| Message ID | d88366e1b749c0100f2480f0036117667b62bc95.1679892337.git.alison.schofield@intel.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | cxl: CXL Inject & Clear Poison | expand |
On 3/26/23 10:03 PM, alison.schofield@intel.com wrote: > From: Alison Schofield <alison.schofield@intel.com> > > Inject and clear poison commands are intended to be used in debug > mode only, and if improperly used, can lead to data corruption. The > kernel provides a debugfs interface to issue these commands [1] > > The CXL driver defines Enabled commands in its ABI.[2] Enabled means > that the device and the driver both support the command. If a device > supports inject and/or clear, those commands are flagged Enabled. > > The ABI also defines another command flag: Exclusive. Exclusive > commands are reserved for kernel use. The exclusive flags can be > temporal, but for inject and clear, the status is permanent. > > Document the exclusivity of Inject and Clear in the ABI kernel doc. > (Clean up a typo in kdoc too: 'CXL_MEM_COMMAND_FLAG_ENABLED') > > Create an exclusive commands bitmap in the memdev driver, add the > inject and clear poison commands, and set it in the cxl_dev_state. > > [1] Documentation/ABI/testing/debugfs-cxl > [2] include/uapi/linux/cxl_mem.h > > Signed-off-by: Alison Schofield <alison.schofield@intel.com> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> > --- > drivers/cxl/core/memdev.c | 6 ++++++ > include/uapi/linux/cxl_mem.h | 20 +++++++++++++++----- > 2 files changed, 21 insertions(+), 5 deletions(-) > > diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c > index 71ebe3795616..617d8378ca9a 100644 > --- a/drivers/cxl/core/memdev.c > +++ b/drivers/cxl/core/memdev.c > @@ -11,6 +11,8 @@ > > static DECLARE_RWSEM(cxl_memdev_rwsem); > > +static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX); > + > /* > * An entire PCI topology full of devices should be enough for any > * config > @@ -628,6 +630,10 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds) > cxlmd->cxlds = cxlds; > cxlds->cxlmd = cxlmd; > > + set_bit(CXL_MEM_COMMAND_ID_INJECT_POISON, exclusive_cmds); > + set_bit(CXL_MEM_COMMAND_ID_CLEAR_POISON, exclusive_cmds); > + set_exclusive_cxl_commands(cxlds, exclusive_cmds); > + > cdev = &cxlmd->cdev; > rc = cdev_device_add(cdev, dev); > if (rc) > diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h > index 86bbacf2a315..6294278f9dcb 100644 > --- a/include/uapi/linux/cxl_mem.h > +++ b/include/uapi/linux/cxl_mem.h > @@ -74,17 +74,27 @@ static const struct { > * @id: ID number for the command. > * @flags: Flags that specify command behavior. > * > - * CXL_MEM_COMMAND_FLAG_USER_ENABLED > + * CXL_MEM_COMMAND_FLAG_ENABLED > * > * The given command id is supported by the driver and is supported by > * a related opcode on the device. > * > * CXL_MEM_COMMAND_FLAG_EXCLUSIVE > * > - * Requests with the given command id will terminate with EBUSY as the > - * kernel actively owns management of the given resource. For example, > - * the label-storage-area can not be written while the kernel is > - * actively managing that space. > + * The given command id is for kernel exclusive use and is not > + * available to userspace. Requests will terminate with EBUSY. > + * > + * The exclusive flag may be temporal, and only set while the > + * kernel actively owns management of the given resource. For > + * example, the label-storage-area can not be written while the > + * kernel is actively managing that space. > + * > + * The exclusive flag can be permanent, as in commands that can > + * never be issued through the ioctl interface. > + * > + * INJECT_POISON and CLEAR_POISON are permanently kernel exclusive, > + * and are supported through a debugfs interface. > + * See: Documentation/ABI/testing/debugfs-cxl > * > * @size_in: Expected input size, or ~0 if variable length. > * @size_out: Expected output size, or ~0 if variable length.
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c index 71ebe3795616..617d8378ca9a 100644 --- a/drivers/cxl/core/memdev.c +++ b/drivers/cxl/core/memdev.c @@ -11,6 +11,8 @@ static DECLARE_RWSEM(cxl_memdev_rwsem); +static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX); + /* * An entire PCI topology full of devices should be enough for any * config @@ -628,6 +630,10 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds) cxlmd->cxlds = cxlds; cxlds->cxlmd = cxlmd; + set_bit(CXL_MEM_COMMAND_ID_INJECT_POISON, exclusive_cmds); + set_bit(CXL_MEM_COMMAND_ID_CLEAR_POISON, exclusive_cmds); + set_exclusive_cxl_commands(cxlds, exclusive_cmds); + cdev = &cxlmd->cdev; rc = cdev_device_add(cdev, dev); if (rc) diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h index 86bbacf2a315..6294278f9dcb 100644 --- a/include/uapi/linux/cxl_mem.h +++ b/include/uapi/linux/cxl_mem.h @@ -74,17 +74,27 @@ static const struct { * @id: ID number for the command. * @flags: Flags that specify command behavior. * - * CXL_MEM_COMMAND_FLAG_USER_ENABLED + * CXL_MEM_COMMAND_FLAG_ENABLED * * The given command id is supported by the driver and is supported by * a related opcode on the device. * * CXL_MEM_COMMAND_FLAG_EXCLUSIVE * - * Requests with the given command id will terminate with EBUSY as the - * kernel actively owns management of the given resource. For example, - * the label-storage-area can not be written while the kernel is - * actively managing that space. + * The given command id is for kernel exclusive use and is not + * available to userspace. Requests will terminate with EBUSY. + * + * The exclusive flag may be temporal, and only set while the + * kernel actively owns management of the given resource. For + * example, the label-storage-area can not be written while the + * kernel is actively managing that space. + * + * The exclusive flag can be permanent, as in commands that can + * never be issued through the ioctl interface. + * + * INJECT_POISON and CLEAR_POISON are permanently kernel exclusive, + * and are supported through a debugfs interface. + * See: Documentation/ABI/testing/debugfs-cxl * * @size_in: Expected input size, or ~0 if variable length. * @size_out: Expected output size, or ~0 if variable length.