| Message ID | 165784335630.1758207.420216490941955417.stgit@dwillia2-xfh.jf.intel.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | CXL PMEM Region Provisioning | expand |
On Thu, 14 Jul 2022 17:02:36 -0700 Dan Williams <dan.j.williams@intel.com> wrote: > After a region's interleave parameters (ways and granularity) are set, > add a way for regions to allocate HPA (host physical address space) from > the free capacity in their parent root-decoder. The allocator for this > capacity reuses the 'struct resource' based allocator used for > CONFIG_DEVICE_PRIVATE. > > Once the tuple of "ways, granularity, and size" is set the > region configuration transitions to the CXL_CONFIG_INTERLEAVE_ACTIVE > state which is a precursor to allowing endpoint decoders to be added to > a region. > > Co-developed-by: Ben Widawsky <bwidawsk@kernel.org> > Signed-off-by: Ben Widawsky <bwidawsk@kernel.org> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> Comments all look to be addressed either in reply to v1 review or here so LGTM Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > Documentation/ABI/testing/sysfs-bus-cxl | 29 ++++++ > drivers/cxl/Kconfig | 3 + > drivers/cxl/core/region.c | 150 +++++++++++++++++++++++++++++++ > drivers/cxl/cxl.h | 2 > 4 files changed, 183 insertions(+), 1 deletion(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl > index bfa42bcc8383..0c6c3da4da5a 100644 > --- a/Documentation/ABI/testing/sysfs-bus-cxl > +++ b/Documentation/ABI/testing/sysfs-bus-cxl > @@ -313,3 +313,32 @@ Description: > (RW) Configures the number of devices participating in the > region is set by writing this value. Each device will provide > 1/interleave_ways of storage for the region. > + > + > +What: /sys/bus/cxl/devices/regionZ/size > +Date: May, 2022 > +KernelVersion: v5.20 > +Contact: linux-cxl@vger.kernel.org > +Description: > + (RW) System physical address space to be consumed by the region. > + When written trigger the driver to allocate space out of the > + parent root decoder's address space. When read the size of the > + address space is reported and should match the span of the > + region's resource attribute. Size shall be set after the > + interleave configuration parameters. Once set it cannot be > + changed, only freed by writing 0. The kernel makes no guarantees > + that data is maintained over an address space freeing event, and > + there is no guarantee that a free followed by an allocate > + results in the same address being allocated. > + > + > +What: /sys/bus/cxl/devices/regionZ/resource > +Date: May, 2022 > +KernelVersion: v5.20 > +Contact: linux-cxl@vger.kernel.org > +Description: > + (RO) A region is a contiguous partition of a CXL root decoder > + address space. Region capacity is allocated by writing to the > + size attribute, the resulting physical address space determined > + by the driver is reflected here. It is therefore not useful to > + read this before writing a value to the size attribute. > diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig > index aa2728de419e..74c2cd069d9d 100644 > --- a/drivers/cxl/Kconfig > +++ b/drivers/cxl/Kconfig > @@ -105,6 +105,9 @@ config CXL_SUSPEND > config CXL_REGION > bool > default CXL_BUS > + # For MAX_PHYSMEM_BITS > + depends on SPARSEMEM > select MEMREGION > + select GET_FREE_REGION > > endif > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 3289caa5d882..b1e847827c6b 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -244,10 +244,152 @@ static ssize_t interleave_granularity_store(struct device *dev, > } > static DEVICE_ATTR_RW(interleave_granularity); > > +static ssize_t resource_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + struct cxl_region *cxlr = to_cxl_region(dev); > + struct cxl_region_params *p = &cxlr->params; > + u64 resource = -1ULL; > + ssize_t rc; > + > + rc = down_read_interruptible(&cxl_region_rwsem); > + if (rc) > + return rc; > + if (p->res) > + resource = p->res->start; > + rc = sysfs_emit(buf, "%#llx\n", resource); > + up_read(&cxl_region_rwsem); > + > + return rc; > +} > +static DEVICE_ATTR_RO(resource); > + > +static int alloc_hpa(struct cxl_region *cxlr, resource_size_t size) > +{ > + struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent); > + struct cxl_region_params *p = &cxlr->params; > + struct resource *res; > + u32 remainder = 0; > + > + lockdep_assert_held_write(&cxl_region_rwsem); > + > + /* Nothing to do... */ > + if (p->res && resource_size(res) == size) > + return 0; > + > + /* To change size the old size must be freed first */ > + if (p->res) > + return -EBUSY; > + > + if (p->state >= CXL_CONFIG_INTERLEAVE_ACTIVE) > + return -EBUSY; > + > + /* ways, granularity and uuid (if PMEM) need to be set before HPA */ > + if (!p->interleave_ways || !p->interleave_granularity || > + (cxlr->mode == CXL_DECODER_PMEM && uuid_is_null(&p->uuid))) > + return -ENXIO; > + > + div_u64_rem(size, SZ_256M * p->interleave_ways, &remainder); > + if (remainder) > + return -EINVAL; > + > + res = alloc_free_mem_region(cxlrd->res, size, SZ_256M, > + dev_name(&cxlr->dev)); > + if (IS_ERR(res)) { > + dev_dbg(&cxlr->dev, "failed to allocate HPA: %ld\n", > + PTR_ERR(res)); > + return PTR_ERR(res); > + } > + > + p->res = res; > + p->state = CXL_CONFIG_INTERLEAVE_ACTIVE; > + > + return 0; > +} > + > +static void cxl_region_iomem_release(struct cxl_region *cxlr) > +{ > + struct cxl_region_params *p = &cxlr->params; > + > + if (device_is_registered(&cxlr->dev)) > + lockdep_assert_held_write(&cxl_region_rwsem); > + if (p->res) { > + remove_resource(p->res); > + kfree(p->res); > + p->res = NULL; > + } > +} > + > +static int free_hpa(struct cxl_region *cxlr) > +{ > + struct cxl_region_params *p = &cxlr->params; > + > + lockdep_assert_held_write(&cxl_region_rwsem); > + > + if (!p->res) > + return 0; > + > + if (p->state >= CXL_CONFIG_ACTIVE) > + return -EBUSY; > + > + cxl_region_iomem_release(cxlr); > + p->state = CXL_CONFIG_IDLE; > + return 0; > +} > + > +static ssize_t size_store(struct device *dev, struct device_attribute *attr, > + const char *buf, size_t len) > +{ > + struct cxl_region *cxlr = to_cxl_region(dev); > + u64 val; > + int rc; > + > + rc = kstrtou64(buf, 0, &val); > + if (rc) > + return rc; > + > + rc = down_write_killable(&cxl_region_rwsem); > + if (rc) > + return rc; > + > + if (val) > + rc = alloc_hpa(cxlr, val); > + else > + rc = free_hpa(cxlr); > + up_write(&cxl_region_rwsem); > + > + if (rc) > + return rc; > + > + return len; > +} > + > +static ssize_t size_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + struct cxl_region *cxlr = to_cxl_region(dev); > + struct cxl_region_params *p = &cxlr->params; > + u64 size = 0; > + ssize_t rc; > + > + rc = down_read_interruptible(&cxl_region_rwsem); > + if (rc) > + return rc; > + if (p->res) > + size = resource_size(p->res); > + rc = sysfs_emit(buf, "%#llx\n", size); > + up_read(&cxl_region_rwsem); > + > + return rc; > +} > +static DEVICE_ATTR_RW(size); > + > static struct attribute *cxl_region_attrs[] = { > &dev_attr_uuid.attr, > &dev_attr_interleave_ways.attr, > &dev_attr_interleave_granularity.attr, > + &dev_attr_resource.attr, > + &dev_attr_size.attr, > NULL, > }; > > @@ -293,7 +435,11 @@ static struct cxl_region *to_cxl_region(struct device *dev) > > static void unregister_region(void *dev) > { > - device_unregister(dev); > + struct cxl_region *cxlr = to_cxl_region(dev); > + > + device_del(dev); > + cxl_region_iomem_release(cxlr); > + put_device(dev); > } > > static struct lock_class_key cxl_region_key; > @@ -445,3 +591,5 @@ static ssize_t delete_region_store(struct device *dev, > return len; > } > DEVICE_ATTR_WO(delete_region); > + > +MODULE_IMPORT_NS(CXL); > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > index a4e65c102bed..837bfa67f469 100644 > --- a/drivers/cxl/cxl.h > +++ b/drivers/cxl/cxl.h > @@ -341,6 +341,7 @@ enum cxl_config_state { > * @uuid: unique id for persistent regions > * @interleave_ways: number of endpoints in the region > * @interleave_granularity: capacity each endpoint contributes to a stripe > + * @res: allocated iomem capacity for this region > * > * State transitions are protected by the cxl_region_rwsem > */ > @@ -349,6 +350,7 @@ struct cxl_region_params { > uuid_t uuid; > int interleave_ways; > int interleave_granularity; > + struct resource *res; > }; > > /** >
diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl index bfa42bcc8383..0c6c3da4da5a 100644 --- a/Documentation/ABI/testing/sysfs-bus-cxl +++ b/Documentation/ABI/testing/sysfs-bus-cxl @@ -313,3 +313,32 @@ Description: (RW) Configures the number of devices participating in the region is set by writing this value. Each device will provide 1/interleave_ways of storage for the region. + + +What: /sys/bus/cxl/devices/regionZ/size +Date: May, 2022 +KernelVersion: v5.20 +Contact: linux-cxl@vger.kernel.org +Description: + (RW) System physical address space to be consumed by the region. + When written trigger the driver to allocate space out of the + parent root decoder's address space. When read the size of the + address space is reported and should match the span of the + region's resource attribute. Size shall be set after the + interleave configuration parameters. Once set it cannot be + changed, only freed by writing 0. The kernel makes no guarantees + that data is maintained over an address space freeing event, and + there is no guarantee that a free followed by an allocate + results in the same address being allocated. + + +What: /sys/bus/cxl/devices/regionZ/resource +Date: May, 2022 +KernelVersion: v5.20 +Contact: linux-cxl@vger.kernel.org +Description: + (RO) A region is a contiguous partition of a CXL root decoder + address space. Region capacity is allocated by writing to the + size attribute, the resulting physical address space determined + by the driver is reflected here. It is therefore not useful to + read this before writing a value to the size attribute. diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig index aa2728de419e..74c2cd069d9d 100644 --- a/drivers/cxl/Kconfig +++ b/drivers/cxl/Kconfig @@ -105,6 +105,9 @@ config CXL_SUSPEND config CXL_REGION bool default CXL_BUS + # For MAX_PHYSMEM_BITS + depends on SPARSEMEM select MEMREGION + select GET_FREE_REGION endif diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 3289caa5d882..b1e847827c6b 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -244,10 +244,152 @@ static ssize_t interleave_granularity_store(struct device *dev, } static DEVICE_ATTR_RW(interleave_granularity); +static ssize_t resource_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct cxl_region *cxlr = to_cxl_region(dev); + struct cxl_region_params *p = &cxlr->params; + u64 resource = -1ULL; + ssize_t rc; + + rc = down_read_interruptible(&cxl_region_rwsem); + if (rc) + return rc; + if (p->res) + resource = p->res->start; + rc = sysfs_emit(buf, "%#llx\n", resource); + up_read(&cxl_region_rwsem); + + return rc; +} +static DEVICE_ATTR_RO(resource); + +static int alloc_hpa(struct cxl_region *cxlr, resource_size_t size) +{ + struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent); + struct cxl_region_params *p = &cxlr->params; + struct resource *res; + u32 remainder = 0; + + lockdep_assert_held_write(&cxl_region_rwsem); + + /* Nothing to do... */ + if (p->res && resource_size(res) == size) + return 0; + + /* To change size the old size must be freed first */ + if (p->res) + return -EBUSY; + + if (p->state >= CXL_CONFIG_INTERLEAVE_ACTIVE) + return -EBUSY; + + /* ways, granularity and uuid (if PMEM) need to be set before HPA */ + if (!p->interleave_ways || !p->interleave_granularity || + (cxlr->mode == CXL_DECODER_PMEM && uuid_is_null(&p->uuid))) + return -ENXIO; + + div_u64_rem(size, SZ_256M * p->interleave_ways, &remainder); + if (remainder) + return -EINVAL; + + res = alloc_free_mem_region(cxlrd->res, size, SZ_256M, + dev_name(&cxlr->dev)); + if (IS_ERR(res)) { + dev_dbg(&cxlr->dev, "failed to allocate HPA: %ld\n", + PTR_ERR(res)); + return PTR_ERR(res); + } + + p->res = res; + p->state = CXL_CONFIG_INTERLEAVE_ACTIVE; + + return 0; +} + +static void cxl_region_iomem_release(struct cxl_region *cxlr) +{ + struct cxl_region_params *p = &cxlr->params; + + if (device_is_registered(&cxlr->dev)) + lockdep_assert_held_write(&cxl_region_rwsem); + if (p->res) { + remove_resource(p->res); + kfree(p->res); + p->res = NULL; + } +} + +static int free_hpa(struct cxl_region *cxlr) +{ + struct cxl_region_params *p = &cxlr->params; + + lockdep_assert_held_write(&cxl_region_rwsem); + + if (!p->res) + return 0; + + if (p->state >= CXL_CONFIG_ACTIVE) + return -EBUSY; + + cxl_region_iomem_release(cxlr); + p->state = CXL_CONFIG_IDLE; + return 0; +} + +static ssize_t size_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct cxl_region *cxlr = to_cxl_region(dev); + u64 val; + int rc; + + rc = kstrtou64(buf, 0, &val); + if (rc) + return rc; + + rc = down_write_killable(&cxl_region_rwsem); + if (rc) + return rc; + + if (val) + rc = alloc_hpa(cxlr, val); + else + rc = free_hpa(cxlr); + up_write(&cxl_region_rwsem); + + if (rc) + return rc; + + return len; +} + +static ssize_t size_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct cxl_region *cxlr = to_cxl_region(dev); + struct cxl_region_params *p = &cxlr->params; + u64 size = 0; + ssize_t rc; + + rc = down_read_interruptible(&cxl_region_rwsem); + if (rc) + return rc; + if (p->res) + size = resource_size(p->res); + rc = sysfs_emit(buf, "%#llx\n", size); + up_read(&cxl_region_rwsem); + + return rc; +} +static DEVICE_ATTR_RW(size); + static struct attribute *cxl_region_attrs[] = { &dev_attr_uuid.attr, &dev_attr_interleave_ways.attr, &dev_attr_interleave_granularity.attr, + &dev_attr_resource.attr, + &dev_attr_size.attr, NULL, }; @@ -293,7 +435,11 @@ static struct cxl_region *to_cxl_region(struct device *dev) static void unregister_region(void *dev) { - device_unregister(dev); + struct cxl_region *cxlr = to_cxl_region(dev); + + device_del(dev); + cxl_region_iomem_release(cxlr); + put_device(dev); } static struct lock_class_key cxl_region_key; @@ -445,3 +591,5 @@ static ssize_t delete_region_store(struct device *dev, return len; } DEVICE_ATTR_WO(delete_region); + +MODULE_IMPORT_NS(CXL); diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index a4e65c102bed..837bfa67f469 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -341,6 +341,7 @@ enum cxl_config_state { * @uuid: unique id for persistent regions * @interleave_ways: number of endpoints in the region * @interleave_granularity: capacity each endpoint contributes to a stripe + * @res: allocated iomem capacity for this region * * State transitions are protected by the cxl_region_rwsem */ @@ -349,6 +350,7 @@ struct cxl_region_params { uuid_t uuid; int interleave_ways; int interleave_granularity; + struct resource *res; }; /**