On 20/11/19 23:31, Liran Alon wrote:
> vmcs->apic_access_page is simply a token that the hypervisor puts into
> the PFN of a 4KB EPTE (or PTE if using shadow-paging) that triggers
> APIC-access VMExit or APIC virtualization logic whenever a CPU running
> in VMX non-root mode read/write from/to this PFN.
>
> As every write either triggers an APIC-access VMExit or write is
> performed on vmcs->virtual_apic_page, the PFN pointed to by
> vmcs->apic_access_page should never actually be touched by CPU.
>
> Therefore, there is no need to mark vmcs02->apic_access_page as dirty
> after unpin it on L2->L1 emulated VMExit or when L1 exit VMX operation.
>
> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
> Reviewed-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
> Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx/nested.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 20692e442d13..2506f431d51e 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -257,7 +257,7 @@ static void free_nested(struct kvm_vcpu *vcpu)
> vmx->nested.cached_shadow_vmcs12 = NULL;
> /* Unpin physical memory we referred to in the vmcs02 */
> if (vmx->nested.apic_access_page) {
> - kvm_release_page_dirty(vmx->nested.apic_access_page);
> + kvm_release_page_clean(vmx->nested.apic_access_page);
> vmx->nested.apic_access_page = NULL;
> }
> kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map, true);
> @@ -2933,7 +2933,7 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
> * to it so we can release it later.
> */
> if (vmx->nested.apic_access_page) { /* shouldn't happen */
> - kvm_release_page_dirty(vmx->nested.apic_access_page);
> + kvm_release_page_clean(vmx->nested.apic_access_page);
> vmx->nested.apic_access_page = NULL;
> }
> page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->apic_access_addr);
> @@ -4126,7 +4126,7 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
>
> /* Unpin physical memory we referred to in vmcs02 */
> if (vmx->nested.apic_access_page) {
> - kvm_release_page_dirty(vmx->nested.apic_access_page);
> + kvm_release_page_clean(vmx->nested.apic_access_page);
> vmx->nested.apic_access_page = NULL;
> }
> kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map, true);
>
Queued, thanks.
Paolo
