From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>, tcs.kernel@gmail.com
Cc: vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
jarkko@kernel.org, Haimin Zhang <tcs_kernel@tencent.com>
Subject: Re: [PATCH v2] KVM: x86: Handle SRCU initialization failure during page track init
Date: Tue, 21 Sep 2021 19:47:28 +0200 [thread overview]
Message-ID: <af562685-673a-489d-6a00-5e77329dc2a4@redhat.com> (raw)
In-Reply-To: <YTJK4aACtboaPAF8@google.com>
On 03/09/21 18:18, Sean Christopherson wrote:
> Before moving forward with a fix, I'd like to get Paolo's input on dropping
> track_srcu in favor of kvm->srcu and avoiding this altogheter. Note, Paolo is on
> vacation at the moment, so this won't get attention for a week or more.
The reason for track_srcu's existence is to avoid complications in
kvm_arch_flush_shadow_memslot, which is called from the _write_ side of
kvm->srcu but is on the _read_ side of track_srcu.
I think this should be fixed easily by taking slots_lock in
kvm_page_track_register_notifier and kvm_page_track_unregister_notifier,
however it's a bit more complicated from the point of view of the lock
hierarchy and possible deadlocks.
So I'm open to patches that drop track_srcu, but for now I applied this
patch.
Paolo
prev parent reply other threads:[~2021-09-21 17:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-03 2:37 tcs.kernel
2021-09-03 6:59 ` Jarkko Sakkinen
2021-09-03 16:18 ` Sean Christopherson
2021-09-21 17:47 ` Paolo Bonzini [this message]
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