kvm_x86_ops.set_dr6 is only ever called with vcpu->arch.dr6 as the
second argument, and for both SVM and VMX the VMCB value is kept
synchronized with vcpu->arch.dr6 on #DB; we can therefore remove the
read accessor.
For the write accessor we can avoid the retpoline penalty on Intel
by accepting a NULL value and just skipping the call in that case.
Suggested-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 -
arch/x86/kvm/svm/svm.c | 6 ------
arch/x86/kvm/vmx/vmx.c | 11 -----------
arch/x86/kvm/x86.c | 8 +++-----
4 files changed, 3 insertions(+), 23 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 90840593cd6c..e218d907ba46 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1100,7 +1100,6 @@ struct kvm_x86_ops {
void (*set_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
void (*get_gdt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
void (*set_gdt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
- u64 (*get_dr6)(struct kvm_vcpu *vcpu);
void (*set_dr6)(struct kvm_vcpu *vcpu, unsigned long value);
void (*sync_dirty_debug_regs)(struct kvm_vcpu *vcpu);
void (*set_dr7)(struct kvm_vcpu *vcpu, unsigned long value);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 6b65c75b6816..d8bc1b78a3c6 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1652,11 +1652,6 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd)
mark_dirty(svm->vmcb, VMCB_ASID);
}
-static u64 svm_get_dr6(struct kvm_vcpu *vcpu)
-{
- return vcpu->arch.dr6;
-}
-
static void svm_set_dr6(struct kvm_vcpu *vcpu, unsigned long value)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -3996,7 +3991,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.set_idt = svm_set_idt,
.get_gdt = svm_get_gdt,
.set_gdt = svm_set_gdt,
- .get_dr6 = svm_get_dr6,
.set_dr6 = svm_set_dr6,
.set_dr7 = svm_set_dr7,
.sync_dirty_debug_regs = svm_sync_dirty_debug_regs,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index fce11f2c4c55..82042b7028a9 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5023,15 +5023,6 @@ static int handle_dr(struct kvm_vcpu *vcpu)
return kvm_skip_emulated_instruction(vcpu);
}
-static u64 vmx_get_dr6(struct kvm_vcpu *vcpu)
-{
- return vcpu->arch.dr6;
-}
-
-static void vmx_set_dr6(struct kvm_vcpu *vcpu, unsigned long val)
-{
-}
-
static void vmx_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
{
get_debugreg(vcpu->arch.db[0], 0);
@@ -7812,8 +7803,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
.set_idt = vmx_set_idt,
.get_gdt = vmx_get_gdt,
.set_gdt = vmx_set_gdt,
- .get_dr6 = vmx_get_dr6,
- .set_dr6 = vmx_set_dr6,
.set_dr7 = vmx_set_dr7,
.sync_dirty_debug_regs = vmx_sync_dirty_debug_regs,
.cache_reg = vmx_cache_reg,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8ec356ac1e6e..0ba83748cd53 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1069,7 +1069,8 @@ static void kvm_update_dr0123(struct kvm_vcpu *vcpu)
static void kvm_update_dr6(struct kvm_vcpu *vcpu)
{
- if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) &&
+ kvm_x86_ops.set_dr6)
kvm_x86_ops.set_dr6(vcpu, vcpu->arch.dr6);
}
@@ -1148,10 +1149,7 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
case 4:
/* fall through */
case 6:
- if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
- *val = vcpu->arch.dr6;
- else
- *val = kvm_x86_ops.get_dr6(vcpu);
+ *val = vcpu->arch.dr6;
break;
case 5:
/* fall through */
--
2.18.2
