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

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Message-ID: <20240726235234.228822-47-seanjc@google.com>
Date: Fri, 26 Jul 2024 16:51:55 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>, 
	Oliver Upton <oliver.upton@...ux.dev>, Tianrui Zhao <zhaotianrui@...ngson.cn>, 
	Bibo Mao <maobibo@...ngson.cn>, Huacai Chen <chenhuacai@...nel.org>, 
	Michael Ellerman <mpe@...erman.id.au>, Anup Patel <anup@...infault.org>, 
	Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, 
	Albert Ou <aou@...s.berkeley.edu>, Christian Borntraeger <borntraeger@...ux.ibm.com>, 
	Janosch Frank <frankja@...ux.ibm.com>, Claudio Imbrenda <imbrenda@...ux.ibm.com>, 
	Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, loongarch@...ts.linux.dev, linux-mips@...r.kernel.org, 
	linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org, 
	linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	David Matlack <dmatlack@...gle.com>, David Stevens <stevensd@...omium.org>
Subject: [PATCH v12 46/84] KVM: x86/mmu: Put refcounted pages instead of
 blindly releasing pfns

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@...gle.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 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