From: David Stevens <stevensd@chromium.org>
To: Marc Zyngier <maz@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>
Cc: James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Will Deacon <will@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, David Stevens <stevensd@chromium.org>
Subject: [PATCH v5 4/4] KVM: mmu: remove over-aggressive warnings
Date: Mon, 29 Nov 2021 12:43:17 +0900 [thread overview]
Message-ID: <20211129034317.2964790-5-stevensd@google.com> (raw)
In-Reply-To: <20211129034317.2964790-1-stevensd@google.com>
From: David Stevens <stevensd@chromium.org>
Remove two warnings that require ref counts for pages to be non-zero, as
mapped pfns from follow_pfn may not have an initialized ref count.
Signed-off-by: David Stevens <stevensd@chromium.org>
---
arch/x86/kvm/mmu/mmu.c | 7 -------
virt/kvm/kvm_main.c | 2 +-
2 files changed, 1 insertion(+), 8 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0626395ff1d9..7c4c7fededf0 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -621,13 +621,6 @@ static int mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
pfn = spte_to_pfn(old_spte);
- /*
- * KVM does not hold the refcount of the page used by
- * kvm mmu, before reclaiming the page, we should
- * unmap it from mmu first.
- */
- WARN_ON(!kvm_is_reserved_pfn(pfn) && !page_count(pfn_to_page(pfn)));
-
if (is_accessed_spte(old_spte))
kvm_set_pfn_accessed(pfn);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 16a8a71f20bf..d81edcb3e107 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -170,7 +170,7 @@ bool kvm_is_zone_device_pfn(kvm_pfn_t pfn)
* the device has been pinned, e.g. by get_user_pages(). WARN if the
* page_count() is zero to help detect bad usage of this helper.
*/
- if (!pfn_valid(pfn) || WARN_ON_ONCE(!page_count(pfn_to_page(pfn))))
+ if (!pfn_valid(pfn) || !page_count(pfn_to_page(pfn)))
return false;
return is_zone_device_page(pfn_to_page(pfn));
--
2.34.0.rc2.393.gf8c9666880-goog
next prev parent reply other threads:[~2021-11-29 3:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 3:43 [PATCH v5 0/4] KVM: allow mapping non-refcounted pages David Stevens
2021-11-29 3:43 ` [PATCH v5 1/4] KVM: mmu: introduce new gfn_to_pfn_page functions David Stevens
2021-12-30 19:26 ` Sean Christopherson
2021-11-29 3:43 ` [PATCH v5 2/4] KVM: x86/mmu: use gfn_to_pfn_page David Stevens
2021-12-30 19:30 ` Sean Christopherson
2021-11-29 3:43 ` [PATCH v5 3/4] KVM: arm64/mmu: " David Stevens
2021-12-30 19:45 ` Sean Christopherson
2021-11-29 3:43 ` David Stevens [this message]
2021-12-30 19:22 ` [PATCH v5 4/4] KVM: mmu: remove over-aggressive warnings Sean Christopherson
2022-01-05 7:14 ` David Stevens
2022-01-05 19:02 ` Sean Christopherson
2022-01-05 19:19 ` Sean Christopherson
2022-01-06 2:42 ` David Stevens
2022-01-06 17:38 ` Sean Christopherson
2022-01-07 2:21 ` David Stevens
2022-01-07 16:31 ` Sean Christopherson
2022-01-07 16:46 ` Sean Christopherson
2022-01-10 23:47 ` David Stevens
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