From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Zdenek Kaspar <zkaspar82@gmail.com>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 5.11 09/12] KVM: x86: Zap the oldest MMU pages, not the newest
Date: Thu, 25 Feb 2021 10:53:43 +0100 [thread overview]
Message-ID: <20210225092515.434032433@linuxfoundation.org> (raw)
In-Reply-To: <20210225092515.015261674@linuxfoundation.org>
From: Sean Christopherson <seanjc@google.com>
commit 8fc517267fb28576dfca2380cc2497a2454b8fae upstream.
Walk the list of MMU pages in reverse in kvm_mmu_zap_oldest_mmu_pages().
The list is FIFO, meaning new pages are inserted at the head and thus
the oldest pages are at the tail. Using a "forward" iterator causes KVM
to zap MMU pages that were just added, which obliterates guest
performance once the max number of shadow MMU pages is reached.
Fixes: 6b82ef2c9cf1 ("KVM: x86/mmu: Batch zap MMU pages when recycling oldest pages")
Reported-by: Zdenek Kaspar <zkaspar82@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210113205030.3481307-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/mmu/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2417,7 +2417,7 @@ static unsigned long kvm_mmu_zap_oldest_
return 0;
restart:
- list_for_each_entry_safe(sp, tmp, &kvm->arch.active_mmu_pages, link) {
+ list_for_each_entry_safe_reverse(sp, tmp, &kvm->arch.active_mmu_pages, link) {
/*
* Don't zap active root pages, the page itself can't be freed
* and zapping it will just force vCPUs to realloc and reload.
next prev parent reply other threads:[~2021-02-25 10:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 9:53 [PATCH 5.11 00/12] 5.11.2-rc1 review Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 01/12] bpf: Fix truncation handling for mod32 dst reg wrt zero Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 02/12] HID: make arrays usage and value to be the same Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 03/12] USB: quirks: sort quirk entries Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 04/12] usb: quirks: add quirk to start video capture on ELMO L-12F document camera reliable Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 05/12] ntfs: check for valid standard information attribute Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 06/12] Bluetooth: btusb: Some Qualcomm Bluetooth adapters stop working Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 07/12] arm64: tegra: Add power-domain for Tegra210 HDA Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 08/12] hwmon: (dell-smm) Add XPS 15 L502X to fan control blacklist Greg Kroah-Hartman
2021-02-25 9:53 ` Greg Kroah-Hartman [this message]
2021-02-25 9:53 ` [PATCH 5.11 10/12] KVM: do not assume PTE is writable after follow_pfn Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 11/12] mm: provide a saner PTE walking API for modules Greg Kroah-Hartman
2021-02-25 9:53 ` [PATCH 5.11 12/12] KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() Greg Kroah-Hartman
2021-02-25 19:52 ` [PATCH 5.11 00/12] 5.11.2-rc1 review Guenter Roeck
2021-02-26 2:24 ` Shuah Khan
2021-02-26 3:45 ` Ross Schmidt
2021-02-26 8:00 ` Naresh Kamboju
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