search for: arch_vring_eschew_dma_api

...ship with a broken BIOS that misdescribes the >> virtio devices (and any assigned PCI devices) as being behind an IOMMU >> when they're not, in the rare case that Qemu actually exposes its >> partially-implemented virtual IOMMU to the guest? >> >> Could we have an arch_vring_eschew_dma_api(dev) function which the >> affected architectures could provide (as a prelude to fixing it so that >> the DMA API does the right thing for *itself*)? > > I'm fine with this. I modified vring_use_dma_api to take a vring_virtqueue* parameter to make this easier. I'm a bit...

...ship with a broken BIOS that misdescribes the >> virtio devices (and any assigned PCI devices) as being behind an IOMMU >> when they're not, in the rare case that Qemu actually exposes its >> partially-implemented virtual IOMMU to the guest? >> >> Could we have an arch_vring_eschew_dma_api(dev) function which the >> affected architectures could provide (as a prelude to fixing it so that >> the DMA API does the right thing for *itself*)? > > I'm fine with this. I modified vring_use_dma_api to take a vring_virtqueue* parameter to make this easier. I'm a bit...

...t... was the issue *just* that Qemu tends to ship with a broken BIOS that misdescribes the virtio devices (and any assigned PCI devices) as being behind an IOMMU when they're not, in the rare case that Qemu actually exposes its partially-implemented virtual IOMMU to the guest? Could we have an arch_vring_eschew_dma_api(dev) function which the affected architectures could provide (as a prelude to fixing it so that the DMA API does the right thing for *itself*)? It would be functionally equivalent, but it would help to push the workarounds to the right place ? rather than entrenching them for ever in tricky "...

...t... was the issue *just* that Qemu tends to ship with a broken BIOS that misdescribes the virtio devices (and any assigned PCI devices) as being behind an IOMMU when they're not, in the rare case that Qemu actually exposes its partially-implemented virtual IOMMU to the guest? Could we have an arch_vring_eschew_dma_api(dev) function which the affected architectures could provide (as a prelude to fixing it so that the DMA API does the right thing for *itself*)? It would be functionally equivalent, but it would help to push the workarounds to the right place ? rather than entrenching them for ever in tricky "...

...that Qemu tends to ship with a broken BIOS that misdescribes the > virtio devices (and any assigned PCI devices) as being behind an IOMMU > when they're not, in the rare case that Qemu actually exposes its > partially-implemented virtual IOMMU to the guest? > > Could we have an arch_vring_eschew_dma_api(dev) function which the > affected architectures could provide (as a prelude to fixing it so that > the DMA API does the right thing for *itself*)? I'm fine with this. > It would be functionally equivalent, but it would help to push the > workarounds to the right place ? rather th...

This switches virtio to use the DMA API on Xen and if requested by module option. This fixes virtio on Xen, and it should break anything because it's off by default on everything except Xen PV on x86. To the Xen people: is this okay? If it doesn't work on other Xen variants (PVH? HVM?), can you submit follow-up patches to fix it? To everyone else: we've waffled on this for way too

This switches virtio to use the DMA API on Xen and if requested by module option. This fixes virtio on Xen, and it should break anything because it's off by default on everything except Xen PV on x86. To the Xen people: is this okay? If it doesn't work on other Xen variants (PVH? HVM?), can you submit follow-up patches to fix it? To everyone else: we've waffled on this for way too