Re: [Xen-devel] [PATCH v13 06/11] x86/hvm/ioreq: add a new mappable resource type...

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 30.10.17 at 18:48, <paul.durrant@xxxxxxxxxx> wrote:
> ... XENMEM_resource_ioreq_server
> 
> This patch adds support for a new resource type that can be mapped using
> the XENMEM_acquire_resource memory op.
> 
> If an emulator makes use of this resource type then, instead of mapping
> gfns, the IOREQ server will allocate pages from the heap. These pages
> will never be present in the P2M of the guest at any point and so are
> not vulnerable to any direct attack by the guest. They are only ever
> accessible by Xen and any domain that has mapping privilege over the
> guest (which may or may not be limited to the domain running the emulator).
> 
> NOTE: Use of the new resource type is not compatible with use of
>       XEN_DMOP_get_ioreq_server_info unless the XEN_DMOP_no_gfns flag is
>       set.
> 
> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
albeit I would have preferred for acquire_ioreq_server() to not
be a separate function anymore now that you have
arch_acquire_resource().

Jan


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