From: Sean Christopherson <seanjc@google.com>
To: Michal Luczaj <mhal@rbox.co>
Cc: pbonzini@redhat.com, shuah@kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH 1/3] KVM: x86: Fix out-of-bounds access in kvm_recalculate_phys_map()
Date: Fri, 26 May 2023 15:27:08 -0700 [thread overview]
Message-ID: <ZHEyPDlw67VOQFs/@google.com> (raw)
In-Reply-To: <f4c2108d-b5a0-bdee-f354-28ed7e5d4bd5@rbox.co>
On Fri, May 26, 2023, Michal Luczaj wrote:
> On 5/26/23 18:17, Sean Christopherson wrote:
> > On Fri, May 26, 2023, Michal Luczaj wrote:
> >> Maybe it's not important, but what about moving xapic_id_mismatch
> >> (re)initialization after "retry:"?
> >
> > Oof, good catch. I think it makes sense to move max_id (re)initialization too,
> > even though I can't imagine it would matter in practice.
>
> Right, I forgot that max APIC ID can decrease along the way.
Actually, we don't want to reset max_id. That would allow userspace or the guest
to put KVM into an infinite loop, e.g. by toggling the APIC of the vCPU with the
highest x2APIC ID between enabled and disabled. The downside of not shrinking the
size is quite negligible.
next prev parent reply other threads:[~2023-05-26 22:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-25 18:33 [PATCH 0/3] Out-of-bounds access in kvm_recalculate_phys_map() Michal Luczaj
2023-05-25 18:33 ` [PATCH 1/3] KVM: x86: Fix out-of-bounds " Michal Luczaj
2023-05-26 0:07 ` Sean Christopherson
2023-05-26 10:52 ` Michal Luczaj
2023-05-26 16:17 ` Sean Christopherson
2023-05-26 17:17 ` Michal Luczaj
2023-05-26 18:11 ` Sean Christopherson
2023-05-26 22:27 ` Sean Christopherson [this message]
2023-05-25 18:33 ` [PATCH 2/3] KVM: x86: Simplify APIC ID selection " Michal Luczaj
2023-05-25 18:33 ` [PATCH 3/3] KVM: selftests: Add test for race in kvm_recalculate_apic_map() Michal Luczaj
2023-05-26 23:40 ` Sean Christopherson
2023-05-28 17:26 ` Michal Luczaj
2023-06-02 0:26 ` Sean Christopherson
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