Commit 4d5523cf authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: x86: fix DR6 delivery for various cases of #DB injection 



Go through kvm_queue_exception_p so that the payload is correctly delivered
through the exit qualification, and add a kvm_update_dr6 call to
kvm_deliver_exception_payload that is needed on AMD.

Reported-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b9b2782c

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -1449,6 +1449,7 @@ bool kvm_rdpmc(struct kvm_vcpu *vcpu); 


void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr);

void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);

void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr, unsigned long payload);

void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr);

void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);

void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault);

arch/x86/kvm/vmx/vmx.c

+2 −6
Original line number Diff line number Diff line
@@ -4677,12 +4677,10 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) 
		dr6 = vmcs_readl(EXIT_QUALIFICATION);

		if (!(vcpu->guest_debug &

		      (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))) {

			vcpu->arch.dr6 &= ~DR_TRAP_BITS;

			vcpu->arch.dr6 |= dr6 | DR6_RTM;

			if (is_icebp(intr_info))

				WARN_ON(!skip_emulated_instruction(vcpu));



			kvm_queue_exception(vcpu, DB_VECTOR);

			kvm_queue_exception_p(vcpu, DB_VECTOR, dr6);

			return 1;

		}

		kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1;
@@ -4936,9 +4934,7 @@ static int handle_dr(struct kvm_vcpu *vcpu) 
			vcpu->run->exit_reason = KVM_EXIT_DEBUG;

			return 0;

		} else {

			vcpu->arch.dr6 &= ~DR_TRAP_BITS;

			vcpu->arch.dr6 |= DR6_BD | DR6_RTM;

			kvm_queue_exception(vcpu, DB_VECTOR);

			kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BD);

			return 1;

		}

	}

arch/x86/kvm/x86.c

+6 −5
Original line number Diff line number Diff line
@@ -104,6 +104,7 @@ static u64 __read_mostly cr4_reserved_bits = CR4_RESERVED_BITS; 
                                    KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK)



static void update_cr8_intercept(struct kvm_vcpu *vcpu);

static void kvm_update_dr6(struct kvm_vcpu *vcpu);

static void process_nmi(struct kvm_vcpu *vcpu);

static void enter_smm(struct kvm_vcpu *vcpu);

static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags);
@@ -473,6 +474,7 @@ void kvm_deliver_exception_payload(struct kvm_vcpu *vcpu) 
		 * breakpoint), it is reserved and must be zero in DR6.

		 */

		vcpu->arch.dr6 &= ~BIT(12);

		kvm_update_dr6(vcpu);

		break;

	case PF_VECTOR:

		vcpu->arch.cr2 = payload;
@@ -572,11 +574,12 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr) 
}

EXPORT_SYMBOL_GPL(kvm_requeue_exception);



static void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr,

void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr,

			   unsigned long payload)

{

	kvm_multiple_exception(vcpu, nr, false, 0, true, payload, false);

}

EXPORT_SYMBOL_GPL(kvm_queue_exception_p);



static void kvm_queue_exception_e_p(struct kvm_vcpu *vcpu, unsigned nr,

				    u32 error_code, unsigned long payload)
@@ -6719,9 +6722,7 @@ static bool kvm_vcpu_check_breakpoint(struct kvm_vcpu *vcpu, int *r) 
					   vcpu->arch.db);



		if (dr6 != 0) {

			vcpu->arch.dr6 &= ~DR_TRAP_BITS;

			vcpu->arch.dr6 |= dr6 | DR6_RTM;

			kvm_queue_exception(vcpu, DB_VECTOR);

			kvm_queue_exception_p(vcpu, DB_VECTOR, dr6);

			*r = 1;

			return true;

		}