From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: "Zhang, Qi Z" <qi.z.zhang@intel.com>
Cc: dev@dpdk.org, "Wu, Jingjing" <jingjing.wu@intel.com>
Subject: Re: [dpdk-dev] [PATCH] eal: fix max number of interrupt request
Date: Mon, 13 Feb 2017 22:28:52 +0100 [thread overview]
Message-ID: <11810388.91RJejsIF6@xps13> (raw)
In-Reply-To: <039ED4275CED7440929022BC67E706115305B067@SHSMSX103.ccr.corp.intel.com>
2017-02-13 01:16, Zhang, Qi Z:
> Hi Thomas:
>
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > 2017-02-09 14:59, Qi Zhang:
> > > The max number of interrupt request is possible be changed after
> > > rte_intr_callback_register, so in get_max_intr, we need to check if
> > > nessesary to update the max_intr.
> >
> > So you are using rte_intr_enable() to update the max_intr field in the case of
> > VFIO_MSIX.
> > What about MSI, INTX and UIO cases?
>
> My thought is, even without my fix, VFIO_MSIX is already the only case that try to modify max_intr field
> In get_max_intr, we have:
> if (!src->intr_handle.max_intr)
> src->intr_handle.max_intr = 1;
> else if (src->intr_handle.max_intr > RTE_MAX_RXTX_INTR_VEC_ID)
> src->intr_handle.max_intr
> = RTE_MAX_RXTX_INTR_VEC_ID + 1;
> So my patch just follow this and fix some problem.
>
> Another option is I can use a local variable that assigned by max_intr with boundary check, so get_max_intr can be totally removed and max_intr in intr_source will not be modified.
>
> To me both fix are not perfect, I think the problem is in rte_intr_callback_register we just save a copy of the pci_dev->intr_handle but not the address point, so we are missing some mechanism to sync them.
> But since we have tight schedule on the 17.02 release and this issue does cause some example code can't work, so we need to a fix it first, we may consider improve the mechanism later.
>
> Thanks
> Qi
Applied with this title: "vfio: fix maximum number of interrupt for MSI-X"
Please check how to document this behaviour and make it consistent
with other types of interrupts.
next prev parent reply other threads:[~2017-02-13 21:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-09 19:59 Qi Zhang
2017-02-10 10:18 ` Thomas Monjalon
2017-02-13 1:16 ` Zhang, Qi Z
2017-02-13 21:28 ` Thomas Monjalon [this message]
2017-02-14 0:13 ` Zhang, Qi Z
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