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    SubjectRe: [PATCH 06/10] x86/PCI: Enable scanning of all pci functions
    On Wed, 13 May 2009 10:08:20 -0700
    Jeremy Fitzhardinge <jeremy@goop.org> wrote:

    > Jesse Barnes wrote:
    > > On Tue, 12 May 2009 14:48:07 -0700
    > > Jeremy Fitzhardinge <jeremy@goop.org> wrote:
    > >
    > >
    > >> From: Alex Nixon <alex.nixon@citrix.com>
    > >>
    > >> Xen may want to enable scanning of all pci functions - if for
    > >> example the device at function 0 is not passed through to the
    > >> guest, but the device at function 1 is.
    > >>
    > >> [Impact: allow passthrough of just some PCI functions.]
    > >> Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
    > >> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
    > >> Reviewed-by: "H. Peter Anvin" <hpa@zytor.com>
    > >> Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
    > >> ---
    > >> arch/x86/include/asm/pci.h | 8 +++++++-
    > >> arch/x86/pci/common.c | 1 +
    > >> 2 files changed, 8 insertions(+), 1 deletions(-)
    > >>
    > >> diff --git a/arch/x86/include/asm/pci.h
    > >> b/arch/x86/include/asm/pci.h index b51a1e8..092706e 100644
    > >> --- a/arch/x86/include/asm/pci.h
    > >> +++ b/arch/x86/include/asm/pci.h
    > >> @@ -21,6 +21,7 @@ struct pci_sysdata {
    > >> extern int pci_routeirq;
    > >> extern int noioapicquirk;
    > >> extern int noioapicreroute;
    > >> +extern int pci_scan_all_fns;
    > >>
    > >> /* scan a bus after allocating a pci_sysdata for it */
    > >> extern struct pci_bus *pci_scan_bus_on_node(int busno, struct
    > >> pci_ops *ops, @@ -48,7 +49,11 @@ extern unsigned int
    > >> pcibios_assign_all_busses(void); #else
    > >> #define pcibios_assign_all_busses() 0
    > >> #endif
    > >> -#define pcibios_scan_all_fns(a, b) 0
    > >> +
    > >> +static inline int pcibios_scan_all_fns(struct pci_bus *bus, int
    > >> devfn) +{
    > >> + return pci_scan_all_fns;
    > >> +}
    > >>
    > >> extern unsigned long pci_mem_start;
    > >> #define PCIBIOS_MIN_IO 0x1000
    > >> @@ -130,6 +135,7 @@ extern void pci_iommu_alloc(void);
    > >>
    > >> /* generic pci stuff */
    > >> #include <asm-generic/pci.h>
    > >> +#undef pcibios_scan_all_fns
    > >>
    > >
    > > This is a little gross... But then I don't see any places where it's
    > > actually defined to something true either.
    >
    > I've got some code to set it in a series I haven't posted yet.
    >
    > > Maybe it should be a weak
    > > function or a new HAVE_FOO define instead.
    > >
    >
    > I'd probably go the weak function path if I were to do either of
    > those, but do you think it would be significantly better?

    Well it would avoid the #undef, which is the gross part. But since
    it's just a boolean, you could also do

    #ifndef PCI_SCAN_ALL_FNS
    #define PCI_SCAN_ALL_FNS 0
    #endif

    in the generic code, then just set it to 1 before asm-generic/pci.h
    gets included. That would mean updating arch code though.

    Anyway it's not a big deal, this code is already ugly (a 0 define for
    all arches? why?) so you shouldn't have to spend too much time
    cleaning it up.

    --
    Jesse Barnes, Intel Open Source Technology Center


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