Messages in this thread | | | Date | Fri, 13 Feb 2009 18:10:19 -0800 | From | Yinghai Lu <> | Subject | Re: [PATCH 2/9] xen: hook io_apic read/write operations |
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Jeremy Fitzhardinge wrote: > In Xen, writes to the IO APIC are paravirtualized via hypercalls, so > implement the appropriate operations. > > This version of the patch just hooks the io_apic read/write functions > directly, rather than introducing another layer of indirection. The > xen_initial_domain() tests compile to 0 if CONFIG_XEN_DOM0 isn't set, > and are cheap if it is. > > (An alternative would be to add io_apic_ops, and point them to the Xen > implementation as needed. HPA deemed this extra level of indirection to > be excessive.)
that will be more clean.
> > Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> > --- > arch/x86/include/asm/io_apic.h | 6 ++++ > arch/x86/kernel/io_apic.c | 32 ++++++++++++++++++++-- > arch/x86/xen/Makefile | 3 +- > arch/x86/xen/apic.c | 57 ++++++++++++++++++++++++++++++++++++++++ > arch/x86/xen/enlighten.c | 2 + > arch/x86/xen/xen-ops.h | 6 ++++ > 6 files changed, 102 insertions(+), 4 deletions(-) > create mode 100644 arch/x86/xen/apic.c > > diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h > index 59cb4a1..20b543a 100644 > --- a/arch/x86/include/asm/io_apic.h > +++ b/arch/x86/include/asm/io_apic.h > @@ -183,4 +183,10 @@ static inline void ioapic_init_mappings(void) { } > static inline void probe_nr_irqs_gsi(void) { } > #endif > > +void xen_io_apic_init(void); > +unsigned int xen_io_apic_read(unsigned apic, unsigned reg); > +void xen_io_apic_write(unsigned int apic, > + unsigned int reg, unsigned int value); > + > + > #endif /* _ASM_X86_IO_APIC_H */ > diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c > index 7248ca1..de0368a 100644 > --- a/arch/x86/kernel/io_apic.c > +++ b/arch/x86/kernel/io_apic.c > @@ -62,6 +62,8 @@ > #include <asm/uv/uv_hub.h> > #include <asm/uv/uv_irq.h> > > +#include <asm/xen/hypervisor.h> > + > #include <asm/genapic.h> > > #define __apicdebuginit(type) static type __init > @@ -399,14 +401,26 @@ static __attribute_const__ struct io_apic __iomem *io_apic_base(int idx) > > static inline unsigned int io_apic_read(unsigned int apic, unsigned int reg) > { > - struct io_apic __iomem *io_apic = io_apic_base(apic); > + struct io_apic __iomem *io_apic; > + > + if (xen_initial_domain()) > + return xen_io_apic_read(apic, reg);
you may have _xen_io_apic_read(apic, reg); and xen_io_apic_read(apic, reg) will call xen_initial_domain internally. or sth like extra if (io_apic_ops) io_apic->read()...
YH
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