From 391931dafc5f34009239e6bd371f91e1a40e8980 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 29 Apr 2022 21:00:21 +0000 Subject: [PATCH] KVM: Put the extra pfn reference when reusing a pfn in the gpc cache commit 3dddf65b4f4c451c345d34ae85bdf1791a746e49 upstream. 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@vger.kernel.org Signed-off-by: Sean Christopherson Message-Id: <20220429210025.3293691-5-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- virt/kvm/pfncache.c | 8 ++++++++ 1 file changed, 8 insertions(+) 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;