On 21-09-08 22:12:49, Dan Williams wrote: > The CXL_PMEM driver expects exclusive control of the label storage area > space. Similar to the LIBNVDIMM expectation that the label storage area > is only writable from userspace when the corresponding memory device is > not active in any region, the expectation is the native CXL_PCI UAPI > path is disabled while the cxl_nvdimm for a given cxl_memdev device is > active in LIBNVDIMM. > > Add the ability to toggle the availability of a given command for the > UAPI path. Use that new capability to shutdown changes to partitions and > the label storage area while the cxl_nvdimm device is actively proxying > commands for LIBNVDIMM. > > Acked-by: Ben Widawsky <[email protected]> > Link: > https://lore.kernel.org/r/162982123298.1124374.22718002900700392.st...@dwillia2-desk3.amr.corp.intel.com > Signed-off-by: Dan Williams <[email protected]>
I really wanted a way to make the exclusivity a property of the command itself and determine whether or not there's an nvdimm bridge connected before dispatching the command. Unfortunately, I couldn't make anything that was less complex than this, so it is upgraded to: Reviewed-by: Ben Widawsky <[email protected]> > --- > drivers/cxl/core/mbox.c | 5 +++++ > drivers/cxl/core/memdev.c | 31 +++++++++++++++++++++++++++++++ > drivers/cxl/cxlmem.h | 4 ++++ > drivers/cxl/pmem.c | 43 ++++++++++++++++++++++++++++++++----------- > 4 files changed, 72 insertions(+), 11 deletions(-) > > diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c > index 422999740649..82e79da195fa 100644 > --- a/drivers/cxl/core/mbox.c > +++ b/drivers/cxl/core/mbox.c > @@ -221,6 +221,7 @@ static bool cxl_mem_raw_command_allowed(u16 opcode) > * * %-EINVAL - Reserved fields or invalid values were used. > * * %-ENOMEM - Input or output buffer wasn't sized properly. > * * %-EPERM - Attempted to use a protected command. > + * * %-EBUSY - Kernel has claimed exclusive access to this opcode > * > * The result of this command is a fully validated command in @out_cmd that > is > * safe to send to the hardware. > @@ -296,6 +297,10 @@ static int cxl_validate_cmd_from_user(struct cxl_mem > *cxlm, > if (!test_bit(info->id, cxlm->enabled_cmds)) > return -ENOTTY; > > + /* Check that the command is not claimed for exclusive kernel use */ > + if (test_bit(info->id, cxlm->exclusive_cmds)) > + return -EBUSY; > + > /* Check the input buffer is the expected size */ > if (info->size_in >= 0 && info->size_in != send_cmd->in.size) > return -ENOMEM; > diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c > index df2ba87238c2..d9ade5b92330 100644 > --- a/drivers/cxl/core/memdev.c > +++ b/drivers/cxl/core/memdev.c > @@ -134,6 +134,37 @@ static const struct device_type cxl_memdev_type = { > .groups = cxl_memdev_attribute_groups, > }; > > +/** > + * set_exclusive_cxl_commands() - atomically disable user cxl commands > + * @cxlm: cxl_mem instance to modify > + * @cmds: bitmap of commands to mark exclusive > + * > + * Flush the ioctl path and disable future execution of commands with > + * the command ids set in @cmds. > + */ > +void set_exclusive_cxl_commands(struct cxl_mem *cxlm, unsigned long *cmds) > +{ > + down_write(&cxl_memdev_rwsem); > + bitmap_or(cxlm->exclusive_cmds, cxlm->exclusive_cmds, cmds, > + CXL_MEM_COMMAND_ID_MAX); > + up_write(&cxl_memdev_rwsem); > +} > +EXPORT_SYMBOL_GPL(set_exclusive_cxl_commands); > + > +/** > + * clear_exclusive_cxl_commands() - atomically enable user cxl commands > + * @cxlm: cxl_mem instance to modify > + * @cmds: bitmap of commands to mark available for userspace > + */ > +void clear_exclusive_cxl_commands(struct cxl_mem *cxlm, unsigned long *cmds) > +{ > + down_write(&cxl_memdev_rwsem); > + bitmap_andnot(cxlm->exclusive_cmds, cxlm->exclusive_cmds, cmds, > + CXL_MEM_COMMAND_ID_MAX); > + up_write(&cxl_memdev_rwsem); > +} > +EXPORT_SYMBOL_GPL(clear_exclusive_cxl_commands); > + > static void cxl_memdev_shutdown(struct device *dev) > { > struct cxl_memdev *cxlmd = to_cxl_memdev(dev); > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > index 16201b7d82d2..468b7b8be207 100644 > --- a/drivers/cxl/cxlmem.h > +++ b/drivers/cxl/cxlmem.h > @@ -101,6 +101,7 @@ struct cxl_mbox_cmd { > * @mbox_mutex: Mutex to synchronize mailbox access. > * @firmware_version: Firmware version for the memory device. > * @enabled_cmds: Hardware commands found enabled in CEL. > + * @exclusive_cmds: Commands that are kernel-internal only > * @pmem_range: Active Persistent memory capacity configuration > * @ram_range: Active Volatile memory capacity configuration > * @total_bytes: sum of all possible capacities > @@ -127,6 +128,7 @@ struct cxl_mem { > struct mutex mbox_mutex; /* Protects device mailbox and firmware */ > char firmware_version[0x10]; > DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX); > + DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX); > > struct range pmem_range; > struct range ram_range; > @@ -200,4 +202,6 @@ int cxl_mem_identify(struct cxl_mem *cxlm); > int cxl_mem_enumerate_cmds(struct cxl_mem *cxlm); > int cxl_mem_create_range_info(struct cxl_mem *cxlm); > struct cxl_mem *cxl_mem_create(struct device *dev); > +void set_exclusive_cxl_commands(struct cxl_mem *cxlm, unsigned long *cmds); > +void clear_exclusive_cxl_commands(struct cxl_mem *cxlm, unsigned long *cmds); > #endif /* __CXL_MEM_H__ */ > diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c > index 9652c3ee41e7..a972af7a6e0b 100644 > --- a/drivers/cxl/pmem.c > +++ b/drivers/cxl/pmem.c > @@ -16,10 +16,7 @@ > */ > static struct workqueue_struct *cxl_pmem_wq; > > -static void unregister_nvdimm(void *nvdimm) > -{ > - nvdimm_delete(nvdimm); > -} > +static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX); > > static int match_nvdimm_bridge(struct device *dev, const void *data) > { > @@ -36,12 +33,25 @@ static struct cxl_nvdimm_bridge > *cxl_find_nvdimm_bridge(void) > return to_cxl_nvdimm_bridge(dev); > } > > +static void cxl_nvdimm_remove(struct device *dev) > +{ > + struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev); > + struct nvdimm *nvdimm = dev_get_drvdata(dev); > + struct cxl_memdev *cxlmd = cxl_nvd->cxlmd; > + struct cxl_mem *cxlm = cxlmd->cxlm; > + > + nvdimm_delete(nvdimm); > + clear_exclusive_cxl_commands(cxlm, exclusive_cmds); > +} > + > static int cxl_nvdimm_probe(struct device *dev) > { > struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev); > + struct cxl_memdev *cxlmd = cxl_nvd->cxlmd; > + struct cxl_mem *cxlm = cxlmd->cxlm; > struct cxl_nvdimm_bridge *cxl_nvb; > + struct nvdimm *nvdimm = NULL; > unsigned long flags = 0; > - struct nvdimm *nvdimm; > int rc = -ENXIO; > > cxl_nvb = cxl_find_nvdimm_bridge(); > @@ -50,25 +60,32 @@ static int cxl_nvdimm_probe(struct device *dev) > > device_lock(&cxl_nvb->dev); > if (!cxl_nvb->nvdimm_bus) > - goto out; > + goto out_unlock; > + > + set_exclusive_cxl_commands(cxlm, exclusive_cmds); > > set_bit(NDD_LABELING, &flags); > + rc = -ENOMEM; > nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags, 0, 0, > NULL); > - if (!nvdimm) > - goto out; > + dev_set_drvdata(dev, nvdimm); > > - rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm); > -out: > +out_unlock: > device_unlock(&cxl_nvb->dev); > put_device(&cxl_nvb->dev); > > - return rc; > + if (!nvdimm) { > + clear_exclusive_cxl_commands(cxlm, exclusive_cmds); > + return rc; > + } > + > + return 0; > } > > static struct cxl_driver cxl_nvdimm_driver = { > .name = "cxl_nvdimm", > .probe = cxl_nvdimm_probe, > + .remove = cxl_nvdimm_remove, > .id = CXL_DEVICE_NVDIMM, > }; > > @@ -194,6 +211,10 @@ static __init int cxl_pmem_init(void) > { > int rc; > > + set_bit(CXL_MEM_COMMAND_ID_SET_PARTITION_INFO, exclusive_cmds); > + set_bit(CXL_MEM_COMMAND_ID_SET_SHUTDOWN_STATE, exclusive_cmds); > + set_bit(CXL_MEM_COMMAND_ID_SET_LSA, exclusive_cmds); > + > cxl_pmem_wq = alloc_ordered_workqueue("cxl_pmem", 0); > if (!cxl_pmem_wq) > return -ENXIO; >
