This is a note to let you know that I've just added the patch titled
KVM: Put the extra pfn reference when reusing a pfn in the gpc cache
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-put-the-extra-pfn-reference-when-reusing-a-pfn-i.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4094f6c440d7010664567898b9271e38ef241895
Author: Sean Christopherson <seanjc@xxxxxxxxxx>
Date: Fri Apr 29 21:00:21 2022 +0000
KVM: Put the extra pfn reference when reusing a pfn in the gpc cache
[ Upstream commit 3dddf65b4f4c451c345d34ae85bdf1791a746e49 ]
Put the struct page reference to pfn acquired by hva_to_pfn() when the
old and new pfns for a gfn=>pfn cache match. The cache already has a
reference via the old/current pfn, and will only put one reference when
the cache is done with the pfn.
Fixes: 982ed0de4753 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Message-Id: <20220429210025.3293691-5-seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index e05a6a1b8eff..40cbe90d52e0 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -206,6 +206,14 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
if (gpc->usage & KVM_HOST_USES_PFN) {
if (new_pfn == old_pfn) {
+ /*
+ * Reuse the existing pfn and khva, but put the
+ * reference acquired hva_to_pfn_retry(); the
+ * cache still holds a reference to the pfn
+ * from the previous refresh.
+ */
+ gpc_release_pfn_and_khva(kvm, new_pfn, NULL);
+
new_khva = old_khva;
old_pfn = KVM_PFN_ERR_FAULT;
old_khva = NULL;
