Commit fe1911aa authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: nVMX: Use kvm_vcpu_map() to get/pin vmcs12's APIC-access page 

Use kvm_vcpu_map() to get/pin the backing for vmcs12's APIC-access page,
there's no reason it has to be restricted to 'struct page' backing.  The
APIC-access page actually doesn't need to be backed by anything, which is
ironically why it got left behind by the series which introduced
kvm_vcpu_map()[1]; the plan was to shove a dummy pfn into vmcs02[2], but
that code never got merged.

Switching the APIC-access page to kvm_vcpu_map() doesn't preclude using a
magic pfn in the future, and will allow a future patch to drop
kvm_vcpu_gpa_to_page().

[1] https://lore.kernel.org/all/1547026933-31226-1-git-send-email-karahmed@amazon.de
[2] https://lore.kernel.org/lkml/1543845551-4403-1-git-send-email-karahmed@amazon.de



Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-6-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8e1c6914

arch/x86/kvm/vmx/nested.c

+12 −27
Original line number Original line Diff line number Diff line
@@ -311,11 +311,12 @@ static void free_nested(struct kvm_vcpu *vcpu) 
	vmx->nested.cached_vmcs12 = NULL;

	vmx->nested.cached_vmcs12 = NULL;

	kfree(vmx->nested.cached_shadow_vmcs12);

	kfree(vmx->nested.cached_shadow_vmcs12);

	vmx->nested.cached_shadow_vmcs12 = NULL;

	vmx->nested.cached_shadow_vmcs12 = NULL;

	/* Unpin physical memory we referred to in the vmcs02 */

	/*

	if (vmx->nested.apic_access_page) {

	 * Unpin physical memory we referred to in the vmcs02.  The APIC access

		kvm_release_page_clean(vmx->nested.apic_access_page);

	 * page's backing page (yeah, confusing) shouldn't actually be accessed,

		vmx->nested.apic_access_page = NULL;

	 * and if it is written, the contents are irrelevant.

	}

	 */

	kvm_vcpu_unmap(vcpu, &vmx->nested.apic_access_page_map, false);

	kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map, true);

	kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map, true);

	kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map, true);

	kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map, true);

	vmx->nested.pi_desc = NULL;

	vmx->nested.pi_desc = NULL;
@@ -3164,8 +3165,6 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu) 
	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);

	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);

	struct vcpu_vmx *vmx = to_vmx(vcpu);

	struct vcpu_vmx *vmx = to_vmx(vcpu);

	struct kvm_host_map *map;

	struct kvm_host_map *map;

	struct page *page;

	u64 hpa;





	if (!vcpu->arch.pdptrs_from_userspace &&

	if (!vcpu->arch.pdptrs_from_userspace &&

	    !nested_cpu_has_ept(vmcs12) && is_pae_paging(vcpu)) {

	    !nested_cpu_has_ept(vmcs12) && is_pae_paging(vcpu)) {
@@ -3180,23 +3179,12 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu) 








	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {

	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {

		/*

		map = &vmx->nested.apic_access_page_map;

		 * Translate L1 physical address to host physical



		 * address for vmcs02. Keep the page pinned, so this

		if (!kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->apic_access_addr), map)) {

		 * physical address remains valid. We keep a reference

			vmcs_write64(APIC_ACCESS_ADDR, pfn_to_hpa(map->pfn));

		 * to it so we can release it later.

		 */

		if (vmx->nested.apic_access_page) { /* shouldn't happen */

			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);

		if (!is_error_page(page)) {

			vmx->nested.apic_access_page = page;

			hpa = page_to_phys(vmx->nested.apic_access_page);

			vmcs_write64(APIC_ACCESS_ADDR, hpa);

		} else {

		} else {

			pr_debug_ratelimited("%s: no backing 'struct page' for APIC-access address in vmcs12\n",

			pr_debug_ratelimited("%s: no backing for APIC-access address in vmcs12\n",

					     __func__);

					     __func__);

			vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;

			vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;

			vcpu->run->internal.suberror =

			vcpu->run->internal.suberror =
@@ -4632,10 +4620,7 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 vm_exit_reason, 
	}

	}





	/* Unpin physical memory we referred to in vmcs02 */

	/* Unpin physical memory we referred to in vmcs02 */

	if (vmx->nested.apic_access_page) {

	kvm_vcpu_unmap(vcpu, &vmx->nested.apic_access_page_map, false);

		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);

	kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map, true);

	kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map, true);

	kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map, true);

	vmx->nested.pi_desc = NULL;

	vmx->nested.pi_desc = NULL;

arch/x86/kvm/vmx/vmx.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -204,7 +204,7 @@ struct nested_vmx { 
	 * Guest pages referred to in the vmcs02 with host-physical

	 * Guest pages referred to in the vmcs02 with host-physical

	 * pointers, so we must keep them pinned while L2 runs.

	 * pointers, so we must keep them pinned while L2 runs.

	 */

	 */

	struct page *apic_access_page;

	struct kvm_host_map apic_access_page_map;

	struct kvm_host_map virtual_apic_map;

	struct kvm_host_map virtual_apic_map;

	struct kvm_host_map pi_desc_map;

	struct kvm_host_map pi_desc_map;