On 7/7/2025 1:03 AM, Kirill A. Shutemov wrote:
> From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
>
> Of all the EFI runtime services, set_virtual_address_map() is the only
> one that is called at its lower mapping, which LASS prohibits regardless
> of EFLAGS.AC setting. The only way to allow this to happen is to disable
> LASS in the CR4 register.
>
> Disable LASS around this low address EFI call.
>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> ---
> arch/x86/platform/efi/efi.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
Reviewed-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>
A minor nit below.
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 463b784499a8..5b23c0daedef 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -787,6 +787,7 @@ static void __init __efi_enter_virtual_mode(void)
> int count = 0, pg_shift = 0;
> void *new_memmap = NULL;
> efi_status_t status;
> + unsigned long lass;
> unsigned long pa;
>
The two unsigned longs can be on the same line.
> if (efi_alloc_page_tables()) {
