Re: [PATCH 4.19 043/190] KVM: hyperv: define VP assist page helpers

On Fri 2019-09-13 14:04:58, Greg Kroah-Hartman wrote:

[ Upstream commit 72bbf9358c3676bd89dc4bd8fb0b1f2a11c288fc ]

The state related to the VP assist page is still managed by the LAPIC code in the pv_eoi field.

I don't get it.

+bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu) +{

• if (!(vcpu->arch.hyperv.hv_vapic & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE))

• return false;
  

• return vcpu->arch.pv_eoi.msr_val & KVM_MSR_ENABLED;

+} +EXPORT_SYMBOL_GPL(kvm_hv_assist_page_enabled);

+bool kvm_hv_get_assist_page(struct kvm_vcpu *vcpu,

• 	    struct hv_vp_assist_page *assist_page)
  

+{

• if (!kvm_hv_assist_page_enabled(vcpu))

• return false;
  

• return !kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.pv_eoi.data,

• 		      assist_page, sizeof(*assist_page));
  

+} +EXPORT_SYMBOL_GPL(kvm_hv_get_assist_page);

This adds two functions, but not their users. What bug is it fixing? I don't see any users in the next patch, either.

Pavel