Intel SDM 17.2.4 (Debug Control Register (DR7)) says: "The processor clears the
GD flag upon entering to the debug exception handler." This sentence may be
misunderstood as if it happens only on #DB due to debug-register protection,
but it happens regardless to the cause of the #DB.
Fix the behavior.
Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 2 --
arch/x86/kvm/x86.c | 6 ++++++
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 04fa1b8..82d39f9 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5176,9 +5176,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
vcpu->run->exit_reason = KVM_EXIT_DEBUG;
return 0;
} else {
- vcpu->arch.dr7 &= ~DR7_GD;
vcpu->arch.dr6 |= DR6_BD | DR6_RTM;
- vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
kvm_queue_exception(vcpu, DB_VECTOR);
return 1;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6857257..fb02371 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5935,6 +5935,12 @@ static int inject_pending_event(struct kvm_vcpu *vcpu, bool req_int_win)
__kvm_set_rflags(vcpu, kvm_get_rflags(vcpu) |
X86_EFLAGS_RF);
+ if (vcpu->arch.exception.nr == DB_VECTOR &&
+ (vcpu->arch.dr7 & DR7_GD)) {
+ vcpu->arch.dr7 &= ~DR7_GD;
+ kvm_update_dr7(vcpu);
+ }
+
kvm_x86_ops->queue_exception(vcpu, vcpu->arch.exception.nr,
vcpu->arch.exception.has_error_code,
vcpu->arch.exception.error_code,
--
1.9.1
--
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