[PATCH v2] x86/cpu/AMD: Fix CPB bit for more processors

[PATCH v2] x86/cpu/AMD: Fix CPB bit for more processors

[Jiaxun Yang]

CPUID Fn8000_0007_EDX[CPB] is wrongly 0 on some newer F17h
procssors but their revision guide has not been released.

For example,Tesed on AMD "Ryzen 7 2700U with Radeon Vega Mobile Gfx"
and "AMD Ryzen 5 2500U with Radeon Vega Mobile Gfx",
their CPUID Fn0000_0001_EAX is 0x00810f10 and should have
CPB feature according AMD product specifications, however
their Fn8000_0007_EDX is 0x00006599, indicating they don't
support CPB feature.

Since whole F17h should support CPB, we set the cap for all of
them.

Cc: stable@vger.kernel.org
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
 arch/x86/kernel/cpu/amd.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index eeea634bee0a..37989fa9e620 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -818,12 +818,13 @@ 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.
+	 * a lot of Family 17h processors and some models are undocumented, since
+	 * whole F17h should support CPB, we set the cap for all of them.
 	 */
-	if (c->x86_model <= 1 && c->x86_stepping <= 1)
-		set_cpu_cap(c, X86_FEATURE_CPB);
+	set_cpu_cap(c, X86_FEATURE_CPB);
 }

 static void init_amd(struct cpuinfo_x86 *c)
--
2.19.1

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

[Borislav Petkov]

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@flygoat.com>
> AuthorDate: Tue, 20 Nov 2018 11:00:18 +0800
> Committer:  Borislav Petkov <bp@suse.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@flygoat.com>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: x86-ml <x86@kernel.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)")

Thx.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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

[Greg KH]

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@flygoat.com>
> > AuthorDate: Tue, 20 Nov 2018 11:00:18 +0800
> > Committer:  Borislav Petkov <bp@suse.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@flygoat.com>
> > Signed-off-by: Borislav Petkov <bp@suse.de>
> > Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
> > Cc: "H. Peter Anvin" <hpa@zytor.com>
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
> > Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: x86-ml <x86@kernel.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

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

[Borislav Petkov]

On Thu, Feb 21, 2019 at 12:52:30PM +0100, Greg KH wrote:
> I would, but I do not see this patch in Linus's tree yet :)

You will soon :)

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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

[Greg KH]

On Thu, Feb 21, 2019 at 01:25:23PM +0100, Borislav Petkov wrote:
> On Thu, Feb 21, 2019 at 12:52:30PM +0100, Greg KH wrote:
> > I would, but I do not see this patch in Linus's tree yet :)
> 
> You will soon :)

I see it now, so it's now queued up, thanks.

greg k-h

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

[Erwan Velu]

Le 08/03/2019 à 11:26, Greg KH a écrit :
> On Thu, Feb 21, 2019 at 01:25:23PM +0100, Borislav Petkov wrote:
>> On Thu, Feb 21, 2019 at 12:52:30PM +0100, Greg KH wrote:
>>> I would, but I do not see this patch in Linus's tree yet :)
>> You will soon :)
> I see it now, so it's now queued up, thanks.
>
> greg k-h
Thanks greg !