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: Peter Xu <peterx@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0dea9f1..8c247bc 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -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);

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c2c6335..bb5a527 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -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;
                }
        }

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d786c7d..109115c 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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,
-                                 unsigned long payload)
+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;
                }