Re: [Xen-devel] [PATCH 3/3] xen: expose that grant table mappings update the IOMMU

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.04.14 at 10:34, <Ian.Campbell@xxxxxxxxxx> wrote:
> On Mon, 2014-04-07 at 18:02 +0200, Roger Pau Monne wrote:
>> Add a new XENFEAT_hvm_gntmap_supports_iommu that is used to check
>> whether the hypervisor properly updates the IOMMU on auto-translated
>> guests when doing a grant table map/unmap operation.
> 
> Is it the case on x86 that all devices are behind the IOMMU?

All PCI ones are. If someone passes through a device through
raw MMIO/PIO/PIRQ ranges, then the IOMMU may or may not
be involved. But I don't think we formally consider this model
valid/supported/secure for HVM guests (and for PV guests it's
insecure anyway, due to not requiring an IOMMU in the first
place).

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel