channel Interrupt Enable Reg */
> +#define MDCCINT_EL1 23 /* Monitor Debug Comms Channel Interrupt Enable Reg */
>
> /* 32bit specific registers. Keep them at the end of the range */
> -#define DACR32_EL2 88 /* Domain Access Control Register */
> -#define IFSR32_EL2 89 /* Instruction Fault Status Register */
> -#define FPEXC32_EL2 90 /* Floating-Point Exception Control Register */
> -#define DBGVCR32_EL2 91 /* Debug Vector Catch Register */
> -#define TEECR32_EL1 92 /* ThumbEE Configuration Register */
> -#define TEEHBR32_EL1 93 /* ThumbEE Handler Base Register */
> -#define NR_SYS_REGS 94
> +#define DACR32_EL2 24 /* Domain Access Control Register */
> +#define IFSR32_EL2 25 /* Instruction Fault Status Register */
> +#define FPEXC32_EL2 26 /* Floating-Point Exception Control Register */
> +#define DBGVCR32_EL2 27 /* Debug Vector Catch Register */
> +#define TEECR32_EL1 28 /* ThumbEE Configuration Register */
> +#define TEEHBR32_EL1 29 /* ThumbEE Handler Base Register */
> +#define NR_SYS_REGS 30
>
> /* 32bit mapping */
> #define c0_MPIDR (MPIDR_EL1 * 2) /* MultiProcessor ID Register */
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index e2db6a6..461d288 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -108,11 +108,25 @@ struct kvm_vcpu_arch {
> /* Exception Information */
> struct kvm_vcpu_fault_info fault;
>
> - /* Debug state */
> + /* Guest debug state */
> u64 debug_flags;
>
> + /*
> + * We maintain more than a single set of debug registers to support
> + * debugging the guest from the host and to maintain separate host and
> + * guest state during world switches. vcpu_debug_state are the debug
> + * registers of the vcpu as the guest sees them. host_debug_state are
> + * the host registers which are saved and restored during world switches.
> + *
> + * debug_ptr points to the set of debug registers that should be loaded
> + * onto the hardware when running the guest.
> + */
> + struct kvm_guest_debug_arch *debug_ptr;
> + struct kvm_guest_debug_arch vcpu_debug_state;
> +
> /* Pointer to host CPU context */
> kvm_cpu_context_t *host_cpu_context;
> + struct kvm_guest_debug_arch host_debug_state;
>
> /* VGIC state */
> struct vgic_cpu vgic_cpu;
> @@ -265,5 +279,6 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
> void kvm_arm_init_debug(void);
> void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
> void kvm_arm_clear_debug(struct kvm_vcpu *vcpu);
> +void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu);
>
> #endif /* __ARM64_KVM_HOST_H__ */
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index dfb25a2..1a8e97c 100644
> --- a/arch/arm64/kernel/asm-offsets.c
> +++ b/arch/arm64/kernel/asm-offsets.c
> @@ -116,10 +116,16 @@ int main(void)
> DEFINE(VCPU_FAR_EL2, offsetof(struct kvm_vcpu, arch.fault.far_el2));
> DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
> DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags));
> + DEFINE(VCPU_DEBUG_PTR, offsetof(struct kvm_vcpu, arch.debug_ptr));
> + DEFINE(DEBUG_BCR, offsetof(struct kvm_guest_debug_arch, dbg_bcr));
> + DEFINE(DEBUG_BVR, offsetof(struct kvm_guest_debug_arch, dbg_bvr));
> + DEFINE(DEBUG_WCR, offsetof(struct kvm_guest_debug_arch, dbg_wcr));
> + DEFINE(DEBUG_WVR, offsetof(struct kvm_guest_debug_arch, dbg_wvr));
> DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2));
> DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2));
> DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines));
> DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context));
> + DEFINE(VCPU_HOST_DEBUG_STATE, offsetof(struct kvm_vcpu, arch.host_debug_state));
> DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl));
> DEFINE(VCPU_TIMER_CNTV_CVAL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_cval));
> DEFINE(KVM_TIMER_CNTVOFF, offsetof(struct kvm, arch.timer.cntvoff));
> diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
> index d439eb8..ffefb97 100644
> --- a/arch/arm64/kvm/debug.c
> +++ b/arch/arm64/kvm/debug.c
> @@ -67,6 +67,15 @@ void kvm_arm_init_debug(void)
> }
>
> /**
> + * kvm_arm_reset_debug_ptr - set the debug registers to be the guests
> + */
> +
> +void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
> +{
> + vcpu->arch.debug_ptr = &vcpu->arch.vcpu_debug_state;
> +}
> +
> +/**
> * kvm_arm_setup_debug - set up debug related stuff
> *
> * @vcpu: the vcpu pointer
> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
> index 77c08df..f56e93f 100644
> --- a/arch/arm64/kvm/hyp.S
> +++ b/arch/arm64/kvm/hyp.S
> @@ -600,6 +600,7 @@ __restore_sysregs:
> /* Save debug state */
> __save_debug:
> // x2: ptr to CPU context
> + // x3: ptr to debug reg struct
> // x4/x5/x6-22/x24-26: trashed
>
> mrs x26, id_aa64dfr0_el1
> @@ -610,15 +611,15 @@ __save_debug:
> sub w25, w26, w25 // How many WPs to skip
>
> mov x5, x24
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> + add x4, x3, #DEBUG_BCR
> save_debug dbgbcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> + add x4, x3, #DEBUG_BVR
> save_debug dbgbvr
>
> mov x5, x25
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> + add x4, x3, #DEBUG_WCR
> save_debug dbgwcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> + add x4, x3, #DEBUG_WVR
> save_debug dbgwvr
>
> mrs x21, mdccint_el1
> @@ -628,6 +629,7 @@ __save_debug:
> /* Restore debug state */
> __restore_debug:
> // x2: ptr to CPU context
> + // x3: ptr to debug reg struct
> // x4/x5/x6-22/x24-26: trashed
>
> mrs x26, id_aa64dfr0_el1
> @@ -638,15 +640,15 @@ __restore_debug:
> sub w25, w26, w25 // How many WPs to skip
>
> mov x5, x24
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> + add x4, x3, #DEBUG_BCR
> restore_debug dbgbcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> + add x4, x3, #DEBUG_BVR
> restore_debug dbgbvr
>
> mov x5, x25
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> + add x4, x3, #DEBUG_WCR
> restore_debug dbgwcr
> - add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> + add x4, x3, #DEBUG_WVR
> restore_debug dbgwvr
>
> ldr x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
> @@ -686,6 +688,7 @@ ENTRY(__kvm_vcpu_run)
> bl __save_sysregs
>
> compute_debug_state 1f
> + add x3, x0, #VCPU_HOST_DEBUG_STATE
> bl __save_debug
> 1:
> activate_traps
> @@ -701,6 +704,8 @@ ENTRY(__kvm_vcpu_run)
> bl __restore_fpsimd
>
> skip_debug_state x3, 1f
> + ldr x3, [x0, #VCPU_DEBUG_PTR]
> + kern_hyp_va x3
> bl __restore_debug
> 1:
> restore_guest_32bit_state
> @@ -721,6 +726,8 @@ __kvm_vcpu_return:
> bl __save_sysregs
>
> skip_debug_state x3, 1f
> + ldr x3, [x0, #VCPU_DEBUG_PTR]
> + kern_hyp_va x3
> bl __save_debug
> 1:
> save_guest_32bit_state
> @@ -743,6 +750,7 @@ __kvm_vcpu_return:
> // already been saved. Note that we nuke the whole 64bit word.
> // If we ever add more flags, we'll have to be more careful...
> str xzr, [x0, #VCPU_DEBUG_FLAGS]
> + add x3, x0, #VCPU_HOST_DEBUG_STATE
> bl __restore_debug
> 1:
> restore_host_regs
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index c370b40..3267b96 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -173,14 +173,14 @@ static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu,
> /*
> * We want to avoid world-switching all the DBG registers all the
> * time:
> - *
> + *
> * - If we've touched any debug register, it is likely that we're
> * going to touch more of them. It then makes sense to disable the
> * traps and start doing the save/restore dance
> * - If debug is active (DBG_MDSCR_KDE or DBG_MDSCR_MDE set), it is
> * then mandatory to save/restore the registers, as the guest
> * depends on them.
> - *
> + *
> * For this, we use a DIRTY bit, indicating the guest has modified the
> * debug registers, used as follow:
> *
> @@ -211,6 +211,187 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +/*
> + * reg_to_dbg/dbg_to_reg - simple masking for 32bit access
important side effect of setting debug dirty flag, note that here.
> + */
> +static inline unsigned long reg_to_dbg(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p)
> +{
> + unsigned long val = *vcpu_reg(vcpu, p->Rt);
> + vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
> + if (p->is_32bit)
> + val &= 0xffffffffUL;
> +
> + return val;
> +}
> +
> +static inline void dbg_to_reg(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p, unsigned long val)
> +{
> + if (p->is_32bit)
> + val &= 0xffffffffUL;
doesn't this potentially zero out the most-significant bits of a 64-bit
value if the access is done in 32-bit mode?
Is this really what you want?
> + *vcpu_reg(vcpu, p->Rt) = val;
> +}
> +
> +static inline bool trap_bvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg]);
> + }
> +
> + return true;
> +}
> +
> +static int set_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_bvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] = rd->val;
> +}
> +
> +static inline bool trap_bcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg]);
> + }
> +
> + return true;
> +}
> +
> +static int set_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_bcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg] = rd->val;
> +}
> +
> +static inline bool trap_wvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg]);
> + }
> +
> + return true;
> +}
> +
> +static int set_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_wvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg] = rd->val;
> +}
> +
> +static inline bool trap_wcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg] =
> + reg_to_dbg(vcpu, p);
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg]);
> + }
> +
> + trace_trap_reg(__func__, rd->reg, p->is_write,
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg]);
> +
> + return true;
> +}
> +
> +static int set_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int get_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static inline void reset_wcr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg] = rd->val;
> +}
> +
> static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 amair;
> @@ -240,16 +421,16 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> #define DBG_BCR_BVR_WCR_WVR_EL1(n) \
> /* DBGBVRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b100), \
> - trap_debug_regs, reset_val, (DBGBVR0_EL1 + (n)), 0 }, \
> + trap_bvr, reset_bvr, n, 0, get_bvr, set_bvr }, \
> /* DBGBCRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b101), \
> - trap_debug_regs, reset_val, (DBGBCR0_EL1 + (n)), 0 }, \
> + trap_bcr, reset_bcr, n, 0, get_bcr, set_bcr }, \
> /* DBGWVRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b110), \
> - trap_debug_regs, reset_val, (DBGWVR0_EL1 + (n)), 0 }, \
> + trap_wvr, reset_wvr, n, 0, get_wvr, set_wvr }, \
> /* DBGWCRn_EL1 */ \
> { Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b111), \
> - trap_debug_regs, reset_val, (DBGWCR0_EL1 + (n)), 0 }
> + trap_wcr, reset_wcr, n, 0, get_wcr, set_wcr }
>
> /*
> * Architected system registers.
> @@ -516,28 +697,51 @@ static bool trap_debug32(struct kvm_vcpu *vcpu,
> return true;
> }
>
> -#define DBG_BCR_BVR_WCR_WVR(n) \
> - /* DBGBVRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_debug32, \
> - NULL, (cp14_DBGBVR0 + (n) * 2) }, \
> - /* DBGBCRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_debug32, \
> - NULL, (cp14_DBGBCR0 + (n) * 2) }, \
> - /* DBGWVRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_debug32, \
> - NULL, (cp14_DBGWVR0 + (n) * 2) }, \
> - /* DBGWCRn */ \
> - { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_debug32, \
> - NULL, (cp14_DBGWCR0 + (n) * 2) }
> -
> -#define DBGBXVR(n) \
> - { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_debug32, \
> - NULL, cp14_DBGBXVR0 + n * 2 }
> +/* AArch32 debug register mappings
> + *
> + * AArch32 DBGBVRn is mapped to DBGBVRn_EL1[31:0]
> + * AArch32 DBGBXVRn is mapped to DBGBVRn_EL1[63:32]
> + *
> + * All control registers and watchpoint value registers are mapped to
> + * the lower 32 bits of their AArch64 equivalents. We share the trap
> + * handlers with the above AArch64 code which checks what mode the
> + * system is in.
> + */
> +
> +static inline bool trap_xvr(struct kvm_vcpu *vcpu,
> + const struct sys_reg_params *p,
> + const struct sys_reg_desc *rd)
> +{
> + if (p->is_write) {
> + u64 val = vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
> + val &= 0xffffffffUL;
> + val |= reg_to_dbg(vcpu, p) << 32;
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] = val;
> + } else {
> + dbg_to_reg(vcpu, p,
> + vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg] >> 32);
> + }
> +
> + return true;
> +}
> +
> +#define DBG_BCR_BVR_WCR_WVR(n) \
> + /* DBGBVRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 4), trap_bvr, NULL, n }, \
> + /* DBGBCRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 5), trap_bcr, NULL, n }, \
> + /* DBGWVRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 6), trap_wvr, NULL, n }, \
> + /* DBGWCRn */ \
> + { Op1( 0), CRn( 0), CRm((n)), Op2( 7), trap_wcr, NULL, n }
> +
> +#define DBGBXVR(n) \
> + { Op1( 0), CRn( 1), CRm((n)), Op2( 1), trap_xvr, NULL, n }
>
> /*
> * Trapped cp14 registers. We generally ignore most of the external
> * debug, on the principle that they don't really make sense to a
> - * guest. Revisit this one day, whould this principle change.
> + * guest. Revisit this one day, would this principle change.
> */
> static const struct sys_reg_desc cp14_regs[] = {
> /* DBGIDR */
> @@ -1288,6 +1492,29 @@ static int demux_c15_set(u64 id, void __user *uaddr)
> }
> }
>
> +/*
> + * Access functions for vcpu_debug_state.
> + */
> +#if 0
> +static int debug_set64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int debug_get64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr)
> +{
> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> + return -EFAULT;
> + return 0;
> +}
> +#endif
> +
> int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> {
> const struct sys_reg_desc *r;
> @@ -1303,6 +1530,9 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
> if (!r)
> return get_invariant_sys_reg(reg->id, uaddr);
>
> + if (r->get)
> + return (r->get)(vcpu, r, reg, uaddr);
> +
> return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
> }
>
> @@ -1321,6 +1551,9 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
> if (!r)
> return set_invariant_sys_reg(reg->id, uaddr);
>
> + if (r->set)
> + return (r->set)(vcpu, r, reg, uaddr);
> +
> return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
> }
>
> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> index d411e25..9265e7d 100644
> --- a/arch/arm64/kvm/sys_regs.h
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -55,6 +55,12 @@ struct sys_reg_desc {
>
> /* Value (usually reset value) */
> u64 val;
> +
> + /* Get/Set functions, fallback if NULL */
> + int (*get)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr);
> + int (*set)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> + const struct kvm_one_reg *reg, void __user *uaddr);
can you call these get_user and set_user instead?
> };
>
> static inline void print_sys_reg_instr(const struct sys_reg_params *p)
> --
> 2.4.5
>
On Fri, Jul 03, 2015 at 08:14:52AM +0100, Alex Benn?e wrote:
>
> Christoffer Dall <[email protected]> writes:
>
> > On Wed, Jul 01, 2015 at 07:29:00PM +0100, Alex Benn?e wrote:
> >> This introduces a level of indirection for the debug registers. Instead
> >> of using the sys_regs[] directly we store registers in a structure in
> >> the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the
> >> guest context.
> >>
> >> This also entails updating the sys_regs code to access this new
> >> structure. New access function have been added for each set of debug
> >> registers. The generic functions are still used for the few registers
> >> stored in the main context.
> >>
> >> New access function pointers have been added to the sys_reg_desc
> >> structure to support the GET/SET_ONE_REG ioctl operations.
> >
> > Why is this needed?
>
> Previously I had a hacky:
>
> if (r->access == trap_debug64)
> return debug_get64(vcpu, r, reg, uaddr);
>
> Which used the same offset information. Now we have a cleaner:
>
> if (r->set)
> return (r->set)(vcpu, r, reg, uaddr);
>
> Which accesses the structure directly, as the trap functions do:
>
> __u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];
> if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> return -EFAULT;
> return 0;
I get it now, had to take another look at sys_regs.c.
I think this commit message needs a littel tweaking saying "Because we
no longer give the sys_regs offset for the sys_reg_desc->reg field, but
instead the index into a debug-specific struct, the generic user-space
access code no longer works, and we are therefore forced to add specific
user_set/get functions for these registers."
At least it was hard for me to understand the rationale without this,
and I think it would be good to have for someone doing git blame later.
>
> <snip>
> >> +#if 0
> >> +static int debug_set64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> >> + const struct kvm_one_reg *reg, void __user *uaddr)
> >> +{
> >> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> >> + if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> >> + return -EFAULT;
> >> + return 0;
> >> +}
> >> +
> >> +static int debug_get64(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
> >> + const struct kvm_one_reg *reg, void __user *uaddr)
> >> +{
> >> + __u64 *r = (__u64 *) ((void * )&vcpu->arch.vcpu_debug_state + rd->reg);
> >> + if (copy_to_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)
> >> + return -EFAULT;
> >> + return 0;
> >> +}
> >> +#endif
> >> +
> >
> > what is this ifdef'ed block of code doing here?
>
> Oops. Yeah looks like I missed removing that after I finished the
> re-factor. These where the old get/set functions I used.
>
> >
> >> int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> >> {
> >> const struct sys_reg_desc *r;
> >> @@ -1303,6 +1530,9 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
> >> if (!r)
> >> return get_invariant_sys_reg(reg->id, uaddr);
> >>
> >> + if (r->get)
> >> + return (r->get)(vcpu, r, reg, uaddr);
> >> +
> >> return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
> >> }
> >>
> >> @@ -1321,6 +1551,9 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
> >> if (!r)
> >> return set_invariant_sys_reg(reg->id, uaddr);
> >>
> >> + if (r->set)
> >> + return (r->set)(vcpu, r, reg, uaddr);
> >> +
> >> return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
> >> }
> >>
> >> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> >> index d411e25..9265e7d 100644
> >> --- a/arch/arm64/kvm/sys_regs.h
> >> +++ b/arch/arm64/kvm/sys_regs.h
> >> @@ -55,6 +55,12 @@ struct sys_reg_desc {
> >>
> >> /* Value (usually reset value) */
> >> u64 val;
> >> +
> >> + /* Get/Set functions, fallback if NULL */
> >
> > Is this only meant for usersapce access or when should one use these?
>
> Yes for GET/SET
>
ok, see other mail for potential rename to get_user / set_user if you
like the idea.
Thanks,
-Christoffer