Re: [PATCH] Revert "vring: Force use of DMA API for ARM-based systems with legacy devices"

2017-02-03 Thread Will Deacon
On Fri, Feb 03, 2017 at 05:49:11AM +0200, Michael S. Tsirkin wrote: > This reverts commit c7070619f3408d9a0dffbed9149e6f00479cf43b. > > This has been shown to regress on some ARM systems: > > by forcing on DMA API usage for ARM systems, we have inadvertently > kicked open a hornets' nest in terms

[PATCH] Revert "vring: Force use of DMA API for ARM-based systems with legacy devices"

2017-02-02 Thread Michael S. Tsirkin
This reverts commit c7070619f3408d9a0dffbed9149e6f00479cf43b. This has been shown to regress on some ARM systems: by forcing on DMA API usage for ARM systems, we have inadvertently kicked open a hornets' nest in terms of cache-coherency. Namely that unless the virtio device is explicitly describe