On Sun, Nov 22, 2015 at 03:54:21PM +0000, David Woodhouse wrote: > On Sun, 2015-11-22 at 15:06 +0200, Marcel Apfelbaum wrote: > > > > > > I tried to generate a DMAR table that excludes some devices from > > IOMMU translation, however it does not help. > > > > The reason is, as far as I understand, that Linux kernel does > > not allow any device being outside an IOMMU scope if the > > iommu kernel option is activated. > > > > Does anybody know if it is "by design" or is simply an uncommon > > configuration? > > (some devices in an IOMMU scope, while others outside *any* IOMMU > > scope) > > That's a kernel bug in the way it handles per-device DMA operations. Or > more to the point, in the way it doesn't — the non-translated devices > end up being pointed to the intel_dma_ops despite the fact they > shouldn't be. I'm working on that... > > -- > dwmw2 >
Interesting. This seems to imply such configurations aren't common, so I wonder whether other guest OS-es treat them correctly. If many of them are, we probably shouldn't use this in QEMU: we care about guests actually working :) -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
