From: Zhenzhong Duan <zhenzhong.duan@oracle.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>, linux-kernel@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>,
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>,
Radim Krcmar <rkrcmar@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH 1/3] KVM: X86: Add "nopvspin" parameter to disable PV spinlocks
Date: Tue, 1 Oct 2019 08:36:58 +0800 [thread overview]
Message-ID: <aae59646-be5f-6455-a033-ed29861107ce@oracle.com> (raw)
In-Reply-To: <87pnjh3i6i.fsf@vitty.brq.redhat.com>
On 2019/9/30 23:41, Vitaly Kuznetsov wrote:
> Zhenzhong Duan<zhenzhong.duan@oracle.com> writes:
>
>> There are cases where a guest tries to switch spinlocks to bare metal
>> behavior (e.g. by setting "xen_nopvspin" on XEN platform and
>> "hv_nopvspin" on HYPER_V).
>>
>> That feature is missed on KVM, add a new parameter "nopvspin" to disable
>> PV spinlocks for KVM guest.
>>
>> This new parameter is also intended to replace "xen_nopvspin" and
>> "hv_nopvspin" in the future.
> Any reason to not do it right now? We will probably need to have compat
> code to support xen_nopvspin/hv_nopvspin too but emit a 'is deprecated'
> warning.
Sorry the description isn't clear, I'll fix it.
I did the compat work in the other two patches.
[PATCH 2/3] xen: Mark "xen_nopvspin" parameter obsolete and map it to "nopvspin"
[PATCH 3/3] x86/hyperv: Mark "hv_nopvspin" parameter obsolete and map it to "nopvspin"
>
>> The global variable pvspin isn't defined as __initdata as it's used at
>> runtime by XEN guest.
>>
>> Refactor the print stuff with pr_* which is preferred.
> Please do it in a separate patch.
Ok, I'll do that in v2. Thanks for review.
Zhenzhong
next prev parent reply other threads:[~2019-10-01 0:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-29 12:21 [PATCH 0/3] Add a unified parameter "nopvspin" Zhenzhong Duan
2019-09-29 12:21 ` [PATCH 1/3] KVM: X86: Add "nopvspin" parameter to disable PV spinlocks Zhenzhong Duan
2019-09-30 15:41 ` Vitaly Kuznetsov
2019-10-01 0:36 ` Zhenzhong Duan [this message]
2019-10-01 8:39 ` Vitaly Kuznetsov
2019-10-01 9:47 ` Zhenzhong Duan
2019-10-02 16:47 ` Sean Christopherson
2019-10-03 9:51 ` Zhenzhong Duan
2019-09-29 12:21 ` [PATCH 2/3] xen: Mark "xen_nopvspin" parameter obsolete and map it to "nopvspin" Zhenzhong Duan
2019-09-30 14:25 ` Jürgen Groß
2019-09-29 12:21 ` [PATCH 3/3] x86/hyperv: Mark "hv_nopvspin" " Zhenzhong Duan
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