As we trap all debug register accesses, we do not need to switch real
DR6 at all. Clean up update_exception_bitmap at this chance, too.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 23 ++++++-----------------
1 files changed, 6 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 834a8eb..75f1785 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -579,17 +579,12 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
{
u32 eb;
- eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR)
- | (1u << NM_VECTOR);
- /*
- * Unconditionally intercept #DB so we can maintain dr6 without
- * reading it every exit.
- */
- eb |= 1u << DB_VECTOR;
- if (vcpu->guest_debug & KVM_GUESTDBG_ENABLE) {
- if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
- eb |= 1u << BP_VECTOR;
- }
+ eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR) |
+ (1u << NM_VECTOR) | (1u << DB_VECTOR);
+ if ((vcpu->guest_debug &
+ (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)) ==
+ (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP))
+ eb |= 1u << BP_VECTOR;
if (to_vmx(vcpu)->rmode.vm86_active)
eb = ~0;
if (enable_ept)
@@ -3781,9 +3776,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
*/
vmcs_writel(HOST_CR0, read_cr0());
- if (vcpu->arch.switch_db_regs)
- set_debugreg(vcpu->arch.dr6, 6);
-
asm(
/* Store host registers */
"push %%"R"dx; push %%"R"bp;"
@@ -3884,9 +3876,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
| (1 << VCPU_EXREG_PDPTR));
vcpu->arch.regs_dirty = 0;
- if (vcpu->arch.switch_db_regs)
- get_debugreg(vcpu->arch.dr6, 6);
-
vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
if (vmx->rmode.irq.pending)
fixup_rmode_irq(vmx);
--
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