On 13.05.2024 15:40, Elias El Yandouzi wrote:
> The early fixed addresses must all fit into the static L1 table.
> Introduce a build assertion to this end.
>
> Signed-off-by: Elias El Yandouzi <elias...@amazon.com>
>
> ----
>
> Changes in v2:
> * New patch
>
> diff --git a/xen/arch/x86/include/asm/fixmap.h
> b/xen/arch/x86/include/asm/fixmap.h
> index a7ac365fc6..904bee0480 100644
> --- a/xen/arch/x86/include/asm/fixmap.h
> +++ b/xen/arch/x86/include/asm/fixmap.h
> @@ -77,6 +77,11 @@ enum fixed_addresses {
> #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
>
> +static inline void fixaddr_build_assertion(void)
> +{
> + BUILD_BUG_ON(FIX_PMAP_END > L1_PAGETABLE_ENTRIES - 1);
> +}
> +
> extern void __set_fixmap(
> enum fixed_addresses idx, unsigned long mfn, unsigned long flags);
>
In addition to earlier comments that were given - this looks like it wants to
be part of another patch (the previous one? a subsequent one?), rather than
being standalone. Such an check makes sense in connection with code actually
leveraging the assumption checked.
Jan
