On 5/4/2023 1:36 PM, Binbin Wu wrote:
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?
Agree although the issue happens in an uncommon case, I'll add some
description in changelog in following version, thanks!
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:
[...]
