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From: Paolo Bonzini <pbonzini@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>,
	kvm@vger.kernel.org, x86@kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Jim Mattson <jmattson@google.com>,
	Vivek Goyal <vgoyal@redhat.com>, Gavin Shan <gshan@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 06/10] KVM: x86: acknowledgment mechanism for async pf page ready notifications
Date: Thu, 28 May 2020 13:44:12 +0200	[thread overview]
Message-ID: <690f1a02-6077-e971-f2e9-aedd89f0901a@redhat.com> (raw)
In-Reply-To: <87wo4w2sra.fsf@vitty.brq.redhat.com>

On 28/05/20 13:39, Vitaly Kuznetsov wrote:
>> How is the pageready_pending flag migrated?  Should we revert the
>> direction of the MSR (i.e. read the flag, and write 0 to clear it)?
> The flag is not migrated so it will be 'false'. This can just cause an
> extra kick in kvm_arch_async_page_present_queued() but this shouldn't be
> a big deal. Also, after migration we will just send 'wakeup all' event,
> async pf queue will be empty.

Ah, that's kvm_pv_enable_async_pf, where the destination writes to
MSR_KVM_ASYNC_PF.  Cool.

> MSR_KVM_ASYNC_PF_ACK by itself is not
> migrated, we don't even store it, not sure how invering it would change
> things.

Yes, it would only be useful to invert it if it needs to be stored and
migrated.

Thanks,

Paolo


  reply	other threads:[~2020-05-28 11:44 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-25 14:41 [PATCH v2 00/10] KVM: x86: Interrupt-based mechanism for async_pf 'page present' notifications Vitaly Kuznetsov
2020-05-25 14:41 ` [PATCH v2 01/10] Revert "KVM: async_pf: Fix #DF due to inject "Page not Present" and "Page Ready" exceptions simultaneously" Vitaly Kuznetsov
2020-05-25 14:41 ` [PATCH v2 02/10] KVM: x86: extend struct kvm_vcpu_pv_apf_data with token info Vitaly Kuznetsov
2020-05-26 18:27   ` Vivek Goyal
2020-05-28  8:42     ` Vitaly Kuznetsov
2020-05-28 10:59       ` Paolo Bonzini
2020-06-03 19:35       ` Vivek Goyal
2020-05-25 14:41 ` [PATCH v2 03/10] KVM: rename kvm_arch_can_inject_async_page_present() to kvm_arch_can_dequeue_async_page_present() Vitaly Kuznetsov
2020-05-25 14:41 ` [PATCH v2 04/10] KVM: introduce kvm_read_guest_offset_cached() Vitaly Kuznetsov
2020-05-25 14:41 ` [PATCH v2 05/10] KVM: x86: interrupt based APF 'page ready' event delivery Vitaly Kuznetsov
2020-06-09 19:10   ` Vivek Goyal
2020-06-09 20:31     ` Paolo Bonzini
2020-06-10  9:01       ` Vitaly Kuznetsov
2020-06-10 11:34         ` Paolo Bonzini
2020-06-10 12:51         ` Vivek Goyal
2020-05-25 14:41 ` [PATCH v2 06/10] KVM: x86: acknowledgment mechanism for async pf page ready notifications Vitaly Kuznetsov
2020-05-28 11:29   ` Paolo Bonzini
2020-05-28 11:39     ` Vitaly Kuznetsov
2020-05-28 11:44       ` Paolo Bonzini [this message]
2020-05-25 14:41 ` [PATCH v2 07/10] KVM: x86: announce KVM_FEATURE_ASYNC_PF_INT Vitaly Kuznetsov
2020-05-25 14:41 ` [PATCH v2 08/10] KVM: x86: Switch KVM guest to using interrupts for page ready APF delivery Vitaly Kuznetsov
2020-06-10 20:51   ` Vivek Goyal
2020-06-10 21:06     ` Paolo Bonzini
2020-05-25 14:41 ` [PATCH v2 09/10] KVM: x86: drop KVM_PV_REASON_PAGE_READY case from kvm_handle_page_fault() Vitaly Kuznetsov
2020-05-25 14:41 ` [PATCH v2 10/10] KVM: x86: deprecate KVM_ASYNC_PF_SEND_ALWAYS Vitaly Kuznetsov
2020-05-28 11:03   ` Paolo Bonzini
2020-05-28 11:14     ` Vitaly Kuznetsov
2020-05-28 11:04 ` [PATCH v2 00/10] KVM: x86: Interrupt-based mechanism for async_pf 'page present' notifications Paolo Bonzini
2020-06-04 17:45   ` Vivek Goyal
2020-06-04 17:56     ` Paolo Bonzini

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