From: David Stevens <stevensd@chromium.org>
To: Marc Zyngier <maz@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
Paul Mackerras <paulus@ozlabs.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Nick Piggin <npiggin@gmail.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>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Zhenyu Wang <zhenyuw@linux.intel.com>,
Zhi Wang <zhi.a.wang@intel.com>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
linux-mips@vger.kernel.org, kvm@vger.kernel.org,
kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
intel-gvt-dev@lists.freedesktop.org,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
David Stevens <stevensd@chromium.org>
Subject: [PATCH v2 5/5] KVM: mmu: remove over-aggressive warnings
Date: Fri, 25 Jun 2021 16:36:16 +0900 [thread overview]
Message-ID: <20210625073616.2184426-6-stevensd@google.com> (raw)
In-Reply-To: <20210625073616.2184426-1-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 dd5cb6e33591..0c47245594c6 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -607,13 +607,6 @@ static int mmu_spte_clear_track_bits(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 1de8702845ac..ce7126bab4b0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -168,7 +168,7 @@ 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));
--
2.32.0.93.g670b81a890-goog
prev parent reply other threads:[~2021-06-25 7:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 7:36 [PATCH v2 0/5] Remove uses of struct page from x86 and arm64 MMU David Stevens
2021-06-25 7:36 ` [PATCH v2 1/5] KVM: do not allow mapping valid but non-refcounted pages David Stevens
2021-06-25 7:58 ` Christian Borntraeger
2021-06-25 8:07 ` Paolo Bonzini
2021-06-25 7:36 ` [PATCH v2 2/5] KVM: mmu: introduce new gfn_to_pfn_page functions David Stevens
2021-06-25 7:36 ` [PATCH v2 3/5] KVM: x86/mmu: use gfn_to_pfn_page David Stevens
2021-06-25 7:36 ` [PATCH v2 4/5] KVM: arm64/mmu: " David Stevens
2021-06-25 7:36 ` David Stevens [this message]
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