linux-kernel - Re: [PATCH] Revert "KVM: Check the allocation of pv cpu mask"

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Message-ID: <87een2htis.fsf@vitty.brq.redhat.com>
Date:   Wed, 16 Sep 2020 13:04:43 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Haiwei Li <lihaiwei.kernel@...il.com>, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Haiwei Li <lihaiwei@...cent.com>, linux-kernel@...r.kernel.org,
        x86@...nel.org
Subject: Re: [PATCH] Revert "KVM: Check the allocation of pv cpu mask"

Haiwei Li <lihaiwei.kernel@...il.com> writes:

> On 20/9/16 17:03, Vitaly Kuznetsov wrote:
>> The commit 0f990222108d ("KVM: Check the allocation of pv cpu mask") we
>> have in 5.9-rc5 has two issue:
>> 1) Compilation fails for !CONFIG_SMP, see:
>>     https://bugzilla.kernel.org/show_bug.cgi?id=209285
>> 
>> 2) This commit completely disables PV TLB flush, see
>>     https://lore.kernel.org/kvm/87y2lrnnyf.fsf@vitty.brq.redhat.com/
>> 
>> The allocation problem is likely a theoretical one, if we don't
>> have memory that early in boot process we're likely doomed anyway.
>> Let's solve it properly later.
>
> Hi, i have sent a patchset to fix this commit.
>
> https://lore.kernel.org/kvm/20200914091148.95654-1-lihaiwei.kernel@gmail.com/T/#m6c27184012ee5438e5d91c09b1ba1b6a3ee30ee4
>
> What do you think?

Saw it, looks good to me. We are, however, already very, very late in 5.9
release cycle and the original issue you were addressing (allocation
failure) is likely a theoretical only I suggest we just revert it before
5.9 is released. For 5.9 we can certainly take your PATCH2 merged with
0f99022210.

This Paolo's call anyway)

-- 
Vitaly