Messages in this thread | | | Date | Thu, 22 Sep 2022 10:02:42 +0800 | Subject | Re: [PATCH v4 3/6] iommu: Add return value rules to attach_dev op and APIs | From | Baolu Lu <> |
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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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