| Date | Thu, 27 May 2021 13:49:05 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH Part1 RFC v2 16/20] x86/kernel: Validate rom memory before accessing when SEV-SNP is active |
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On Fri, Apr 30, 2021 at 07:16:12AM -0500, Brijesh Singh wrote: > + /* > + * The ROM memory is not part of the E820 system RAM and is not pre-validated > + * by the BIOS. The kernel page table maps the ROM region as encrypted memory, > + * the SEV-SNP requires the encrypted memory must be validated before the > + * access. Validate the ROM before accessing it. > + */ > + n = ((system_rom_resource.end + 1) - video_rom_resource.start) >> PAGE_SHIFT; > + early_snp_set_memory_private((unsigned long)__va(video_rom_resource.start), > + video_rom_resource.start, n);
From last review:
I don't like this sprinkling of SNP-special stuff that needs to be done, around the tree. Instead, pls define a function called
snp_prep_memory(unsigned long pa, unsigned int num_pages, enum operation);
or so which does all the manipulation needed and the callsites only simply unconditionally call that function so that all detail is extracted and optimized away when not config-enabled.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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