[PATCH 1/7] powerpc: Add interface to get msi region information
Bhushan Bharat-R65777
R65777 at freescale.com
Fri Oct 4 15:19:10 EST 2013
> -----Original Message-----
> From: linux-pci-owner at vger.kernel.org [mailto:linux-pci-owner at vger.kernel.org]
> On Behalf Of Bjorn Helgaas
> Sent: Wednesday, September 25, 2013 5:28 AM
> To: Bhushan Bharat-R65777
> Cc: alex.williamson at redhat.com; joro at 8bytes.org; benh at kernel.crashing.org;
> galak at kernel.crashing.org; linux-kernel at vger.kernel.org; linuxppc-
> dev at lists.ozlabs.org; linux-pci at vger.kernel.org; agraf at suse.de; Wood Scott-
> B07421; iommu at lists.linux-foundation.org; Bhushan Bharat-R65777
> Subject: Re: [PATCH 1/7] powerpc: Add interface to get msi region information
>
> On Thu, Sep 19, 2013 at 12:59:17PM +0530, Bharat Bhushan wrote:
> > This patch adds interface to get following information
> > - Number of MSI regions (which is number of MSI banks for powerpc).
> > - Get the region address range: Physical page which have the
> > address/addresses used for generating MSI interrupt
> > and size of the page.
> >
> > These are required to create IOMMU (Freescale PAMU) mapping for
> > devices which are directly assigned using VFIO.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhushan at freescale.com>
> > ---
> > arch/powerpc/include/asm/machdep.h | 8 +++++++
> > arch/powerpc/include/asm/pci.h | 2 +
> > arch/powerpc/kernel/msi.c | 18 ++++++++++++++++
> > arch/powerpc/sysdev/fsl_msi.c | 39 +++++++++++++++++++++++++++++++++--
> > arch/powerpc/sysdev/fsl_msi.h | 11 ++++++++-
> > drivers/pci/msi.c | 26 ++++++++++++++++++++++++
> > include/linux/msi.h | 8 +++++++
> > include/linux/pci.h | 13 ++++++++++++
> > 8 files changed, 120 insertions(+), 5 deletions(-)
> >
> > ...
>
> > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index
> > aca7578..6d85c15 100644
> > --- a/drivers/pci/msi.c
> > +++ b/drivers/pci/msi.c
> > @@ -30,6 +30,20 @@ static int pci_msi_enable = 1;
> >
> > /* Arch hooks */
> >
> > +#ifndef arch_msi_get_region_count
> > +int arch_msi_get_region_count(void)
> > +{
> > + return 0;
> > +}
> > +#endif
> > +
> > +#ifndef arch_msi_get_region
> > +int arch_msi_get_region(int region_num, struct msi_region *region) {
> > + return 0;
> > +}
> > +#endif
>
> This #define strategy is gone; see 4287d824 ("PCI: use weak functions for MSI
> arch-specific functions"). Please use the weak function strategy for your new
> MSI region functions.
ok
>
> > +
> > #ifndef arch_msi_check_device
> > int arch_msi_check_device(struct pci_dev *dev, int nvec, int type) {
> > @@ -903,6 +917,18 @@ void pci_disable_msi(struct pci_dev *dev) }
> > EXPORT_SYMBOL(pci_disable_msi);
> >
> > +int msi_get_region_count(void)
> > +{
> > + return arch_msi_get_region_count();
> > +}
> > +EXPORT_SYMBOL(msi_get_region_count);
> > +
> > +int msi_get_region(int region_num, struct msi_region *region) {
> > + return arch_msi_get_region(region_num, region); }
> > +EXPORT_SYMBOL(msi_get_region);
>
> Please split these interface additions, i.e., the drivers/pci/msi.c,
> include/linux/msi.h, and include/linux/pci.h changes, into a separate patch.
ok
>
> I don't know enough about VFIO to understand why these new interfaces are
> needed. Is this the first VFIO IOMMU driver? I see vfio_iommu_spapr_tce.c and
> vfio_iommu_type1.c but I don't know if they're comparable to the Freescale PAMU.
> Do other VFIO IOMMU implementations support MSI? If so, do they handle the
> problem of mapping the MSI regions in a different way?
PAMU is an aperture type of IOMMU while other are paging type, So they are completely different from what PAMU is and handle that differently.
>
> > /**
> > * pci_msix_table_size - return the number of device's MSI-X table entries
> > * @dev: pointer to the pci_dev data structure of MSI-X device
> > function diff --git a/include/linux/msi.h b/include/linux/msi.h index
> > ee66f3a..ae32601 100644
> > --- a/include/linux/msi.h
> > +++ b/include/linux/msi.h
> > @@ -50,6 +50,12 @@ struct msi_desc {
> > struct kobject kobj;
> > };
> >
> > +struct msi_region {
> > + int region_num;
> > + dma_addr_t addr;
> > + size_t size;
> > +};
>
> This needs some sort of explanatory comment.
Ok
-Bharat
>
> > /*
> > * The arch hook for setup up msi irqs
> > */
> > @@ -58,5 +64,7 @@ void arch_teardown_msi_irq(unsigned int irq); int
> > arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type); void
> > arch_teardown_msi_irqs(struct pci_dev *dev); int
> > arch_msi_check_device(struct pci_dev* dev, int nvec, int type);
> > +int arch_msi_get_region_count(void);
> > +int arch_msi_get_region(int region_num, struct msi_region *region);
> >
> > #endif /* LINUX_MSI_H */
> > diff --git a/include/linux/pci.h b/include/linux/pci.h index
> > 186540d..2b26a59 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -1126,6 +1126,7 @@ struct msix_entry {
> > u16 entry; /* driver uses to specify entry, OS writes */
> > };
> >
> > +struct msi_region;
> >
> > #ifndef CONFIG_PCI_MSI
> > static inline int pci_enable_msi_block(struct pci_dev *dev, unsigned
> > int nvec) @@ -1168,6 +1169,16 @@ static inline int
> > pci_msi_enabled(void) {
> > return 0;
> > }
> > +
> > +static inline int msi_get_region_count(void) {
> > + return 0;
> > +}
> > +
> > +static inline int msi_get_region(int region_num, struct msi_region
> > +*region) {
> > + return 0;
> > +}
> > #else
> > int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec);
> > int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int
> > *maxvec); @@ -1180,6 +1191,8 @@ void pci_disable_msix(struct pci_dev
> > *dev); void msi_remove_pci_irq_vectors(struct pci_dev *dev); void
> > pci_restore_msi_state(struct pci_dev *dev); int
> > pci_msi_enabled(void);
> > +int msi_get_region_count(void);
> > +int msi_get_region(int region_num, struct msi_region *region);
> > #endif
> >
> > #ifdef CONFIG_PCIEPORTBUS
> > --
> > 1.7.0.4
> >
> >
> > --
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