Re: [libvirt] [PATCH v3 2/2] drm/i915/gvt: export migration_version to mdev sysfs for Intel vGPU

This feature implements the migration_version attribute for Intel's vGPU mdev devices. migration_version attribute is rw. It's used to check migration compatibility for two mdev devices of the same mdev type. migration_version string is defined by vendor driver and opaque to userspace. For Intel vGPU of gen8 and gen9, the format of migration_version string is: <vendor id>-<device id>-<vgpu type>-<software version>. For future platforms, the format of migration_version string is to be expanded to include more meta data to identify Intel vGPUs for live migration compatibility check For old platforms, and for GVT not supporting vGPU live migration feature, -ENODEV is returned on read(2)/write(2) of migration_version attribute. For vGPUs running old GVT who do not expose migration_version attribute, live migration is regarded as not supported for those vGPUs. Cc: Alex Williamson <alex.williamson(a)redhat.com&gt; Cc: Erik Skultety <eskultet(a)redhat.com&gt; Cc: "Dr. David Alan Gilbert" <dgilbert(a)redhat.com&gt; Cc: Cornelia Huck <cohuck(a)redhat.com&gt; Cc: "Tian, Kevin" <kevin.tian(a)intel.com&gt; Cc: Zhenyu Wang <zhenyuw(a)linux.intel.com&gt; Cc: "Wang, Zhi A" <zhi.a.wang(a)intel.com&gt; c: Neo Jia <cjia(a)nvidia.com&gt; Cc: Kirti Wankhede <kwankhede(a)nvidia.com&gt; Signed-off-by: Yan Zhao <yan.y.zhao(a)intel.com&gt; --- v3: 1. renamed version to migration_version (Christophe de Dinechin, Cornelia Huck, Alex Williamson) 2. instead of generating migration version strings each time, storing them in vgpu types generated during initialization. (Zhenyu Wang, Cornelia Huck) 3. replaced multiple snprintf to one big snprintf in intel_gvt_get_vfio_migration_version() (Dr. David Alan Gilbert) 4. printed detailed error log (Alex Williamson, Erik Skultety, Cornelia Huck, Dr. David Alan Gilbert) 5. incorporated <software version> into migration_version string (Alex Williamson) 6. do not use ifndef macro to switch off migration_version attribute (Zhenyu Wang) 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) --- drivers/gpu/drm/i915/gvt/Makefile | 2 +- drivers/gpu/drm/i915/gvt/gvt.c | 39 +++++ drivers/gpu/drm/i915/gvt/gvt.h | 5 + drivers/gpu/drm/i915/gvt/migration_version.c | 167 +++++++++++++++++++ drivers/gpu/drm/i915/gvt/vgpu.c | 13 +- 5 files changed, 223 insertions(+), 3 deletions(-) create mode 100644 drivers/gpu/drm/i915/gvt/migration_version.c

diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c index 43f4242062dd..be2980e8ac75 100644 --- a/drivers/gpu/drm/i915/gvt/gvt.c +++ b/drivers/gpu/drm/i915/gvt/gvt.c @@ -105,14 +105,53 @@ static ssize_t description_show(struct kobject *kobj, struct device *dev, type->weight); } +static ssize_t migration_version_show(struct kobject *kobj, struct device *dev, + char *buf)

+{ + struct intel_vgpu_type *type; + void *gvt = kdev_to_i915(dev)->gvt; + + type = intel_gvt_find_vgpu_type(gvt, kobject_name(kobj)); + if (!type || !type->migration_version) { + gvt_err("Does not support migraion on type %s. Please search previous detailed log\n",

+ kobject_name(kobj)); + return -ENODEV; + } + + return snprintf(buf, strlen(type->migration_version) + 2, + "%s\n", type->migration_version); +} + +static ssize_t migration_version_store(struct kobject *kobj, struct device *dev, + const char *buf, size_t count) +{ + int ret = 0; + struct intel_vgpu_type *type; + void *gvt = kdev_to_i915(dev)->gvt; + + type = intel_gvt_find_vgpu_type(gvt, kobject_name(kobj)); + if (!type || !type->migration_version) { + gvt_err("Does not support migraion on type %s. Please search previous detailed log\n", + kobject_name(kobj)); + return -ENODEV; + } + + ret = intel_gvt_check_vfio_migration_version(gvt, + type->migration_version, buf); + + return (ret < 0 ? ret : count); +} + 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(migration_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_migration_version.attr, NULL, };

+char * +intel_gvt_get_vfio_migration_version(struct intel_gvt *gvt, + const char *vgpu_type) +{ + int cnt = 0; + struct drm_i915_private *dev_priv = gvt->dev_priv; + char *version = NULL; + + /* currently only gen8 & gen9 are supported */ + if (!IS_GEN(dev_priv, 8) && !IS_GEN(dev_priv, 9)) { + gvt_err("Local hardware does not support migration on %d\n", + INTEL_INFO(dev_priv)->gen); + return NULL; + } + + if (GVT_VFIO_MIGRATION_SOFTWARE_VERSION == INV_SOFTWARE_VERSION) { + gvt_err("Local GVT does not support migration\n"); + return NULL; + } + + version = kzalloc(MIGRATION_VERSION_TOTAL_LEN, GFP_KERNEL); + + if (unlikely(!version)) { + gvt_err("memory allocation failed when get local migraiton version\n");

+ return NULL; + } + + /* vendor id + device id + vgpu type + software version */ + cnt = snprintf(version, MIGRATION_VERSION_TOTAL_LEN, PRINTF_FORMAT, + PCI_VENDOR_ID_INTEL, + INTEL_DEVID(dev_priv), + vgpu_type, + GVT_VFIO_MIGRATION_SOFTWARE_VERSION); + + if (cnt) + return version; + + gvt_err("string generation failed when get local migration version\n"); + return NULL; +}