From: Paolo Bonzini <pbonzini@redhat.com>
To: Junaid Shahid <junaids@google.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Jim Mattson <jmattson@google.com>
Cc: kvm@vger.kernel.org, John Sperbeck <jsperbeck@google.com>
Subject: Re: [PATCH] kvm: call kvm_arch_destroy_vm if vm creation fails
Date: Thu, 24 Oct 2019 12:08:29 +0200 [thread overview]
Message-ID: <4d81887e-12d7-baaf-586b-b85020bd5eaf@redhat.com> (raw)
In-Reply-To: <7e1fe902-65e3-5381-1ac8-b280f39a677d@google.com>
On 24/10/19 04:59, Junaid Shahid wrote:
> AFAICT the kvm->users_count is already 0 before kvm_arch_destroy_vm()
> is called from kvm_destroy_vm() in the normal case.
Yes:
if (refcount_dec_and_test(&kvm->users_count))
kvm_destroy_vm(kvm);
where
| int atomic_inc_and_test(atomic_t *v);
| int atomic_dec_and_test(atomic_t *v);
|
| These two routines increment and decrement by 1, respectively, the
| given atomic counter. They return a boolean indicating whether the
| resulting counter value was zero or not.
> So there really
> shouldn't be any arch that does a kvm_put_kvm() inside
> kvm_arch_destroy_vm(). I think it might be better to keep the
> kvm_arch_destroy_vm() call after the refcount_set() to be consistent
> with the normal path.
I agree, so I am applying Jim's patch. If anything, we may want to WARN
if the refcount is not 1 before the refcount_set.
Paolo
next prev parent reply other threads:[~2019-10-24 10:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-23 17:14 [PATCH] kvm: call kvm_arch_destroy_vm if vm creation fails Jim Mattson
2019-10-23 18:21 ` Sean Christopherson
2019-10-24 2:59 ` Junaid Shahid
2019-10-24 10:08 ` Paolo Bonzini [this message]
2019-10-24 18:14 ` Sean Christopherson
2019-10-24 18:55 ` Paolo Bonzini
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