From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: 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>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
David Woodhouse <dwmw@amazon.co.uk>,
Mingwei Zhang <mizhang@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH v2 0/8] KVM: Fix mmu_notifier vs. pfncache vs. pfncache races
Date: Wed, 27 Apr 2022 01:39:56 +0000 [thread overview]
Message-ID: <20220427014004.1992589-1-seanjc@google.com> (raw)
Fix races between mmu_notifier invalidation and pfncache refresh, and
within the pfncache itself.
The first two patches are reverts of the patches sitting in kvm/queue,
trying to separate and fix the races independently is nigh impossible.
I assume/hope they can be ignored and the original patches dropped.
I verified internal races using the attached hack-a-test. Running the
test against the current implementation fails due to KVM writing the
current GPA into the wrong page.
I don't think the race with the mmu_notifier is technically proven, e.g. I
never encountered a use-after-free even running with KASAN.
Ran with PROVE_LOCKING and DEBUG_ATOMIC_SLEEP, so in theory there shouldn't
be any lurking locking goofs this time...
v2:
- Map the pfn=>khva outside of gpc->lock. [Maxim]
- Fix a page leak.
- Fix more races.
v1:
https://lore.kernel.org/all/20220420004859.3298837-1-seanjc@google.com
Sean Christopherson (8):
Revert "KVM: Do not speculatively mark pfn cache valid to "fix" race"
Revert "KVM: Fix race between mmu_notifier invalidation and pfncache
refresh"
KVM: Drop unused @gpa param from gfn=>pfn cache's __release_gpc()
helper
KVM: Put the extra pfn reference when reusing a pfn in the gpc cache
KVM: Do not incorporate page offset into gfn=>pfn cache user address
KVM: Fix multiple races in gfn=>pfn cache refresh
KVM: Do not pin pages tracked by gfn=>pfn caches
DO NOT MERGE: Hack-a-test to verify gpc invalidation+refresh
arch/x86/kvm/x86.c | 30 ++++
include/linux/kvm_host.h | 2 +
include/linux/kvm_types.h | 1 +
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 2 +
tools/testing/selftests/kvm/gpc_test.c | 217 +++++++++++++++++++++++++
virt/kvm/pfncache.c | 188 +++++++++++++--------
7 files changed, 372 insertions(+), 69 deletions(-)
create mode 100644 tools/testing/selftests/kvm/gpc_test.c
base-commit: 2a39d8b39bffdaf1a4223d0d22f07baee154c8f3
--
2.36.0.rc2.479.g8af0fa9b8e-goog
next reply other threads:[~2022-04-27 1:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-27 1:39 Sean Christopherson [this message]
2022-04-27 1:39 ` [PATCH v2 1/8] Revert "KVM: Do not speculatively mark pfn cache valid to "fix" race" Sean Christopherson
2022-04-27 1:39 ` [PATCH v2 2/8] Revert "KVM: Fix race between mmu_notifier invalidation and pfncache refresh" Sean Christopherson
2022-04-27 1:39 ` [PATCH v2 3/8] KVM: Drop unused @gpa param from gfn=>pfn cache's __release_gpc() helper Sean Christopherson
2022-04-27 1:40 ` [PATCH v2 4/8] KVM: Put the extra pfn reference when reusing a pfn in the gpc cache Sean Christopherson
2022-04-27 1:40 ` [PATCH v2 5/8] KVM: Do not incorporate page offset into gfn=>pfn cache user address Sean Christopherson
2022-04-27 1:40 ` [PATCH v2 6/8] KVM: Fix multiple races in gfn=>pfn cache refresh Sean Christopherson
2022-04-27 14:10 ` Sean Christopherson
2022-04-28 3:39 ` Lai Jiangshan
2022-04-28 14:33 ` Sean Christopherson
2022-05-20 14:49 ` Paolo Bonzini
2022-05-20 14:58 ` Paolo Bonzini
2022-05-20 15:02 ` Sean Christopherson
2022-05-20 14:59 ` Sean Christopherson
2022-04-27 1:40 ` [PATCH v2 7/8] KVM: Do not pin pages tracked by gfn=>pfn caches Sean Christopherson
2022-04-27 1:40 ` [PATCH v2 8/8] DO NOT MERGE: Hack-a-test to verify gpc invalidation+refresh Sean Christopherson
2022-04-27 15:17 ` David Woodhouse
2022-04-27 20:23 ` Sean Christopherson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220427014004.1992589-1-seanjc@google.com \
--to=seanjc@google.com \
--cc=dwmw@amazon.co.uk \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mizhang@google.com \
--cc=mlevitsk@redhat.com \
--cc=pbonzini@redhat.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).