linux-kernel - Re: [tip:x86/cpu] x86/CPU/AMD: Set the CPB bit unconditionally on F17h

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Message-ID: <20190221115230.GB25198@kroah.com>
Date:   Thu, 21 Feb 2019 12:52:30 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Borislav Petkov <bp@...en8.de>
Cc:     stable <stable@...r.kernel.org>, linux-tip-commits@...r.kernel.org,
        suravee.suthikulpanit@....com, jiaxun.yang@...goat.com,
        tglx@...utronix.de, x86@...nel.org, linux-kernel@...r.kernel.org,
        sherry.hurwitz@....com, mingo@...hat.com, mingo@...nel.org,
        thomas.lendacky@....com, hpa@...or.com,
        Erwan Velu <e.velu@...teo.com>
Subject: Re: [tip:x86/cpu] x86/CPU/AMD: Set the CPB bit unconditionally on
 F17h

On Wed, Feb 20, 2019 at 09:53:34AM +0100, Borislav Petkov wrote:
> On Fri, Jan 18, 2019 at 07:48:59AM -0800, tip-bot for Jiaxun Yang wrote:
> > Commit-ID:  0237199186e7a4aa5310741f0a6498a20c820fd7
> > Gitweb:     https://git.kernel.org/tip/0237199186e7a4aa5310741f0a6498a20c820fd7
> > Author:     Jiaxun Yang <jiaxun.yang@...goat.com>
> > AuthorDate: Tue, 20 Nov 2018 11:00:18 +0800
> > Committer:  Borislav Petkov <bp@...e.de>
> > CommitDate: Fri, 18 Jan 2019 16:44:03 +0100
> > 
> > x86/CPU/AMD: Set the CPB bit unconditionally on F17h
> > 
> > Some F17h models do not have CPB set in CPUID even though the CPU
> > supports it. Set the feature bit unconditionally on all F17h.
> > 
> >  [ bp: Rewrite commit message and patch. ]
> > 
> > Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
> > Signed-off-by: Borislav Petkov <bp@...e.de>
> > Acked-by: Tom Lendacky <thomas.lendacky@....com>
> > Cc: "H. Peter Anvin" <hpa@...or.com>
> > Cc: Ingo Molnar <mingo@...hat.com>
> > Cc: Sherry Hurwitz <sherry.hurwitz@....com>
> > Cc: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
> > Cc: Thomas Gleixner <tglx@...utronix.de>
> > Cc: x86-ml <x86@...nel.org>
> > Link: https://lkml.kernel.org/r/20181120030018.5185-1-jiaxun.yang@flygoat.com
> > ---
> >  arch/x86/kernel/cpu/amd.c | 8 +++-----
> >  1 file changed, 3 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> > index 69f6bbb41be0..01004bfb1a1b 100644
> > --- a/arch/x86/kernel/cpu/amd.c
> > +++ b/arch/x86/kernel/cpu/amd.c
> > @@ -819,11 +819,9 @@ static void init_amd_bd(struct cpuinfo_x86 *c)
> >  static void init_amd_zn(struct cpuinfo_x86 *c)
> >  {
> >  	set_cpu_cap(c, X86_FEATURE_ZEN);
> > -	/*
> > -	 * Fix erratum 1076: CPB feature bit not being set in CPUID. It affects
> > -	 * all up to and including B1.
> > -	 */
> > -	if (c->x86_model <= 1 && c->x86_stepping <= 1)
> > +
> > +	/* Fix erratum 1076: CPB feature bit not being set in CPUID. */
> > +	if (!cpu_has(c, X86_FEATURE_CPB))
> >  		set_cpu_cap(c, X86_FEATURE_CPB);
> 
> Stable folks, please take this one above into those stable trees which
> have backported
> 
> f7f3dc00f612 ("x86/cpu/AMD: Fix erratum 1076 (CPB bit)")

I would, but I do not see this patch in Linus's tree yet :)

thanks,

greg k-h