RE: [PATCH v2 6/8] x86: Add hardware prefetch control support for x86

From: "tarumizu.kohei@fujitsu.com" <tarumizu.kohei@fujitsu.com>
To: 'Dave Hansen' <dave.hansen@intel.com>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"will@kernel.org" <will@kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 6/8] x86: Add hardware prefetch control support for x86
Date: Fri, 18 Mar 2022 06:41:04 +0000	[thread overview]
Message-ID: <OSBPR01MB2037E49B416A30182901F70C80139@OSBPR01MB2037.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <6b28a6f3-8d3d-76f4-d517-62260ac5b337@intel.com>

> > +static int broadwell_write_pfreg(enum pfctl_attr pattr, unsigned int cpu,
> > +				 unsigned int level, u64 val)
> > +{
> > +	int ret;
> > +	u64 reg;
> > +
> > +	ret = rdmsrl_on_cpu(cpu, MSR_MISC_FEATURE_CONTROL, &reg);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = broadwell_modify_pfreg(pattr, &reg, level, val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = wrmsrl_on_cpu(cpu, MSR_MISC_FEATURE_CONTROL, reg);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return 0;
> > +}
> 
> This needs to integrate _somehow_ with the pseudo_lock.c code.  Right now, I
> suspect that code would just overwrite any MSR changes made by this code.

I lacked consideration for pseudo_lock.c code. I try to integration
with that code.