Hi,
On 16/08/2019 00:36, Stefano Stabellini wrote:
Don't allow reserved-memory regions to be remapped into any unprivileged
guests, until reserved-memory regions are properly supported in Xen. For
now, do not call iomem_permit_access on them, because giving
iomem_permit_access to dom0 means that the toolstack will be able to
assign the region to a domU.
Signed-off-by: Stefano Stabellini <stefa...@xilinx.com>
---
Changes in v6:
- compare against "/reserved-memory/"
Changes in v5:
- fix check condition
- use strnicmp
- return error
- improve commit message
Changes in v4:
- compare the parent name with reserved-memory
- use dt_node_cmp
Changes in v3:
- new patch
---
xen/arch/arm/domain_build.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 4c8404155a..673ffa453f 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1155,15 +1155,23 @@ static int __init map_range_to_domain(const struct
dt_device_node *dev,
bool need_mapping = !dt_device_for_passthrough(dev);
int res;
- res = iomem_permit_access(d, paddr_to_pfn(addr),
- paddr_to_pfn(PAGE_ALIGN(addr + len - 1)));
- if ( res )
+ /*
+ * Don't give iomem permissions for reserved-memory ranges to domUs
In upstream Xen, this is only called for Dom0. So what are you referring to?
+ * until reserved-memory support is complete.
But as I pointed out before reserved-memory support is not going to happen via
iomem. This is an abuse of the interface.
+ */
A better comment would be:
"reserved-memory regions are RAM carved out for special purpose. They are not
MMIO and therefore a domain should not be able to manage them via the IOMEM
interface".
+ if ( strnicmp(dt_node_full_name(dev), "/reserved-memory/",
+ strlen("/reserved-memory/")) != 0 )
{
- printk(XENLOG_ERR "Unable to permit to dom%d access to"
- " 0x%"PRIx64" - 0x%"PRIx64"\n",
- d->domain_id,
- addr & PAGE_MASK, PAGE_ALIGN(addr + len) - 1);
- return res;
+ res = iomem_permit_access(d, paddr_to_pfn(addr),
+ paddr_to_pfn(PAGE_ALIGN(addr + len - 1)));
+ if ( res )
+ {
+ printk(XENLOG_ERR "Unable to permit to dom%d access to"
+ " 0x%"PRIx64" - 0x%"PRIx64"\n",
+ d->domain_id,
+ addr & PAGE_MASK, PAGE_ALIGN(addr + len) - 1);
+ return res;
+ }
}
if ( need_mapping )
Cheers,
--
Julien Grall
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