On 5/4/2023 11:41 AM, Yang, Weijiang wrote:
On 4/28/2023 2:09 PM, Binbin Wu wrote:
On 4/21/2023 9:46 PM, Yang Weijiang wrote:
Add handling for Control Protection (#CP) exceptions(vector 21).
The new vector is introduced for Intel's Control-Flow Enforcement
Technology (CET) relevant violation cases.
See Intel's SDM for details.
[...]
-static int exception_class(int vector)
+static int exception_class(struct kvm_vcpu *vcpu, int vector)
{
switch (vector) {
case PF_VECTOR:
return EXCPT_PF;
+ case CP_VECTOR:
+ if (vcpu->arch.cr4_guest_rsvd_bits & X86_CR4_CET)
+ return EXCPT_BENIGN;
+ return EXCPT_CONTRIBUTORY;
By definition, #CP is Contributory.
Can you explain more about this change here which treats #CP as
EXCPT_BENIGN when CET is not enabled in guest?
I check the history of this patch, found maintainer modified the patch
due to some unit test issue in L1. You can check the
details here:
Re: [PATCH v15 04/14] KVM: x86: Add #CP support in guest exception
dispatch - Sean Christopherson (kernel.org)
<https://lore.kernel.org/all/YBsZwvwhshw+s7yQ@xxxxxxxxxx/>
OK, is it better to add the reason in changelog?
IIUC, a new contributory exception vector (if any) should be handled
similarly (i.e., treated as contributory conditionally) in the future,
right?
In current KVM code, there is suppose no #CP triggered in guest if
CET is not enalbed in guest, right?
Yes.
case DE_VECTOR:
case TS_VECTOR:
case NP_VECTOR:
[...]
