linux-kernel - Re: [PATCH v2] x86/efi: Correct ident mapping of efi old

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Date:   Mon, 8 May 2017 17:25:14 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Baoquan He <bhe@...hat.com>
Cc:     Bhupesh Sharma <bhsharma@...hat.com>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        linux-kernel@...r.kernel.org, Dave Young <dyoung@...hat.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Garnier <thgarnie@...gle.com>,
        Kees Cook <keescook@...omium.org>, x86@...nel.org,
        linux-efi@...r.kernel.org, Alex Thorlton <athorlton@....com>,
        Russ Anderson <rja@....com>,
        Dimitri Sivanich <sivanich@....com>,
        Mike Travis <travis@....com>
Subject: Re: [PATCH v2] x86/efi: Correct ident mapping of efi old_map when
 kalsr enabled

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.