Date: Mon, 9 Mar 2009 16:28:47 +0800
From: Yu Zhao <yu.zhao@intel.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: "jbarnes@virtuousgeek.org" <jbarnes@virtuousgeek.org>,
       "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
       "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v10 5/7] PCI: handle SR-IOV Virtual Function Migration
Message-ID: <20090309082847.GD4638@yzhao-otc.sh.intel.com>
References: <1235112888-9524-1-git-send-email-yu.zhao@intel.com> <1235112888-9524-6-git-send-email-yu.zhao@intel.com> <20090306211341.GH25995@parisc-linux.org>
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On Sat, Mar 07, 2009 at 05:13:41AM +0800, Matthew Wilcox wrote:
> On Fri, Feb 20, 2009 at 02:54:46PM +0800, Yu Zhao wrote:
> > +static int sriov_migration(struct pci_dev *dev)
> > +{
> > +	u16 status;
> > +	struct pci_sriov *iov = dev->sriov;
> > +
> > +	if (!iov->nr_virtfn)
> > +		return 0;
> > +
> > +	if (!(iov->cap & PCI_SRIOV_CAP_VFM))
> > +		return 0;
> > +
> > +	pci_read_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, &status);
> 
> You passed in dev here, you don't need to use iov->self, right?

Will do.

> > +	if (!(status & PCI_SRIOV_STATUS_VFM))
> > +		return 0;
> > +
> > +	schedule_work(&iov->mtask);
> > +
> > +	return 1;
> > +}
> 
> > +/**
> > + * pci_sriov_migration - notify SR-IOV core of Virtual Function Migration
> > + * @dev: the PCI device
> > + *
> > + * Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.
> > + *
> > + * Physical Function driver is responsible to register IRQ handler using
> > + * VF Migration Interrupt Message Number, and call this function when the
> > + * interrupt is generated by the hardware.
> > + */
> > +irqreturn_t pci_sriov_migration(struct pci_dev *dev)
> > +{
> > +	if (!dev->sriov)
> > +		return IRQ_NONE;
> > +
> > +	return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;
> > +}
> > +EXPORT_SYMBOL_GPL(pci_sriov_migration);
> 
> OK, I think I get it -- you've basically written an interrupt handler
> for the driver to call from its interrupt handler.  Am I right in
> thinking that the reason the driver needs to do the interrupt handler
> here is because we don't currently have an interface that looks like:
> 
> int pci_get_msix_interrupt(struct pci_dev *dev, unsigned vector);
> 
> ?  If so, we should probably add it; I want it for my MSI-X rewrite
> anyway.

Right, we really need this function. But I guess we still have to keep the
handler in case the PF only has MSI, right?

Thanks,
Yu
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