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From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, H Peter Anvin <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Radim Krcmar <rkrcmar@redhat.com>,
	Ashok Raj <ashok.raj@intel.com>, Tony Luck <tony.luck@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
	Ravi V Shankar <ravi.v.shankar@intel.com>,
	linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
	kvm@vger.kernel.org
Subject: Re: [RFD] x86/split_lock: Request to Intel
Date: Fri, 18 Oct 2019 10:36:41 +0800	[thread overview]
Message-ID: <5da90713-9a0d-6466-64f7-db435ba07dbe@intel.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1910171322530.1824@nanos.tec.linutronix.de>

On 10/17/2019 8:29 PM, Thomas Gleixner wrote:
> The more I look at this trainwreck, the less interested I am in merging any
> of this at all.
> 
> The fact that it took Intel more than a year to figure out that the MSR is
> per core and not per thread is yet another proof that this industry just
> works by pure chance.
> 

Whether it's per-core or per-thread doesn't affect much how we implement 
for host/native.

And also, no matter it's per-core or per-thread, we always can do 
something in VIRT.

Maybe what matters is below.

> Seriously, this makes only sense when it's by default enabled and not
> rendered useless by VIRT. Otherwise we never get any reports and none of
> the issues are going to be fixed.
>

For VIRT, it doesn't want old guest to be killed due to #AC. But for 
native, it doesn't want VIRT to disable the #AC detection

I think it's just about the default behavior that whether to disable the 
host's #AC detection or kill the guest (SIGBUS or something else) once 
there is an split-lock #AC in guest.

So we can provide CONFIG option to set the default behavior and module 
parameter to let KVM set/change the default behavior.


  parent reply	other threads:[~2019-10-18  4:58 UTC|newest]

Thread overview: 85+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-18 22:41 [PATCH v9 00/17] x86/split_lock: Enable split lock detection Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 01/17] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 02/17] drivers/net/b44: Align pwol_mask to unsigned long for better performance Fenghua Yu
2019-06-24 15:12   ` David Laight
2019-06-24 18:43     ` Paolo Bonzini
2019-06-18 22:41 ` [PATCH v9 03/17] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access Fenghua Yu
2019-06-24 15:12   ` David Laight
2019-06-25 23:54     ` Fenghua Yu
2019-06-26 19:15       ` Thomas Gleixner
2019-06-18 22:41 ` [PATCH v9 04/17] x86/msr-index: Define MSR_IA32_CORE_CAP and split lock detection bit Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 05/17] x86/cpufeatures: Enumerate MSR_IA32_CORE_CAP Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 06/17] x86/split_lock: Enumerate split lock detection by MSR_IA32_CORE_CAP Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 07/17] x86/split_lock: Enumerate split lock detection on Icelake mobile processor Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 08/17] x86/split_lock: Define MSR TEST_CTL register Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 09/17] x86/split_lock: Handle #AC exception for split lock Fenghua Yu
2019-06-26 20:20   ` Thomas Gleixner
2019-06-26 20:36     ` Fenghua Yu
2019-06-26 21:47       ` Thomas Gleixner
2019-09-25 18:09         ` Sean Christopherson
2019-10-16  6:58           ` Xiaoyao Li
2019-10-16  9:29           ` Thomas Gleixner
2019-10-16 15:59             ` Sean Christopherson
2019-10-16  9:40           ` Paolo Bonzini
2019-10-16  9:47             ` Thomas Gleixner
2019-10-16 10:16               ` Paolo Bonzini
2019-10-16 11:23                 ` Xiaoyao Li
2019-10-16 11:26                   ` Paolo Bonzini
2019-10-16 13:13                     ` Xiaoyao Li
2019-10-16 14:43                       ` Thomas Gleixner
2019-10-16 15:37                         ` Paolo Bonzini
2019-10-16 16:25                           ` Xiaoyao Li
2019-10-16 16:38                             ` Paolo Bonzini
2019-10-17 12:29                           ` [RFD] x86/split_lock: Request to Intel Thomas Gleixner
2019-10-17 17:23                             ` Sean Christopherson
2019-10-17 21:31                               ` Thomas Gleixner
2019-10-17 23:38                                 ` Sean Christopherson
2019-10-17 23:28                             ` Luck, Tony
2019-10-18 10:45                               ` David Laight
2019-10-18 21:03                                 ` hpa
2019-10-18  2:36                             ` Xiaoyao Li [this message]
2019-10-18  9:02                               ` Thomas Gleixner
2019-10-18 10:20                                 ` Xiaoyao Li
2019-10-18 10:43                                   ` Peter Zijlstra
2019-10-16 11:49                 ` [PATCH v9 09/17] x86/split_lock: Handle #AC exception for split lock Thomas Gleixner
2019-10-16 11:58                   ` Paolo Bonzini
2019-10-16 13:51                     ` Xiaoyao Li
2019-10-16 14:08                       ` Paolo Bonzini
2019-10-16 14:14                         ` David Laight
2019-10-16 15:03                           ` Thomas Gleixner
2019-10-16 15:41                         ` Sean Christopherson
2019-10-16 15:43                           ` Paolo Bonzini
2019-10-16 16:23                             ` Sean Christopherson
2019-10-16 17:42                               ` Sean Christopherson
2019-10-17  1:23                                 ` Xiaoyao Li
2019-10-21 13:06                                   ` Paolo Bonzini
2019-10-21 13:03                                 ` Paolo Bonzini
2019-10-21 13:02                               ` Paolo Bonzini
2019-10-16 14:50                       ` Thomas Gleixner
2019-06-18 22:41 ` [PATCH v9 10/17] kvm/x86: Emulate MSR IA32_CORE_CAPABILITY Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 11/17] kvm/vmx: Emulate MSR TEST_CTL Fenghua Yu
2019-06-27  2:24   ` Xiaoyao Li
2019-06-27  7:12     ` Thomas Gleixner
2019-06-27  7:58       ` Xiaoyao Li
2019-06-27 12:11         ` Thomas Gleixner
2019-06-27 12:22           ` Xiaoyao Li
2019-06-18 22:41 ` [PATCH v9 12/17] x86/split_lock: Enable split lock detection by default Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 13/17] x86/split_lock: Disable split lock detection by kernel parameter "nosplit_lock_detect" Fenghua Yu
2019-06-26 20:34   ` Thomas Gleixner
2019-06-26 20:37     ` Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 14/17] x86/split_lock: Add a debugfs interface to enable/disable split lock detection during run time Fenghua Yu
2019-06-26 21:37   ` Thomas Gleixner
2019-06-18 22:41 ` [PATCH v9 15/17] x86/split_lock: Add documentation for split lock detection interface Fenghua Yu
2019-06-26 21:51   ` Thomas Gleixner
2019-06-18 22:41 ` [PATCH v9 16/17] x86/split_lock: Reorganize few header files in order to call WARN_ON_ONCE() in atomic bit ops Fenghua Yu
2019-06-18 22:41 ` [PATCH v9 17/17] x86/split_lock: Warn on unaligned address in atomic bit operations Fenghua Yu
2019-06-26 22:00   ` Thomas Gleixner
2019-09-16 22:39 ` [PATCH 0/3] Fix some 4-byte vs. 8-byte alignment issues Tony Luck
2019-09-16 22:39   ` [PATCH 1/3] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Tony Luck
2019-11-15 19:26     ` [tip: x86/cpu] x86/cpu: " tip-bot2 for Fenghua Yu
2019-09-16 22:39   ` [PATCH 2/3] drivers/net/b44: Align pwol_mask to unsigned long for better performance Tony Luck
2019-09-16 22:39   ` [PATCH 3/3] x86/split_lock: Align the x86_capability array to size of unsigned long Tony Luck
2019-09-17  8:29     ` David Laight
2019-09-17 19:14       ` Luck, Tony
2019-09-18  8:54         ` David Laight
2019-11-15 19:26     ` [tip: x86/cpu] x86/cpu: " tip-bot2 for Fenghua Yu

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