From: Stefan Hajnoczi <stefanha@redhat.com>
To: Elena Afanasova <eafanasova@gmail.com>
Cc: kvm@vger.kernel.org, jag.raman@oracle.com, elena.ufimtseva@oracle.com
Subject: Re: [RFC v2 0/4] Introduce MMIO/PIO dispatch file descriptors (ioregionfd)
Date: Sat, 30 Jan 2021 14:56:16 +0000 [thread overview]
Message-ID: <20210130145616.GA98016@stefanha-x1.localdomain> (raw)
In-Reply-To: <cover.1611850290.git.eafanasova@gmail.com>
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On Thu, Jan 28, 2021 at 09:32:19PM +0300, Elena Afanasova wrote:
> This patchset introduces a KVM dispatch mechanism which can be used
> for handling MMIO/PIO accesses over file descriptors without returning
> from ioctl(KVM_RUN). This allows device emulation to run in another task
> separate from the vCPU task.
>
> This is achieved through KVM vm ioctl for registering MMIO/PIO regions and
> a wire protocol that KVM uses to communicate with a task handling an
> MMIO/PIO access.
>
> TODOs:
> * Implement KVM_EXIT_IOREGIONFD_FAILURE
> * Add non-x86 arch support
This is an interesting topic for discussion with the KVM maintainers.
The ioctl(KVM_RUN) exit code is arch-specific in the sense that there is
no standard approach for PIO/MMIO accesses to return to userspace and
resume processing when ioctl(KVM_RUN) is called again.
This RFC series is x86-specific, but part of it can be made cross-arch
by introducing a core KVM ->complete_user_exit() function pointer that
MMIO/PIO and other users (EINTR?) can use to resume processing when
ioctl(KVM_RUN) is called again.
Maybe the benefit for a generic ->complete_user_exit() function is too
small so each arch open codes this behavior?
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next prev parent reply other threads:[~2021-01-30 15:22 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 18:32 [RFC v2 0/4] Introduce MMIO/PIO dispatch file descriptors (ioregionfd) Elena Afanasova
2021-01-28 18:32 ` [RFC v2 2/4] KVM: x86: add support for ioregionfd signal handling Elena Afanasova
2021-01-30 16:58 ` Stefan Hajnoczi
2021-02-03 14:00 ` Elena Afanasova
2021-02-09 6:21 ` Jason Wang
2021-02-09 14:49 ` Stefan Hajnoczi
2021-02-10 19:06 ` Elena Afanasova
2021-02-09 6:26 ` Jason Wang
2021-01-28 18:32 ` [RFC v2 3/4] KVM: add support for ioregionfd cmds/replies serialization Elena Afanasova
2021-01-30 18:54 ` Stefan Hajnoczi
2021-02-03 14:10 ` Elena Afanasova
2021-01-28 18:32 ` [RFC v2 4/4] KVM: enforce NR_IOBUS_DEVS limit if kmemcg is disabled Elena Afanasova
2021-01-29 18:48 ` [RESEND RFC v2 1/4] KVM: add initial support for KVM_SET_IOREGION Elena Afanasova
2021-01-30 15:04 ` Stefan Hajnoczi
2021-02-04 13:03 ` Cornelia Huck
2021-02-05 18:39 ` Elena Afanasova
2021-02-08 11:49 ` Cornelia Huck
2021-02-08 6:21 ` Jason Wang
2021-02-09 14:59 ` Stefan Hajnoczi
2021-02-18 6:17 ` Jason Wang
2021-02-10 19:31 ` Elena Afanasova
2021-02-11 14:59 ` Stefan Hajnoczi
2021-02-17 23:05 ` Elena Afanasova
2021-02-18 6:22 ` Jason Wang
2021-02-18 6:20 ` Jason Wang
2021-01-30 14:56 ` Stefan Hajnoczi [this message]
2021-02-02 14:59 ` [RFC v2 0/4] Introduce MMIO/PIO dispatch file descriptors (ioregionfd) Stefan Hajnoczi
2021-02-08 6:02 ` Jason Wang
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