Messages in this thread | | | Subject | Re: [PATCH 0/4] vfio-pci/zdev: Fixing s390 vfio-pci ISM support | From | Pierre Morel <> | Date | Wed, 20 Jan 2021 10:02:08 +0100 |
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On 1/19/21 9:02 PM, Matthew Rosato wrote: > Today, ISM devices are completely disallowed for vfio-pci passthrough as > QEMU will reject the device due to an (inappropriate) MSI-X check. > However, in an effort to enable ISM device passthrough, I realized that the > manner in which ISM performs block write operations is highly incompatible > with the way that QEMU s390 PCI instruction interception and > vfio_pci_bar_rw break up I/O operations into 8B and 4B operations -- ISM > devices have particular requirements in regards to the alignment, size and > order of writes performed. Furthermore, they require that legacy/non-MIO > s390 PCI instructions are used, which is also not guaranteed when the I/O > is passed through the typical userspace channels. > > As a result, this patchset proposes a new VFIO region to allow a guest to > pass certain PCI instruction intercepts directly to the s390 host kernel > PCI layer for execution, pinning the guest buffer in memory briefly in > order to execute the requested PCI instruction. > > Changes from RFC -> v1: > - No functional changes, just minor commentary changes -- Re-posting along > with updated QEMU set. >
Hi,
there are is a concerns about this patch series: As the title says it is strongly related to ISM hardware.
Why being so specific?
Regards, Pierre
-- Pierre Morel IBM Lab Boeblingen
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