From: David Woodhouse <dwmw2@infradead.org>
To: sashiko-bot@kernel.org
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
rcu@vger.kernel.org, pbonzini@redhat.com, seanjc@google.com,
paul@xen.org, paulmck@kernel.org, nh-open-source@amazon.com
Subject: Re: [PATCH 11/17] KVM: nVMX: Use pinned pfncache for L1 APIC virtualization pages
Date: Mon, 21 Sep 2026 16:31:37 +0200 [thread overview]
Message-ID: <2a6d520d7663eb637b2ebd5d079a2e5082dd1d2b.camel@infradead.org> (raw)
In-Reply-To: <20260920215738.E90CB1F000FF@smtp.kernel.org>
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On Sun, 2026-09-20 at 21:57 +0000, sashiko-bot@kernel.org wrote:
> [Severity: High]
> Does this allow an untrusted L1 guest to crash the VM by triggering a
> KVM_EXIT_INTERNAL_ERROR? The L1 guest can write a non-page-aligned
> address to the APIC_ACCESS_ADDR field in vmcs12 and execute VMLAUNCH.
No, that would be caught by nested_vmx_check_apic_access_controls()
which calls page_address_valid() and requires page alignment. So the
VMLAUNCH should fail.
(... s/should/does/ fail, as I made my friend throw up a self-test to
prove it. Want that added to the existing tests?)
> [Severity: Medium]
> Will this nested lock cause an AB-BA circular locking dependency
> warning from lockdep?
No, RCU isn't really a 'lock'; those nest just fine (unlike the special
case I just fixed in EVTCHNOP_send which was spinning inside the read
section, waiting for something that could never complete until it
*left* the read section — a completely different kind of deadlock).
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next prev parent reply other threads:[~2026-09-21 14:31 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-20 20:49 [PATCH 00/17] KVM: Use atomic SRCU for gfn-to-pfn cache, reinstate guest mode for x86 nesting David Woodhouse
2026-09-20 20:49 ` [PATCH 01/17] KVM: pfncache: Use atomic SRCU for readers instead of a rwlock David Woodhouse
2026-09-20 21:55 ` sashiko-bot
2026-09-21 1:42 ` Hillf Danton
2026-09-21 9:54 ` David Woodhouse
2026-09-21 11:21 ` Hillf Danton
2026-09-21 11:29 ` Paolo Bonzini
2026-09-20 20:49 ` [PATCH 02/17] KVM: x86/xen: Extract delivery of event to vCPU into a separate helper David Woodhouse
2026-09-20 20:49 ` [PATCH 03/17] KVM: x86/xen: Explicitly tag "shared info" page as never being dirty tracked David Woodhouse
2026-09-20 20:49 ` [PATCH 04/17] KVM: x86/xen: Don't dirty track "vCPU info" page David Woodhouse
2026-09-20 20:49 ` [PATCH 05/17] KVM: x86: Request the guest TLB flush from record_steal_time() David Woodhouse
2026-09-20 20:49 ` [PATCH 06/17] KVM: x86: Use gfn_to_pfn_cache for steal time / preempted status David Woodhouse
2026-09-20 22:06 ` sashiko-bot
2026-09-20 20:49 ` [PATCH 07/17] KVM: pfncache: Add guest-mode pinning (GUEST_USES_PFN successor) David Woodhouse
2026-09-20 21:53 ` sashiko-bot
2026-09-21 14:17 ` David Woodhouse
2026-09-20 20:49 ` [PATCH 08/17] KVM: pfncache: Return -EAGAIN for a lookup which hits an invalid memslot David Woodhouse
2026-09-20 21:53 ` sashiko-bot
2026-09-20 20:49 ` [PATCH 09/17] KVM: x86: Post KVM_REQ_GET_NESTED_STATE_PAGES on memslot updates David Woodhouse
2026-09-20 20:49 ` [PATCH 10/17] KVM: nVMX: Implement cache for L1 MSR bitmap David Woodhouse
2026-09-20 21:56 ` sashiko-bot
2026-09-20 20:49 ` [PATCH 11/17] KVM: nVMX: Use pinned pfncache for L1 APIC virtualization pages David Woodhouse
2026-09-20 21:57 ` sashiko-bot
2026-09-21 14:31 ` David Woodhouse [this message]
2026-09-20 20:49 ` [PATCH 12/17] KVM: selftests: Add nested VMX APIC cache invalidation test David Woodhouse
2026-09-20 21:51 ` sashiko-bot
2026-09-20 20:49 ` [PATCH 13/17] KVM: x86: Move nested GPC lock helpers to x86.h as kvm_gpc_lock_page() David Woodhouse
2026-09-20 20:49 ` [PATCH 14/17] KVM: nSVM: Use a gfn_to_pfn_cache for the vmcb12 page David Woodhouse
2026-09-20 20:49 ` [PATCH 15/17] KVM: nSVM: Cache L1's MSR permissions map pages David Woodhouse
2026-09-20 20:49 ` [PATCH 16/17] KVM: nSVM: Cache L1's IO " David Woodhouse
2026-09-20 20:49 ` [PATCH 17/17] KVM: selftests: Add nested transition benchmark David Woodhouse
2026-09-20 21:52 ` sashiko-bot
2026-09-21 14:10 ` [PATCH 00/17] KVM: Use atomic SRCU for gfn-to-pfn cache, reinstate guest mode for x86 nesting David Woodhouse
2026-09-22 3:16 ` KunWu Chan
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