Re: [PATCH v3 07/13] KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page

Raslan, KarimAllah
2018-10-21T08:09:19Z

Sorry! please ignore this patch in favor of its RESEND. I realized that a few
lines from it leaked into another patch series. The "RESEND" should have this
fixed.

On Sun, 2018-10-21 at 00:22 +0200, KarimAllah Ahmed wrote:
> Use kvm_vcpu_map when mapping the virtual APIC page since using
> kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
> a "struct page".
>
> One additional semantic change is that the virtual host mapping lifecycle
> has changed a bit. It now has the same lifetime of the pinning of the
> virtual APIC page on the host side.
>
> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
> ---
> v1 -> v2:
> - Do not change the lifecycle of the mapping (pbonzini)
> - Use pfn_to_hpa instead of gfn_to_gpa
> ---
> arch/x86/kvm/vmx.c | 34 +++++++++++-----------------------
> 1 file changed, 11 insertions(+), 23 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 5b15ca2..83a5e95 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -845,9 +845,8 @@ struct nested_vmx {
> * pointers, so we must keep them pinned while L2 runs.
> */
> struct page *apic_access_page;
> - struct page *virtual_apic_page;
> + struct kvm_host_map virtual_apic_map;
> struct page *pi_desc_page;
> -
> struct kvm_host_map msr_bitmap_map;
>
> struct pi_desc *pi_desc;
> @@ -6152,11 +6151,12 @@ static void vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu)
>
> max_irr = find_last_bit((unsigned long *)vmx->nested.pi_desc->pir, 256);
> if (max_irr != 256) {
> - vapic_page = kmap(vmx->nested.virtual_apic_page);
> + vapic_page = vmx->nested.virtual_apic_map.hva;
> + if (!vapic_page)
> + return;
> +
> __kvm_apic_update_irr(vmx->nested.pi_desc->pir,
> vapic_page, &max_irr);
> - kunmap(vmx->nested.virtual_apic_page);
> -
> status = vmcs_read16(GUEST_INTR_STATUS);
> if ((u8)max_irr > ((u8)status & 0xff)) {
> status &= ~0xff;
> @@ -8468,10 +8468,7 @@ static void free_nested(struct vcpu_vmx *vmx)
> kvm_release_page_dirty(vmx->nested.apic_access_page);
> vmx->nested.apic_access_page = NULL;
> }
> - if (vmx->nested.virtual_apic_page) {
> - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> - vmx->nested.virtual_apic_page = NULL;
> - }
> + kvm_vcpu_unmap(&vmx->nested.virtual_apic_map);
> if (vmx->nested.pi_desc_page) {
> kunmap(vmx->nested.pi_desc_page);
> kvm_release_page_dirty(vmx->nested.pi_desc_page);
> @@ -11394,6 +11391,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
> {
> struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
> struct vcpu_vmx *vmx = to_vmx(vcpu);
> + struct kvm_host_map *map;
> struct page *page;
> u64 hpa;
>
> @@ -11426,11 +11424,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
> }
>
> if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) {
> - if (vmx->nested.virtual_apic_page) { /* shouldn't happen */
> - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> - vmx->nested.virtual_apic_page = NULL;
> - }
> - page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->virtual_apic_page_addr);
> + map = &vmx->nested.virtual_apic_map;
>
> /*
> * If translation failed, VM entry will fail because
> @@ -11445,11 +11439,8 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
> * control. But such a configuration is useless, so
> * let's keep the code simple.
> */
> - if (!is_error_page(page)) {
> - vmx->nested.virtual_apic_page = page;
> - hpa = page_to_phys(vmx->nested.virtual_apic_page);
> - vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, hpa);
> - }
> + if (!kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->virtual_apic_page_addr), map))
> + vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, pfn_to_hpa(map->pfn));
> }
>
> if (nested_cpu_has_posted_intr(vmcs12)) {
> @@ -13353,10 +13344,7 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
> kvm_release_page_dirty(vmx->nested.apic_access_page);
> vmx->nested.apic_access_page = NULL;
> }
> - if (vmx->nested.virtual_apic_page) {
> - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> - vmx->nested.virtual_apic_page = NULL;
> - }
> + kvm_vcpu_unmap(&vmx->nested.virtual_apic_map);
> if (vmx->nested.pi_desc_page) {
> kunmap(vmx->nested.pi_desc_page);
> kvm_release_page_dirty(vmx->nested.pi_desc_page);
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