From: Vivek Goyal <vgoyal@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kvm@vger.kernel.org, x86@kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
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>, Gavin Shan <gshan@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/8] KVM: x86: interrupt based APF page-ready event delivery
Date: Wed, 13 May 2020 14:46:41 -0400 [thread overview]
Message-ID: <20200513184641.GF173965@redhat.com> (raw)
In-Reply-To: <87ftc3lxqc.fsf@vitty.brq.redhat.com>
On Wed, May 13, 2020 at 04:23:55PM +0200, Vitaly Kuznetsov wrote:
[..]
> >> Also,
> >> kdump kernel may not even support APF so it will get very confused when
> >> APF events get delivered.
> >
> > New kernel can just ignore these events if it does not support async
> > pf?
> >
> > This is somewhat similar to devices still doing interrupts in new
> > kernel. And solution for that seemed to be doing a "reset" of devices
> > in new kernel. We probably need similar logic where in new kernel
> > we simply disable "async pf" so that we don't get new notifications.
>
> Right and that's what we're doing - just disabling new notifications.
Nice.
So why there is a need to deliver "page ready" notifications
to guest after guest has disabled async pf. Atleast kdump does not
seem to need it. It will boot into second kernel anyway, irrespective
of the fact whether it receives page ready or not.
Thanks
Vivek
next prev parent reply other threads:[~2020-05-13 18:46 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 16:47 [PATCH 0/8] KVM: x86: Interrupt-based mechanism for async_pf 'page present' notifications Vitaly Kuznetsov
2020-05-11 16:47 ` [PATCH 1/8] Revert "KVM: async_pf: Fix #DF due to inject "Page not Present" and "Page Ready" exceptions simultaneously" Vitaly Kuznetsov
2020-05-11 16:47 ` [PATCH 2/8] KVM: x86: extend struct kvm_vcpu_pv_apf_data with token info Vitaly Kuznetsov
2020-05-12 15:27 ` Vivek Goyal
2020-05-12 15:40 ` Vitaly Kuznetsov
2020-05-12 15:53 ` Vivek Goyal
2020-05-12 17:50 ` Sean Christopherson
2020-05-13 9:09 ` Vitaly Kuznetsov
2020-05-13 12:52 ` Vivek Goyal
2020-05-15 15:59 ` Paolo Bonzini
2020-05-15 18:46 ` Sean Christopherson
2020-05-15 19:18 ` Paolo Bonzini
2020-05-15 20:33 ` Vivek Goyal
2020-05-15 20:53 ` Sean Christopherson
2020-05-15 20:43 ` Sean Christopherson
2020-05-15 22:23 ` Paolo Bonzini
2020-05-15 23:16 ` Sean Christopherson
2020-05-21 14:59 ` Vitaly Kuznetsov
2020-05-22 7:33 ` Paolo Bonzini
2020-05-12 21:15 ` Vivek Goyal
2020-05-21 18:38 ` Vivek Goyal
2020-05-23 16:34 ` Vitaly Kuznetsov
2020-05-26 12:50 ` Vivek Goyal
2020-05-11 16:47 ` [PATCH 3/8] KVM: introduce kvm_read_guest_offset_cached() Vitaly Kuznetsov
2020-05-11 16:47 ` [PATCH 4/8] KVM: x86: interrupt based APF page-ready event delivery Vitaly Kuznetsov
2020-05-12 14:24 ` Vivek Goyal
2020-05-12 15:50 ` Vitaly Kuznetsov
2020-05-12 18:07 ` Vivek Goyal
2020-05-13 9:03 ` Vitaly Kuznetsov
2020-05-13 13:53 ` Vivek Goyal
2020-05-13 14:03 ` Vivek Goyal
2020-05-13 14:23 ` Vitaly Kuznetsov
2020-05-13 18:46 ` Vivek Goyal [this message]
2020-05-14 8:08 ` Vitaly Kuznetsov
2020-05-14 13:31 ` Vivek Goyal
2020-05-11 16:47 ` [PATCH 5/8] KVM: x86: acknowledgment mechanism for async pf page ready notifications Vitaly Kuznetsov
2020-05-11 16:47 ` [PATCH 6/8] KVM: x86: announce KVM_FEATURE_ASYNC_PF_INT Vitaly Kuznetsov
2020-05-11 16:47 ` [PATCH 7/8] KVM: x86: Switch KVM guest to using interrupts for page ready APF delivery Vitaly Kuznetsov
2020-05-13 1:44 ` [kbuild-all] " kbuild test robot
2020-05-11 16:47 ` [PATCH 8/8] KVM: x86: drop KVM_PV_REASON_PAGE_READY case from kvm_handle_page_fault() Vitaly Kuznetsov
2020-05-12 15:32 ` [PATCH 0/8] KVM: x86: Interrupt-based mechanism for async_pf 'page present' notifications Vivek Goyal
2020-05-12 16:12 ` Vitaly Kuznetsov
2020-05-13 14:16 ` Vivek Goyal
2020-05-14 18:14 ` Vitaly Kuznetsov
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