linux-kernel - Re: [PATCH v6 09/16] x86/bugs: Add mitigation to spectre and no meltdown for Hygon Dhyana

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Message-ID: <20180911103828.GF12094@zn.tnic>
Date:   Tue, 11 Sep 2018 12:38:28 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Pu Wen <puwen@...on.cn>
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, thomas.lendacky@....com, pbonzini@...hat.com,
        linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH v6 09/16] x86/bugs: Add mitigation to spectre and no
 meltdown for Hygon Dhyana

On Mon, Sep 10, 2018 at 09:17:40PM +0800, Pu Wen wrote:
> The Hygon Dhyana CPU has the same speculative execution as AMD family
> 17h, so share AMD spectre mitigation code for Hygon Dhyana.
> 
> Also Hygon Dhyana is not affected by meltdown vulnerability as AMD,
> so add the exception for Hygon Dhyana.
> 
> Signed-off-by: Pu Wen <puwen@...on.cn>
> ---
>  arch/x86/kernel/cpu/bugs.c   | 6 ++++--
>  arch/x86/kernel/cpu/common.c | 1 +
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
> index 40bdaea..726010d 100644
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -312,8 +312,9 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
>  	}
>  
>  	if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD &&
> +	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON &&
>  	    boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
> -		pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
> +		pr_err("retpoline,amd selected but CPU is not AMD or Hygon. Switching to AUTO select\n");

Didn't we say, no user-visible changes pls?

-- 
Regards/Gruss,
    Boris.

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