Re: [Xen-devel] [PATCH v2 09/11] vpci: register as an internal ioreq server

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

On Tue, Sep 10, 2019 at 03:49:41PM +0200, Paul Durrant wrote:
> > -----Original Message-----
> > From: Roger Pau Monne <roger.pau@xxxxxxxxxx>
> > Sent: 03 September 2019 17:14
> > To: xen-devel@xxxxxxxxxxxxxxxxxxxx
> > Cc: Roger Pau Monne <roger.pau@xxxxxxxxxx>; Ian Jackson 
> > <Ian.Jackson@xxxxxxxxxx>; Wei Liu
> > <wl@xxxxxxx>; Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; George Dunlap 
> > <George.Dunlap@xxxxxxxxxx>; Jan
> > Beulich <jbeulich@xxxxxxxx>; Julien Grall <julien.grall@xxxxxxx>; Konrad 
> > Rzeszutek Wilk
> > <konrad.wilk@xxxxxxxxxx>; Stefano Stabellini <sstabellini@xxxxxxxxxx>; Tim 
> > (Xen.org) <tim@xxxxxxx>;
> > Paul Durrant <Paul.Durrant@xxxxxxxxxx>
> > Subject: [PATCH v2 09/11] vpci: register as an internal ioreq server
> > @@ -478,6 +480,67 @@ void vpci_write(pci_sbdf_t sbdf, unsigned int reg, 
> > unsigned int size,
> >      spin_unlock(&pdev->vpci->lock);
> >  }
> > 
> > +#ifdef __XEN__
> > +static int ioreq_handler(struct vcpu *v, ioreq_t *req, void *data)
> > +{
> > +    pci_sbdf_t sbdf;
> > +
> > +    if ( req->type == IOREQ_TYPE_INVALIDATE )
> > +        /*
> > +         * Ignore invalidate requests, those can be received even without
> > +         * having any memory ranges registered, see send_invalidate_req.
> > +         */
> > +        return X86EMUL_OKAY;
> 
> In general, I wonder whether internal servers will ever need to deal with 
> invalidate? The code only exists to get QEMU to drop its map cache after a 
> decrease_reservation so that the page refs get dropped.

I think the best solution here is to rename hvm_broadcast_ioreq to
hvm_broadcast_ioreq_external and switch it's callers. Both
send_timeoffset_req and send_invalidate_req seem only relevant to
external ioreq servers.

Thanks, Roger.

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