Re: [PATCH v2] x86/efi: Correct ident mapping of efi old_map when kalsr enabled

Borislav Petkov
2017-05-08T15:25:33Z

On Mon, May 08, 2017 at 09:36:49AM +0800, Baoquan He wrote:
> Thanks for explaining, Bhupesh.
>
> BIOS issue of SGI uv1 is still not fixed. There's a quirk for uv1 to
> use efi old map:
>
> void __init efi_apply_memmap_quirks(void)
> {
> ...
> ...
> /* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */
> if (dmi_check_system(sgi_uv1_dmi))
> set_bit(EFI_OLD_MEMMAP, &efi.flags);
> }
>
> And because of some reasons, redhat also need efi old_map now.
>
> Hi Matt,
>
> This v2 patch works on my kvm guest, however there's still problem on
> SGI system. I will post v3 later after it's handled. So nack this v2
> patch.

Please do not top-post, you should know better.

Can you apply this debug patch and upload full dmesg?

---
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index c488625c9712..ca9df6283040 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -88,9 +88,18 @@ pgd_t * __init efi_call_phys_prolog(void)
n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);

+ pr_info("%s: PAGE_OFFSET: 0x%lx\n", __func__, PAGE_OFFSET);
+
for (pgd = 0; pgd < n_pgds; pgd++) {
save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
+
+ pr_info("%s: pgd: 0x%x: va: 0x%lx, 0x%lx -> 0x%lx\n",
+ __func__, pgd,
+ vaddress,
+ pgd_val(*pgd_offset_k(pgd * PGDIR_SIZE)),
+ pgd_val(*pgd_offset_k(vaddress)));
+
set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
}
out:
---

Thanks.

--
Regards/Gruss,
Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.