[Xen-devel] [PATCH v6 7/8] xen/arm: don't iomem_permit_access for reserved-memory regions

[Stefano Stabellini <sstabellini@kernel.org>]

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 <stefanos@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
+     * until reserved-memory support is complete.
+     */
+    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 )
-- 
2.17.1


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