Re: [PATCH 2/2] virtio-mmio: Devices parameter parsing

From: Sasha Levin
Date: Mon Apr 09 2012 - 12:32:27 EST


Ping? Was this patch forgotten?

On Mon, Dec 12, 2011 at 6:57 PM, Pawel Moll <pawel.moll@xxxxxxx> wrote:
> This patch adds an option to instantiate guest virtio-mmio devices
> basing on a kernel command line (or module) parameter, for example:
>
>        virtio_mmio.devices=0x100@0x100b0000:48
>
> Signed-off-by: Pawel Moll <pawel.moll@xxxxxxx>
> ---
>  Documentation/kernel-parameters.txt |   17 ++++
>  drivers/virtio/Kconfig              |   11 +++
>  drivers/virtio/virtio_mmio.c        |  163 +++++++++++++++++++++++++++++++++++
>  3 files changed, 191 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index a0c5c5f..c155d13 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -110,6 +110,7 @@ parameter is applicable:
>        USB     USB support is enabled.
>        USBHID  USB Human Interface Device support is enabled.
>        V4L     Video For Linux support is enabled.
> +       VMMIO   Driver for memory mapped virtio devices is enabled.
>        VGA     The VGA console has been enabled.
>        VT      Virtual terminal support is enabled.
>        WDT     Watchdog support is enabled.
> @@ -2720,6 +2721,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>        video=          [FB] Frame buffer configuration
>                        See Documentation/fb/modedb.txt.
>
> +       virtio_mmio.device=
> +                       [VMMIO] Memory mapped virtio (platform) device.
> +
> +                               <size>@<baseaddr>:<irq>[:<id>]
> +                       where:
> +                               <size>     := size (can use standard suffixes
> +                                               like K, M and G)
> +                               <baseaddr> := physical base address
> +                               <irq>      := interrupt number (as passed to
> +                                               request_irq())
> +                               <id>       := (optional) platform device id
> +                       example:
> +                               virtio_mmio.device=1K@0x100b0000:48:7
> +
> +                       Can be used multiple times for multiple devices.
> +
>        vga=            [BOOT,X86-32] Select a particular video mode
>                        See Documentation/x86/boot.txt and
>                        Documentation/svga.txt.
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index 1a61939..f38b17a 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -46,4 +46,15 @@ config VIRTIO_BALLOON
>
>         If unsure, say N.
>
> +config VIRTIO_MMIO_CMDLINE_DEVICES
> +       bool "Memory mapped virtio devices parameter parsing"
> +       depends on VIRTIO_MMIO
> +       ---help---
> +        Allow virtio-mmio devices instantiation via the kernel command line
> +        or module parameters. Be aware that using incorrect parameters (base
> +        address in particular) can crash your system - you have been warned.
> +        See Documentation/kernel-parameters.txt for details.
> +
> +        If unsure, say 'N'.
> +
>  endmenu
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 7317dc2..eab0007 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -6,6 +6,50 @@
>  * This module allows virtio devices to be used over a virtual, memory mapped
>  * platform device.
>  *
> + * The guest device(s) may be instantiated in one of three equivalent ways:
> + *
> + * 1. Static platform device in board's code, eg.:
> + *
> + *     static struct platform_device v2m_virtio_device = {
> + *             .name = "virtio-mmio",
> + *             .id = -1,
> + *             .num_resources = 2,
> + *             .resource = (struct resource []) {
> + *                     {
> + *                             .start = 0x1001e000,
> + *                             .end = 0x1001e0ff,
> + *                             .flags = IORESOURCE_MEM,
> + *                     }, {
> + *                             .start = 42 + 32,
> + *                             .end = 42 + 32,
> + *                             .flags = IORESOURCE_IRQ,
> + *                     },
> + *             }
> + *     };
> + *
> + * 2. Device Tree node, eg.:
> + *
> + *             virtio_block@1e000 {
> + *                     compatible = "virtio,mmio";
> + *                     reg = <0x1e000 0x100>;
> + *                     interrupts = <42>;
> + *             }
> + *
> + * 3. Kernel module (or command line) parameter. Can be used more than once -
> + *    one device will be created for each one. Syntax:
> + *
> + *             [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
> + *    where:
> + *             <size>     := size (can use standard suffixes like K, M or G)
> + *             <baseaddr> := physical base address
> + *             <irq>      := interrupt number (as passed to request_irq())
> + *             <id>       := (optional) platform device id
> + *    eg.:
> + *             virtio_mmio.device=0x100@0x100b0000:48 \
> + *                             virtio_mmio.device=1K@0x1001e000:74
> + *
> + *
> + *
>  * Registers layout (all 32-bit wide):
>  *
>  * offset d. name             description
> @@ -42,6 +86,8 @@
>  * See the COPYING file in the top-level directory.
>  */
>
> +#define pr_fmt(fmt) "virtio-mmio: " fmt
> +
>  #include <linux/highmem.h>
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
> @@ -443,6 +489,122 @@ static int __devexit virtio_mmio_remove(struct platform_device *pdev)
>
>
>
> +/* Devices list parameter */
> +
> +#if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
> +
> +static struct device vm_cmdline_parent = {
> +       .init_name = "virtio-mmio-cmdline",
> +};
> +
> +static int vm_cmdline_parent_registered;
> +static int vm_cmdline_id;
> +
> +static int vm_cmdline_set(const char *device,
> +               const struct kernel_param *kp)
> +{
> +       int err;
> +       struct resource resources[2] = {};
> +       char *str;
> +       long long int base;
> +       int processed, consumed = 0;
> +       struct platform_device *pdev;
> +
> +       resources[0].flags = IORESOURCE_MEM;
> +       resources[1].flags = IORESOURCE_IRQ;
> +
> +       resources[0].end = memparse(device, &str) - 1;
> +
> +       processed = sscanf(str, "@%lli:%u%n:%d%n",
> +                       &base, &resources[1].start, &consumed,
> +                       &vm_cmdline_id, &consumed);
> +
> +       if (processed < 2 || processed > 3 || str[consumed])
> +               return -EINVAL;
> +
> +       resources[0].start = base;
> +       resources[0].end += base;
> +       resources[1].end = resources[1].start;
> +
> +       if (!vm_cmdline_parent_registered) {
> +               err = device_register(&vm_cmdline_parent);
> +               if (err) {
> +                       pr_err("Failed to register parent device!\n");
> +                       return err;
> +               }
> +               vm_cmdline_parent_registered = 1;
> +       }
> +
> +       pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
> +                      vm_cmdline_id++,
> +                      (unsigned long long)resources[0].start,
> +                      (unsigned long long)resources[0].end,
> +                      (int)resources[1].start);
> +
> +       pdev = platform_device_register_resndata(&vm_cmdline_parent,
> +                       "virtio-mmio", vm_cmdline_id++,
> +                       resources, ARRAY_SIZE(resources), NULL, 0);
> +       if (IS_ERR(pdev))
> +               return PTR_ERR(pdev);
> +
> +       return 0;
> +}
> +
> +static int vm_cmdline_get_device(struct device *dev, void *data)
> +{
> +       char *buffer = data;
> +       unsigned int len = strlen(buffer);
> +       struct platform_device *pdev = to_platform_device(dev);
> +
> +       snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
> +                       pdev->resource[0].end - pdev->resource[0].start + 1ULL,
> +                       (unsigned long long)pdev->resource[0].start,
> +                       (unsigned long long)pdev->resource[1].start,
> +                       pdev->id);
> +       return 0;
> +}
> +
> +static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
> +{
> +       buffer[0] = '\0';
> +       device_for_each_child(&vm_cmdline_parent, buffer,
> +                       vm_cmdline_get_device);
> +       return strlen(buffer) + 1;
> +}
> +
> +static struct kernel_param_ops vm_cmdline_param_ops = {
> +       .set = vm_cmdline_set,
> +       .get = vm_cmdline_get,
> +};
> +
> +device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
> +
> +static int vm_unregister_cmdline_device(struct device *dev,
> +               void *data)
> +{
> +       platform_device_unregister(to_platform_device(dev));
> +
> +       return 0;
> +}
> +
> +static void vm_unregister_cmdline_devices(void)
> +{
> +       if (vm_cmdline_parent_registered) {
> +               device_for_each_child(&vm_cmdline_parent, NULL,
> +                               vm_unregister_cmdline_device);
> +               device_unregister(&vm_cmdline_parent);
> +               vm_cmdline_parent_registered = 0;
> +       }
> +}
> +
> +#else
> +
> +static void vm_unregister_cmdline_devices(void)
> +{
> +}
> +
> +#endif
> +
>  /* Platform driver */
>
>  static struct of_device_id virtio_mmio_match[] = {
> @@ -469,6 +631,7 @@ static int __init virtio_mmio_init(void)
>  static void __exit virtio_mmio_exit(void)
>  {
>        platform_driver_unregister(&virtio_mmio_driver);
> +       vm_unregister_cmdline_devices();
>  }
>
>  module_init(virtio_mmio_init);
> --
> 1.7.5.4
>
>
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