Messages in this thread | | | Date | Mon, 18 Sep 2023 17:13:50 -0700 | Subject | Re: [PATCH vfio] vfio/pci: remove msi domain on msi disable | From | "Nelson, Shannon" <> |
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On 9/18/2023 4:32 PM, Jason Gunthorpe wrote: > > On Mon, Sep 18, 2023 at 10:48:54AM -0700, Nelson, Shannon wrote: > >> In our case, the VF device's msix count value found in PCI config space is >> changed by device configuration management outside of the baremetal host and >> read by the QEMU instance when it starts up, and then read by the vfio PCI >> core when QEMU requests the first IRQ. > > Oh, you definitely can't do that! > > PCI config space is not allowed to change outside the OS's view and we > added sriov_set_msix_vec_count() specifically as a way to provide the > necessary synchronization between all the parts. > > Randomly changing, what should be immutable, parts of the config space > from under a running OS is just non-compliant PCI behavior.
Hmmm... I guess I need to have a little chat with my friendly HW/FW folks.
Thanks, sln
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