From: Baolu Lu <baolu.lu@linux.intel.com>
To: Nicolin Chen <nicolinc@nvidia.com>,
joro@8bytes.org, suravee.suthikulpanit@amd.com, will@kernel.org,
robin.murphy@arm.com, robdclark@gmail.com, dwmw2@infradead.org,
agross@kernel.org, bjorn.andersson@linaro.org,
matthias.bgg@gmail.com, orsonzhai@gmail.com,
baolin.wang@linux.alibaba.com, zhang.lyra@gmail.com,
jean-philippe@linaro.org, sricharan@codeaurora.org
Cc: quic_saipraka@quicinc.com, konrad.dybcio@somainline.org,
virtualization@lists.linux-foundation.org,
thierry.reding@gmail.com, jon@solid-run.com,
jonathanh@nvidia.com, iommu@lists.linux.dev,
yong.wu@mediatek.com, jgg@nvidia.com, yangyingliang@huawei.com,
kevin.tian@intel.com, linux-arm-msm@vger.kernel.org,
christophe.jaillet@wanadoo.fr, thunder.leizhen@huawei.com,
linux-tegra@vger.kernel.org, tglx@linutronix.de,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
shameerali.kolothum.thodi@huawei.com,
linux-mediatek@lists.infradead.org, baolu.lu@linux.intel.com
Subject: Re: [PATCH v4 3/6] iommu: Add return value rules to attach_dev op and APIs
Date: Thu, 22 Sep 2022 10:02:42 +0800 [thread overview]
Message-ID: <73008702-87e1-688f-b194-c259c9c03caa@linux.intel.com> (raw)
In-Reply-To: <8c3dbf153b63a3002a46bab6e707c63fd8635bb8.1663744983.git.nicolinc@nvidia.com>
On 9/21/22 4:23 PM, Nicolin Chen wrote:
> 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 why the attach failed is because of domain incompatibility.
>
> VFIO can use this to know that the 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 to add rules of return value to the attach_dev op and APIs.
>
> Suggested-by: Jason Gunthorpe<jgg@nvidia.com>
> Signed-off-by: Nicolin Chen<nicolinc@nvidia.com>
> ---
> drivers/iommu/iommu.c | 22 ++++++++++++++++++++++
> include/linux/iommu.h | 12 ++++++++++++
> 2 files changed, 34 insertions(+)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 3a808146b50f..1d1e32aeaae6 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1975,6 +1975,17 @@ static int __iommu_attach_device(struct iommu_domain *domain,
> return ret;
> }
>
> +/**
> + * iommu_attach_device - Attach a device to an IOMMU domain
Normally we say "attach an iommu domain to a device/group ...".
Best regards,
baolu
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next prev parent reply other threads:[~2022-09-22 2:10 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 8:22 [PATCH v4 0/6] Define EINVAL as device/domain incompatibility Nicolin Chen
2022-09-21 8:23 ` [PATCH v4 3/6] iommu: Add return value rules to attach_dev op and APIs Nicolin Chen
2022-09-22 2:02 ` Baolu Lu [this message]
2022-09-22 5:09 ` Nicolin Chen
2022-09-22 8:17 ` Tian, Kevin
2022-09-22 8:38 ` Nicolin Chen
2022-09-21 8:23 ` [PATCH v4 4/6] iommu: Regulate EINVAL in ->attach_dev callback functions Nicolin Chen
2022-09-22 2:14 ` Baolu Lu
2022-09-22 8:18 ` Tian, Kevin
2022-09-21 8:23 ` [PATCH v4 5/6] iommu: Use EINVAL for incompatible device/domain in ->attach_dev Nicolin Chen
2022-09-22 2:16 ` Baolu Lu
2022-09-22 8:19 ` Tian, Kevin
2022-09-21 8:23 ` [PATCH v4 6/6] iommu: Propagate return value in ->attach_dev callback functions Nicolin Chen
2022-09-21 8:55 ` [PATCH v4 0/6] Define EINVAL as device/domain incompatibility Jean-Philippe Brucker
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