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KVM: VMX: Use __kvm_faultin_page() to get APIC access page/pfn

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Use __kvm_faultin_page() get the APIC access page so that KVM can
precisely release the refcounted page, i.e. to remove yet another user
of kvm_pfn_to_refcounted_page().  While the path isn't handling a guest
page fault, the semantics are effectively the same; KVM just happens to
be mapping the pfn into a VMCS field instead of a secondary MMU.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-52-seanjc@google.com>
This commit is contained in:
Sean Christopherson
2024-10-10 11:23:53 -07:00
committed by Paolo Bonzini
parent cb444acb69
commit 93091f0fc7
1 changed files with 9 additions and 4 deletions
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arch/x86/kvm/vmx/vmx.c
+9 -4
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@@ -6790,8 +6790,10 @@ void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu)
struct kvm *kvm = vcpu->kvm;
struct kvm_memslots *slots = kvm_memslots(kvm);
struct kvm_memory_slot *slot;
struct page *refcounted_page;
unsigned long mmu_seq;
kvm_pfn_t pfn;
bool writable;
/* Defer reload until vmcs01 is the current VMCS. */
if (is_guest_mode(vcpu)) {
@@ -6827,7 +6829,7 @@ void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu)
* controls the APIC-access page memslot, and only deletes the memslot
* if APICv is permanently inhibited, i.e. the memslot won't reappear.
*/
pfn = gfn_to_pfn_memslot(slot, gfn);
pfn = __kvm_faultin_pfn(slot, gfn, FOLL_WRITE, &writable, &refcounted_page);
if (is_error_noslot_pfn(pfn))
return;
@@ -6838,10 +6840,13 @@ void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu)
vmcs_write64(APIC_ACCESS_ADDR, pfn_to_hpa(pfn));
/*
* Do not pin apic access page in memory, the MMU notifier
* will call us again if it is migrated or swapped out.
* Do not pin the APIC access page in memory so that it can be freely
* migrated, the MMU notifier will call us again if it is migrated or
* swapped out. KVM backs the memslot with anonymous memory, the pfn
* should always point at a refcounted page (if the pfn is valid).
*/
kvm_release_pfn_clean(pfn);
if (!WARN_ON_ONCE(!refcounted_page))
kvm_release_page_clean(refcounted_page);
/*
* No need for a manual TLB flush at this point, KVM has already done a