Message-ID: <20190422083739.GZ17995@zhen-hp.sh.intel.com>
Date:   Mon, 22 Apr 2019 16:37:39 +0800
From:   Zhenyu Wang <zhenyuw@...ux.intel.com>
To:     Yan Zhao <yan.y.zhao@...el.com>
Cc:     intel-gvt-dev@...ts.freedesktop.org, cjia@...dia.com,
        kvm@...r.kernel.org, aik@...abs.ru, Zhengxiao.zx@...baba-inc.com,
        shuangtai.tst@...baba-inc.com, qemu-devel@...gnu.org,
        kwankhede@...dia.com, eauger@...hat.com, yi.l.liu@...el.com,
        eskultet@...hat.com, ziye.yang@...el.com, mlevitsk@...hat.com,
        pasic@...ux.ibm.com, libvir-list@...hat.com,
        arei.gonglei@...wei.com, felipe@...anix.com, Ken.Xue@....com,
        kevin.tian@...el.com, dgilbert@...hat.com, zhenyuw@...ux.intel.com,
        alex.williamson@...hat.com, changpeng.liu@...el.com,
        cohuck@...hat.com, linux-kernel@...r.kernel.org,
        zhi.a.wang@...el.com, jonathan.davies@...anix.com,
        shaopeng.he@...el.com
Subject: Re: [PATCH 2/2] drm/i915/gvt: export mdev device version to sysfs
 for Intel vGPU

On 2019.04.19 04:35:59 -0400, Yan Zhao wrote:
> This feature implements the version attribute for Intel's vGPU mdev
> devices.
> 
> version attribute is rw. It is queried by userspace software like libvirt
> to check whether two vGPUs are compatible for live migration.
> 
> It consists of two parts: common part and vendor proprietary part.
> common part: 32 bit. lower 16 bits is vendor id and higher 16 bits
>              identifies device type. e.g., for pci device, it is
>              "pci vendor id" | (VFIO_DEVICE_FLAGS_PCI << 16).
> vendor proprietary part: this part is varied in length. vendor driver can
>              specify any string to identify a device.
> 
> For Intel vGPU of gen8 and gen9, the vendor proprietary part currently
> consists of 2 fields: "device id" + "mdev type".
> 
> Reading from a vGPU's version attribute, a string is returned in below
> format: 00028086-<device id>-<mdev type>. e.g.
> 00028086-193b-i915-GVTg_V5_2.
> 
> Writing a string to a vGPU's version attribute will trigger GVT to check
> whether a vGPU identified by the written string is compatible with
> current vGPU owning this version attribute. errno is returned if the two
> vGPUs are incompatible. The length of written string is returned in
> compatible case.
> 
> For other platforms, and for GVT not supporting vGPU live migration
> feature, errnos are returned when read/write of mdev devices' version
> attributes.
> 
> For old GVT versions where no version attributes exposed in sysfs, it is
> regarded as not supporting vGPU live migration.
> 
> For future platforms, besides the current 2 fields in vendor proprietary
> part, more fields may be added to identify Intel vGPU well for live
> migration purpose.
> 
> Cc: Alex Williamson <alex.williamson@...hat.com>
> Cc: Erik Skultety <eskultet@...hat.com>
> Cc: "Dr. David Alan Gilbert" <dgilbert@...hat.com>
> Cc: Cornelia Huck <cohuck@...hat.com>
> Cc: "Tian, Kevin" <kevin.tian@...el.com>
> Cc: Zhenyu Wang <zhenyuw@...ux.intel.com>
> Cc: "Wang, Zhi A" <zhi.a.wang@...el.com>
> c: Neo Jia <cjia@...dia.com>
> Cc: Kirti Wankhede <kwankhede@...dia.com>
> 
> Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
> ---
>  drivers/gpu/drm/i915/gvt/Makefile         |  2 +-
>  drivers/gpu/drm/i915/gvt/device_version.c | 94 +++++++++++++++++++++++
>  drivers/gpu/drm/i915/gvt/gvt.c            | 55 +++++++++++++
>  drivers/gpu/drm/i915/gvt/gvt.h            |  6 ++
>  4 files changed, 156 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/i915/gvt/device_version.c
> 
> diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
> index 271fb46d4dd0..54e209a23899 100644
> --- a/drivers/gpu/drm/i915/gvt/Makefile
> +++ b/drivers/gpu/drm/i915/gvt/Makefile
> @@ -3,7 +3,7 @@ GVT_DIR := gvt
>  GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
>  	interrupt.o gtt.o cfg_space.o opregion.o mmio.o display.o edid.o \
>  	execlist.o scheduler.o sched_policy.o mmio_context.o cmd_parser.o debugfs.o \
> -	fb_decoder.o dmabuf.o page_track.o
> +	fb_decoder.o dmabuf.o page_track.o device_version.o
>  
>  ccflags-y				+= -I$(src) -I$(src)/$(GVT_DIR)
>  i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
> diff --git a/drivers/gpu/drm/i915/gvt/device_version.c b/drivers/gpu/drm/i915/gvt/device_version.c
> new file mode 100644
> index 000000000000..c64010d2bc54
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/device_version.c
> @@ -0,0 +1,94 @@
> +/*
> + * Copyright(c) 2011-2017 Intel Corporation. All rights reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
> + * SOFTWARE.
> + */
> +#include <linux/vfio.h>
> +#include "i915_drv.h"
> +
> +#define GVT_VFIO_DEVICE_VENDOR_ID ((0x8086) |	\
> +		((VFIO_DEVICE_FLAGS_PCI & 0xff) << 16))
> +
> +#define GVT_DEVICE_VERSION_COMMON_LEN 0x8
> +#define GVT_DEVICE_VERSION_DEVICE_ID_LEN 0x4
> +
> +static bool is_compatible(const char *self, const char *remote)
> +{
> +	if (strlen(remote) != strlen(self))
> +		return false;
> +
> +	return (strncmp(self, remote, strlen(self))) ? false : true;
> +}
> +
> +ssize_t intel_gvt_get_vfio_device_version_len(struct drm_i915_private *dev_priv)
> +{
> +	if (!IS_GEN(dev_priv, 8) && !IS_GEN(dev_priv, 9))
> +		return -ENODEV;
> +
> +	return PAGE_SIZE;
> +}
> +
> +ssize_t intel_gvt_get_vfio_device_version(struct drm_i915_private *dev_priv,
> +		char *buf, const char *mdev_type)
> +{
> +	int cnt = 0, ret = 0;
> +	const char *str = NULL;
> +
> +	/* currently only gen8 & gen9 are supported */
> +	if (!IS_GEN(dev_priv, 8) && !IS_GEN(dev_priv, 9))
> +		return -ENODEV;
> +
> +	/* first 32 bit common part specifying vendor id and it's a pci
> +	 * device
> +	 */
> +	cnt = snprintf(buf, GVT_DEVICE_VERSION_COMMON_LEN + 1,
> +			"%08x", GVT_VFIO_DEVICE_VENDOR_ID);
> +	buf += cnt;
> +	ret += cnt;
> +
> +	/* vendor proprietary part: device id + mdev type */
> +	/* device id */
> +	cnt = snprintf(buf, GVT_DEVICE_VERSION_DEVICE_ID_LEN + 2,
> +			"-%04x", INTEL_DEVID(dev_priv));
> +	buf += cnt;
> +	ret += cnt;
> +
> +	/* mdev type */
> +	str = mdev_type;
> +	cnt = snprintf(buf, strlen(str) + 3, "-%s\n", mdev_type);
> +	buf += cnt;
> +	ret += cnt;
> +
> +	return ret;
> +}
> +
> +ssize_t intel_gvt_check_vfio_device_version(struct drm_i915_private *dev_priv,
> +		const char *self, const char *remote)
> +{
> +
> +	/* currently only gen8 & gen9 are supported */
> +	if (!IS_GEN(dev_priv, 8) && !IS_GEN(dev_priv, 9))
> +		return -ENODEV;
> +
> +	if (!is_compatible(self, remote))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
> index 43f4242062dd..e720465b93d8 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.c
> +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> @@ -105,14 +105,69 @@ static ssize_t description_show(struct kobject *kobj, struct device *dev,
>  		       type->weight);
>  }
>  
> +static ssize_t version_show(struct kobject *kobj, struct device *dev,
> +		char *buf)
> +{
> +#ifdef GVT_MIGRATION_VERSION
> +	struct drm_i915_private *i915 = kdev_to_i915(dev);
> +	const char *mdev_type = kobject_name(kobj);
> +
> +	return intel_gvt_get_vfio_device_version(i915, buf, mdev_type);
> +#else
> +	/* do not support live migration */
> +	return -EINVAL;
> +#endif
> +}
> +
> +static ssize_t version_store(struct kobject *kobj, struct device *dev,
> +		const char *buf, size_t count)
> +{
> +#ifdef GVT_MIGRATION_VERSION
> +	char *remote = NULL, *self = NULL;
> +	int len, ret = 0;
> +	struct drm_i915_private *i915 = kdev_to_i915(dev);
> +	const char *mdev_type = kobject_name(kobj);
> +
> +	len = intel_gvt_get_vfio_device_version_len(i915);
> +	if (len < 0)
> +		return len;
> +
> +	self = kmalloc(len, GFP_KERNEL);
> +	if (!self)
> +		return -ENOMEM;
> +
> +	ret = intel_gvt_get_vfio_device_version(i915, self, mdev_type);
> +	if (ret < 0)
> +		goto out;
> +

device version string should be allocated and specified during device instance
setup instead of version attribute r/w time.

> +	remote = kstrndup(buf, count, GFP_KERNEL);
> +	if (!remote) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	ret = intel_gvt_check_vfio_device_version(i915, self, remote);
> +
> +out:
> +	kfree(self);
> +	kfree(remote);
> +	return (ret < 0 ? ret : count);
> +#else
> +	/* do not support live migration */
> +	return -EINVAL;
> +#endif
> +}
> +
>  static MDEV_TYPE_ATTR_RO(available_instances);
>  static MDEV_TYPE_ATTR_RO(device_api);
>  static MDEV_TYPE_ATTR_RO(description);
> +static MDEV_TYPE_ATTR_RW(version);
>  
>  static struct attribute *gvt_type_attrs[] = {
>  	&mdev_type_attr_available_instances.attr,
>  	&mdev_type_attr_device_api.attr,
>  	&mdev_type_attr_description.attr,
> +	&mdev_type_attr_version.attr,
>  	NULL,
>  };
>  
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index f5a328b5290a..4062f6b26acf 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -687,6 +687,12 @@ void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu);
>  int intel_gvt_debugfs_init(struct intel_gvt *gvt);
>  void intel_gvt_debugfs_clean(struct intel_gvt *gvt);
>  
> +ssize_t intel_gvt_get_vfio_device_version(struct drm_i915_private *i915,
> +		char *buf, const char *mdev_type);
> +ssize_t intel_gvt_check_vfio_device_version(struct drm_i915_private *dev_priv,
> +		const char *self, const char *remote);
> +ssize_t
> +intel_gvt_get_vfio_device_version_len(struct drm_i915_private *dev_priv);
>  
>  #include "trace.h"
>  #include "mpt.h"
> -- 
> 2.17.1
> 
> _______________________________________________
> intel-gvt-dev mailing list
> intel-gvt-dev@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev

-- 
Open Source Technology Center, Intel ltd.

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