Re: kexec regression since 4.9 caused by efi

Omar Sandoval
2017-03-16T17:50:48Z

On Thu, Mar 16, 2017 at 12:41:32PM +0000, Matt Fleming wrote:
> On Mon, 13 Mar, at 03:37:48PM, Dave Young wrote:
> >
> > Omar, could you try below patch? Looking at the efi_mem_desc_lookup, it is not
> > correct to be used in efi_arch_mem_reserve, if it passed your test, I
> > can rewrite patch log with more background and send it out:
> >
> > for_each_efi_memory_desc(md) {
> > [snip]
> > if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
> > md->type != EFI_BOOT_SERVICES_DATA &&
> > md->type != EFI_RUNTIME_SERVICES_DATA) {
> > continue;
> > }
> >
> > In above code, it meant to get a md of EFI_MEMORY_RUNTIME of either boot
> > data or runtime data, this is wrong for efi_mem_reserve, because we are
> > reserving boot data which has no EFI_MEMORY_RUNTIME attribute at the
> > running time. Just is happened to work and we did not capture the error.
>
> Wouldn't something like this be simpler?
>
> ---
>
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index 30031d5293c4..cdfe8c628959 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -201,6 +201,10 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
> return;
> }
>
> + /* No need to reserve regions that will never be freed. */
> + if (md.attribute & EFI_MEMORY_RUNTIME)
> + return;
> +
> size += addr % EFI_PAGE_SIZE;
> size = round_up(size, EFI_PAGE_SIZE);
> addr = round_down(addr, EFI_PAGE_SIZE);

This works for me.

Reported-and-tested-by: Omar Sandoval <osandov@fb.com>