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 <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
