From: Sean Christopherson <seanjc@google.com>
To: Dmytro Maluka <dmy@semihalf.com>
Cc: Auger Eric <eric.auger@redhat.com>,
Micah Morton <mortonm@chromium.org>,
Alex Williamson <alex.williamson@redhat.com>,
kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Rong L Liu <rong.l.liu@intel.com>,
Tomasz Nowicki <tn@semihalf.com>,
Grzegorz Jaszczyk <jaz@semihalf.com>,
Dmitry Torokhov <dtor@google.com>
Subject: Re: Add vfio-platform support for ONESHOT irq forwarding?
Date: Wed, 6 Jul 2022 20:39:54 +0000 [thread overview]
Message-ID: <YsXzGkRIVVYEQNE3@google.com> (raw)
In-Reply-To: <31420943-8c5f-125c-a5ee-d2fde2700083@semihalf.com>
On Wed, Jul 06, 2022, Dmytro Maluka wrote:
> This is not a problem on native, since for oneshot irq we keep the interrupt
> masked until the thread exits, so that the EOI at the end of hardirq doesn't
> result in immediate re-assert. In vfio + KVM case, however, the host doesn't
> check that the interrupt is still masked in the guest, so
> vfio_platform_unmask() is called regardless.
Isn't not checking that an interrupt is unmasked the real bug? Fudging around vfio
(or whatever is doing the premature unmasking) bugs by delaying an ack notification
in KVM is a hack, no?
> Therefore, since the interrupt has not yet been acked in the guest's threaded
> handler, a new (unwanted) physical interrupt is generated in the host and
> queued for injection to the guest in vfio_automasked_irq_handler().
next prev parent reply other threads:[~2022-07-06 20:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-25 15:46 Add vfio-platform support for ONESHOT irq forwarding? Micah Morton
2021-01-25 17:31 ` Auger Eric
2021-01-25 18:32 ` Micah Morton
2021-01-26 8:48 ` Auger Eric
2021-01-26 15:31 ` Micah Morton
2021-01-26 16:05 ` Auger Eric
2021-01-25 20:36 ` Alex Williamson
2021-01-26 8:53 ` Auger Eric
2021-01-26 15:15 ` Micah Morton
2021-01-26 16:19 ` Auger Eric
2021-01-27 15:58 ` Micah Morton
2021-01-29 19:57 ` Micah Morton
2021-01-30 16:38 ` Auger Eric
2022-07-06 15:25 ` Dmytro Maluka
2022-07-06 20:39 ` Sean Christopherson [this message]
2022-07-07 7:38 ` Dmytro Maluka
2022-07-07 15:00 ` Sean Christopherson
2022-07-07 17:38 ` Dmytro Maluka
2022-07-12 16:02 ` Liu, Rong L
2022-08-04 14:44 ` Eric Auger
2022-08-08 21:15 ` Liu, Rong L
2022-07-07 8:25 ` Eric Auger
2022-07-07 9:15 ` Dmytro Maluka
2022-07-25 22:03 ` Liu, Rong L
2022-08-04 14:39 ` Eric Auger
2022-08-08 17:34 ` Liu, Rong L
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