linux-kernel - Re: [PATCH v3 4/6] x86,s390/mm: Move sme_active() and sme_me

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Message-ID: <cf48e778-130a-df2a-d94b-170bd85d692c@amd.com>
Date:   Thu, 18 Jul 2019 17:42:18 +0000
From:   "Lendacky, Thomas" <Thomas.Lendacky@....com>
To:     Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
        "x86@...nel.org" <x86@...nel.org>
CC:     "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-s390@...r.kernel.org" <linux-s390@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, Christoph Hellwig <hch@....de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Robin Murphy <robin.murphy@....com>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Alexey Dobriyan <adobriyan@...il.com>,
        Halil Pasic <pasic@...ux.ibm.com>,
        Mike Anderson <andmike@...ux.ibm.com>,
        Ram Pai <linuxram@...ibm.com>
Subject: Re: [PATCH v3 4/6] x86,s390/mm: Move sme_active() and sme_me_mask to
 x86-specific header

On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
> Now that generic code doesn't reference them, move sme_active() and
> sme_me_mask to x86's <asm/mem_encrypt.h>.
> 
> Also remove the export for sme_active() since it's only used in files that
> won't be built as modules. sme_me_mask on the other hand is used in
> arch/x86/kvm/svm.c (via __sme_set() and __psp_pa()) which can be built as a
> module so its export needs to stay.

You may want to try and build the out-of-tree nvidia driver just to be
sure you can remove the EXPORT_SYMBOL(). But I believe that was related
to the DMA mask check, which now removed, may no longer be a problem.

> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>

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

> ---
>  arch/s390/include/asm/mem_encrypt.h |  4 +---
>  arch/x86/include/asm/mem_encrypt.h  | 10 ++++++++++
>  arch/x86/mm/mem_encrypt.c           |  1 -
>  include/linux/mem_encrypt.h         | 14 +-------------
>  4 files changed, 12 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/s390/include/asm/mem_encrypt.h b/arch/s390/include/asm/mem_encrypt.h
> index 3eb018508190..ff813a56bc30 100644
> --- a/arch/s390/include/asm/mem_encrypt.h
> +++ b/arch/s390/include/asm/mem_encrypt.h
> @@ -4,9 +4,7 @@
>  
>  #ifndef __ASSEMBLY__
>  
> -#define sme_me_mask	0ULL
> -
> -static inline bool sme_active(void) { return false; }
> +static inline bool mem_encrypt_active(void) { return false; }
>  extern bool sev_active(void);
>  
>  int set_memory_encrypted(unsigned long addr, int numpages);
> diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
> index 0c196c47d621..848ce43b9040 100644
> --- a/arch/x86/include/asm/mem_encrypt.h
> +++ b/arch/x86/include/asm/mem_encrypt.h
> @@ -92,6 +92,16 @@ early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0;
>  
>  extern char __start_bss_decrypted[], __end_bss_decrypted[], __start_bss_decrypted_unused[];
>  
> +static inline bool mem_encrypt_active(void)
> +{
> +	return sme_me_mask;
> +}
> +
> +static inline u64 sme_get_me_mask(void)
> +{
> +	return sme_me_mask;
> +}
> +
>  #endif	/* __ASSEMBLY__ */
>  
>  #endif	/* __X86_MEM_ENCRYPT_H__ */
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index c805f0a5c16e..7139f2f43955 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -344,7 +344,6 @@ bool sme_active(void)
>  {
>  	return sme_me_mask && !sev_enabled;
>  }
> -EXPORT_SYMBOL(sme_active);
>  
>  bool sev_active(void)
>  {
> diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
> index 470bd53a89df..0c5b0ff9eb29 100644
> --- a/include/linux/mem_encrypt.h
> +++ b/include/linux/mem_encrypt.h
> @@ -18,23 +18,11 @@
>  
>  #else	/* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
>  
> -#define sme_me_mask	0ULL
> -
> -static inline bool sme_active(void) { return false; }
> +static inline bool mem_encrypt_active(void) { return false; }
>  static inline bool sev_active(void) { return false; }
>  
>  #endif	/* CONFIG_ARCH_HAS_MEM_ENCRYPT */
>  
> -static inline bool mem_encrypt_active(void)
> -{
> -	return sme_me_mask;
> -}
> -
> -static inline u64 sme_get_me_mask(void)
> -{
> -	return sme_me_mask;
> -}
> -
>  #ifdef CONFIG_AMD_MEM_ENCRYPT
>  /*
>   * The __sme_set() and __sme_clr() macros are useful for adding or removing
>