Re: [PATCH 1/5] pci: Introduce parse_pci_sbdf{_seg}()

[Teddy Astie <teddy.astie@xxxxxxxxxx>]

Le 20/05/2026 à 04:43, dmukhin@xxxxxxxx a écrit :
> On Mon, May 18, 2026 at 05:21:25PM +0200, Teddy Astie wrote:
> > In many places, we're parsing a PCI string into individual parts
> > (seg, bus, dev, fn) and then transform it into a pci_sbdf_t using PCI_SBDF
> > macro. Rather than converting from parts to pci_sbdf_t and vice versa,
> > introduce a new function that parses a PCI string into a pci_sbdf_t structure
> > directly.
> >
> > Signed-off-by: Teddy Astie <teddy.astie@xxxxxxxxxx>
> > ---
> >   xen/drivers/pci/pci.c | 18 ++++++++++++++++++
> >   xen/include/xen/pci.h |  3 +++
> >   2 files changed, 21 insertions(+)
> >
> > diff --git a/xen/drivers/pci/pci.c b/xen/drivers/pci/pci.c
> > index 084be3880c..1d06cb035b 100644
> > --- a/xen/drivers/pci/pci.c
> > +++ b/xen/drivers/pci/pci.c
> > @@ -202,3 +202,21 @@ const char *__init parse_pci_seg(const char *s, unsigned 
> > int *seg_p,
> >   
> >       return s;
> >   }
> > +
> > +const char *parse_pci_sbdf(const char *s, pci_sbdf_t *sbdf)
> > +{
> > +    unsigned int seg, bus, dev, func;
> > +    const char *out = parse_pci(s, &seg, &bus, &dev, &func);
> IMO, both parse_pci() and parse_pci_seg() should be merged into
> parse_pci_sbdf() and parse_pci_sbdf_seg() at the end of the series,
> since there will be no remaining consumers of the old APIs.
>
> What do you think?
That was my plan, but parse_phantom_dev() (in 
xen/drivers/passthrough/pci.c) wants to parse the PCI string without the 
function part (i.e XXXX:YY:ZZ) which can't be expressed with a full SBDF 
parse function.
It currently works by passing NULL to `func_p`, which has special 
handling in parse_pci.
We could eventually allow omitting PCI function and make default it to 
zero, so that we will be able migrate parse_phantom_dev to this new 
function (so it now allows parsing full SBDF, but ignore the function 
part of it).
> > +
> > +    *sbdf = PCI_SBDF(seg, bus, dev, func);
> > +    return out;
> > +}
> > +
> > +const char *parse_pci_sbdf_seg(const char *s, pci_sbdf_t *sbdf, bool *def_seg)
> > +{
> > +    unsigned int seg, bus, dev, func;
> > +    const char *out = parse_pci_seg(s, &seg, &bus, &dev, &func, def_seg);
> > +
> > +    *sbdf = PCI_SBDF(seg, bus, dev, func);
> > +    return out;
> > +}
> > diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
> > index afb6bbf50d..7bfc59cd75 100644
> > --- a/xen/include/xen/pci.h
> > +++ b/xen/include/xen/pci.h
> > @@ -280,6 +280,9 @@ const char *parse_pci_seg(const char *s, unsigned int 
> > *seg_p,
> >                             unsigned int *bus_p, unsigned int *dev_p,
> >                             unsigned int *func_p, bool *def_seg);
> >   
> > +const char *parse_pci_sbdf(const char *s, pci_sbdf_t *sbdf);
> > +const char *parse_pci_sbdf_seg(const char *s, pci_sbdf_t *sbdf, bool *def_seg);
> > +
> >   #define PCI_BAR_VF      (1u << 0)
> >   #define PCI_BAR_LAST    (1u << 1)
> >   #define PCI_BAR_ROM     (1u << 2)
> > --
> > 2.52.0
> >
> >
> >
> > --
> > Teddy Astie | Vates XCP-ng Developer
> >
> > XCP-ng & Xen Orchestra - Vates solutions
> >
> > web: https://vates.tech
Teddy

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