From: Sean Christopherson <seanjc@google.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>, kvm <kvm@vger.kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Joao Martins <joao.m.martins@oracle.com>,
"jmattson @ google . com" <jmattson@google.com>,
"wanpengli @ tencent . com" <wanpengli@tencent.com>,
"vkuznets @ redhat . com" <vkuznets@redhat.com>,
"mtosatti @ redhat . com" <mtosatti@redhat.com>,
"joro @ 8bytes . org" <joro@8bytes.org>,
karahmed@amazon.com, Marc Zyngier <maz@kernel.org>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Anup Patel <anup.patel@wdc.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
kvm-riscv@lists.infradead.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH v3 08/12] KVM: Propagate vcpu explicitly to mark_page_dirty_in_slot()
Date: Thu, 18 Nov 2021 18:50:55 +0000 [thread overview]
Message-ID: <YZagjzYUsixbFre9@google.com> (raw)
In-Reply-To: <YZaeL5YztL3p1nLM@google.com>
On Thu, Nov 18, 2021, Sean Christopherson wrote:
> On Thu, Nov 18, 2021, David Woodhouse wrote:
> > That leaves the one in TDP MMU handle_changed_spte_dirty_log() which
> > AFAICT can trigger the same crash seen by butt3rflyh4ck — can't that
> > happen from a thread where kvm_get_running_vcpu() is NULL too? For that
> > one I'm not sure.
>
> I think could be trigger in the TDP MMU via kvm_mmu_notifier_release()
> -> kvm_mmu_zap_all(), e.g. if the userspace VMM exits while dirty logging is
> enabled. That should be easy to (dis)prove via a selftest.
Scratch that, the dirty log update is guarded by the new_spte being present, so
zapping of any kind won't trigger it.
Currently, I believe the only path that would create a present SPTE without an
active vCPU is mmu_notifer.change_pte, but that squeaks by because its required
to be wrapped with invalidate_range_{start,end}(MMU_NOTIFY_CLEAR), and KVM zaps
in that situation.
Ben's series to promote pages on disabling of dirty logging will also sqeuak by
because dirty logging is obviously disabled.
next prev parent reply other threads:[~2021-11-18 18:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 17:39 [PATCH v3 00/12] KVM: x86/xen: Add in-kernel Xen event channel delivery David Woodhouse
2021-11-17 17:39 ` [PATCH v3 01/12] KVM: Introduce CONFIG_HAVE_KVM_DIRTY_RING David Woodhouse
2021-11-17 17:39 ` [PATCH v3 02/12] KVM: Add Makefile.kvm for common files, use it for x86 David Woodhouse
2021-11-17 18:11 ` Marc Zyngier
2021-11-17 17:39 ` [PATCH v3 03/12] KVM: s390: Use Makefile.kvm for common files David Woodhouse
2021-11-17 17:39 ` [PATCH v3 04/12] KVM: mips: " David Woodhouse
2021-11-17 17:39 ` [PATCH v3 05/12] KVM: RISC-V: " David Woodhouse
2021-11-17 17:39 ` [PATCH v3 06/12] KVM: powerpc: " David Woodhouse
2021-11-17 23:50 ` Michael Ellerman
2021-11-17 17:39 ` [PATCH v3 07/12] KVM: arm64: " David Woodhouse
2021-11-17 18:11 ` Marc Zyngier
2021-11-17 17:39 ` [PATCH v3 08/12] KVM: Propagate vcpu explicitly to mark_page_dirty_in_slot() David Woodhouse
2021-11-17 18:13 ` Marc Zyngier
2021-11-17 18:31 ` David Woodhouse
2021-11-17 19:30 ` David Woodhouse
2021-11-17 21:09 ` David Woodhouse
2021-11-18 12:04 ` Paolo Bonzini
2021-11-18 14:22 ` David Woodhouse
2021-11-18 18:40 ` Sean Christopherson
2021-11-18 18:50 ` Sean Christopherson [this message]
2021-11-18 19:23 ` David Woodhouse
2021-11-18 19:46 ` Sean Christopherson
2021-11-19 9:23 ` David Woodhouse
2021-11-17 17:40 ` [PATCH v3 09/12] KVM: Reinstate gfn_to_pfn_cache with invalidation support David Woodhouse
2021-11-17 17:40 ` [PATCH v3 10/12] KVM: x86/xen: Maintain valid mapping of Xen shared_info page David Woodhouse
2021-11-17 17:40 ` [PATCH v3 11/12] KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery David Woodhouse
2021-11-17 17:40 ` [PATCH v3 12/12] KVM: x86: First attempt at converting nested virtual APIC page to gpc David Woodhouse
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=YZagjzYUsixbFre9@google.com \
--to=seanjc@google.com \
--cc=aleksandar.qemu.devel@gmail.com \
--cc=alexandru.elisei@arm.com \
--cc=anup.patel@wdc.com \
--cc=benh@kernel.crashing.org \
--cc=boris.ostrovsky@oracle.com \
--cc=borntraeger@de.ibm.com \
--cc=catalin.marinas@arm.com \
--cc=chenhuacai@kernel.org \
--cc=dwmw2@infradead.org \
--cc=james.morse@arm.com \
--cc=jmattson@google.com \
--cc=joao.m.martins@oracle.com \
--cc=joro@8bytes.org \
--cc=karahmed@amazon.com \
--cc=kvm-riscv@lists.infradead.org \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=maz@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=mtosatti@redhat.com \
--cc=pbonzini@redhat.com \
--cc=suzuki.poulose@arm.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=will@kernel.org \
/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).