linux-kernel - Re: [PATCH] x86/mm: Fix PAGE_KERNEL

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Message-ID: <a155df16-ce8f-e884-221b-c3ff9b11eca7@amd.com>
Date:   Thu, 2 Dec 2021 09:52:28 -0600
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Joerg Roedel <joro@...tes.org>, x86@...nel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>
Cc:     Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>, hpa@...or.com,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Brijesh Singh <brijesh.singh@....com>,
        linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>,
        Lucas De Marchi <lucas.demarchi@...el.com>
Subject: Re: [PATCH] x86/mm: Fix PAGE_KERNEL_IO removal breakage

On 12/2/21 8:46 AM, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@...e.de>
> 
> The removal of PAGE_KERNEL_IO broke SEV-ES because it changed the
> mapping of ioremap and some fixmap areas (like the local APIC page)
> from unencrypted to encrypted. Change those mappings back to
> be unencrypted.

SME was also broken and I can verify this patch fixes SME, too.

Tested-by: Tom Lendacky <thomas.lendacky@....com>

Thanks,
Tom

> 
> Cc: Lucas De Marchi <lucas.demarchi@...el.com>
> Fixes: 27dff0f58bde ("x86/mm: Nuke PAGE_KERNEL_IO")
> Signed-off-by: Joerg Roedel <jroedel@...e.de>
> ---
>   arch/x86/include/asm/fixmap.h        |  2 +-
>   arch/x86/include/asm/pgtable_types.h | 21 +++++++++++----------
>   arch/x86/mm/ioremap.c                |  2 +-
>   3 files changed, 13 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
> index 5e186a69db10..a2eaf265f784 100644
> --- a/arch/x86/include/asm/fixmap.h
> +++ b/arch/x86/include/asm/fixmap.h
> @@ -173,7 +173,7 @@ static inline void __set_fixmap(enum fixed_addresses idx,
>    * supported for MMIO addresses, so make sure that the memory encryption
>    * mask is not part of the page attributes.
>    */
> -#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
> +#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE_NOENC
>   
>   /*
>    * Early memremap routines used for in-place encryption. The mappings created
> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
> index a87224767ff3..fc9b6995cb22 100644
> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -208,16 +208,17 @@ enum page_cache_mode {
>   
>   #define __pgprot_mask(x)	__pgprot((x) & __default_kernel_pte_mask)
>   
> -#define PAGE_KERNEL		__pgprot_mask(__PAGE_KERNEL            | _ENC)
> -#define PAGE_KERNEL_NOENC	__pgprot_mask(__PAGE_KERNEL            |    0)
> -#define PAGE_KERNEL_RO		__pgprot_mask(__PAGE_KERNEL_RO         | _ENC)
> -#define PAGE_KERNEL_EXEC	__pgprot_mask(__PAGE_KERNEL_EXEC       | _ENC)
> -#define PAGE_KERNEL_EXEC_NOENC	__pgprot_mask(__PAGE_KERNEL_EXEC       |    0)
> -#define PAGE_KERNEL_ROX		__pgprot_mask(__PAGE_KERNEL_ROX        | _ENC)
> -#define PAGE_KERNEL_NOCACHE	__pgprot_mask(__PAGE_KERNEL_NOCACHE    | _ENC)
> -#define PAGE_KERNEL_LARGE	__pgprot_mask(__PAGE_KERNEL_LARGE      | _ENC)
> -#define PAGE_KERNEL_LARGE_EXEC	__pgprot_mask(__PAGE_KERNEL_LARGE_EXEC | _ENC)
> -#define PAGE_KERNEL_VVAR	__pgprot_mask(__PAGE_KERNEL_VVAR       | _ENC)
> +#define PAGE_KERNEL			__pgprot_mask(__PAGE_KERNEL            | _ENC)
> +#define PAGE_KERNEL_NOENC		__pgprot_mask(__PAGE_KERNEL            |    0)
> +#define PAGE_KERNEL_RO			__pgprot_mask(__PAGE_KERNEL_RO         | _ENC)
> +#define PAGE_KERNEL_EXEC		__pgprot_mask(__PAGE_KERNEL_EXEC       | _ENC)
> +#define PAGE_KERNEL_EXEC_NOENC		__pgprot_mask(__PAGE_KERNEL_EXEC       |    0)
> +#define PAGE_KERNEL_ROX			__pgprot_mask(__PAGE_KERNEL_ROX        | _ENC)
> +#define PAGE_KERNEL_NOCACHE		__pgprot_mask(__PAGE_KERNEL_NOCACHE    | _ENC)
> +#define PAGE_KERNEL_NOCACHE_NOENC	__pgprot_mask(__PAGE_KERNEL_NOCACHE    |    0)
> +#define PAGE_KERNEL_LARGE		__pgprot_mask(__PAGE_KERNEL_LARGE      | _ENC)
> +#define PAGE_KERNEL_LARGE_EXEC		__pgprot_mask(__PAGE_KERNEL_LARGE_EXEC | _ENC)
> +#define PAGE_KERNEL_VVAR		__pgprot_mask(__PAGE_KERNEL_VVAR       | _ENC)
>   
>   #endif	/* __ASSEMBLY__ */
>   
> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
> index 3102dda4b152..4fe8d43d53bb 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -243,7 +243,7 @@ __ioremap_caller(resource_size_t phys_addr, unsigned long size,
>   	 * make sure the memory encryption attribute is enabled in the
>   	 * resulting mapping.
>   	 */
> -	prot = PAGE_KERNEL;
> +	prot = PAGE_KERNEL_NOENC;
>   	if ((io_desc.flags & IORES_MAP_ENCRYPTED) || encrypted)
>   		prot = pgprot_encrypted(prot);
>   
>