[xen master] xen/arm: fix iomem permissions cfg in map_range_to_domain()

[patchbot@xxxxxxx]

commit 9568ceb2877dae593dbac29a1154f63bdea65c20
Author:     Grygorii Strashko <gragst.linux@xxxxxxxxx>
AuthorDate: Tue Feb 18 13:22:52 2025 +0200
Commit:     Julien Grall <julien@xxxxxxx>
CommitDate: Wed Mar 12 19:47:04 2025 +0000

    xen/arm: fix iomem permissions cfg in map_range_to_domain()
    
    Now the following code in map_range_to_domain()
    
        res = iomem_permit_access(d, paddr_to_pfn(addr),
                        paddr_to_pfn(PAGE_ALIGN(addr + len - 1)));
    
    calculates the iomem range end address by rounding it up to the next Xen
    page with incorrect assumption that iomem range end address passed to
    iomem_permit_access() is exclusive, while it is expected to be inclusive.
    It gives Control domain (Dom0) access to manage incorrect MMIO range with
    one additional page.
    
    For example, if requested range is [00e6140000:00e6141004] then it expected
    to add [e6140:e6141] range (num_pages=2) to the domain iomem_caps rangeset,
    but will add [e6140:e6142] (num_pages=3) instead.
    
    To fix it, drop PAGE_ALIGN() from the iomem range end address calculation
    formula.
    
    Fixes: 33233c2758345 ("arch/arm: domain build: let dom0 access I/O memory 
of mapped devices")
    Signed-off-by: Grygorii Strashko <grygorii_strashko@xxxxxxxx>
    Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 xen/arch/arm/device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/device.c b/xen/arch/arm/device.c
index 5610cddcba..97e613e06a 100644
--- a/xen/arch/arm/device.c
+++ b/xen/arch/arm/device.c
@@ -71,7 +71,7 @@ int map_range_to_domain(const struct dt_device_node *dev,
                      strlen("/reserved-memory/")) != 0 )
     {
         res = iomem_permit_access(d, paddr_to_pfn(addr),
-                paddr_to_pfn(PAGE_ALIGN(addr + len - 1)));
+                                  paddr_to_pfn(addr + len - 1));
         if ( res )
         {
             printk(XENLOG_ERR "Unable to permit to dom%d access to"
--
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