[PATCH v13 47/85] KVM: x86/mmu: Put refcounted pages instead of blindly releasing pfns

Sean Christopherson
2024-10-10T18:26:32Z

Now that all x86 page fault paths precisely track refcounted pages, use
Use kvm_page_fault.refcounted_page to put references to struct page memory
when finishing page faults. This is a baby step towards eliminating
kvm_pfn_to_refcounted_page().

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a038cde74f0d..f9b7e3a7370f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4373,6 +4373,9 @@ static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu,
lockdep_assert_once(lockdep_is_held(&vcpu->kvm->mmu_lock) ||
r == RET_PF_RETRY);

+ if (!fault->refcounted_page)
+ return;
+
/*
* If the page that KVM got from the *primary MMU* is writable, and KVM
* installed or reused a SPTE, mark the page/folio dirty. Note, this
@@ -4384,9 +4387,9 @@ static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu,
* folio dirty if KVM could locklessly make the SPTE writable.
*/
if (!fault->map_writable || r == RET_PF_RETRY)
- kvm_release_pfn_clean(fault->pfn);
+ kvm_release_page_clean(fault->refcounted_page);
else
- kvm_release_pfn_dirty(fault->pfn);
+ kvm_release_page_dirty(fault->refcounted_page);
}

static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu,
--
2.47.0.rc1.288.g06298d1525-goog