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From: Jason Gunthorpe <jgg@nvidia.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
	Christoph Hellwig <hch@lst.de>,
	Kirti Wankhede <kwankhede@nvidia.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] vfio/mdev: don't warn if ->request is not set
Date: Tue, 27 Jul 2021 14:32:09 -0300	[thread overview]
Message-ID: <20210727173209.GG1721383@nvidia.com> (raw)
In-Reply-To: <87wnpc47j3.fsf@redhat.com>

On Tue, Jul 27, 2021 at 08:04:16AM +0200, Cornelia Huck wrote:
> On Mon, Jul 26 2021, Alex Williamson <alex.williamson@redhat.com> wrote:
> 
> > On Mon, 26 Jul 2021 20:09:06 -0300
> > Jason Gunthorpe <jgg@nvidia.com> wrote:
> >
> >> On Mon, Jul 26, 2021 at 07:07:04PM +0200, Cornelia Huck wrote:
> >> 
> >> > But I wonder why nobody else implements this? Lack of surprise removal?  
> >> 
> >> The only implementation triggers an eventfd that seems to be the same
> >> eventfd as the interrupt..
> >> 
> >> Do you know how this works in userspace? I'm surprised that the
> >> interrupt eventfd can trigger an observation that the kernel driver
> >> wants to be unplugged?
> >
> > I think we're talking about ccw, but I see QEMU registering separate
> > eventfds for each of the 3 IRQ indexes and the mdev driver specifically
> > triggering the req_trigger...?  Thanks,
> >
> > Alex
> 
> Exactly, ccw has a trigger for normal I/O interrupts, CRW (machine
> checks), and this one.

If it is a dedicated eventfd for 'device being removed' why is it in
the CCW implementation and not core code?

Is PCI doing the same?

Jason 

  reply	other threads:[~2021-07-27 17:32 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26 14:35 two small mdev fixups Christoph Hellwig
2021-07-26 14:35 ` [PATCH 1/2] vfio/mdev: turn mdev_init into a subsys_initcall Christoph Hellwig
2021-07-26 17:00   ` Cornelia Huck
2021-07-26 23:06   ` Jason Gunthorpe
2021-07-26 14:35 ` [PATCH 2/2] vfio/mdev: don't warn if ->request is not set Christoph Hellwig
2021-07-26 17:07   ` Cornelia Huck
2021-07-26 23:09     ` Jason Gunthorpe
2021-07-26 23:28       ` Alex Williamson
2021-07-27  6:04         ` Cornelia Huck
2021-07-27 17:32           ` Jason Gunthorpe [this message]
2021-07-27 18:53             ` Alex Williamson
2021-07-27 19:03               ` Jason Gunthorpe
2021-07-27 19:25                 ` Alex Williamson
2021-07-26 23:07   ` Jason Gunthorpe
2021-08-03 18:45 ` two small mdev fixups Alex Williamson

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