iommu: vfio: pass vf_token only when SR-IOV is involved#59
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lsgunth
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I've reviewed this PR and it looks good to me save one question I could go either way on:
If VFTOKEN is set in the environment but not used because pci_is_sriov_supported() is false, should the user get a warning message saying the value was ignored?
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The VF token mechanism is only relevant when SR-IOV is in use: either the device being opened is a VF, or it is a PF that supports SR-IOV. Passing a vf_token to VFIO_GROUP_GET_DEVICE_FD for a device that has nothing to do with SR-IOV causes the ioctl to fail. Guard the vf_token handling with a new helper pci_is_sriov_supported, which returns true if the device is an SR-IOV capable PF (pci_is_pf) or a VF (pci_is_vf). pci_is_pf checks for the presence of sriov_numvfs in sysfs; devices that do not support SR-IOV simply lack that file. Link: https://lore.kernel.org/all/20200319182730.16f4c476.cohuck@redhat.com Signed-off-by: Jonghwi Jeong <jongh2.jeong@samsung.com> Signed-off-by: Minwoo Im <minwoo.im@samsung.com>
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The VF token mechanism is only relevant when SR-IOV is in use: either the device being opened is a VF, or it is a PF that supports SR-IOV. Passing a vf_token to VFIO_GROUP_GET_DEVICE_FD for a device that has nothing to do with SR-IOV causes the ioctl to fail.
Guard the vf_token handling with a new helper pci_is_sriov_supported, which returns true if the device is an SR-IOV capable PF (pci_is_pf) or a VF (pci_is_vf). pci_is_pf checks for the presence of sriov_numvfs in sysfs; devices that do not support SR-IOV simply lack that file.
Link: https://lore.kernel.org/all/20200319182730.16f4c476.cohuck@redhat.com