From: Nicolin Chen <nicolinc@nvidia.com>
To: <joro@8bytes.org>, <suravee.suthikulpanit@amd.com>,
<will@kernel.org>, <robin.murphy@arm.com>, <robdclark@gmail.com>,
<dwmw2@infradead.org>, <baolu.lu@linux.intel.com>,
<agross@kernel.org>, <bjorn.andersson@linaro.org>,
<konrad.dybcio@somainline.org>, <matthias.bgg@gmail.com>,
<heiko@sntech.de>, <orsonzhai@gmail.com>,
<baolin.wang@linux.alibaba.com>, <zhang.lyra@gmail.com>,
<thierry.reding@gmail.com>, <jean-philippe@linaro.org>,
<jgg@nvidia.com>, <sricharan@codeaurora.org>
Cc: <yong.wu@mediatek.com>, <vdumpa@nvidia.com>,
<jonathanh@nvidia.com>, <tglx@linutronix.de>,
<shameerali.kolothum.thodi@huawei.com>,
<thunder.leizhen@huawei.com>, <christophe.jaillet@wanadoo.fr>,
<yangyingliang@huawei.com>, <jon@solid-run.com>,
<iommu@lists.linux.dev>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-arm-msm@vger.kernel.org>,
<linux-mediatek@lists.infradead.org>,
<linux-rockchip@lists.infradead.org>,
<linux-tegra@vger.kernel.org>,
<virtualization@lists.linux-foundation.org>,
<kevin.tian@intel.com>, <quic_jjohnson@quicinc.com>
Subject: [PATCH v2 03/13] iommu: Add return value rules to attach_dev op
Date: Tue, 13 Sep 2022 22:12:34 -0700 [thread overview]
Message-ID: <20220914051234.10006-2-nicolinc@nvidia.com> (raw)
In-Reply-To: <20220914051234.10006-1-nicolinc@nvidia.com>
Cases like VFIO wish to attach a device to an existing domain that was
not allocated specifically from the device. This raises a condition
where the IOMMU driver can fail the domain attach because the domain and
device are incompatible with each other.
This is a soft failure that can be resolved by using a different domain.
Provide a dedicated errno EINVAL from the IOMMU driver during attach that
the reason attached failed is because of domain incompatability.
VFIO can use this to know attach is a soft failure and it should continue
searching. Otherwise the attach will be a hard failure and VFIO will
return the code to userspace.
Update kdocs first to add rules of return value to the attach_dev op.
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
include/linux/iommu.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index ea30f00dc145..aacf9a2b151f 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -266,6 +266,17 @@ struct iommu_ops {
/**
* struct iommu_domain_ops - domain specific operations
* @attach_dev: attach an iommu domain to a device
+ * Return:
+ * * 0 - success
+ * * EINVAL - exclusively, device and domain are incompatible. Must avoid
+ * kernel prints along with this errno. Any EINVAL returned from
+ * a kAPI must be converted to ENODEV if it is device-specific,
+ * or to some other reasonable errno being listed below
+ * * ENOMEM - out of memory
+ * * ENOSPC - no space left on device
+ * * EBUSY - device is attached to a domain and cannot be changed
+ * * ENODEV - device specific errors, not able to be attached
+ * * <others> - treated as ENODEV by the caller. Use is discouraged
* @detach_dev: detach an iommu domain from a device
* @map: map a physically contiguous memory region to an iommu domain
* @map_pages: map a physically contiguous set of pages of the same size to
--
2.17.1
next prev parent reply other threads:[~2022-09-14 5:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-14 5:12 [PATCH v2 00/13] iommu: Define EINVAL as device/domain incompatibility Nicolin Chen
2022-09-14 5:12 ` Nicolin Chen [this message]
2022-09-14 5:29 ` Nicolin Chen
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=20220914051234.10006-2-nicolinc@nvidia.com \
--to=nicolinc@nvidia.com \
--cc=agross@kernel.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=baolu.lu@linux.intel.com \
--cc=bjorn.andersson@linaro.org \
--cc=christophe.jaillet@wanadoo.fr \
--cc=dwmw2@infradead.org \
--cc=heiko@sntech.de \
--cc=iommu@lists.linux.dev \
--cc=jean-philippe@linaro.org \
--cc=jgg@nvidia.com \
--cc=jon@solid-run.com \
--cc=jonathanh@nvidia.com \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=konrad.dybcio@somainline.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=linux-rockchip@lists.infradead.org \
--cc=linux-tegra@vger.kernel.org \
--cc=matthias.bgg@gmail.com \
--cc=orsonzhai@gmail.com \
--cc=quic_jjohnson@quicinc.com \
--cc=robdclark@gmail.com \
--cc=robin.murphy@arm.com \
--cc=shameerali.kolothum.thodi@huawei.com \
--cc=sricharan@codeaurora.org \
--cc=suravee.suthikulpanit@amd.com \
--cc=tglx@linutronix.de \
--cc=thierry.reding@gmail.com \
--cc=thunder.leizhen@huawei.com \
--cc=vdumpa@nvidia.com \
--cc=virtualization@lists.linux-foundation.org \
--cc=will@kernel.org \
--cc=yangyingliang@huawei.com \
--cc=yong.wu@mediatek.com \
--cc=zhang.lyra@gmail.com \
/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).