From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Gonda <pgonda@google.com>
Cc: John Sperbeck <jsperbeck@google.com>,
kvm list <kvm@vger.kernel.org>,
David Rientjes <rientjes@google.com>,
Sean Christopherson <seanjc@google.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] KVM: SEV: Mark nested locking of vcpu->lock
Date: Fri, 29 Apr 2022 19:21:33 +0200 [thread overview]
Message-ID: <CABgObfa0ubOwNv2Vi9ziEjHXQMR_Sa6P-fwuXfPq76qy0N61kA@mail.gmail.com> (raw)
In-Reply-To: <CAMkAt6o8u9=H_kjr_xyRO05J=RDFUZRiTc_Bw-FFDKEUaiyp2Q@mail.gmail.com>
On Fri, Apr 29, 2022 at 7:12 PM Peter Gonda <pgonda@google.com> wrote:
> Sounds good. Instead of doing this prev_vcpu solution we could just
> keep the 1st vcpu for source and target. I think this could work since
> all the vcpu->mutex.dep_maps do not point to the same string.
>
> Lock:
> bool acquired = false;
> kvm_for_each_vcpu(...) {
> if (mutex_lock_killable_nested(&vcpu->mutex, role)
> goto out_unlock;
> acquired = true;
> if (acquired)
> mutex_release(&vcpu->mutex, role)
> }
Almost:
bool first = true;
kvm_for_each_vcpu(...) {
if (mutex_lock_killable_nested(&vcpu->mutex, role)
goto out_unlock;
if (first)
++role, first = false;
else
mutex_release(&vcpu->mutex, role);
}
and to unlock:
bool first = true;
kvm_for_each_vcpu(...) {
if (first)
first = false;
else
mutex_acquire(&vcpu->mutex, role);
mutex_unlock(&vcpu->mutex);
acquired = false;
}
because you cannot use the first vCPU's role again when locking.
Paolo
next prev parent reply other threads:[~2022-04-29 17:22 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 19:59 [PATCH v3] KVM: SEV: Mark nested locking of vcpu->lock Peter Gonda
2022-04-07 21:17 ` John Sperbeck
2022-04-08 15:08 ` Peter Gonda
2022-04-20 20:14 ` Peter Gonda
2022-04-21 15:56 ` Paolo Bonzini
2022-04-26 19:06 ` Peter Gonda
2022-04-27 16:04 ` Paolo Bonzini
2022-04-27 20:18 ` Peter Gonda
2022-04-28 21:28 ` Peter Gonda
2022-04-28 23:59 ` Paolo Bonzini
2022-04-29 15:35 ` Peter Gonda
2022-04-29 15:38 ` Paolo Bonzini
2022-04-29 15:51 ` Peter Gonda
2022-04-29 15:58 ` Paolo Bonzini
2022-04-29 17:12 ` Peter Gonda
2022-04-29 17:21 ` Paolo Bonzini [this message]
2022-04-29 17:27 ` Peter Gonda
2022-04-29 17:32 ` Paolo Bonzini
2022-04-29 17:33 ` Peter Gonda
[not found] ` <20220429010312.4013-1-hdanton@sina.com>
2022-04-29 8:48 ` Paolo Bonzini
[not found] ` <20220429114012.4127-1-hdanton@sina.com>
2022-04-29 13:44 ` Paolo Bonzini
[not found] ` <20220430015008.4257-1-hdanton@sina.com>
2022-04-30 8:11 ` Paolo Bonzini
2022-04-30 8:11 ` Paolo Bonzini
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