From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Sean Christopherson <seanjc@google.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Mingwei Zhang <mizhang@google.com>
Subject: [PATCH v3 1/8] Revert "KVM: Do not speculatively mark pfn cache valid to "fix" race"
Date: Fri, 29 Apr 2022 21:00:18 +0000 [thread overview]
Message-ID: <20220429210025.3293691-2-seanjc@google.com> (raw)
In-Reply-To: <20220429210025.3293691-1-seanjc@google.com>
This reverts commit 55111927df1cd140aa7b7ea3f33f524b87776381.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
virt/kvm/pfncache.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index 72eee096a7cd..71c84a43024c 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -81,8 +81,6 @@ bool kvm_gfn_to_pfn_cache_check(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
{
struct kvm_memslots *slots = kvm_memslots(kvm);
- lockdep_assert_held_read(&gpc->lock);
-
if ((gpa & ~PAGE_MASK) + len > PAGE_SIZE)
return false;
@@ -228,6 +226,11 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
if (!old_valid || old_uhva != gpc->uhva) {
void *new_khva = NULL;
+ /* Placeholders for "hva is valid but not yet mapped" */
+ gpc->pfn = KVM_PFN_ERR_FAULT;
+ gpc->khva = NULL;
+ gpc->valid = true;
+
new_pfn = hva_to_pfn_retry(kvm, gpc);
if (is_error_noslot_pfn(new_pfn)) {
ret = -EFAULT;
@@ -256,7 +259,7 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
gpc->pfn = KVM_PFN_ERR_FAULT;
gpc->khva = NULL;
} else {
- gpc->valid = true;
+ /* At this point, gpc->valid may already have been cleared */
gpc->pfn = new_pfn;
gpc->khva = new_khva;
}
--
2.36.0.464.gb9c8b46e94-goog
next prev parent reply other threads:[~2022-04-29 21:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-29 21:00 [PATCH v3 0/8] KVM: Fix mmu_notifier vs. pfncache vs. pfncache races Sean Christopherson
2022-04-29 21:00 ` Sean Christopherson [this message]
2022-04-29 21:00 ` [PATCH v3 2/8] Revert "KVM: Fix race between mmu_notifier invalidation and pfncache refresh" Sean Christopherson
2022-04-29 21:00 ` [PATCH v3 3/8] KVM: Drop unused @gpa param from gfn=>pfn cache's __release_gpc() helper Sean Christopherson
2022-04-29 21:00 ` [PATCH v3 4/8] KVM: Put the extra pfn reference when reusing a pfn in the gpc cache Sean Christopherson
2022-04-29 21:00 ` [PATCH v3 5/8] KVM: Do not incorporate page offset into gfn=>pfn cache user address Sean Christopherson
2022-04-29 21:00 ` [PATCH v3 6/8] KVM: Fully serialize gfn=>pfn cache refresh via mutex Sean Christopherson
2022-05-20 15:24 ` Paolo Bonzini
2022-05-20 15:53 ` Sean Christopherson
2022-05-20 16:01 ` Paolo Bonzini
2022-04-29 21:00 ` [PATCH v3 7/8] KVM: Fix multiple races in gfn=>pfn cache refresh Sean Christopherson
2022-04-29 21:00 ` [PATCH v3 8/8] KVM: Do not pin pages tracked by gfn=>pfn caches Sean Christopherson
2022-05-20 16:04 ` [PATCH v3 0/8] KVM: Fix mmu_notifier vs. pfncache vs. pfncache races Paolo Bonzini
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