On Tue, Dec 29, 2015 at 9:50 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Tuesday 29 December 2015 21:25:15 Santosh Shukla wrote: >> mistakenly added wrong email-id of alex, looping his correct one. >> >> On 29 December 2015 at 21:23, Santosh Shukla <santosh.shukla@xxxxxxxxxx> wrote: >> > 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. >> > >> > > So what's wrong with just using the existing read/write API on all > architectures? > nothing wrong, infact read/write api will still be used so to access mmaped io pci bar at userspace. But right now vfio_pci_map() doesn't map io pci bar in particular (i.e.. ioresource_io) so I guess need to add that bar mapping in vfio. pl. correct me if i misunderstood anything. > Arnd -- 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
