From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>, "H Peter Anvin" <hpa@zytor.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Dave Hansen" <dave.hansen@intel.com>,
"Ashok Raj" <ashok.raj@intel.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Ravi V Shankar" <ravi.v.shankar@intel.com>,
"Xiaoyao Li " <xiaoyao.li@intel.com>,
"Christopherson Sean J" <sean.j.christopherson@intel.com>,
"Kalle Valo" <kvalo@codeaurora.org>,
"Michael Chan" <michael.chan@broadcom.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
"x86" <x86@kernel.org>,
kvm@vger.kernel.org, netdev@vger.kernel.org,
linux-wireless@vger.kernel.org, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v7 21/21] x86/clearcpuid: Change document for kernel option clearcpuid
Date: Wed, 17 Apr 2019 14:34:11 -0700 [thread overview]
Message-ID: <1555536851-17462-22-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1555536851-17462-1-git-send-email-fenghua.yu@intel.com>
Since kernel option clearcpuid now supports multiple options and CPU
capability flags, the document needs to be changed.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
.../admin-guide/kernel-parameters.txt | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2b8ee90bb644..0cbeda6d7f16 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -563,17 +563,21 @@
loops can be debugged more effectively on production
systems.
- clearcpuid=BITNUM [X86]
+ clearcpuid=BITNUM | FLAG [X86]
Disable CPUID feature X for the kernel. See
arch/x86/include/asm/cpufeatures.h for the valid bit
- numbers. Note the Linux specific bits are not necessarily
+ numbers or /proc/cpuinfo for valid CPU flags.
+ Multiple options can be used to disable a few features.
+ This prevents the feature from being used by the
+ kernel or shown in /proc/cpuinfo or shown in CPUID
+ called directly by user programs.
+ A few notes:
+ - The Linux specific bits are not necessarily
stable over kernel options, but the vendor specific
ones should be.
- Also note that user programs calling CPUID directly
- or using the feature without checking anything
- will still see it. This just prevents it from
- being used by the kernel or shown in /proc/cpuinfo.
- Also note the kernel might malfunction if you disable
+ - User programs using the feature without checking
+ anything will still use it.
+ - The kernel might malfunction if you disable
some critical bits.
cma=nn[MG]@[start[MG][-end[MG]]]
--
2.19.1
prev parent reply other threads:[~2019-04-17 21:43 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-17 21:33 [PATCH v7 00/21] x86/split_lock: Enable split lock detection Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 01/21] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 02/21] drivers/net/b44: Align pwol_mask to unsigned long for better performance Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 03/21] wlcore: simplify/fix/optimize reg_ch_conf_pending operations Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 04/21] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access Fenghua Yu
2019-04-18 9:20 ` David Laight
2019-04-18 11:08 ` David Laight
2019-04-18 11:49 ` Thomas Gleixner
2019-04-18 13:14 ` David Laight
2019-04-18 13:26 ` David Laight
2019-04-17 21:33 ` [PATCH v7 05/21] x86/msr-index: Define MSR_IA32_CORE_CAPABILITY and split lock detection bit Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 06/21] x86/cpufeatures: Enumerate MSR_IA32_CORE_CAPABILITY Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 07/21] x86/split_lock: Enumerate split lock detection by MSR_IA32_CORE_CAPABILITY Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 08/21] x86/split_lock: Enumerate split lock detection on Icelake mobile processor Fenghua Yu
2019-04-17 21:33 ` [PATCH v7 09/21] x86/split_lock: Define MSR TEST_CTL register Fenghua Yu
2019-04-17 21:34 ` [PATCH v7 10/21] x86/split_lock: Define per CPU variable to cache MSR TEST_CTL Fenghua Yu
2019-04-17 22:14 ` Thomas Gleixner
2019-04-18 1:28 ` Fenghua Yu
2019-04-18 6:31 ` Thomas Gleixner
2019-04-17 21:34 ` [PATCH v7 11/21] x86/split_lock: Handle #AC exception for split lock Fenghua Yu
2019-04-17 21:34 ` [PATCH v7 12/21] kvm/x86: Emulate MSR IA32_CORE_CAPABILITY Fenghua Yu
2019-04-17 21:34 ` [PATCH v7 13/21] kvm/vmx: Emulate MSR TEST_CTL Fenghua Yu
2019-04-17 21:34 ` [PATCH v7 14/21] x86/split_lock: Enable split lock detection by default Fenghua Yu
2019-04-17 22:41 ` Thomas Gleixner
2019-04-17 21:34 ` [PATCH v7 15/21] x86/split_lock: Add a sysfs interface to enable/disable split lock detection during run time Fenghua Yu
2019-04-17 22:47 ` Thomas Gleixner
2019-04-18 0:57 ` Fenghua Yu
2019-04-18 6:41 ` Thomas Gleixner
2019-04-23 20:48 ` Fenghua Yu
2019-04-24 13:45 ` David Laight
2019-04-17 21:34 ` [PATCH v7 16/21] x86/split_lock: Document the new sysfs file for split lock detection Fenghua Yu
2019-04-17 21:34 ` [PATCH v7 17/21] x86/clearcpuid: Support multiple clearcpuid options Fenghua Yu
2019-04-17 23:05 ` Thomas Gleixner
2019-04-17 21:34 ` [PATCH v7 18/21] x86/clearcpuid: Support feature flag string in kernel option clearcpuid Fenghua Yu
2019-04-17 23:19 ` Thomas Gleixner
2019-04-17 23:47 ` Fenghua Yu
2019-04-18 6:16 ` Thomas Gleixner
2019-04-17 21:34 ` [PATCH v7 19/21] x86/clearcpuid: Apply cleared feature bits that are forced set before Fenghua Yu
2019-04-17 21:34 ` [PATCH v7 20/21] x86/clearcpuid: Clear CPUID bit in CPUID faulting Fenghua Yu
2019-04-17 21:34 ` Fenghua Yu [this message]
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