From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53427) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ekBCv-0006jS-Jf for qemu-devel@nongnu.org; Fri, 09 Feb 2018 11:07:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ekBCs-0000sp-GP for qemu-devel@nongnu.org; Fri, 09 Feb 2018 11:07:25 -0500 Received: from newton.telenet-ops.be ([2a02:1800:120:4::f00:d]:53566) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ekBCs-0000rq-8A for qemu-devel@nongnu.org; Fri, 09 Feb 2018 11:07:22 -0500 Received: from michel.telenet-ops.be (michel.telenet-ops.be [IPv6:2a02:1800:110:4::f00:18]) by newton.telenet-ops.be (Postfix) with ESMTPS id 3zdJvz2flVzMr0h8 for ; Fri, 9 Feb 2018 16:32:15 +0100 (CET) From: Geert Uytterhoeven Date: Fri, 9 Feb 2018 16:16:47 +0100 Message-Id: <1518189413-2761-1-git-send-email-geert+renesas@glider.be> Subject: [Qemu-devel] [PATCH/RFC 0/6] R-Car Gen3 GPIO Pass-Through Prototype (Linux) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Baptiste Reynal , Alex Williamson Cc: Arnd Bergmann , Alexander Graf , Magnus Damm , Laurent Pinchart , Wolfram Sang , kvm@vger.kernel.org, linux-renesas-soc@vger.kernel.org, qemu-devel@nongnu.org, Geert Uytterhoeven Hi all, This RFC patch series is the Linux side of a GPIO Pass-Through prototype for Renesas R-Car platforms using vfio-platform. Together with its counterpart for QEMU, it provides direct access from a QEMU+KVM guest to a GPIO controller in an R-Car Gen3 SoC. This allows the guest to control the LEDs on a Renesas Salvator-X(S) board. This patch series is not meant to be upstreamed as-is. Indeed, for various reasons (e.g. security, as the different GPIOs on the same GPIO controller may control different parts of the system) access to GPIOs is better not implemented using Device Pass-Through, but by paravirtualization. Yet, this is still a simple and valuable proof-of-concept, which can serve as a basis for the future development of Pass-Through support for more complex platform devices on R-Car Gen3 SoCs. This patch series consists of two parts: 1. Patches 1-4 are Linux host patches. They provide workarounds for missing virtualization platform support (vfio reset, IOMMU group, clock domain), and a defconfig update for testing. These allow a GPIO controller to be unbound from its host driver, and rebound to vfio-platform, for pass-through to a guest: echo e6055400.gpio > /sys/bus/platform/drivers/gpio_rcar/unbind echo vfio-platform > \ /sys/bus/platform/devices/e6055400.gpio/driver_override echo e6055400.gpio > /sys/bus/platform/drivers/vfio-platform/bind 2. Patches 5-6 are Linux guest patches. They provide workarounds for missing pass-through support (clock, interrupt), and a guest defconfig for testing. These allow the gpio-rcar driver to bind to a pass-through GPIO device, and thus control the LEDs from the guest. Several questions and TODOs are appended to the individual patches. Please see https://elinux.org/R-Car/Virtualization/VFIO for full usage instructions of this prototype. Thanks for your comments! Geert Uytterhoeven (6): vfio: platform: Allow runtime override of reset_required vfio: Ignore real IOMMUs if CONFIG_VFIO_NOIOMMU=y clk: renesas: r8a7795: Mark the GPIO6 clock critical arm64: renesas_defconfig: Enable VFIO_PLATFORM and VFIO_NOIOMMU gpio: rcar: Add virtualization workarounds arm64: Add virt_defconfig arch/arm64/configs/renesas_defconfig | 2 + arch/arm64/configs/virt_defconfig | 722 +++++++++++++++++++++++++++++++++ drivers/clk/renesas/r8a7795-cpg-mssr.c | 1 + drivers/gpio/Kconfig | 2 +- drivers/gpio/gpio-rcar.c | 28 +- drivers/vfio/platform/vfio_platform.c | 2 +- drivers/vfio/vfio.c | 6 +- 7 files changed, 744 insertions(+), 19 deletions(-) create mode 100644 arch/arm64/configs/virt_defconfig -- 2.7.4 Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds