Hi Stefano,
On 02/04/2022 01:04, Stefano Stabellini wrote:
On Mon, 21 Feb 2022, Julien Grall wrote:
From: Julien Grall <julien.gr...@arm.com>
Now that xen_pt_update_entry() is able to deal with different mapping
size, we can replace the open-coding of the page-tables update by a call
to modify_xen_mappings().
As the function is not meant to fail, a BUG_ON() is added to check the
return.
Signed-off-by: Julien Grall <julien.gr...@arm.com>
Signed-off-by: Julien Grall <jgr...@amazon.com>
Nice!
---
Changes in v2:
- Stay consistent with how function name are used in the commit
message
- Add my AWS signed-off-by
---
xen/arch/arm/mm.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 7b4b9de8693e..f088a4b2de96 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -599,11 +599,11 @@ void * __init early_fdt_map(paddr_t fdt_paddr)
void __init remove_early_mappings(void)
{
- lpae_t pte = {0};
- write_pte(xen_second + second_table_offset(BOOT_FDT_VIRT_START), pte);
- write_pte(xen_second + second_table_offset(BOOT_FDT_VIRT_START + SZ_2M),
- pte);
- flush_xen_tlb_range_va(BOOT_FDT_VIRT_START, BOOT_FDT_SLOT_SIZE);
+ int rc;
+
+ rc = modify_xen_mappings(BOOT_FDT_VIRT_START, BOOT_FDT_VIRT_END,
+ _PAGE_BLOCK);
+ BUG_ON(rc);
Am I right that we are actually destroying the mapping, which usually is
done by calling destroy_xen_mappings, but we cannot call
destroy_xen_mappings in this case because it doesn't take a flags
parameter?
You are right.
If so, then I would add a flags parameter to destroy_xen_mappings
instead of calling modify_xen_mappings just to pass _PAGE_BLOCK.
But I don't feel strongly about it so if you don't feel like making the
change to destroy_xen_mappings, you can add my acked-by here anyway.
destroy_xen_mappings() is a function used by common code. This is the
only place so far where I need to pass _PAGE_BLOCK and I don't expect it
to be used by the common code any time soon.
So I am not in favor to add an extra parameter for destroy_xen_mappings().
Would you prefer if I open-code the call to xen_pt_update?
Cheers,
--
Julien Grall
