[dpdk-dev] [bug] dpdk-vfio: Invalid region/index assumption
Thomas Monjalon
thomas.monjalon at 6wind.com
Thu Jul 28 08:54:42 CEST 2016
Hi,
2016-07-27 16:14, Alex Williamson:
> I took a quick look at the dpdk vfio code and spotted an invalid
> assumption that should probably be corrected ASAP.
It can theoretically be a bug but the value may never change in the kernel,
right?
So when you say ASAP, I feel it can wait the next DPDK release
(we plan to release today).
Do you agree?
> That is:
>
> lib/librte_eal/linuxapp/eal/eal_vfio.h:
> #define VFIO_GET_REGION_ADDR(x) ((uint64_t) x << 40ULL)
> #define VFIO_GET_REGION_IDX(x) (x >> 40)
>
> Region offset to index is an implementation detail of the kernel, the
> vfio API defines that the offset of a given region (BAR) is found via
> the offset field of struct vfio_region_info returned via the
> VFIO_DEVICE_GET_REGION_INFO ioctl. You're free to cache the offset
> into any sort of local variable you like, but the kernel may change the
> implementation of region index to offset at any point in time. This is
> explicitly not part of the ABI. Is there a place to file a bug, or is
> this sufficient? Thanks,
Thanks for the report. This email is sufficient :)
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