From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Auger Subject: Re: [RFC PATCH v3 0/3] vfio: platform: return device properties for a platform device Date: Thu, 27 Aug 2015 14:52:00 +0200 Message-ID: <55DF07F0.3070405@linaro.org> References: <1419024032-1269-1-git-send-email-a.motakis@virtualopensystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1419024032-1269-1-git-send-email-a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: antonios.motakis-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Baptiste Reynal Cc: tech-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org, christoffer.dall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org List-Id: iommu@lists.linux-foundation.org Hi Baptiste, Antonios, What are the plans wrt this series? I am currently integrating another QEMU VFIO platform devices where this series could be useful I think (Feb 2015). Do you intend to follow up and bring it upstream? Alex, do you see some show-stoppers in this series or do you advise to simply follow-up? Thank you in advance Best Regards Eric On 12/19/2014 10:20 PM, Antonios Motakis wrote: > This RFC's intention is to show what an interface to access device > properties for the VFIO platform driver can look like. These properties > can be from the device tree node describing the device, or ACPI properties > in the future. > > If a device property corresponding to a platform device bound by VFIO PLATFORM > or VFIO AMBA is available, this patch series will allow the user to query > for this information. This can be useful for userspace drivers to automatically > query parameters related to the device. > > Specifically for QEMU, reading the "compatible" property of the device tree > node could be of use to find out what device is being assigned to the guest and > handle appropriately a wider range of devices in the future, and to generate an > appropriate device tree for the guest. > > Older versions of this series where specifically targeted at device tree > properties. This version has been reworked on top of Rafael J. Wysocki's > uniform device properties API for device tree and ACPI devices. This will allow > us to use the API in the future with devices described via ACPI. > > This also means a kernel including the uniform device properties API is needed > to apply these patches, in additon to the VFIO patches, e.g. branch pm+acpi-3.19-rc1 > from https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/ > > The API to get the list of available properties and the device tree full_name > have been removed. These probably don't serve an useful purpose, as the user > of this API need to know anyway what properties are specific to the device he > wants to access with VFIO. If we decide to reintroduce the list of properties > in the future, the generic device properties API in the kernel will have to > be extended accordingly. > > A kernel with this series and all the dependencies applied can be pulled from > branch vfio-device-properties-v3 from the repository: > https://github.com/virtualopensystems/linux-kvm-arm.git > > Changes since v2: > - Reworked on top of Rafael J. Wysocki's uniform device properties API for > device tree and ACPI > - Support for u64 array properties > - Removed API to get list of available properties and device tree full_name > Changes since v1: > - Updated for VFIO platform patch series v8: > VFIO AMBA devices now supported in addition to VFIO PLATFORM devices > - Refactored and cleaned up the code > > Antonios Motakis (3): > vfio: platform: add device properties skeleton and user API > vfio: platform: access device property as a list of strings > vfio: platform: return device properties as arrays of unsigned > integers > > drivers/vfio/platform/Makefile | 3 +- > drivers/vfio/platform/properties.c | 162 ++++++++++++++++++++++++++ > drivers/vfio/platform/vfio_platform_common.c | 35 ++++++ > drivers/vfio/platform/vfio_platform_private.h | 7 ++ > include/uapi/linux/vfio.h | 26 +++++ > 5 files changed, 232 insertions(+), 1 deletion(-) > create mode 100644 drivers/vfio/platform/properties.c >