From: Dave Hansen <dave.hansen@intel.com>
To: Fenghua Yu <fenghua.yu@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, H Peter Anvin <hpa@zytor.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Ashok Raj <ashok.raj@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Xiaoyao Li <xiaoyao.li@intel.com>,
Michael Chan <michael.chan@broadcom.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH v5 12/18] x86/split_lock: Enable #AC for split lock by default
Date: Tue, 12 Mar 2019 16:43:25 -0700 [thread overview]
Message-ID: <8098a229-e853-12fc-c8e8-d5e2cb4436a2@intel.com> (raw)
In-Reply-To: <1552431636-31511-13-git-send-email-fenghua.yu@intel.com>
On 3/12/19 4:00 PM, Fenghua Yu wrote:
> Split locked access locks bus and degradates overall memory access
Either "split locked accesses lock" or "A split lock access locks".
s/degradates/degrades/
> performance. When split lock detection feature is enumerated, we want to
^ the
Also, you need to go back and remove all the "we"'s. Our friendly x86
maintainers prefer phrasing this like:
When split lock detection feature is enumerated, enable the
feature...
> enable the feature by default to find any split lock issue and then fix
> the issue.
Generally, the changelogs here are passable but pretty rough. They have
a ton of issues like this and I'm sure they can be improved. I'm sure
that with some love an attention they can be brought up to the highest
standards.
> +#define DISABLE_SPLIT_LOCK_DETECT 0
> +#define ENABLE_SPLIT_LOCK_DETECT 1
These are a bit overkill, but oh well.
> +static int split_lock_detect_val;
> +
> /*
> * Just in case our CPU detection goes bad, or you have a weird system,
> * allow a way to override the automatic disabling of MPX.
> @@ -161,10 +166,35 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
> return false;
> }
>
> +static u32 new_sp_test_ctl_val(u32 test_ctl_val)
> +{
> + /* Change the split lock setting. */
> + if (split_lock_detect_val == DISABLE_SPLIT_LOCK_DETECT)
> + test_ctl_val &= ~TEST_CTL_ENABLE_SPLIT_LOCK_DETECT;
> + else
> + test_ctl_val |= TEST_CTL_ENABLE_SPLIT_LOCK_DETECT;
> +
> + return test_ctl_val;
> +}
> +
> +static void init_split_lock_detect(struct cpuinfo_x86 *c)
> +{
> + if (cpu_has(c, X86_FEATURE_SPLIT_LOCK_DETECT)) {
> + u32 l, h;
> +
> + rdmsr(MSR_TEST_CTL, l, h);
> + l = new_sp_test_ctl_val(l);
> + wrmsr(MSR_TEST_CTL, l, h);
> + pr_info_once("#AC for split lock is enabled\n");
> + }
> +}
Please make sure you've removed all the "#AC for split lock"
nomenclature in these patches. It's acronym nonsense and there's no
reason to be so oblique. Just say "split lock detection enabled". This
also needs a proper prefix, like "x86/intel:". Look around for examples.
next prev parent reply other threads:[~2019-03-12 23:43 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-12 23:00 [PATCH v5 00/18] x86/split_lock: Enable #AC exception for split locked accesses Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 01/18] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 02/18] drivers/net/b44: Align pwol_mask to unsigned long for better performance Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 03/18] wlcore: simplify/fix/optimize reg_ch_conf_pending operations Fenghua Yu
2019-03-14 13:16 ` Kalle Valo
2019-03-14 23:16 ` Fenghua Yu
2019-03-15 17:17 ` Paolo Bonzini
2019-03-26 7:55 ` Kalle Valo
2019-03-12 23:00 ` [PATCH v5 04/18] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 05/18] x86/cpufeatures: Enumerate IA32_CORE_CAPABILITIES MSR Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 06/18] x86/msr-index: Define IA32_CORE_CAPABILITY MSR and #AC exception for split lock bit Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 07/18] x86/split_lock: Enumerate #AC for split lock by MSR IA32_CORE_CAPABILITY Fenghua Yu
2019-03-12 23:52 ` Dave Hansen
2019-03-13 0:56 ` Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 08/18] x86/split_lock: Define MSR TEST_CTL register Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 09/18] x86/split_lock: Handle #AC exception for split lock Fenghua Yu
2019-03-12 23:51 ` Dave Hansen
2019-03-13 0:49 ` Fenghua Yu
2019-03-13 16:22 ` Dave Hansen
2019-03-12 23:00 ` [PATCH v5 10/18] kvm/x86: Emulate MSR IA32_CORE_CAPABILITY Fenghua Yu
2019-03-13 8:15 ` Paolo Bonzini
2019-03-12 23:00 ` [PATCH v5 11/18] kvm/vmx: Emulate MSR TEST_CTL Fenghua Yu
2019-03-13 8:15 ` Paolo Bonzini
2019-03-12 23:00 ` [PATCH v5 12/18] x86/split_lock: Enable #AC for split lock by default Fenghua Yu
2019-03-12 23:43 ` Dave Hansen [this message]
2019-03-12 23:00 ` [PATCH v5 13/18] x86/split_lock: Add a sysfs interface to allow user to enable or disable split lock detection on all CPUs during run time Fenghua Yu
2019-03-12 23:48 ` Dave Hansen
2019-03-13 0:53 ` Fenghua Yu
2019-03-13 1:08 ` Dave Hansen
2019-03-12 23:00 ` [PATCH v5 14/18] x86/clearcpuid: Support multiple clearcpuid options Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 15/18] x86/clearcpuid: Support feature flag string in kernel option clearcpuid Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 16/18] x86/clearcpuid: Apply cleared feature bits that are forced set before Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 17/18] x86/clearcpuid: Clear CPUID bit in CPUID faulting Fenghua Yu
2019-03-12 23:00 ` [PATCH v5 18/18] Change document for kernel option clearcpuid Fenghua Yu
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