Hi Vitaly,
+
+static inline void svm_hv_update_vp_id(struct vmcb *vmcb,
+ struct kvm_vcpu *vcpu)
+{
+ struct hv_enlightenments *hve =
+ (struct hv_enlightenments *)vmcb->control.reserved_sw;
+
+ if (hve->hv_vp_id != to_hv_vcpu(vcpu)->vp_index) {
+ hve->hv_vp_id = to_hv_vcpu(vcpu)->vp_index;
+ vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
+ }
This blows up in testing when no Hyper-V context was created on a vCPU,
e.g. when running KVM selftests (to_hv_vcpu(vcpu) is NULL when no
Hyper-V emulation features were requested on a vCPU but
svm_hv_update_vp_id() is called unconditionally by svm_vcpu_run()).
I'll be sending a patch to fix the immediate issue but I was wondering
why we need to call svm_hv_update_vp_id() from svm_vcpu_run() as VP
index is unlikely to change; we can probably just call it from
kvm_hv_set_msr() instead.
Thanks a lot for catching this.
I think you are right, updating at kvm_hv_set_msr() makes sense. I was
following the vmx logic where it also sets the vp_id in vmx_vcpu_run. But it
calls a wrapper "kvm_hv_get_vpindex" which actually checks if hv_vcpu is not
null before the assignment. I should have used that instead, my mistake.
I will look a bit more into it and send out a patch for vmx and svm
after little
more investigation.
Thanks,
Vineeth
