From: Cornelia Huck <cohuck@redhat.com>
To: Pierre Morel <pmorel@linux.ibm.com>
Cc: Halil Pasic <pasic@linux.ibm.com>,
linux-kernel@vger.kernel.org, borntraeger@de.ibm.com,
frankja@linux.ibm.com, mst@redhat.com, jasowang@redhat.com,
kvm@vger.kernel.org, linux-s390@vger.kernel.org,
virtualization@lists.linux-foundation.org,
thomas.lendacky@amd.com, david@gibson.dropbear.id.au,
linuxram@us.ibm.com, heiko.carstens@de.ibm.com,
gor@linux.ibm.com
Subject: Re: [PATCH v3 1/1] s390: virtio: let arch accept devices without IOMMU feature
Date: Mon, 29 Jun 2020 15:44:39 +0200 [thread overview]
Message-ID: <20200629154439.14cc5ae7.cohuck@redhat.com> (raw)
In-Reply-To: <7fe6e9ab-fd5a-3f92-1f3a-f9e6805d3730@linux.ibm.com>
On Mon, 29 Jun 2020 15:14:04 +0200
Pierre Morel <pmorel@linux.ibm.com> wrote:
> On 2020-06-19 11:20, Cornelia Huck wrote:
> > On Thu, 18 Jun 2020 00:29:56 +0200
> > Halil Pasic <pasic@linux.ibm.com> wrote:
> >
> >> On Wed, 17 Jun 2020 12:43:57 +0200
> >> Pierre Morel <pmorel@linux.ibm.com> wrote:
> >>> @@ -179,6 +194,13 @@ int virtio_finalize_features(struct virtio_device *dev)
> >>> if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
> >>> return 0;
> >>>
> >>> + if (arch_needs_virtio_iommu_platform(dev) &&
> >>> + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
> >>> + dev_warn(&dev->dev,
> >>> + "virtio: device must provide VIRTIO_F_IOMMU_PLATFORM\n");
[Side note: wasn't there a patch renaming this bit on the list? I think
this name is only kept for userspace compat.]
> >>
> >> I'm not sure, divulging the current Linux name of this feature bit is a
> >> good idea, but if everybody else is fine with this, I don't care that
> >
> > Not sure if that feature name will ever change, as it is exported in
> > headers. At most, we might want to add the new ACCESS_PLATFORM define
> > and keep the old one, but that would still mean some churn.
> >
> >> much. An alternative would be:
> >> "virtio: device falsely claims to have full access to the memory,
> >> aborting the device"
> >
> > "virtio: device does not work with limited memory access" ?
> >
> > But no issue with keeping the current message.
> >
>
> If it is OK, I would like to specify that the arch is responsible to
> accept or not the device.
> The reason why the device is not accepted without IOMMU_PLATFORM is arch
> specific.
Hm, I'd think the reason is always the same (the device cannot access
the memory directly), just the way to figure out whether that is the
case or not is arch-specific, as with so many other things. No real
need to go into detail here, I think.
next prev parent reply other threads:[~2020-06-29 18:46 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-17 10:43 [PATCH v3 0/1] s390: virtio: let arch choose to accept devices without IOMMU feature Pierre Morel
2020-06-17 10:43 ` [PATCH v3 1/1] s390: virtio: let arch " Pierre Morel
2020-06-17 11:22 ` Heiko Carstens
2020-06-17 11:59 ` Pierre Morel
2020-06-17 13:36 ` Tom Lendacky
2020-06-17 14:12 ` Pierre Morel
2020-06-17 22:29 ` Halil Pasic
2020-06-19 9:20 ` Cornelia Huck
2020-06-19 12:02 ` Halil Pasic
2020-06-29 13:15 ` Pierre Morel
2020-06-29 13:14 ` Pierre Morel
2020-06-29 13:44 ` Cornelia Huck [this message]
2020-06-29 16:10 ` Pierre Morel
2020-06-29 13:21 ` Pierre Morel
2020-06-29 15:57 ` Michael S. Tsirkin
2020-06-29 16:05 ` Cornelia Huck
2020-07-02 13:03 ` Pierre Morel
2020-07-06 13:37 ` Pierre Morel
2020-07-06 14:33 ` Cornelia Huck
2020-07-06 15:01 ` Pierre Morel
2020-06-29 16:09 ` Pierre Morel
2020-06-29 16:09 ` Michael S. Tsirkin
2020-06-29 16:48 ` Pierre Morel
2020-06-29 21:18 ` Michael S. Tsirkin
2020-06-30 7:08 ` Cornelia Huck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200629154439.14cc5ae7.cohuck@redhat.com \
--to=cohuck@redhat.com \
--cc=borntraeger@de.ibm.com \
--cc=david@gibson.dropbear.id.au \
--cc=frankja@linux.ibm.com \
--cc=gor@linux.ibm.com \
--cc=heiko.carstens@de.ibm.com \
--cc=jasowang@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxram@us.ibm.com \
--cc=mst@redhat.com \
--cc=pasic@linux.ibm.com \
--cc=pmorel@linux.ibm.com \
--cc=thomas.lendacky@amd.com \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).