Now the following code in map_range_to_domain()

 res = rangeset_add_range(mr_data->iomem_ranges,
                          paddr_to_pfn(addr),
                          paddr_to_pfn_aligned(addr + len - 1));
 where
  paddr_to_pfn_aligned(paddr) defined as paddr_to_pfn(PAGE_ALIGN(paddr))

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
rangeset_add_range() is exclusive, while it is expected to be inclusive.

For example, if requested range is [00e6140000:00e6141004] then it expected
to add [e6140:e6141] range (num_pages=2) to the mr_data->iomem_ranges
rangeset, but will add [e6140:e6142] (num_pages=3) instead.

To fix it, drop PAGE_ALIGN() from the iomem range end address calculation
formula and just use paddr_to_pfn(addr + len - 1).

Fixes: 57d4d7d4e8f3b (arm/asm/setup.h: Update struct map_range_data to add
rangeset.")
Signed-off-by: Grygorii Strashko <grygorii_strashko@epam.com>
---
 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 97e613e06afa..5e1c1cc326ac 100644
--- a/xen/arch/arm/device.c
+++ b/xen/arch/arm/device.c
@@ -107,7 +107,7 @@ int map_range_to_domain(const struct dt_device_node *dev,
     {
         res = rangeset_add_range(mr_data->iomem_ranges,
                                  paddr_to_pfn(addr),
-                                 paddr_to_pfn_aligned(addr + len - 1));
+                                 paddr_to_pfn(addr + len - 1));
         if ( res )
             return res;
     }
-- 
2.34.1

Hi Grygorii,

On 18/02/2025 11:22, Grygorii Strashko wrote:
> Now the following code in map_range_to_domain()
> 
>   res = rangeset_add_range(mr_data->iomem_ranges,
>                            paddr_to_pfn(addr),
>                            paddr_to_pfn_aligned(addr + len - 1));
>   where
>    paddr_to_pfn_aligned(paddr) defined as paddr_to_pfn(PAGE_ALIGN(paddr))
> 
> 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
> rangeset_add_range() is exclusive, while it is expected to be inclusive.
> 
> For example, if requested range is [00e6140000:00e6141004] then it expected
> to add [e6140:e6141] range (num_pages=2) to the mr_data->iomem_ranges
> rangeset, but will add [e6140:e6142] (num_pages=3) instead.
> 
> To fix it, drop PAGE_ALIGN() from the iomem range end address calculation
> formula and just use paddr_to_pfn(addr + len - 1).
> 
> Fixes: 57d4d7d4e8f3b (arm/asm/setup.h: Update struct map_range_data to add
> rangeset.")
> Signed-off-by: Grygorii Strashko <grygorii_strashko@epam.com>

Reviewed-by: Julien Grall <jgrall@amazon.com>

Cheers,

-- 
Julien Grall