Re: [PATCH RFC 3/6] efi: Add EFI_MEMORY_ISA_{MASK,VALID}

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The newly introduced EFI_MEMORY_ISA_MASK and EFI_MEMORY_ISA_VALID attributes are omitted from the known attributes mask in efi_md_typeattr_format(), breaking human-readable formatting for memory regions using these attributes.
--

--- Patch [3]: [PATCH RFC 3/6] efi: Add EFI_MEMORY_ISA_{MASK,VALID} ---
commit c6357eb92aeb854ab69dbec9ea5006a518bddfd0
Author: Sven Peter <sven@kernel.org>

efi: Add EFI_MEMORY_ISA_{MASK,VALID}

This commit introduces new memory region attributes defined in UEFI 2.10
that allow mapping with ISA-specific cacheability attributes.

Link: https://uefi.org/specs/UEFI/2.10/07_Services_Boot_Services.html#efi-boot-services-getmemorymap
Link: https://uefi.org/specs/UEFI/2.10/02_Overview.html#memory-types

> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index f3db3a18b5404..882148114068f 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -128,6 +128,8 @@ typedef	struct {
>  #define EFI_MEMORY_SP			BIT_ULL(18)	/* soft reserved */
>  #define EFI_MEMORY_CPU_CRYPTO		BIT_ULL(19)	/* supports encryption */
>  #define EFI_MEMORY_HOT_PLUGGABLE	BIT_ULL(20)	/* supports unplugging at runtime */
> +#define EFI_MEMORY_ISA_MASK		GENMASK_ULL(59, 44)	/* ISA-specific attributes */
> +#define EFI_MEMORY_ISA_VALID		BIT_ULL(62)	/* EFI_MEMORY_ISA_MASK bits are valid */

[Severity: Medium]
Should these new attributes be added to the known attributes whitelist in
efi_md_typeattr_format() over in drivers/firmware/efi/efi.c?

Because they are omitted from the inverted mask check there, if system
firmware provides a memory descriptor containing these new UEFI 2.10
attributes, won't the formatter fall back to printing a raw hexadecimal
string instead of human-readable attributes?

drivers/firmware/efi/efi.c:efi_md_typeattr_format() {
    ...
    if (attr & ~(EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT |
                 EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_RO |
                 EFI_MEMORY_WP | EFI_MEMORY_RP | EFI_MEMORY_XP |
                 EFI_MEMORY_NV | EFI_MEMORY_SP | EFI_MEMORY_CPU_CRYPTO |
                 EFI_MEMORY_MORE_RELIABLE | EFI_MEMORY_HOT_PLUGGABLE |
                 EFI_MEMORY_RUNTIME))
        snprintf(pos, size, "|attr=0x%016llx]",
                 (unsigned long long)attr);
    ...
}

>  #define EFI_MEMORY_RUNTIME		BIT_ULL(63)	/* range requires runtime mapping */
>  
>  #define EFI_MEMORY_DESCRIPTOR_VERSION	1

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260708-efi-psci-v1-0-9efb3abf0e4c@kernel.org?part=3