[PATCH v2 5/5] KVM: x86: Do not clear RFLAGS.TF when a singlestep trap occurs.

[Kyle Huey]

The trap flag stays set until software clears it.

Signed-off-by: Kyle Huey <kh...@kylehuey.com>
---
 arch/x86/kvm/x86.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7b38c5e..dd6b41e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5414,17 +5414,16 @@ static void kvm_vcpu_check_singlestep(struct kvm_vcpu 
*vcpu, unsigned long rflag
                if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
                        kvm_run->debug.arch.dr6 = DR6_BS | DR6_FIXED_1 |
                                                  DR6_RTM;
                        kvm_run->debug.arch.pc = vcpu->arch.singlestep_rip;
                        kvm_run->debug.arch.exception = DB_VECTOR;
                        kvm_run->exit_reason = KVM_EXIT_DEBUG;
                        *r = EMULATE_USER_EXIT;
                } else {
-                       vcpu->arch.emulate_ctxt.eflags &= ~X86_EFLAGS_TF;
                        /*
                         * "Certain debug exceptions may clear bit 0-3.  The
                         * remaining contents of the DR6 register are never
                         * cleared by the processor".
                         */
                        vcpu->arch.dr6 &= ~15;
                        vcpu->arch.dr6 |= DR6_BS | DR6_RTM;
                        kvm_queue_exception(vcpu, DB_VECTOR);
-- 
2.10.2