[PATCH v12 46/84] KVM: x86/mmu: Put refcounted pages instead of blindly releasing pfns

From: Sean Christopherson
Date: Fri Jul 26 2024 - 20:09:14 EST


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().

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
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 146e57c9c86d..3cdb1bd80823 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4326,6 +4326,9 @@ 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
@@ -4337,9 +4340,9 @@ 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,
--
2.46.0.rc1.232.g9752f9e123-goog