[RFC v2 08/12] xen/arm: mm: Allow xen_pt_update() to work with the current root table

[Julien Grall <julien@xxxxxxx>]

From: Julien Grall <jgrall@xxxxxxxxxx>

At the moment, xen_pt_update() will only work on the runtime page tables.
In follow-up patches, we will also want to use the helper to update
the boot page tables.

All the existing callers of xen_pt_update() expects to modify the
current page-tables. Therefore, we can read the root physical address
directly from TTBR0_EL2.

Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
----

    Changes in v2:
        - Patch added
---
 xen/arch/arm/mm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 2c6648a0dfe5..a3f604e0e2d1 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1123,7 +1123,7 @@ static int xen_pt_update(unsigned long virt,
      *
      * XXX: Add a check.
      */
-    const mfn_t root = virt_to_mfn(THIS_CPU_PGTABLE);
+    const mfn_t root = maddr_to_mfn(READ_SYSREG64(TTBR0_EL2));
 
     /*
      * The hardware was configured to forbid mapping both writeable and
-- 
2.37.1