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.
WARNING: multiple messages have this Message-ID (diff)
From: Cornelia Huck <cohuck@redhat.com> To: Pierre Morel <pmorel@linux.ibm.com> Cc: gor@linux.ibm.com, linux-s390@vger.kernel.org, frankja@linux.ibm.com, kvm@vger.kernel.org, mst@redhat.com, heiko.carstens@de.ibm.com, linuxram@us.ibm.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Halil Pasic <pasic@linux.ibm.com>, borntraeger@de.ibm.com, thomas.lendacky@amd.com, david@gibson.dropbear.id.au 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: 37+ 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 2020-06-19 12:02 ` Halil Pasic 2020-06-29 13:15 ` Pierre Morel 2020-06-29 13:15 ` Pierre Morel 2020-06-29 13:14 ` Pierre Morel 2020-06-29 13:14 ` Pierre Morel 2020-06-29 13:44 ` Cornelia Huck [this message] 2020-06-29 13:44 ` Cornelia Huck 2020-06-29 16:10 ` Pierre Morel 2020-06-29 16:10 ` Pierre Morel 2020-06-29 13:21 ` Pierre Morel 2020-06-29 13:21 ` Pierre Morel 2020-06-29 15:57 ` Michael S. Tsirkin 2020-06-29 15:57 ` Michael S. Tsirkin 2020-06-29 16:05 ` Cornelia Huck 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 ` Pierre Morel 2020-06-29 16:09 ` Michael S. Tsirkin 2020-06-29 16:09 ` Michael S. Tsirkin 2020-06-29 16:48 ` Pierre Morel 2020-06-29 16:48 ` Pierre Morel 2020-06-29 21:18 ` Michael S. Tsirkin 2020-06-29 21:18 ` Michael S. Tsirkin 2020-06-30 7:08 ` Cornelia Huck
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