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From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <kernellwp@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v2 3/3] KVM: X86: Let's harden the ipi fastpath condition edge-trigger mode
Date: Tue, 8 Jun 2021 19:40:52 +0200	[thread overview]
Message-ID: <2a643f94-d159-c1ac-6bd2-cc6b45372630@redhat.com> (raw)
In-Reply-To: <YL+cX8K3r7EWrk33@google.com>

On 08/06/21 18:35, Sean Christopherson wrote:
> Related side topic, anyone happen to know if KVM (and Qemu's) emulation of IPIs
> intentionally follows AMD instead of Intel?  I suspect it's unintentional,
> especially since KVM's initial xAPIC emulation came from Intel.  Not that it's
> likely to matter, but allowing level-triggered IPIs is bizarre, e.g. getting an
> EOI sent to the right I/O APIC at the right time via a level-triggered IPI seems
> extremely convoluted.

QEMU traditionally followed AMD a bit more than Intel for historical 
reasons.  Probably the code went QEMU->Xen->KVM even though it was 
contributed by Intel.

Paolo


  reply	other threads:[~2021-06-08 17:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-07  7:19 [PATCH v2 1/3] KVM: LAPIC: Write 0 to TMICT should also cancel vmx-preemption timer Wanpeng Li
2021-06-07  7:19 ` [PATCH v2 2/3] KVM: LAPIC: Reset TMCCT during vCPU reset Wanpeng Li
2021-06-08 16:27   ` Paolo Bonzini
2021-06-09  2:15     ` Wanpeng Li
2021-06-09  5:51       ` Paolo Bonzini
2021-06-09  7:18         ` Wanpeng Li
2021-06-07  7:19 ` [PATCH v2 3/3] KVM: X86: Let's harden the ipi fastpath condition edge-trigger mode Wanpeng Li
2021-06-08 16:27   ` Paolo Bonzini
2021-06-08 16:35   ` Sean Christopherson
2021-06-08 17:40     ` Paolo Bonzini [this message]
2021-06-09  2:08     ` Wanpeng Li
2021-06-08 16:27 ` [PATCH v2 1/3] KVM: LAPIC: Write 0 to TMICT should also cancel vmx-preemption timer Paolo Bonzini

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