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Re: [Xen-devel] [PATCH 1/2] Xen acpi pad implement



On Thu, Oct 25, 2012 at 6:19 AM, Liu, Jinsong <jinsong.liu@xxxxxxxxx> wrote:
> From f233ad06cf924116693d7d38be9ae9d8c11f8a9b Mon Sep 17 00:00:00 2001
> From: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
> Date: Fri, 26 Oct 2012 02:32:48 +0800
> Subject: [PATCH 1/2] Xen acpi pad implement
>
> PAD is acpi Processor Aggregator Device which provides a control point
> that enables the platform to perform specific processor configuration
> and control that applies to all processors in the platform.
>
> This patch is to implement Xen acpi pad logic. When running under Xen
> virt platform, native pad driver would not work. Instead Xen pad driver,
> a self-contained and very thin logic level, would take over acpi pad staff.

"logic" instead of staff (guessing this is supposed to stuff)

> When acpi pad notify OSPM, xen pad logic intercept and parse _PUR object
> and then hypercall to hyervisor for the rest work, say, core parking.
hypervisor
rest of the work? - could you add more details on what is handled by
this think PAD driver and what would be left to the host pad driver.
>
> Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
> ---
>  drivers/xen/Makefile             |    1 +
>  drivers/xen/xen_acpi_pad.c       |  173 
> ++++++++++++++++++++++++++++++++++++++
>  include/xen/interface/platform.h |   17 ++++
>  3 files changed, 191 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/xen/xen_acpi_pad.c
>
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index 0e86370..a2af622 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_XEN_MCE_LOG)             += mcelog.o
>  obj-$(CONFIG_XEN_PCIDEV_BACKEND)       += xen-pciback/
>  obj-$(CONFIG_XEN_PRIVCMD)              += xen-privcmd.o
>  obj-$(CONFIG_XEN_ACPI_PROCESSOR)       += xen-acpi-processor.o
> +obj-$(CONFIG_XEN_DOM0)                 += xen_acpi_pad.o
>  xen-evtchn-y                           := evtchn.o
>  xen-gntdev-y                           := gntdev.o
>  xen-gntalloc-y                         := gntalloc.o
> diff --git a/drivers/xen/xen_acpi_pad.c b/drivers/xen/xen_acpi_pad.c
> new file mode 100644
> index 0000000..e7b7dca
> --- /dev/null
> +++ b/drivers/xen/xen_acpi_pad.c
> @@ -0,0 +1,173 @@
> +/*
> + * xen_acpi_pad.c - Xen pad interface
> + *
> + * Copyright (c) 2012, Intel Corporation.
> + *    Author: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/types.h>
> +#include <acpi/acpi_bus.h>
> +#include <acpi/acpi_drivers.h>
> +#include <asm/xen/hypercall.h>
> +
> +#if defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR) || \
> +               defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR_MODULE)
> +
> +#define ACPI_PROCESSOR_AGGREGATOR_CLASS        "acpi_pad"
> +#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
> +#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
> +
> +static int xen_acpi_pad_idle_cpus(int *num_cpus)
> +{
> +       int ret;
> +
> +       struct xen_platform_op op = {
> +               .cmd = XENPF_core_parking,
> +               .interface_version = XENPF_INTERFACE_VERSION,
> +       };
> +
> +       /* set cpu nums expected to be idled */
> +       op.u.core_parking.type = XEN_CORE_PARKING_SET;
> +       op.u.core_parking.idle_nums = (uint32_t)*num_cpus;
> +       ret = HYPERVISOR_dom0_op(&op);
> +       if (ret)
> +               return ret;
> +
> +       /*
> +        * get cpu nums actually be idled
> +        * cannot get it by using hypercall once (shared with _SET)
> +        * because of the characteristic of Xen continue_hypercall_on_cpu
> +        */
> +       op.u.core_parking.type = XEN_CORE_PARKING_GET;
> +       ret = HYPERVISOR_dom0_op(&op);
> +       if (ret)
> +               return ret;
> +
> +       *num_cpus = op.u.core_parking.idle_nums;
> +       return 0;
> +}
> +
> +/*
> + * Query firmware how many CPUs should be idle
> + * return -1 on failure
> + */
> +static int xen_acpi_pad_pur(acpi_handle handle)
> +{
> +       struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
> +       union acpi_object *package;
> +       int num = -1;
> +
> +       if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
> +               return num;
> +
> +       if (!buffer.length || !buffer.pointer)
> +               return num;
> +
> +       package = buffer.pointer;
> +
> +       if (package->type == ACPI_TYPE_PACKAGE &&
> +               package->package.count == 2 &&
> +               package->package.elements[0].integer.value == 1) /* rev 1 */
> +
> +               num = package->package.elements[1].integer.value;
> +
> +       kfree(buffer.pointer);
> +       return num;
> +}
> +
> +/* Notify firmware how many CPUs are idle */
> +static void xen_acpi_pad_ost(acpi_handle handle, int stat,
> +       uint32_t idle_cpus)
> +{
> +       union acpi_object params[3] = {
> +               {.type = ACPI_TYPE_INTEGER,},
> +               {.type = ACPI_TYPE_INTEGER,},
> +               {.type = ACPI_TYPE_BUFFER,},
> +       };
> +       struct acpi_object_list arg_list = {3, params};
> +
> +       params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
> +       params[1].integer.value =  stat;
> +       params[2].buffer.length = 4;
> +       params[2].buffer.pointer = (void *)&idle_cpus;
> +       acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
> +}
> +
> +static void xen_acpi_pad_handle_notify(acpi_handle handle)
> +{
> +       int ret, num_cpus;
> +
> +       num_cpus = xen_acpi_pad_pur(handle);
> +       if (num_cpus < 0)
> +               return;
> +
> +       ret = xen_acpi_pad_idle_cpus(&num_cpus);
> +       if (ret)
> +               return;
> +
> +       xen_acpi_pad_ost(handle, 0, num_cpus);
> +}
> +
> +static void xen_acpi_pad_notify(acpi_handle handle, u32 event,
> +       void *data)
> +{
> +       switch (event) {
> +       case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
> +               xen_acpi_pad_handle_notify(handle);
> +               break;
> +       default:
> +               pr_warn("Unsupported event [0x%x]\n", event);
> +               break;
> +       }
> +}
> +
> +static int xen_acpi_pad_add(struct acpi_device *device)
> +{
> +       acpi_status status;
> +
> +       strcpy(acpi_device_name(device), 
> ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
> +       strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
> +
> +       status = acpi_install_notify_handler(device->handle,
> +                ACPI_DEVICE_NOTIFY, xen_acpi_pad_notify, device);
> +       if (ACPI_FAILURE(status))
> +               return -ENODEV;
> +
> +       return 0;
> +}
> +
> +static const struct acpi_device_id pad_device_ids[] = {
> +       {"ACPI000C", 0},
> +       {"", 0},
> +};
> +
> +static struct acpi_driver xen_acpi_pad_driver = {
> +       .name = "processor_aggregator",
> +       .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
> +       .ids = pad_device_ids,
> +       .ops = {
> +               .add = xen_acpi_pad_add,
> +       },
> +};
> +
> +static int __init xen_acpi_pad_init(void)
> +{
> +       /* Only DOM0 is responsible for Xen acpi pad */
> +       if (xen_initial_domain())
> +               return acpi_bus_register_driver(&xen_acpi_pad_driver);
> +
> +       return -ENODEV;
> +}
> +subsys_initcall(xen_acpi_pad_init);
> +
> +#endif
> diff --git a/include/xen/interface/platform.h 
> b/include/xen/interface/platform.h
> index 4755b5f..0f44376 100644
> --- a/include/xen/interface/platform.h
> +++ b/include/xen/interface/platform.h
> @@ -324,6 +324,22 @@ struct xenpf_cpu_ol {
>  };
>  DEFINE_GUEST_HANDLE_STRUCT(xenpf_cpu_ol);
>
> +/*
> + * CMD 58 and 59 are reserved for cpu hotadd and memory hotadd,
> + * which already occupied at Xen hypervisor side.
> + */
> +#define XENPF_core_parking     60
> +struct xenpf_core_parking {
> +       /* IN variables */
> +#define XEN_CORE_PARKING_SET   1
> +#define XEN_CORE_PARKING_GET   2
> +       uint32_t type;
> +       /* IN variables:  set cpu nums expected to be idled */
> +       /* OUT variables: get cpu nums actually be idled */
> +       uint32_t idle_nums;
> +};
> +DEFINE_GUEST_HANDLE_STRUCT(xenpf_core_parking);
> +
>  struct xen_platform_op {
>         uint32_t cmd;
>         uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
> @@ -341,6 +357,7 @@ struct xen_platform_op {
>                 struct xenpf_set_processor_pminfo set_pminfo;
>                 struct xenpf_pcpuinfo          pcpu_info;
>                 struct xenpf_cpu_ol            cpu_ol;
> +               struct xenpf_core_parking      core_parking;
>                 uint8_t                        pad[128];
>         } u;
>  };
> --
> 1.7.1

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