Re: [PATCH v4 11/11] KVM: x86: First attempt at converting nested virtual APIC page to gpc

On 20.11.2021 18.21, David Woodhouse wrote:

On Sat, 2021-11-20 at 17:48 +0200, Mika Penttilä wrote:

quoted

quoted

@@ -9785,6 +9787,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
        local_irq_disable();
        vcpu->mode = IN_GUEST_MODE;
    
+     /*
+      * If the guest requires direct access to mapped L1 pages, check
+      * the caches are valid. Will raise KVM_REQ_GET_NESTED_STATE_PAGES
+      * to go and revalidate them, if necessary.
+      */
+     if (is_guest_mode(vcpu) && kvm_x86_ops.nested_ops->check_guest_maps)
+             kvm_x86_ops.nested_ops->check_guest_maps(vcpu);

But KVM_REQ_GET_NESTED_STATE_PAGES is not check until next
vcpu_enter_guest() entry ?

Sure, but that's why this call to ->check_guest_maps() comes just a few
lines *before* the 'if (kvm_cpu_exit_request(vcpu))' that will bounce
us back out so that we go through vcpu_enter_guest() from the start
again?

Yes, I had forgotten that...

Thanks,
Mika