[Xen-changelog] [xen staging] xen/arm: don't iomem_permit_access for reserved-memory regions

[patchbot@xxxxxxx]

commit f9335bd4b89ba398ae993a0655c40c545b75d7c1
Author:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
AuthorDate: Mon Aug 19 10:43:37 2019 -0700
Commit:     Julien Grall <julien.grall@xxxxxxx>
CommitDate: Tue Aug 20 13:40:20 2019 +0100

    xen/arm: don't iomem_permit_access for reserved-memory regions
    
    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@xxxxxxxxxx>
    Acked-by: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/domain_build.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 4e51e22927..d3ca5fe203 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1165,15 +1165,24 @@ 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 )
+    /*
+     * reserved-memory regions are RAM carved out for a 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 )
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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