From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Wanpeng Li" <wanpengli@tencent.com>,
"Jim Mattson" <jmattson@google.com>,
"Joerg Roedel" <joro@8bytes.org>,
kvm@vger.kernel.org
Subject: Re: Async page fault delivered while irq are disabled?
Date: Thu, 19 Dec 2019 07:57:46 -0800 [thread overview]
Message-ID: <20191219155745.GA6439@linux.intel.com> (raw)
In-Reply-To: <20191219152814.GA24080@lenoir>
On Thu, Dec 19, 2019 at 04:28:15PM +0100, Frederic Weisbecker wrote:
> Hi,
>
> While checking the x86 async page fault code, I can't
> find anything that prevents KVM_PV_REASON_PAGE_READY to be injected
> while the guest has interrupts disabled. If that page fault happens
> to trap in an interrupt disabled section, there may be a deadlock due to the
> call to wake_up_process() which locks the rq->lock (among others).
>
> Given how long that code is there, I guess such an issue would
> have been reported for a while already. But I just would like to
> be sure we are checking that.
>
> Can someone enlighten me?
The check is triggered from the caller of kvm_async_page_present().
kvm_check_async_pf_completion()
|
|-> kvm_arch_can_inject_async_page_present()
|
|-> kvm_can_do_async_pf()
|
|-> kvm_x86_ops->interrupt_allowed()
next prev parent reply other threads:[~2019-12-19 15:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-19 15:28 Async page fault delivered while irq are disabled? Frederic Weisbecker
2019-12-19 15:57 ` Sean Christopherson [this message]
2019-12-19 16:15 ` Frederic Weisbecker
2019-12-19 19:00 ` Sean Christopherson
2019-12-20 9:34 ` Paolo Bonzini
2019-12-23 2:17 ` Frederic Weisbecker
2019-12-23 8:38 ` Paolo Bonzini
2019-12-26 17:28 ` Frederic Weisbecker
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