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From: "Kang, Luwei" <luwei.kang@intel.com>
To: "Kang, Luwei" <luwei.kang@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Cc: "rkrcmar@redhat.com" <rkrcmar@redhat.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>, "hpa@zytor.com" <hpa@zytor.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] KVM: x86: Sync the pending Posted-Interrupts
Date: Tue, 29 Jan 2019 09:32:36 +0000	[thread overview]
Message-ID: <82D7661F83C1A047AF7DC287873BF1E172CD4BDD@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <82D7661F83C1A047AF7DC287873BF1E172CD3820@SHSMSX101.ccr.corp.intel.com>

> > However, you should at least change the comment in vcpu_enter_guest to
> > mention "before reading PIR" instead of "before reading PIR.ON".
> 
> Will do that. I think the "checking PIR.ON" should be PID.ON. I will fix it.
> 
Hi Paolo,
    I reconsidered the comment in vcpu_enter_guest() and think it may don't need to change. The original comment as below:
         * 2) For APICv, we should set ->mode before checking  PIR.ON.  This
         * pairs with the memory barrier implicit in pi_test_and_set_on
         * (see vmx_deliver_posted_interrupt).

    I think "before checking PIR.ON" is mean "before checking PID.PIR and PID.ON". Because there indeed have this two flag check in  vmx_deliver_posted_interrupt() function. If PID.ON is already Set at the time of hardware posting an interrupt to PIR field, notification event is not generated (from VT-d spec 9.12).

Thanks,
Luwei Kang

  parent reply	other threads:[~2019-01-29  9:32 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-18  6:34 [PATCH] KVM: x86: Sync the pending Posted-Interrupts Luwei Kang
2019-01-25 16:33 ` Konrad Rzeszutek Wilk
2019-01-28  6:17   ` Kang, Luwei
2019-01-25 18:27 ` Paolo Bonzini
2019-01-28  8:08   ` Kang, Luwei
2019-01-28  9:18     ` Paolo Bonzini
2019-01-29  9:32     ` Kang, Luwei [this message]
2019-01-29 13:30       ` Paolo Bonzini
2019-01-30  0:37         ` Kang, Luwei

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