From: Sean Christopherson <seanjc@google.com>
Date: Thu, 10 Oct 2024 18:23:42 +0000 (-0700)
Subject: KVM: x86/mmu: Add helper to "finish" handling a guest page fault
X-Git-Tag: v6.13-rc1~13^2~20^2~45
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=7103853952957cad58f957142c72bf7a4644b7a9;p=linux-2.6-block.git

KVM: x86/mmu: Add helper to "finish" handling a guest page fault

Add a helper to finish/complete the handling of a guest page, e.g. to
mark the pages accessed and put any held references.  In the near
future, this will allow improving the logic without having to copy+paste
changes into all page fault paths.  And in the less near future, will
allow sharing the "finish" API across all architectures.

No functional change intended.

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: <20241010182427.1434605-41-seanjc@google.com>
---

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 25aed61c6727..226648fd2150 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4364,6 +4364,12 @@ static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn,
 	return max_level;
 }
 
+static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu,
+				      struct kvm_page_fault *fault, int r)
+{
+	kvm_release_pfn_clean(fault->pfn);
+}
+
 static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu,
 				       struct kvm_page_fault *fault)
 {
@@ -4529,7 +4535,7 @@ static int kvm_mmu_faultin_pfn(struct kvm_vcpu *vcpu,
 	 * mmu_lock is acquired.
 	 */
 	if (mmu_invalidate_retry_gfn_unsafe(vcpu->kvm, fault->mmu_seq, fault->gfn)) {
-		kvm_release_pfn_clean(fault->pfn);
+		kvm_mmu_finish_page_fault(vcpu, fault, RET_PF_RETRY);
 		return RET_PF_RETRY;
 	}
 
@@ -4605,8 +4611,8 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	r = direct_map(vcpu, fault);
 
 out_unlock:
+	kvm_mmu_finish_page_fault(vcpu, fault, r);
 	write_unlock(&vcpu->kvm->mmu_lock);
-	kvm_release_pfn_clean(fault->pfn);
 	return r;
 }
 
@@ -4692,8 +4698,8 @@ static int kvm_tdp_mmu_page_fault(struct kvm_vcpu *vcpu,
 	r = kvm_tdp_mmu_map(vcpu, fault);
 
 out_unlock:
+	kvm_mmu_finish_page_fault(vcpu, fault, r);
 	read_unlock(&vcpu->kvm->mmu_lock);
-	kvm_release_pfn_clean(fault->pfn);
 	return r;
 }
 #endif
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index a476a5428017..35d0c3f1a789 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -836,8 +836,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	r = FNAME(fetch)(vcpu, fault, &walker);
 
 out_unlock:
+	kvm_mmu_finish_page_fault(vcpu, fault, r);
 	write_unlock(&vcpu->kvm->mmu_lock);
-	kvm_release_pfn_clean(fault->pfn);
 	return r;
 }