From: Thomas Gleixner <tglx@linutronix.de>
To: paulmck@kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
KVM <kvm@vger.kernel.org>
Subject: Re: [patch 2/2] x86/kvm: Sanitize kvm_async_pf_task_wait()
Date: Sat, 07 Mar 2020 02:02:25 +0100 [thread overview]
Message-ID: <874kv1asf2.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200307002210.GJ2935@paulmck-ThinkPad-P72>
"Paul E. McKenney" <paulmck@kernel.org> writes:
>> In #2c RCU is eventually not watching, but as that state cannot schedule
>> anyway there is no point to worry about it so it has to invoke
>> rcu_irq_enter() before running that code. This can be optimized, but this
>> will be done as an extra step in course of the entry code consolidation
>> work.
>
> In other words, any needed rcu_irq_enter() and rcu_irq_exit() are added
> in one of the entry-code consolidation patches, and patch below depends
> on that patch, correct?
No. The patch itself is already correct when applied to mainline. It has
no dependencies.
It invokes rcu_irq_enter()/exit() for the case (#2c) where it is
relevant. All other case are already RCU safe today.
The fact that the invocation is misplaced is a different story and yes,
that is part of the entry code cleanup along with some optimization
which are possible once the entry voodoo is out of ASM and adjustable
for a particular entry point in C.
Thanks,
tglx
next prev parent reply other threads:[~2020-03-07 1:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-06 23:42 [patch 0/2] x86/kvm: Sanitize async page fault Thomas Gleixner
2020-03-06 23:42 ` [patch 1/2] x86/kvm: Handle async page faults directly through do_page_fault() Thomas Gleixner
2020-03-17 8:47 ` [x86/kvm] aec3011ae9: WARNING:at_arch/x86/kernel/kvm.c:#kvm_guest_init kernel test robot
2020-03-17 8:47 ` kernel test robot
2020-03-06 23:42 ` [patch 2/2] x86/kvm: Sanitize kvm_async_pf_task_wait() Thomas Gleixner
2020-03-07 0:22 ` Paul E. McKenney
2020-03-07 1:02 ` Thomas Gleixner [this message]
2020-03-07 3:48 ` Paul E. McKenney
2020-03-07 2:18 ` Andy Lutomirski
2020-03-07 10:01 ` Thomas Gleixner
2020-03-07 15:10 ` Andy Lutomirski
2020-03-07 15:51 ` Andy Lutomirski
2020-03-07 19:18 ` Thomas Gleixner
2020-03-07 19:30 ` Andy Lutomirski
2020-03-07 15:52 ` Thomas Gleixner
2020-03-07 16:06 ` Andy Lutomirski
2020-03-07 20:08 ` Thomas Gleixner
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