Re: [Xen-devel] [PATCH 04/10] vpci/msix: add teardown cleanup

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Jun 29, 2018 at 11:52:07AM +0100, Wei Liu wrote:
> On Wed, Jun 20, 2018 at 04:42:28PM +0200, Roger Pau Monne wrote:
> > So that interrupts are properly freed.
> > 
> > Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> > ---
> > Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> > Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
> > Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> > Cc: Jan Beulich <jbeulich@xxxxxxxx>
> > Cc: Julien Grall <julien.grall@xxxxxxx>
> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> > Cc: Tim Deegan <tim@xxxxxxx>
> > Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
> > ---
> >  xen/drivers/vpci/msix.c | 43 ++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 42 insertions(+), 1 deletion(-)
> > 
> > diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
> > index 6132f576b6..cfca1cd43a 100644
> > --- a/xen/drivers/vpci/msix.c
> > +++ b/xen/drivers/vpci/msix.c
> > @@ -450,7 +450,48 @@ static int init_msix(struct pci_dev *pdev)
> >  
> >      return 0;
> >  }
> > -REGISTER_VPCI_INIT(init_msix, NULL, VPCI_PRIORITY_HIGH);
> > +
> > +static void teardown_msix(struct pci_dev *pdev)
> > +{
> > +    struct vpci_msix *msix = pdev->vpci->msix;
> > +    unsigned int i;
> > +
> > +    if ( !msix )
> > +        return;
> > +
> > +    if ( msix->enabled )
> > +    {
> > +        /* Disable MSIX. */
> > +        unsigned int pos = pci_find_cap_offset(pdev->seg, pdev->bus,
> > +                                               PCI_SLOT(pdev->devfn),
> > +                                               PCI_FUNC(pdev->devfn),
> > +                                               PCI_CAP_ID_MSIX);
> > +        uint16_t control = pci_conf_read16(pdev->seg, pdev->bus,
> > +                                           PCI_SLOT(pdev->devfn),
> > +                                           PCI_FUNC(pdev->devfn),
> > +                                           msix_control_reg(pos));
> > +
> > +        pci_conf_write16(pdev->seg, pdev->bus, PCI_SLOT(pdev->devfn),
> > +                         PCI_FUNC(pdev->devfn), msix_control_reg(pos),
> > +                         (control & ~PCI_MSIX_FLAGS_ENABLE));
> > +    }
> > +
> > +    write_lock(&pdev->domain->arch.hvm_domain.msix_lock);
> > +    list_del(&pdev->vpci->msix->next);
> > +    write_unlock(&pdev->domain->arch.hvm_domain.msix_lock);
> > +
> > +    for ( i = 0; i < msix->max_entries && msix->enabled; i++ )
> 
> Maybe lift checking msix->enabled outside of the loop? Afaict nothing
> in the loop manipulates that flag.

I've done it that way to skip one indentation level, but I can put it
outside if that's preferred.

> > +    {
> > +        int rc = vpci_msix_arch_disable_entry(&msix->entries[i], pdev);
> > +
> > +        if ( rc && rc != -ENOENT )
> > +            gprintk(XENLOG_WARNING,
> > +                    "%04x:%02x:%02x.%u: unable to disable MSIX entry %u: 
> > %d\n",
> > +                    pdev->seg, pdev->bus, PCI_SLOT(pdev->devfn),
> > +                    PCI_FUNC(pdev->devfn), i, rc);
> > +    }
> 
> No freeing msix here?

msix is freed by vpci_remove_device. I can move the freeing inside of
the teardown function now, since it makes it clearer.

Thanks, Roger.

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