Re: [Qemu-devel] [PATCH v2 2/2] drm/i915/gvt: export mdev device version to sysfs for Intel vGPU

[Zhenyu Wang]

On 2019.05.06 11:20:32 +0800, Zhenyu Wang wrote:
> On 2019.05.05 21:51:02 -0400, Yan Zhao wrote:
> > This feature implements the version attribute for Intel's vGPU mdev
> > devices.
> > 
> > version attribute is rw.
> > It's used to check device compatibility for two mdev devices.
> > version string format and length are private for vendor driver. vendor
> > driver is able to define them freely.
> > 
> > For Intel vGPU of gen8 and gen9, the mdev device version
> > consists of 3 fields: "vendor id" + "device id" + "mdev type".
> > 
> > Reading from a vGPU's version attribute, a string is returned in below
> > format: <vendor id>-<device id>-<mdev type>. e.g.
> > 8086-193b-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.
> > 
> > v2:
> > 1. removed 32 common part of version string
> > (Alex Williamson)
> > 2. do not register version attribute for GVT not supporting live
> > migration.(Cornelia Huck)
> > 3. for platforms out of gen8, gen9, return -EINVAL --> -ENODEV for
> > incompatible. (Cornelia Huck)
> > 
> > Cc: Alex Williamson <address@hidden>
> > Cc: Erik Skultety <address@hidden>
> > Cc: "Dr. David Alan Gilbert" <address@hidden>
> > Cc: Cornelia Huck <address@hidden>
> > Cc: "Tian, Kevin" <address@hidden>
> > Cc: Zhenyu Wang <address@hidden>
> > Cc: "Wang, Zhi A" <address@hidden>
> > c: Neo Jia <address@hidden>
> > Cc: Kirti Wankhede <address@hidden>
> > 
> > Signed-off-by: Yan Zhao <address@hidden>
> > ---
> >  drivers/gpu/drm/i915/gvt/Makefile         |  2 +-
> >  drivers/gpu/drm/i915/gvt/device_version.c | 87 +++++++++++++++++++++++
> >  drivers/gpu/drm/i915/gvt/gvt.c            | 51 +++++++++++++
> >  drivers/gpu/drm/i915/gvt/gvt.h            |  6 ++
> >  4 files changed, 145 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..bd4cdcbdba95
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/gvt/device_version.c
> > @@ -0,0 +1,87 @@
> > +/*
> > + * 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.
> > + *
> > + * Authors:
> > + *    Yan Zhao <address@hidden>
> > + */
> > +#include <linux/vfio.h>
> > +#include "i915_drv.h"
> > +
> > +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;
> > +
> > +   /* vendor id + device id + mdev type */
> > +   /* vendor id */
> > +   cnt = snprintf(buf, 5, "%04x", PCI_VENDOR_ID_INTEL);
> > +   buf += cnt;
> > +   ret += cnt;
> > +
> > +   /* device id */
> > +   cnt = snprintf(buf, 6, "-%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..19f16eec5a4c 100644
> > --- a/drivers/gpu/drm/i915/gvt/gvt.c
> > +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> > @@ -105,14 +105,65 @@ static ssize_t description_show(struct kobject *kobj, 
> > struct device *dev,
> >                    type->weight);
> >  }
> >  
> > +#ifdef GVT_MIGRATION_VERSION
> 
> No extra define.
> 
> > +static ssize_t version_show(struct kobject *kobj, struct device *dev,
> > +           char *buf)
> > +{
> > +   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);
> > +}
> > +
> > +static ssize_t version_store(struct kobject *kobj, struct device *dev,
> > +           const char *buf, size_t count)
> > +{
> > +   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;
> > +
> > +   remote = kstrndup(buf, count, GFP_KERNEL);
> > +   if (!remote) {
> > +           ret = -ENOMEM;
> > +           goto out;
> > +   }
> 
> Please make device version as attribute for vgpu instead of allocating memory
> everytime to generate it.
>

Seems this is attribute for mdev type instead of instance, I was wrong
to take it as vgpu instance attribute, so we could add it for vgpu type
definition for device with migration.

> > +
> > +   ret = intel_gvt_check_vfio_device_version(i915, self, remote);
> > +
> > +out:
> > +   kfree(self);
> > +   kfree(remote);
> > +   return (ret < 0 ? ret : count);
> > +}
> > +#endif
> > +
> >  static MDEV_TYPE_ATTR_RO(available_instances);
> >  static MDEV_TYPE_ATTR_RO(device_api);
> >  static MDEV_TYPE_ATTR_RO(description);
> > +#ifdef GVT_MIGRATION_VERSION
> > +static MDEV_TYPE_ATTR_RW(version);
> > +#endif
> 
> Don't need extra define.
> 
> >  
> >  static struct attribute *gvt_type_attrs[] = {
> >     &mdev_type_attr_available_instances.attr,
> >     &mdev_type_attr_device_api.attr,
> >     &mdev_type_attr_description.attr,
> > +#ifdef GVT_MIGRATION_VERSION
> > +   &mdev_type_attr_version.attr,
> > +#endif
> >     NULL,
> >  };
> 
> I think you need another group of attrs for type that could support
> migration, it will be assigned during host init for current platform
> with driver support. So just add new group of attrs for like
> gvt_migration_type_attrs[] with version.
> 
> >  
> > 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
> > 
> 
> -- 
> Open Source Technology Center, Intel ltd.
> 
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