On 18/04/16 23:05, Christophe Lombard wrote:
In the POWERVM environement, the PHYP CoherentAccel component manages
environment
the state of the Coherant Accelerator Processor Interface adapter and
Coherent
virtualizes CAPI resources, handles CAPP, PSL, PSL Slice errors - and
interrupts - and provides a new set of HCALLs for the OS APIs to utilize
AFUs.
During the course of operation, a coherent platform function can
encounter errors. Some possible reason for errors are:
• Hardware recoverable and unrecoverable errors
• Transient and over-threshold correctable errors
PHYP implements its own state model for the coherent platform function.
The current state of this Acclerator Fonction Unit (AFU) is available
Accelerator Function Unit
through a hcall.
In case of low-level troubles (or error injection), The PHYP component
the
may reset the card and change the AFU state. The PHYP interface doesn't
provide any way to be notified when that happens.
The current implementation of the cxl driver, for the POWERVM
environment, follows the general error recovery procedures required to
reset operation of the coherent platform function. The platform firmware
resets and reconfigures hardware when an external action is required -
attach/detach a process, link ok, ....
The purpose of this patch is to interact with the external driver
(where the AFU is shown) even if no action is required. A kernel thread
is needed to check every x seconds the current state of the AFU to see
if we need to enter an error recovery path.
Signed-off-by: Christophe Lombard <clomb...@linux.vnet.ibm.com>
A few minor issues below.
diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
index 8213372..06dfe7f 100644
--- a/drivers/misc/cxl/guest.c
+++ b/drivers/misc/cxl/guest.c
@@ -19,6 +19,10 @@
#define CXL_SLOT_RESET_EVENT 2
#define CXL_RESUME_EVENT 3
+#define CXL_KTHREAD "cxl_kthread"
+
+void stop_state_thread(struct cxl_afu *afu);
static?
[...]
-static int afu_do_recovery(struct cxl_afu *afu)
+static int handle_state_thread(void *data)
{
- int rc;
+ struct cxl_afu *afu;
+ int rc = 0;
It looks like we don't use rc (see also comment below).
- /* many threads can arrive here, in case of detach_all for example.
- * Only one needs to drive the recovery
- */
- if (mutex_trylock(&afu->guest->recovery_lock)) {
- rc = afu_update_state(afu);
- mutex_unlock(&afu->guest->recovery_lock);
- return rc;
+ pr_devel("in %s\n", __func__);
+
+ afu = (struct cxl_afu*)data;
CodingStyle: space between cxl_afu and *
+ do {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (afu) {
+ afu_update_state(afu);
Should we be checking the retval here?
+ if (afu->guest->previous_state ==
H_STATE_PERM_UNAVAILABLE)
+ goto out;
+ } else
+ return -ENODEV;
+ schedule_timeout(msecs_to_jiffies(3000));
+ } while(!kthread_should_stop());
CodingStyle: space between while and (
+
+out:
+ afu->guest->kthread_tsk = NULL;
+ return rc;
+}
+
+void start_state_thread(struct cxl_afu *afu)
static?
+{
+ if (afu->guest->kthread_tsk)
+ return;
+
+ /* start kernel thread to handle the state of the afu */
+ afu->guest->kthread_tsk = kthread_run(&handle_state_thread,
+ (void *)afu, CXL_KTHREAD);
+ if (IS_ERR(afu->guest->kthread_tsk)) {
+ pr_devel("cannot start state kthread\n");
+ afu->guest->kthread_tsk = NULL;
}
- return 0;
+}
+
+void stop_state_thread(struct cxl_afu *afu)
static?
--
Andrew Donnellan OzLabs, ADL Canberra
andrew.donnel...@au1.ibm.com IBM Australia Limited
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
