Message-ID: <20190507054325.GB14284@joy-OptiPlex-7040>
Date:   Tue, 7 May 2019 01:43:25 -0400
From:   Yan Zhao <yan.y.zhao@...el.com>
To:     Zhenyu Wang <zhenyuw@...ux.intel.com>
Cc:     "cjia@...dia.com" <cjia@...dia.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "aik@...abs.ru" <aik@...abs.ru>,
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        "shuangtai.tst@...baba-inc.com" <shuangtai.tst@...baba-inc.com>,
        "qemu-devel@...gnu.org" <qemu-devel@...gnu.org>,
        "kwankhede@...dia.com" <kwankhede@...dia.com>,
        "eauger@...hat.com" <eauger@...hat.com>,
        "Liu, Yi L" <yi.l.liu@...el.com>,
        "eskultet@...hat.com" <eskultet@...hat.com>,
        "Yang, Ziye" <ziye.yang@...el.com>,
        "mlevitsk@...hat.com" <mlevitsk@...hat.com>,
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        "Ken.Xue@....com" <Ken.Xue@....com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        "dgilbert@...hat.com" <dgilbert@...hat.com>,
        "dinechin@...hat.com" <dinechin@...hat.com>,
        "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
        "intel-gvt-dev@...ts.freedesktop.org" 
        <intel-gvt-dev@...ts.freedesktop.org>,
        "Liu, Changpeng" <changpeng.liu@...el.com>,
        "berrange@...hat.com" <berrange@...hat.com>,
        "cohuck@...hat.com" <cohuck@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Wang, Zhi A" <zhi.a.wang@...el.com>,
        "jonathan.davies@...anix.com" <jonathan.davies@...anix.com>,
        "He, Shaopeng" <shaopeng.he@...el.com>
Subject: Re: [PATCH v2 2/2] drm/i915/gvt: export mdev device version to sysfs
 for Intel vGPU

On Mon, May 06, 2019 at 03:41:58PM +0800, Zhenyu Wang wrote:
> 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 <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 | 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 <yan.y.zhao@...el.com>
> > > + */
> > > +#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.
> >
ok. I'll try to define a variable in struct intel_gvt.
e.g. 

gvt->is_migration_enabled.

> > > +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.
>
ok. I'll try to add one version field in struct intel_vgpu_type.

> > > +
> > > +   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.
> >
> > $gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827
> 
> 
> 
> --
> Open Source Technology Center, Intel ltd.
> 
> $gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827


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