| Message ID | 82199c54a421aeb05fb0e3b4a353a4fed8c98bc9.1677704994.git.alison.schofield@intel.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | cxl: CXL Inject & Clear Poison | expand |
On Wed, 1 Mar 2023 13:36:32 -0800 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 sysfs interface that provides the protection needed > 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/sysfs-bus-cxl > [2] include/uapi/linux/cxl_mem.h > > Signed-off-by: Alison Schofield <alison.schofield@intel.com> > --- > drivers/cxl/core/memdev.c | 6 ++++++ > include/uapi/linux/cxl_mem.h | 21 ++++++++++++++++----- > 2 files changed, 22 insertions(+), 5 deletions(-) > > diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c > index ed3e4517dc3a..f746a0c222b6 100644 > --- a/drivers/cxl/core/memdev.c > +++ b/drivers/cxl/core/memdev.c > @@ -10,6 +10,8 @@ > > static DECLARE_RWSEM(cxl_memdev_rwsem); > > +static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX); Seems like a macro to wrap up the DECLARE_BITMAP and the length so that we don't have to be careful these are the correct size might be useful. > + > /* > * An entire PCI topology full of devices should be enough for any > * config > @@ -571,6 +573,10 @@ 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..6f9ae244f7fd 100644 > --- a/include/uapi/linux/cxl_mem.h > +++ b/include/uapi/linux/cxl_mem.h > @@ -74,17 +74,28 @@ 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 I'm guessing tabs and space differences to the above? Other than those little things LGTM Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > + * 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. > + * They are supported through a sysfs interface that validates the > + * safety of each command based on the state of the memdev. > + * See: Documentation/ABI/testing/sysfs-bus-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 ed3e4517dc3a..f746a0c222b6 100644 --- a/drivers/cxl/core/memdev.c +++ b/drivers/cxl/core/memdev.c @@ -10,6 +10,8 @@ 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 @@ -571,6 +573,10 @@ 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..6f9ae244f7fd 100644 --- a/include/uapi/linux/cxl_mem.h +++ b/include/uapi/linux/cxl_mem.h @@ -74,17 +74,28 @@ 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. + * They are supported through a sysfs interface that validates the + * safety of each command based on the state of the memdev. + * See: Documentation/ABI/testing/sysfs-bus-cxl * * @size_in: Expected input size, or ~0 if variable length. * @size_out: Expected output size, or ~0 if variable length.