From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Eric Auger <eric.auger@redhat.com>
Cc: kevin.tian@intel.com, mst@redhat.com,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, pasic@linux.ibm.com,
iommu@lists.linux-foundation.org, sebastien.boeuf@intel.com,
will@kernel.org, jasowang@redhat.com
Subject: Re: [PATCH v2 2/5] iommu/virtio: Support bypass domains
Date: Mon, 29 Nov 2021 15:36:47 +0000 [thread overview]
Message-ID: <YaTzj6x0nIYoL1WD@myrica> (raw)
In-Reply-To: <fd03ac99-9bd4-197b-26c8-dcc5de1b3057@redhat.com>
On Sat, Nov 27, 2021 at 05:18:28PM +0100, Eric Auger wrote:
> Hi Jean,
>
> On 11/23/21 4:52 PM, Jean-Philippe Brucker wrote:
> > The VIRTIO_IOMMU_F_BYPASS_CONFIG feature adds a new flag to the ATTACH
> > request, that creates a bypass domain. Use it to enable identity
> > domains.
> >
> > When VIRTIO_IOMMU_F_BYPASS_CONFIG is not supported by the device, we
> > currently fail attaching to an identity domain. Future patches will
> > instead create identity mappings in this case.
> >
> > Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > ---
> > drivers/iommu/virtio-iommu.c | 20 +++++++++++++++++++-
> > 1 file changed, 19 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> > index 80930ce04a16..ee8a7afd667b 100644
> > --- a/drivers/iommu/virtio-iommu.c
> > +++ b/drivers/iommu/virtio-iommu.c
> > @@ -71,6 +71,7 @@ struct viommu_domain {
> > struct rb_root_cached mappings;
> >
> > unsigned long nr_endpoints;
> > + bool bypass;
> > };
> >
> > struct viommu_endpoint {
> > @@ -587,7 +588,9 @@ static struct iommu_domain *viommu_domain_alloc(unsigned type)
> > {
> > struct viommu_domain *vdomain;
> >
> > - if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
> > + if (type != IOMMU_DOMAIN_UNMANAGED &&
> > + type != IOMMU_DOMAIN_DMA &&
> > + type != IOMMU_DOMAIN_IDENTITY)
> > return NULL;
> >
> > vdomain = kzalloc(sizeof(*vdomain), GFP_KERNEL);
> > @@ -630,6 +633,17 @@ static int viommu_domain_finalise(struct viommu_endpoint *vdev,
> > vdomain->map_flags = viommu->map_flags;
> > vdomain->viommu = viommu;
> >
> > + if (domain->type == IOMMU_DOMAIN_IDENTITY) {
> > + if (!virtio_has_feature(viommu->vdev,
> nit: couldn't the check be done before the ida_alloc_range(),
> simplifying the failure cleanup?
It could, but patch 5 falls back to identity mappings, which is better
left at the end of the function to keep the error path simple. I put this
at the end already here, so patch 5 doesn't need to move things around.
Thanks,
Jean
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next prev parent reply other threads:[~2021-11-29 15:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 15:52 [PATCH v2 0/5] iommu/virtio: Add identity domains Jean-Philippe Brucker
2021-11-23 15:52 ` [PATCH v2 1/5] iommu/virtio: Add definitions for VIRTIO_IOMMU_F_BYPASS_CONFIG Jean-Philippe Brucker
2021-11-27 7:59 ` Eric Auger
2021-11-29 15:33 ` Jean-Philippe Brucker
2021-11-23 15:52 ` [PATCH v2 2/5] iommu/virtio: Support bypass domains Jean-Philippe Brucker
2021-11-27 16:18 ` Eric Auger
2021-11-29 15:36 ` Jean-Philippe Brucker [this message]
2021-11-23 15:53 ` [PATCH v2 3/5] iommu/virtio: Sort reserved regions Jean-Philippe Brucker
2021-11-27 17:09 ` Eric Auger
2021-11-23 15:53 ` [PATCH v2 4/5] iommu/virtio: Pass end address to viommu_add_mapping() Jean-Philippe Brucker
2021-11-27 17:09 ` Eric Auger
2021-11-27 23:09 ` Michael S. Tsirkin
2021-11-29 15:42 ` Jean-Philippe Brucker
2021-11-23 15:53 ` [PATCH v2 5/5] iommu/virtio: Support identity-mapped domains Jean-Philippe Brucker
2021-11-27 17:09 ` Eric Auger
2021-11-29 15:44 ` Jean-Philippe Brucker
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