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cxl: Adapter failure handling

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Check the AFU state whenever an API is called. The hypervisor may
issue a reset of the adapter when it detects a fault. When it happens,
it launches an error recovery which will either move the AFU to a
permanent failure state, or in the disabled state.
If the AFU is found to be disabled, detach all existing contexts from
it before issuing a AFU reset to re-enable it.

Before detaching contexts, notify any kernel driver through the EEH
callbacks of the AFU pci device.

Co-authored-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Lombard
2016-03-04 12:26:41 +01:00
committed by Michael Ellerman
parent d601ea918b
commit 0d400f77c1
7 changed files with 198 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

167
drivers/misc/cxl/guest.c
View File

@@ -15,6 +15,46 @@
#include "hcalls.h"
#include "trace.h"
#define CXL_ERROR_DETECTED_EVENT 1
#define CXL_SLOT_RESET_EVENT 2
#define CXL_RESUME_EVENT 3
static void pci_error_handlers(struct cxl_afu *afu,
int bus_error_event,
pci_channel_state_t state)
{
struct pci_dev *afu_dev;
if (afu->phb == NULL)
return;
list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
if (!afu_dev->driver)
continue;
switch (bus_error_event) {
case CXL_ERROR_DETECTED_EVENT:
afu_dev->error_state = state;
if (afu_dev->driver->err_handler &&
afu_dev->driver->err_handler->error_detected)
afu_dev->driver->err_handler->error_detected(afu_dev, state);
break;
case CXL_SLOT_RESET_EVENT:
afu_dev->error_state = state;
if (afu_dev->driver->err_handler &&
afu_dev->driver->err_handler->slot_reset)
afu_dev->driver->err_handler->slot_reset(afu_dev);
break;
case CXL_RESUME_EVENT:
if (afu_dev->driver->err_handler &&
afu_dev->driver->err_handler->resume)
afu_dev->driver->err_handler->resume(afu_dev);
break;
}
}
}
static irqreturn_t guest_handle_psl_slice_error(struct cxl_context *ctx, u64 dsisr,
u64 errstat)
@@ -133,6 +173,22 @@ static irqreturn_t guest_psl_irq(int irq, void *data)
return rc;
}
static int afu_read_error_state(struct cxl_afu *afu, int *state_out)
{
u64 state;
int rc = 0;
rc = cxl_h_read_error_state(afu->guest->handle, &state);
if (!rc) {
WARN_ON(state != H_STATE_NORMAL &&
state != H_STATE_DISABLE &&
state != H_STATE_TEMP_UNAVAILABLE &&
state != H_STATE_PERM_UNAVAILABLE);
*state_out = state & 0xffffffff;
}
return rc;
}
static irqreturn_t guest_slice_irq_err(int irq, void *data)
{
struct cxl_afu *afu = data;
@@ -201,10 +257,26 @@ static int irq_free_range(struct cxl *adapter, int irq, int len)
static int guest_reset(struct cxl *adapter)
{
int rc;
struct cxl_afu *afu = NULL;
int i, rc;
pr_devel("Adapter reset request\n");
for (i = 0; i < adapter->slices; i++) {
if ((afu = adapter->afu[i])) {
pci_error_handlers(afu, CXL_ERROR_DETECTED_EVENT,
pci_channel_io_frozen);
cxl_context_detach_all(afu);
}
}
rc = cxl_h_reset_adapter(adapter->guest->handle);
for (i = 0; i < adapter->slices; i++) {
if (!rc && (afu = adapter->afu[i])) {
pci_error_handlers(afu, CXL_SLOT_RESET_EVENT,
pci_channel_io_normal);
pci_error_handlers(afu, CXL_RESUME_EVENT, 0);
}
}
return rc;
}
@@ -556,7 +628,7 @@ static int guest_detach_process(struct cxl_context *ctx)
pr_devel("in %s\n", __func__);
trace_cxl_detach(ctx);
if (!cxl_ops->link_ok(ctx->afu->adapter))
if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
return -EIO;
if (ctx->afu->current_mode == CXL_MODE_DIRECTED)
@@ -730,8 +802,95 @@ static void guest_unmap_slice_regs(struct cxl_afu *afu)
iounmap(afu->p2n_mmio);
}
static bool guest_link_ok(struct cxl *cxl)
static int afu_update_state(struct cxl_afu *afu)
{
int rc, cur_state;
rc = afu_read_error_state(afu, &cur_state);
if (rc)
return rc;
if (afu->guest->previous_state == cur_state)
return 0;
pr_devel("AFU(%d) update state to %#x\n", afu->slice, cur_state);
switch (cur_state) {
case H_STATE_NORMAL:
afu->guest->previous_state = cur_state;
rc = 1;
break;
case H_STATE_DISABLE:
pci_error_handlers(afu, CXL_ERROR_DETECTED_EVENT,
pci_channel_io_frozen);
cxl_context_detach_all(afu);
if ((rc = cxl_ops->afu_reset(afu)))
pr_devel("reset hcall failed %d\n", rc);
rc = afu_read_error_state(afu, &cur_state);
if (!rc && cur_state == H_STATE_NORMAL) {
pci_error_handlers(afu, CXL_SLOT_RESET_EVENT,
pci_channel_io_normal);
pci_error_handlers(afu, CXL_RESUME_EVENT, 0);
rc = 1;
}
afu->guest->previous_state = 0;
break;
case H_STATE_TEMP_UNAVAILABLE:
afu->guest->previous_state = cur_state;
break;
case H_STATE_PERM_UNAVAILABLE:
dev_err(&afu->dev, "AFU is in permanent error state\n");
pci_error_handlers(afu, CXL_ERROR_DETECTED_EVENT,
pci_channel_io_perm_failure);
afu->guest->previous_state = cur_state;
break;
default:
pr_err("Unexpected AFU(%d) error state: %#x\n",
afu->slice, cur_state);
return -EINVAL;
}
return rc;
}
static int afu_do_recovery(struct cxl_afu *afu)
{
int rc;
/* 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;
}
return 0;
}
static bool guest_link_ok(struct cxl *cxl, struct cxl_afu *afu)
{
int state;
if (afu) {
if (afu_read_error_state(afu, &state) ||
state != H_STATE_NORMAL) {
if (afu_do_recovery(afu) > 0) {
/* check again in case we've just fixed it */
if (!afu_read_error_state(afu, &state) &&
state == H_STATE_NORMAL)
return true;
}
return false;
}
}
return true;
}
@@ -770,6 +929,8 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n
return -ENOMEM;
}
mutex_init(&afu->guest->recovery_lock);
if ((rc = dev_set_name(&afu->dev, "afu%i.%i",
adapter->adapter_num,
slice)))