On 29 December 2015 at 18:58, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Wednesday 23 December 2015 17:04:40 Santosh Shukla wrote: >> On 23 December 2015 at 03:26, Arnd Bergmann <arnd@xxxxxxxx> wrote: >> > On Tuesday 22 December 2015, Santosh Shukla wrote: >> >> } >> >> >> >> So I care for /dev/ioport types interface who could do more than byte >> >> data copy to/from user-space. I tested this patch with little >> >> modification and could able to run pmd driver for arm/arm64 case. >> >> >> >> Like to know how to address pci_io region mapping problem for >> >> arm/arm64, in-case /dev/ioports approach is not acceptable or else I >> >> can spent time on restructuring the patch? >> >> >> > >> > For the use case you describe, can't you use the vfio framework to >> > access the PCI BARs? >> > >> >> I looked at file: drivers/vfio/pci/vfio_pci.c, func vfio_pci_map() and >> it look to me that it only maps ioresource_mem pci region, pasting >> code snap: >> >> if (!(pci_resource_flags(pdev, index) & IORESOURCE_MEM)) >> return -EINVAL; >> .... >> >> and I want to map ioresource_io pci region for arm platform in my >> use-case. Not sure vfio maps pci_iobar region? > > Mapping I/O BARs is not portable, notably it doesn't work on x86. > > You should be able access them using the read/write interface on > the vfio device. > Right, x86 doesn't care as iopl() could give userspace application direct access to ioports. Also, Alex in other dpdk thread [1] suggested someone to propose io bar mapping in vfio-pci, I guess in particular to non-x86 arch so I started working on it. Thanks. [1] http://dpdk.org/ml/archives/dev/2015-December/030852.html > Arnd > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
