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powerpc/papr_scm: Implement initial support for injecting smart errors

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Presently PAPR doesn't support injecting smart errors on an
NVDIMM. This makes testing the NVDIMM health reporting functionality
difficult as simulating NVDIMM health related events need a hacked up
qemu version.

To solve this problem this patch proposes simulating certain set of
NVDIMM health related events in papr_scm. Specifically 'fatal' health
state and 'dirty' shutdown state. These error can be injected via the
user-space 'ndctl-inject-smart(1)' command. With the proposed patch and
corresponding ndctl patches following command flow is expected:

$ sudo ndctl list -DH -d nmem0
...
      "health_state":"ok",
      "shutdown_state":"clean",
...
 # inject unsafe shutdown and fatal health error
$ sudo ndctl inject-smart nmem0 -Uf
...
      "health_state":"fatal",
      "shutdown_state":"dirty",
...
 # uninject all errors
$ sudo ndctl inject-smart nmem0 -N
...
      "health_state":"ok",
      "shutdown_state":"clean",
...

The patch adds a new member 'health_bitmap_inject_mask' inside struct
papr_scm_priv which is then bitwise ANDed to the health bitmap fetched from the
hypervisor. The value for 'health_bitmap_inject_mask' is accessible from sysfs
at nmemX/papr/health_bitmap_inject.

A new PDSM named 'SMART_INJECT' is proposed that accepts newly
introduced 'struct nd_papr_pdsm_smart_inject' as payload thats
exchanged between libndctl and papr_scm to indicate the requested
smart-error states.

When the processing the PDSM 'SMART_INJECT', papr_pdsm_smart_inject()
constructs a pair or 'inject_mask' and 'clear_mask' bitmaps from the payload
and bit-blt it to the 'health_bitmap_inject_mask'. This ensures the after being
fetched from the hypervisor, the health_bitmap reflects requested smart-error
states.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220124202204.1488346-1-vaibhav@linux.ibm.com
This commit is contained in:
Vaibhav Jain 2022-01-25 01:52:04 +05:30 committed by Michael Ellerman
parent 76b372814b
commit bbbca72352
3 changed files with 117 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
Documentation/ABI/testing/sysfs-bus-papr-pmem
View File

@ -61,3 +61,15 @@ Description:
* "CchRHCnt" : Cache Read Hit Count
* "CchWHCnt" : Cache Write Hit Count
* "FastWCnt" : Fast Write Count
What: /sys/bus/nd/devices/nmemX/papr/health_bitmap_inject
Date: Jan, 2022
KernelVersion: v5.17
Contact: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, nvdimm@lists.linux.dev,
Description:
(RO) Reports the health bitmap inject bitmap that is applied to
bitmap received from PowerVM via the H_SCM_HEALTH. This is used
to forcibly set specific bits returned from Hcall. These is then
used to simulate various health or shutdown states for an nvdimm
and are set by user-space tools like ndctl by issuing a PAPR DSM.

18
arch/powerpc/include/uapi/asm/papr_pdsm.h
View File

@ -116,6 +116,22 @@ struct nd_papr_pdsm_health {
};
};
/* Flags for injecting specific smart errors */
#define PDSM_SMART_INJECT_HEALTH_FATAL (1 << 0)
#define PDSM_SMART_INJECT_BAD_SHUTDOWN (1 << 1)
struct nd_papr_pdsm_smart_inject {
union {
struct {
/* One or more of PDSM_SMART_INJECT_ */
__u32 flags;
__u8 fatal_enable;
__u8 unsafe_shutdown_enable;
};
__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
};
};
/*
* Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel
* via 'nd_cmd_pkg.nd_command' member of the ioctl struct
@ -123,12 +139,14 @@ struct nd_papr_pdsm_health {
enum papr_pdsm {
PAPR_PDSM_MIN = 0x0,
PAPR_PDSM_HEALTH,
PAPR_PDSM_SMART_INJECT,
PAPR_PDSM_MAX,
};
/* Maximal union that can hold all possible payload types */
union nd_pdsm_payload {
struct nd_papr_pdsm_health health;
struct nd_papr_pdsm_smart_inject smart_inject;
__u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE];
} __packed;

90
arch/powerpc/platforms/pseries/papr_scm.c
View File

@ -120,6 +120,10 @@ struct papr_scm_priv {
/* length of the stat buffer as expected by phyp */
size_t stat_buffer_len;
/* The bits which needs to be overridden */
u64 health_bitmap_inject_mask;
};
static int papr_scm_pmem_flush(struct nd_region *nd_region,
@ -347,19 +351,29 @@ static ssize_t drc_pmem_query_stats(struct papr_scm_priv *p,
static int __drc_pmem_query_health(struct papr_scm_priv *p)
{
unsigned long ret[PLPAR_HCALL_BUFSIZE];
u64 bitmap = 0;
long rc;
/* issue the hcall */
rc = plpar_hcall(H_SCM_HEALTH, ret, p->drc_index);
if (rc != H_SUCCESS) {
if (rc == H_SUCCESS)
bitmap = ret[0] & ret[1];
else if (rc == H_FUNCTION)
dev_info_once(&p->pdev->dev,
"Hcall H_SCM_HEALTH not implemented, assuming empty health bitmap");
else {
dev_err(&p->pdev->dev,
"Failed to query health information, Err:%ld\n", rc);
return -ENXIO;
}
p->lasthealth_jiffies = jiffies;
p->health_bitmap = ret[0] & ret[1];
/* Allow injecting specific health bits via inject mask. */
if (p->health_bitmap_inject_mask)
bitmap = (bitmap & ~p->health_bitmap_inject_mask) |
p->health_bitmap_inject_mask;
WRITE_ONCE(p->health_bitmap, bitmap);
dev_dbg(&p->pdev->dev,
"Queried dimm health info. Bitmap:0x%016lx Mask:0x%016lx\n",
ret[0], ret[1]);
@ -669,6 +683,56 @@ out:
return rc;
}
/* Inject a smart error Add the dirty-shutdown-counter value to the pdsm */
static int papr_pdsm_smart_inject(struct papr_scm_priv *p,
union nd_pdsm_payload *payload)
{
int rc;
u32 supported_flags = 0;
u64 inject_mask = 0, clear_mask = 0;
u64 mask;
/* Check for individual smart error flags and update inject/clear masks */
if (payload->smart_inject.flags & PDSM_SMART_INJECT_HEALTH_FATAL) {
supported_flags |= PDSM_SMART_INJECT_HEALTH_FATAL;
if (payload->smart_inject.fatal_enable)
inject_mask |= PAPR_PMEM_HEALTH_FATAL;
else
clear_mask |= PAPR_PMEM_HEALTH_FATAL;
}
if (payload->smart_inject.flags & PDSM_SMART_INJECT_BAD_SHUTDOWN) {
supported_flags |= PDSM_SMART_INJECT_BAD_SHUTDOWN;
if (payload->smart_inject.unsafe_shutdown_enable)
inject_mask |= PAPR_PMEM_SHUTDOWN_DIRTY;
else
clear_mask |= PAPR_PMEM_SHUTDOWN_DIRTY;
}
dev_dbg(&p->pdev->dev, "[Smart-inject] inject_mask=%#llx clear_mask=%#llx\n",
inject_mask, clear_mask);
/* Prevent concurrent access to dimm health bitmap related members */
rc = mutex_lock_interruptible(&p->health_mutex);
if (rc)
return rc;
/* Use inject/clear masks to set health_bitmap_inject_mask */
mask = READ_ONCE(p->health_bitmap_inject_mask);
mask = (mask & ~clear_mask) | inject_mask;
WRITE_ONCE(p->health_bitmap_inject_mask, mask);
/* Invalidate cached health bitmap */
p->lasthealth_jiffies = 0;
mutex_unlock(&p->health_mutex);
/* Return the supported flags back to userspace */
payload->smart_inject.flags = supported_flags;
return sizeof(struct nd_papr_pdsm_health);
}
/*
* 'struct pdsm_cmd_desc'
* Identifies supported PDSMs' expected length of in/out payloads
@ -702,6 +766,12 @@ static const struct pdsm_cmd_desc __pdsm_cmd_descriptors[] = {
.size_out = sizeof(struct nd_papr_pdsm_health),
.service = papr_pdsm_health,
},
[PAPR_PDSM_SMART_INJECT] = {
.size_in = sizeof(struct nd_papr_pdsm_smart_inject),
.size_out = sizeof(struct nd_papr_pdsm_smart_inject),
.service = papr_pdsm_smart_inject,
},
/* Empty */
[PAPR_PDSM_MAX] = {
.size_in = 0,
@ -838,6 +908,19 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
return 0;
}
static ssize_t health_bitmap_inject_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct nvdimm *dimm = to_nvdimm(dev);
struct papr_scm_priv *p = nvdimm_provider_data(dimm);
return sprintf(buf, "%#llx\n",
READ_ONCE(p->health_bitmap_inject_mask));
}
static DEVICE_ATTR_ADMIN_RO(health_bitmap_inject);
static ssize_t perf_stats_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -952,6 +1035,7 @@ static struct attribute *papr_nd_attributes[] = {
&dev_attr_flags.attr,
&dev_attr_perf_stats.attr,
&dev_attr_dirty_shutdown.attr,
&dev_attr_health_bitmap_inject.attr,
NULL,
};