On 04/04/14 16:13, Roger Pau Monné wrote: > On 04/04/14 17:01, David Vrabel wrote: >> On 04/04/14 15:41, Roger Pau Monne wrote: >>> Blkback cannot work properly on auto-translated guests if Xen doesn't >>> update the IOMMU when performing grant maps/unmaps, so only attach if >>> the newly introduced XENFEAT_hvm_gntmap_supports_iommu is found. >> >> Can you explain the problem in more detail and which guest >> configurations are affected? >> >> This isn't a problem that is specific to blkback, but any backend that >> grant maps and passes the foreign pages to a device so there needs to be >> a generic solution. >> >> Why can't this be fixed by having the swiotlb bounce foreign pages? > > Yes, it could be fixed with that, FreeBSD has been doing it for a long time. > > But since nobody has complained about this, and the issue has been there > for a long time, I'm not sure it's worth adding all the bounce buffer > code for what seems to be an unused configuration.
Ok. Now that netback also grant maps. Can you make this a generic function and call from netback and blkback? David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
