Hi,
On Wed, 13 Nov 2024 at 02:53, Nicolas Saenz Julienne nsaenz@amazon.com wrote:
Kexec bypasses EFI's switch to virtual mode. In exchange, it has its own routine, kexec_enter_virtual_mode(), which replays the mappings made by the original kernel. Unfortunately, that function fails to reinstate EFI's memory attributes, which would've otherwise been set after entering virtual mode. Remediate this by calling efi_runtime_update_mappings() within kexec's routine.
In the function __map_region(), there are playing with the flags similar to the efi_runtime_update_mappings though it looks a little different. Is this extra callback really necessary?
Have you seen a real bug happened?
Cc: stable@vger.kernel.org Fixes: 18141e89a76c ("x86/efi: Add support for EFI_MEMORY_ATTRIBUTES_TABLE") Signed-off-by: Nicolas Saenz Julienne nsaenz@amazon.com
Notes:
- Tested with QEMU/OVMF.
arch/x86/platform/efi/efi.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 375ebd78296a..a7ff189421c3 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -765,6 +765,7 @@ static void __init kexec_enter_virtual_mode(void)
efi_sync_low_kernel_mappings(); efi_native_runtime_setup();
efi_runtime_update_mappings();#endif }
-- 2.40.1
Thanks Dave