On Wed, Jul 10, 2024 at 07:06:43PM +0300, Alexander Shishkin wrote:
> In order to map the EFI runtime services, set_virtual_address_map
> needs to be called, which resides in the lower half of the address
> space. This means that LASS needs to be temporarily disabled around
> this call. This can only be done before the CR pinning is set up.
>
> Move CR pinning setup behind the EFI initialization.
>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
So the previous patch makes us not boot, and this fixes it up? Perhaps
order things differently?
> ---
> arch/x86/kernel/cpu/common.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 8aa621dc7d30..c93c59a27dfa 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1948,7 +1948,6 @@ static __init void identify_boot_cpu(void)
> enable_sep_cpu();
> #endif
> cpu_detect_tlb(&boot_cpu_data);
> - setup_cr_pinning();
>
> tsx_init();
> tdx_init();
> @@ -2367,10 +2366,16 @@ void __init arch_cpu_finalize_init(void)
>
> /*
> * This needs to follow the FPU initializtion, since EFI depends on it.
> + * It also needs to precede the CR pinning setup, because we need to be
> + * able to temporarily clear the CR4.LASS bit in order to execute the
> + * set_virtual_address_map call, which resides in lower addresses and
> + * would trip LASS if enabled.
> */
> if (efi_enabled(EFI_RUNTIME_SERVICES))
> efi_enter_virtual_mode();
>
> + setup_cr_pinning();
> +
> /*
> * Ensure that access to the per CPU representation has the initial
> * boot CPU configuration.
> --
> 2.43.0
>