Avi Kivity wrote:
On 12/08/2010 01:27 PM, Andre Przywara wrote:
The handling of CR8 writes in KVM is currently somewhat cumbersome.
This patch makes it look like the other CR register handlers
and fixes a possible issue in VMX, where the RIP would be incremented
despite an injected #GP.
unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu)
@@ -4104,7 +4098,7 @@ static int emulator_set_cr(int cr, unsigned long val, struct kvm_vcpu *vcpu)
res = kvm_set_cr4(vcpu, mk_cr_64(kvm_read_cr4(vcpu), val));
break;
case 8:
- res = __kvm_set_cr8(vcpu, val& 0xfUL);
+ res = kvm_set_cr8(vcpu, val);
break;
default:
vcpu_printf(vcpu, "%s: unexpected cr %u\n", __func__, cr);
Why drop the mask?
Because it is checked in kvm_set_cr8 itself. If it is wrong, the caller
should get a #GP as described in the manual. By masking this out we
would never deliver the #GP to the guest.
Regards,
Andre.
--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448-3567-12
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