Hi Edgar,
On 26/01/2017 12:52, Edgar E. Iglesias wrote:
On Thu, Jan 19, 2017 at 12:40:45PM +0000, Julien Grall wrote:
On 10/01/2017 11:37, Edgar E. Iglesias wrote:
From: "Edgar E. Iglesias" <edgar.igles...@xilinx.com>
Relax the hardware domains mapping attributes to p2m_mmio_direct_c.
This will allow the hardware domain to fully control the
attribtues via its S1 mappings.
s/attribtues/attributes/
Fixed for v2.
I would like some rationale in the commit message to explain why it is fine
to do this relaxation (e.g the hardware domain is a trusted domain).
I've added the following for v2:
Since the hardware domain is a trusted domain, we extend the
trust to include making final decisions on what attributes to
use when mapping memory regions.
For device-tree configured hardware domains, this patch relaxes
I would drop the "For device-tree configured hardware domains" as you
will also fix ACPI. The rest looks good to me.
the hardware domains mapping attributes to p2m_mmio_direct_c.
This will allow the hardware domain to control the attributes
via its S1 mappings.
A such relaxation would probably be necessary for the ACPI case too (see
map_dev_mmio_region).
I don't have testcases for ACPI but I'll try to fix it.
Please correct me if I'm wrong. IIUC, when using ACPI, we map in a few
selected devices (UART, GIC, SMMU, RAM) to dom0 but leave the rest unmapped.
Dom0 then parses ACPI tables and issues hypervisor calls to map individual
devices (XENMEM_add_to_physmap with XENMAPSPACE_dev_mmio).
That is correct.
Since XENMEM_add_to_physmap with XENMAPSPACE_dev_mmio is only used
for dom0 mappings, I think this relaxation would be safe:
+++ b/xen/arch/arm/p2m.c
@@ -1185,7 +1185,7 @@ int map_dev_mmio_region(struct domain *d,
if ( !(nr && iomem_access_permitted(d, mfn_x(mfn), mfn_x(mfn) + nr - 1)) )
return 0;
- res = map_mmio_regions(d, gfn, nr, mfn);
+ res = p2m_insert_mapping(d, gfn, nr, mfn, p2m_mmio_direct_c);
if ( res < 0 )
{
This change looks good to me. I will give a try when the new version
will be sent.
Anyway, I'll send the v2 series out and we can discuss from there.
Can you also please modify the comment on "XENMEMSPACE_dev_mmio" in
xen/include/public/memory.h regarding the memory attribute used to map?
Cheers,
--
Julien Grall
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