[Xen-devel] Re: [PATCH 16/20] x86: Introduce x86_msi_ops

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, Aug 04, 2010 at 02:19:11PM -0400, Konrad Rzeszutek Wilk wrote:
> From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> 
> Introduce an x86 specific indirect mechanism to setup MSIs.
> The MSI setup functions become function pointers in an x86_msi_ops
> struct, that defaults to the implementation in io_apic.c

Hey Peter,

I was wondering if you have time to take a look at this?

The patchset introduces a driver which takes care of allowing
pci_conf_read/write in a virtualized environements with PCI
passthrough devices. Unfortunatly for MSI operations that is not
so simple, so this patch alongside with the previous one
(https://patchwork.kernel.org/patch/117105/)
expands the arch_* calls. This makes it possible to register on top
of the native callback, the virtualized ones if required.

> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
> ---
>  arch/x86/include/asm/pci.h      |   26 +++++++++++++++++++++++---
>  arch/x86/include/asm/x86_init.h |    9 +++++++++
>  arch/x86/kernel/apic/io_apic.c  |    8 ++++----
>  arch/x86/kernel/x86_init.c      |    6 ++++++
>  4 files changed, 42 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
> index bcf84e1..861d0d0 100644
> --- a/arch/x86/include/asm/pci.h
> +++ b/arch/x86/include/asm/pci.h
> @@ -7,6 +7,7 @@
>  #include <linux/string.h>
>  #include <asm/scatterlist.h>
>  #include <asm/io.h>
> +#include <asm/x86_init.h>
>  
>  #ifdef __KERNEL__
>  
> @@ -92,9 +93,28 @@ static inline void early_quirks(void) { }
>  
>  extern void pci_iommu_alloc(void);
>  
> -/* MSI arch hook */
> -#define arch_setup_msi_irqs arch_setup_msi_irqs
> -#define arch_teardown_msi_irqs arch_teardown_msi_irqs
> +/* MSI arch specific hooks */
> +static inline int x86_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> +{
> +     return x86_msi.setup_msi_irqs(dev, nvec, type);
> +}
> +
> +static inline void x86_teardown_msi_irqs(struct pci_dev *dev)
> +{
> +     x86_msi.teardown_msi_irqs(dev);
> +}
> +
> +static inline void x86_teardown_msi_irq(unsigned int irq)
> +{
> +     x86_msi.teardown_msi_irq(irq);
> +}
> +
> +#define arch_setup_msi_irqs x86_setup_msi_irqs
> +#define arch_teardown_msi_irqs x86_teardown_msi_irqs
> +#define arch_teardown_msi_irq x86_teardown_msi_irq
> +int native_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
> +void native_teardown_msi_irq(unsigned int irq);
> +void native_teardown_msi_irqs(struct pci_dev *dev);
>  
>  #define PCI_DMA_BUS_IS_PHYS (dma_ops->is_phys)
>  
> diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
> index baa579c..64642ad 100644
> --- a/arch/x86/include/asm/x86_init.h
> +++ b/arch/x86/include/asm/x86_init.h
> @@ -154,9 +154,18 @@ struct x86_platform_ops {
>       int (*i8042_detect)(void);
>  };
>  
> +struct pci_dev;
> +
> +struct x86_msi_ops {
> +     int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
> +     void (*teardown_msi_irq)(unsigned int irq);
> +     void (*teardown_msi_irqs)(struct pci_dev *dev);
> +};
> +
>  extern struct x86_init_ops x86_init;
>  extern struct x86_cpuinit_ops x86_cpuinit;
>  extern struct x86_platform_ops x86_platform;
> +extern struct x86_msi_ops x86_msi;
>  
>  extern void x86_init_noop(void);
>  extern void x86_init_uint_noop(unsigned int unused);
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index a8d069e..0b552ec 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -3531,7 +3531,7 @@ static int setup_msi_irq(struct pci_dev *dev, struct 
> msi_desc *msidesc, int irq)
>       return 0;
>  }
>  
> -int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> +int native_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>  {
>       unsigned int irq;
>       int ret, sub_handle;
> @@ -3592,12 +3592,12 @@ error:
>       return ret;
>  }
>  
> -void arch_teardown_msi_irq(unsigned int irq)
> +void native_teardown_msi_irq(unsigned int irq)
>  {
>       destroy_irq(irq);
>  }
>  
> -void arch_teardown_msi_irqs(struct pci_dev *dev)
> +void native_teardown_msi_irqs(struct pci_dev *dev)
>  {
>       struct msi_desc *entry;
>  
> @@ -3607,7 +3607,7 @@ void arch_teardown_msi_irqs(struct pci_dev *dev)
>                       continue;
>               nvec = 1 << entry->msi_attrib.multiple;
>               for (i = 0; i < nvec; i++)
> -                     arch_teardown_msi_irq(entry->irq + i);
> +                     x86_msi.teardown_msi_irq(entry->irq + i);
>       }
>  }
>  
> diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
> index cd6da6b..91b5209 100644
> --- a/arch/x86/kernel/x86_init.c
> +++ b/arch/x86/kernel/x86_init.c
> @@ -6,6 +6,7 @@
>  #include <linux/init.h>
>  #include <linux/ioport.h>
>  #include <linux/module.h>
> +#include <linux/pci.h>
>  
>  #include <asm/bios_ebda.h>
>  #include <asm/paravirt.h>
> @@ -99,3 +100,8 @@ struct x86_platform_ops x86_platform = {
>  };
>  
>  EXPORT_SYMBOL_GPL(x86_platform);
> +struct x86_msi_ops x86_msi = {
> +     .setup_msi_irqs = native_setup_msi_irqs,
> +     .teardown_msi_irq = native_teardown_msi_irq,
> +     .teardown_msi_irqs = native_teardown_msi_irqs,
> +};
> -- 
> 1.7.0.1
> 
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