Hi Michael, On 11/23/22 07:34, Michael S. Tsirkin wrote: > On Fri, May 06, 2022 at 03:25:08PM +0200, Eric Auger wrote: >> The CRB command buffer currently is a RAM MemoryRegion and given >> its base address alignment, it causes an error report on >> vfio_listener_region_add(). This region could have been a RAM device >> region, easing the detection of such safe situation but this option >> was not well received. > Eric could you point me at this discussion please? > We are now asked to proliferate stuff like this into vdpa > as well, this just doesn't scale. I'd like to see whether we > can make it a RAM device region after all - was a patch > like that posted? The bulk of the discussion happened in https://lore.kernel.org/all/20220208133842.112017-1-eric.au...@redhat.com/#r
See exchanges with Peter who was against turning the CRB cmd/response buffer into a RAM device region at that time, hence the current workaround. You will see there also discussions about the buffer size in https://lore.kernel.org/all/eae7e6e6-2f56-c263-f1d2-19104201c...@redhat.com/ Thanks Eric > >> So let's add a helper function that uses the >> memory region owner type to detect the situation is safe wrt >> the assignment. Other device types can be checked here if such kind >> of problem occurs again. >> >> As TPM devices can be compiled out we need to introduce a stub >> for TPM_IS_CRB. >> >> Best Regards >> >> Eric >> >> This series can be found at: >> https://github.com/eauger/qemu/tree/tpm-crb-vfio-v5 >> >> History: >> >> v4 -> v5: >> - Add sysemu: tpm: Add a stub function for TPM_IS_CRB to fix >> compilation error if CONFIG_TPM is unset >> >> Eric Auger (2): >> sysemu: tpm: Add a stub function for TPM_IS_CRB >> vfio/common: remove spurious tpm-crb-cmd misalignment warning >> >> hw/vfio/common.c | 27 ++++++++++++++++++++++++++- >> hw/vfio/trace-events | 1 + >> include/sysemu/tpm.h | 6 ++++++ >> 3 files changed, 33 insertions(+), 1 deletion(-) >> >> -- >> 2.35.1 >> >> >>
