From: Sean Christopherson <seanjc@google.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: kvm@vger.kernel.org, Jim Mattson <jmattson@google.com>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Wanpeng Li <wanpengli@tencent.com>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org
Subject: Re: [PATCH 4/4] KVM: x86: lapic: don't allow to set non default apic id when not using x2apic api
Date: Thu, 3 Mar 2022 19:49:05 +0000 [thread overview]
Message-ID: <YiEbsasKjrvKKyff@google.com> (raw)
In-Reply-To: <YiEZJ6tg0+I+MdW5@google.com>
On Thu, Mar 03, 2022, Sean Christopherson wrote:
> With your proposed change, KVM_SET_LAPIC will fail and we've broken a functional,
> if sketchy, setup. Is there likely to be such a real-world setup that doesn't
> barf on the inconsistent x2APIC ID? Probably not, but I don't see any reason to
> find out.
I take back the "probably not", this isn't even all that contrived. Prior to the
"migration", the guest will see a consistent x2APIC ID. It's not hard to imagine
a guest that snapshots the ID and never re-reads the value from "hardware".
next prev parent reply other threads:[~2022-03-03 19:49 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-01 13:55 [PATCH 0/4] SVM fixes + apic fix Maxim Levitsky
2022-03-01 13:55 ` [PATCH 1/4] KVM: x86: mark synthetic SMM vmexit as SVM_EXIT_SW Maxim Levitsky
2022-03-01 16:31 ` Sean Christopherson
2022-03-01 17:13 ` Maxim Levitsky
2022-03-09 15:46 ` Paolo Bonzini
2022-03-01 13:55 ` [PATCH 2/4] KVM: x86: SVM: disable preemption in avic_refresh_apicv_exec_ctrl Maxim Levitsky
2022-03-01 17:15 ` Sean Christopherson
2022-03-01 17:20 ` Maxim Levitsky
2022-03-01 17:23 ` Paolo Bonzini
2022-03-01 13:55 ` [PATCH 3/4] KVM: x86: SVM: use vmcb01 in avic_init_vmcb Maxim Levitsky
2022-03-01 16:21 ` Sean Christopherson
2022-03-01 17:25 ` Maxim Levitsky
2022-03-01 17:35 ` Sean Christopherson
2022-03-09 15:48 ` Paolo Bonzini
2022-03-15 12:27 ` Maxim Levitsky
2022-03-01 13:55 ` [PATCH 4/4] KVM: x86: lapic: don't allow to set non default apic id when not using x2apic api Maxim Levitsky
2022-03-01 16:56 ` Sean Christopherson
2022-03-01 17:09 ` Maxim Levitsky
2022-03-01 17:46 ` Sean Christopherson
2022-03-01 17:56 ` Maxim Levitsky
2022-03-02 11:50 ` Maxim Levitsky
2022-03-03 16:51 ` Sean Christopherson
2022-03-03 18:15 ` Maxim Levitsky
2022-03-03 19:38 ` Sean Christopherson
2022-03-03 19:49 ` Sean Christopherson [this message]
2022-03-04 10:54 ` Maxim Levitsky
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