From: Thomas Gleixner <tglx@linutronix.de>
To: Xiaoyao Li <xiaoyao.li@intel.com>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
hpa@zytor.com, Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
kvm@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
Fenghua Yu <fenghua.yu@intel.com>,
Tony Luck <tony.luck@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Jim Mattson <jmattson@google.com>
Subject: Re: [PATCH v5 3/9] x86/split_lock: Re-define the kernel param option for split_lock_detect
Date: Wed, 25 Mar 2020 02:03:56 +0100 [thread overview]
Message-ID: <878sjpz1mr.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <54b2b9b5-2307-b5da-6b63-319e9626bcc1@intel.com>
Xiaoyao Li <xiaoyao.li@intel.com> writes:
> On 3/24/2020 6:40 PM, Thomas Gleixner wrote:
>> Xiaoyao Li <xiaoyao.li@intel.com> writes:
>>> On 3/24/2020 1:10 AM, Thomas Gleixner wrote:
>>>> Xiaoyao Li <xiaoyao.li@intel.com> writes:
>>>>
>>>>> Change sld_off to sld_disable, which means disabling feature split lock
>>>>> detection and it cannot be used in kernel nor can kvm expose it guest.
>>>>> Of course, the X86_FEATURE_SPLIT_LOCK_DETECT is not set.
>>>>>
>>>>> Add a new optioin sld_kvm_only, which means kernel turns split lock
>>>>> detection off, but kvm can expose it to guest.
>>>>
>>>> What's the point of this? If the host is not clean, then you better fix
>>>> the host first before trying to expose it to guests.
>>>
>>> It's not about whether or not host is clean. It's for the cases that
>>> users just don't want it enabled on host, to not break the applications
>>> or drivers that do have split lock issue.
>>
>> It's very much about whether the host is split lock clean.
>>
>> If your host kernel is not, then this wants to be fixed first. If your
>> host application is broken, then either fix it or use "warn".
>>
>
> My thought is for CSPs that they might not turn on SLD on their product
> environment. Any split lock in kernel or drivers may break their service
> for tenants.
Again you are proliferating crap and making excuses for Common Sense
violating Purposes (CSP).
Thanks,
tglx
next prev parent reply other threads:[~2020-03-25 1:14 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-15 5:05 [PATCH v5 0/9] x86/split_lock: Add feature split lock detection Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 1/9] x86/split_lock: Rework the initialization flow of " Xiaoyao Li
2020-03-21 0:41 ` Luck, Tony
2020-03-23 17:02 ` Thomas Gleixner
2020-03-23 20:24 ` Thomas Gleixner
2020-03-24 1:10 ` Xiaoyao Li
2020-03-24 10:29 ` Thomas Gleixner
2020-03-25 0:18 ` Xiaoyao Li
2020-03-25 0:52 ` Thomas Gleixner
2020-03-24 11:51 ` Xiaoyao Li
2020-03-24 13:31 ` Thomas Gleixner
2020-03-15 5:05 ` [PATCH v5 2/9] x86/split_lock: Avoid runtime reads of the TEST_CTRL MSR Xiaoyao Li
2020-03-21 0:43 ` Luck, Tony
2020-03-23 17:06 ` Thomas Gleixner
2020-03-23 17:06 ` Thomas Gleixner
2020-03-24 1:16 ` Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 3/9] x86/split_lock: Re-define the kernel param option for split_lock_detect Xiaoyao Li
2020-03-21 0:46 ` Luck, Tony
2020-03-23 17:10 ` Thomas Gleixner
2020-03-24 1:38 ` Xiaoyao Li
2020-03-24 10:40 ` Thomas Gleixner
2020-03-24 18:02 ` Sean Christopherson
2020-03-24 18:42 ` Thomas Gleixner
2020-03-25 0:43 ` Xiaoyao Li
2020-03-25 1:03 ` Thomas Gleixner [this message]
2020-03-15 5:05 ` [PATCH v5 4/9] x86/split_lock: Export handle_user_split_lock() Xiaoyao Li
2020-03-21 0:48 ` Luck, Tony
2020-03-15 5:05 ` [PATCH v5 5/9] kvm: x86: Emulate split-lock access as a write Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 6/9] kvm: vmx: Extend VMX's #AC interceptor to handle split lock #AC happens in guest Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 7/9] kvm: x86: Emulate MSR IA32_CORE_CAPABILITIES Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 8/9] kvm: vmx: Enable MSR_TEST_CTRL for intel guest Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 9/9] x86: vmx: virtualize split lock detection Xiaoyao Li
2020-03-23 2:18 ` [PATCH v5 0/9] x86/split_lock: Add feature " Xiaoyao Li
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