[PATCH] KVM: x86/mmu: Release the pfn in handle_abnormal_pfn() error path

From: Fuad Tabba
Date: Fri Oct 21 2022 - 07:19:54 EST


Currently in case of error it returns without releasing the pfn
faulted in earlier.

Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---

Applies to 6.1-rc1. I think that kvm_release_pfn_clean() has been
replaced with kvm_mmu_release_fault() in development branches,
but the same issue is still there.
---
arch/x86/kvm/mmu/mmu.c | 3 ++-
arch/x86/kvm/mmu/paging_tmpl.h | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6f81539061d6..9adae837ccdd 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4250,7 +4250,7 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault

r = handle_abnormal_pfn(vcpu, fault, ACC_ALL);
if (r != RET_PF_CONTINUE)
- return r;
+ goto out_release;

r = RET_PF_RETRY;

@@ -4276,6 +4276,7 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
read_unlock(&vcpu->kvm->mmu_lock);
else
write_unlock(&vcpu->kvm->mmu_lock);
+out_release:
kvm_release_pfn_clean(fault->pfn);
return r;
}
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 5ab5f94dcb6f..4a1e4e460990 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -847,7 +847,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault

r = handle_abnormal_pfn(vcpu, fault, walker.pte_access);
if (r != RET_PF_CONTINUE)
- return r;
+ goto out_release;

/*
* Do not change pte_access if the pfn is a mmio page, otherwise
@@ -881,6 +881,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault

out_unlock:
write_unlock(&vcpu->kvm->mmu_lock);
+out_release:
kvm_release_pfn_clean(fault->pfn);
return r;
}

base-commit: 9abf2313adc1ca1b6180c508c25f22f9395cc780
--
2.38.0.135.g90850a2211-goog