From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 5/5] iommu: Allow default domain type to be set on the kernel command line
Date: Tue, 21 Mar 2017 18:17:29 +0000 [thread overview]
Message-ID: <20170321181729.GG30948@arm.com> (raw)
In-Reply-To: <807ecbb0-c9d7-fc0a-25d2-93b5c4374107@arm.com>
On Tue, Mar 21, 2017 at 05:46:29PM +0000, Robin Murphy wrote:
> On 21/03/17 17:21, Will Deacon wrote:
> > On Tue, Mar 21, 2017 at 04:45:27PM +0100, Joerg Roedel wrote:
> >> On Fri, Mar 10, 2017 at 08:49:36PM +0000, Will Deacon wrote:
> >>> @@ -1014,8 +1027,8 @@ struct iommu_group *iommu_group_get_for_dev(struct device *dev)
> >>> * IOMMU driver.
> >>> */
> >>> if (!group->default_domain) {
> >>> - group->default_domain = __iommu_domain_alloc(dev->bus,
> >>> - IOMMU_DOMAIN_DMA);
> >>> + group->default_domain =
> >>> + __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
> >>
> >> It would be good to have a fall-back here if we are talking to an IOMMU
> >> driver that uses default domains, but does not support identity-mapped
> >> domains (yet). Exynos and Rockchip IOMMU drivers seem to fall into this
> >> category. A dev_warn() also makes sense in case allocating a identity
> >> domain fails.
> >
> > Sure, something like the diff below?
> >
> > Will
> >
> > --->8
> >
> >
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index 42a842e3f95f..f787626a745d 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -1027,10 +1027,19 @@ struct iommu_group *iommu_group_get_for_dev(struct device *dev)
> > * IOMMU driver.
> > */
> > if (!group->default_domain) {
> > - group->default_domain =
> > - __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
> > + struct iommu_domain *dom;
> > +
> > + dom = __iommu_domain_alloc(dev->bus, iommu_def_domain_type);
> > + if (!dom) {
> > + dev_warn(dev,
> > + "failed to allocate default IOMMU domain of type %u; falling back to IOMMU_DOMAIN_DMA",
> > + iommu_def_domain_type);
>
> Conversely, that's going to be noisy if iommu_def_domain_type was
> IOMMU_DOMAIN_DMA to begin with. I think it makes sense to warn if the
> user asked for a specific default domain type on the command line and
> that didn't work, but maybe not to bother otherwise. Plus, if they asked
> for passthrough, then not allocating a default domain at all is probably
> closer to the desired result than installing a DMA ops domain would be.
You're right -- I'll hack this about to check if the default type isn't
DOMAIN_DMA before warning about the allocation failure.
Cheers,
Will
next prev parent reply other threads:[~2017-03-21 18:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-10 20:49 [PATCH v2 0/5] Implement SMMU passthrough using the default domain Will Deacon
2017-03-10 20:49 ` [PATCH v2 1/5] iommu/arm-smmu: Restrict domain attributes to UNMANAGED domains Will Deacon
2017-03-10 20:49 ` [PATCH v2 2/5] iommu/arm-smmu: Install bypass S2CRs for IOMMU_DOMAIN_IDENTITY domains Will Deacon
2017-03-10 20:49 ` [PATCH v2 3/5] iommu/arm-smmu-v3: Make arm_smmu_install_ste_for_dev return void Will Deacon
2017-03-16 16:55 ` Nate Watterson
2017-03-10 20:49 ` [PATCH v2 4/5] iommu/arm-smmu-v3: Install bypass STEs for IOMMU_DOMAIN_IDENTITY domains Will Deacon
2017-03-16 16:24 ` Nate Watterson
2017-03-16 18:19 ` Robin Murphy
2017-03-21 17:08 ` Will Deacon
2017-03-21 17:33 ` Robin Murphy
2017-03-10 20:49 ` [PATCH v2 5/5] iommu: Allow default domain type to be set on the kernel command line Will Deacon
2017-03-21 15:45 ` Joerg Roedel
2017-03-21 17:21 ` Will Deacon
2017-03-21 17:46 ` Robin Murphy
2017-03-21 18:17 ` Will Deacon [this message]
2017-03-23 10:22 ` Sricharan R
2017-03-23 10:38 ` Sricharan R
2017-03-22 11:25 ` Joerg Roedel
2017-03-21 15:46 ` [PATCH v2 0/5] Implement SMMU passthrough using the default domain Joerg Roedel
2017-03-21 16:42 ` Will Deacon
2017-03-21 16:46 ` Joerg Roedel
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=20170321181729.GG30948@arm.com \
--to=will.deacon@arm$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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