From: "Jan Beulich" <JBeulich@suse.com>
To: Chao Gao <chao.gao@intel.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Kevin Tian <kevin.tian@intel.com>,
Julien Grall <julien.grall@linaro.org>,
Jun Nakajima <jun.nakajima@intel.com>,
xen-devel@lists.xen.org
Subject: Re: [PATCH v3 for 4.10] x86/vpt: guarantee the return value of pt_update_irq() set in vIRR or PIR
Date: Fri, 20 Oct 2017 05:42:34 -0600 [thread overview]
Message-ID: <59E9FD4A0200007800188AD6@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1508459700-6725-1-git-send-email-chao.gao@intel.com>
>>> On 20.10.17 at 02:35, <chao.gao@intel.com> wrote:
> pt_update_irq() is expected to return the vector number of periodic
> timer interrupt, which should be set in vIRR of vlapic or in PIR.
> Otherwise it would trigger the assertion in vmx_intr_assist(), please
> seeing
> https://lists.xenproject.org/archives/html/xen-devel/2017-10/msg00915.html.
>
> But it fails to achieve that in the following two case:
> 1. hvm_isa_irq_assert() may not set the corresponding bit in vIRR for
> mask field of IOAPIC RTE is set. Please refer to the call tree
> vmx_intr_assist() -> pt_update_irq() -> hvm_isa_irq_assert() ->
> assert_irq() -> assert_gsi() -> vioapic_irq_positive_edge(). The patch
> checks whether the vector is set or not in vIRR of vlapic or PIR before
> returning.
>
> 2. someone changes the vector field of IOAPIC RTE between asserting
> the irq and getting the vector of the irq, leading to setting the
> old vector number but returning a different vector number. This patch
> allows hvm_isa_irq_assert() to accept a callback which can get the
> interrupt vector with irq_lock held. Thus, no one can change the vector
> between the two operations.
>
> BTW, the first argument of pi_test_and_set_pir() should be uint8_t
> and I take this chance to fix it.
>
> Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
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next prev parent reply other threads:[~2017-10-20 11:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 0:35 [PATCH v3 for 4.10] x86/vpt: guarantee the return value of pt_update_irq() set in vIRR or PIR Chao Gao
2017-10-20 11:42 ` Jan Beulich [this message]
2017-10-20 13:23 ` Julien Grall
2017-10-20 14:16 ` Jan Beulich
2017-10-23 13:59 ` Julien Grall
2017-10-23 8:08 ` Tian, Kevin
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