KVM: VMX: Do not skip the instruction if handle_dr injects a fault

If kvm_get_dr or kvm_set_dr reports that it raised a fault, we must not
advance the instruction pointer. Otherwise the exception will hit the
wrong instruction.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 31eb5776d854..9cc54842ae14 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5137,10 +5137,14 @@ static int handle_dr(struct kvm_vcpu *vcpu)
         reg = DEBUG_REG_ACCESS_REG(exit_qualification);
         if (exit_qualification & TYPE_MOV_FROM_DR) {
                 unsigned long val;
-                if (!kvm_get_dr(vcpu, dr, &val))
-                        kvm_register_write(vcpu, reg, val);
+
+                if (kvm_get_dr(vcpu, dr, &val))
+                        return 1;
+                kvm_register_write(vcpu, reg, val);
         } else
-                kvm_set_dr(vcpu, dr, vcpu->arch.regs[reg]);
+                if (kvm_set_dr(vcpu, dr, vcpu->arch.regs[reg]))
+                        return 1;
+
         skip_emulated_instruction(vcpu);
         return 1;
 }