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Commit ae561ede authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini
Browse files

KVM: x86: DR0-DR3 are not clear on reset 



DR0-DR3 are not cleared as they should during reset and when they are set from
userspace.  It appears to be caused by c77fb5fe ("KVM: x86: Allow the guest
to run with dirty debug registers").

Force their reload on these situations.

Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427933438-12782-4-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 58d269d8

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -340,6 +340,7 @@ struct kvm_pmu { 
enum {

	KVM_DEBUGREG_BP_ENABLED = 1,

	KVM_DEBUGREG_WONT_EXIT = 2,

	KVM_DEBUGREG_RELOAD = 4,

};



struct kvm_vcpu_arch {

arch/x86/kvm/x86.c

+14 −0
Original line number Diff line number Diff line
@@ -801,6 +801,17 @@ unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu) 
}

EXPORT_SYMBOL_GPL(kvm_get_cr8);



static void kvm_update_dr0123(struct kvm_vcpu *vcpu)

{

	int i;



	if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {

		for (i = 0; i < KVM_NR_DB_REGS; i++)

			vcpu->arch.eff_db[i] = vcpu->arch.db[i];

		vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD;

	}

}



static void kvm_update_dr6(struct kvm_vcpu *vcpu)

{

	if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
@@ -3150,6 +3161,7 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu, 
		return -EINVAL;



	memcpy(vcpu->arch.db, dbgregs->db, sizeof(vcpu->arch.db));

	kvm_update_dr0123(vcpu);

	vcpu->arch.dr6 = dbgregs->dr6;

	kvm_update_dr6(vcpu);

	vcpu->arch.dr7 = dbgregs->dr7;
@@ -6323,6 +6335,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) 
		set_debugreg(vcpu->arch.eff_db[2], 2);

		set_debugreg(vcpu->arch.eff_db[3], 3);

		set_debugreg(vcpu->arch.dr6, 6);

		vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD;

	}



	trace_kvm_entry(vcpu->vcpu_id);
@@ -7104,6 +7117,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu) 
	kvm_clear_exception_queue(vcpu);



	memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));

	kvm_update_dr0123(vcpu);

	vcpu->arch.dr6 = DR6_INIT;

	kvm_update_dr6(vcpu);

	vcpu->arch.dr7 = DR7_FIXED_1;