Implement support for fetching nvdimm health information via H_SCM_HEALTH hcall as documented in Ref[1]. The hcall returns a pair of 64-bit big-endian integers, bitwise-and of which is then stored in 'struct papr_scm_priv' and subsequently partially exposed to user-space via newly introduced dimm specific attribute 'papr/flags'. Since the hcall is costly, the health information is cached and only re-queried, 60s after the previous successful hcall.
The patch also adds a new asm header named 'papr_scm.h' describing the interface between PHYP and guest kernel. A documentation text describing flags reported by the the new sysfs attribute 'papr/flags' is also introduced at Documentation/ABI/testing/sysfs-bus-papr-scm. [1] commit 58b278f568f0 ("powerpc: Provide initial documentation for PAPR hcalls") Cc: Dan Williams <dan.j.willi...@intel.com> Cc: Michael Ellerman <m...@ellerman.id.au> Cc: "Aneesh Kumar K . V" <aneesh.ku...@linux.ibm.com> Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com> --- Changelog v5..v6 : * Change the flags sysfs attribute from 'papr_flags' to 'papr/flags' [Dan Williams] * Include documentation for 'papr/flags' attr [Dan Williams] * Change flag 'save_fail' to 'flush_fail' [Dan Williams] * Caching of health bitmap to reduce expensive hcalls [Dan Williams] * Removed usage of PPC_BIT from 'papr-scm.h' header [Mpe] * Replaced two __be64 integers from papr_scm_priv to a single u64 integer [Mpe] * Updated patch description to reflect the changes made in this version. * Removed avoidable usage of 'papr_scm_priv.dimm_mutex' from flags_show() [Dan Williams] v4..v5 : * None v3..v4 : * None v2..v3 : * Removed PAPR_SCM_DIMM_HEALTH_NON_CRITICAL as a condition for NVDIMM unarmed [Aneesh] v1..v2 : * New patch in the series. --- Documentation/ABI/testing/sysfs-bus-papr-scm | 27 ++++ arch/powerpc/include/asm/papr_scm.h | 49 ++++++++ arch/powerpc/platforms/pseries/papr_scm.c | 126 ++++++++++++++++++- 3 files changed, 200 insertions(+), 2 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-bus-papr-scm create mode 100644 arch/powerpc/include/asm/papr_scm.h diff --git a/Documentation/ABI/testing/sysfs-bus-papr-scm b/Documentation/ABI/testing/sysfs-bus-papr-scm new file mode 100644 index 000000000000..001e4d34ab5c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-papr-scm @@ -0,0 +1,27 @@ +What: /sys/bus/nd/devices/nmemX/papr/flags +Date: Apr, 2020 +KernelVersion: v5.8 +Contact: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, linux-nvd...@lists.01.org, +Description: + (RO) Report flags indicating various states of a + papr-scm NVDIMM device. Each flag maps to a one or + more bits set in the dimm-health-bitmap retrieved in + response to H_SCM_HEALTH hcall. The details of the bit + flags returned in response to this hcall is available + at 'Documentation/powerpc/papr_hcalls.rst' . Below are + the flags reported in this sysfs file: + + * "not_armed" : Indicating that nvdimm contents will not + survive a power cycle. + * "flush_fail" : Indicating that nvdimm contents + couldn't be flushed during last + shutdown event. + * "restore_fail": Indicating that nvdimm contents + couldn't be restored during dimm + initialization. + * "encrypted" : Dimm contents are encrypted. + * "smart_notify": There is health event for the nvdimm. + * "scrubbed" : Indicating that contents of the + nvdimm have been scrubbed. + * "locked" : Indicating that nvdimm contents cant + be modified until next power cycle. diff --git a/arch/powerpc/include/asm/papr_scm.h b/arch/powerpc/include/asm/papr_scm.h new file mode 100644 index 000000000000..b51c048e906a --- /dev/null +++ b/arch/powerpc/include/asm/papr_scm.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Structures and defines needed to manage nvdimms for spapr guests. + */ +#ifndef _ASM_POWERPC_PAPR_SCM_H_ +#define _ASM_POWERPC_PAPR_SCM_H_ + +#include <linux/types.h> +#include <asm/bitsperlong.h> + +/* DIMM health bitmap bitmap indicators */ + +/* SCM device is unable to persist memory contents */ +#define PAPR_SCM_DIMM_UNARMED (1ULL << (63 - 0)) +/* SCM device failed to persist memory contents */ +#define PAPR_SCM_DIMM_SHUTDOWN_DIRTY (1ULL << (63 - 1)) +/* SCM device contents are persisted from previous IPL */ +#define PAPR_SCM_DIMM_SHUTDOWN_CLEAN (1ULL << (63 - 2)) +/* SCM device contents are not persisted from previous IPL */ +#define PAPR_SCM_DIMM_EMPTY (1ULL << (63 - 3)) +/* SCM device memory life remaining is critically low */ +#define PAPR_SCM_DIMM_HEALTH_CRITICAL (1ULL << (63 - 4)) +/* SCM device will be garded off next IPL due to failure */ +#define PAPR_SCM_DIMM_HEALTH_FATAL (1ULL << (63 - 5)) +/* SCM contents cannot persist due to current platform health status */ +#define PAPR_SCM_DIMM_HEALTH_UNHEALTHY (1ULL << (63 - 6)) +/* SCM device is unable to persist memory contents in certain conditions */ +#define PAPR_SCM_DIMM_HEALTH_NON_CRITICAL (1ULL << (63 - 7)) +/* SCM device is encrypted */ +#define PAPR_SCM_DIMM_ENCRYPTED (1ULL << (63 - 8)) +/* SCM device has been scrubbed and locked */ +#define PAPR_SCM_DIMM_SCRUBBED_AND_LOCKED (1ULL << (63 - 9)) + +/* Bits status indicators for health bitmap indicating unarmed dimm */ +#define PAPR_SCM_DIMM_UNARMED_MASK (PAPR_SCM_DIMM_UNARMED | \ + PAPR_SCM_DIMM_HEALTH_UNHEALTHY) + +/* Bits status indicators for health bitmap indicating unflushed dimm */ +#define PAPR_SCM_DIMM_BAD_SHUTDOWN_MASK (PAPR_SCM_DIMM_SHUTDOWN_DIRTY) + +/* Bits status indicators for health bitmap indicating unrestored dimm */ +#define PAPR_SCM_DIMM_BAD_RESTORE_MASK (PAPR_SCM_DIMM_EMPTY) + +/* Bit status indicators for smart event notification */ +#define PAPR_SCM_DIMM_SMART_EVENT_MASK (PAPR_SCM_DIMM_HEALTH_CRITICAL | \ + PAPR_SCM_DIMM_HEALTH_FATAL | \ + PAPR_SCM_DIMM_HEALTH_UNHEALTHY) + +#endif diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index 0b4467e378e5..f8fe579e6f2e 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -14,6 +14,7 @@ #include <linux/delay.h> #include <asm/plpar_wrappers.h> +#include <asm/papr_scm.h> #define BIND_ANY_ADDR (~0ul) @@ -39,6 +40,15 @@ struct papr_scm_priv { struct resource res; struct nd_region *region; struct nd_interleave_set nd_set; + + /* Protect dimm health data from concurrent read/writes */ + struct mutex dimm_mutex; + + /* Last time the health information of the dimm was updated */ + unsigned long lasthealth_jiffies; + + /* Health information for the dimm */ + u64 health_bitmap; }; static int drc_pmem_bind(struct papr_scm_priv *p) @@ -144,6 +154,56 @@ static int drc_pmem_query_n_bind(struct papr_scm_priv *p) return drc_pmem_bind(p); } +/* Min interval in seconds between successive H_SCM_HEALTH hcalls */ +#define MIN_HEALTH_QUERY_INTERVAL 60 + +/* + * Issue hcall if needed to retrieve dimm health info. Information is cached + * and subsequent calls may return success without issueing the hcall. + * Use 'force == true' to force issue of the hcall ignoring the cache + * timeout. + */ +static int drc_pmem_query_health(struct papr_scm_priv *p, bool force) +{ + unsigned long ret[PLPAR_HCALL_BUFSIZE]; + s64 rc; + unsigned long cache_timeout; + + /* Protect concurrent modifications to papr_scm_priv */ + rc = mutex_lock_interruptible(&p->dimm_mutex); + if (rc) + return rc; + + /* Jiffies offset for which the health data is assumed to be same */ + cache_timeout = p->lasthealth_jiffies + + msecs_to_jiffies(MIN_HEALTH_QUERY_INTERVAL * 1000); + + /* Dont issue the hcall if health information is relatively new */ + if (!force && time_after(cache_timeout, jiffies)) { + rc = 0; + goto out; + } + + /* issue the hcall */ + rc = plpar_hcall(H_SCM_HEALTH, ret, p->drc_index); + if (rc != H_SUCCESS) { + dev_err(&p->pdev->dev, + "Failed to query health information, Err:%lld\n", rc); + rc = -ENXIO; + goto out; + } + + p->lasthealth_jiffies = jiffies; + p->health_bitmap = ret[0] & ret[1]; + + dev_dbg(&p->pdev->dev, + "Queried dimm health info. Bitmap:0x%016lx Mask:0x%016lx\n", + ret[0], ret[1]); + +out: + mutex_unlock(&p->dimm_mutex); + return rc; +} static int papr_scm_meta_get(struct papr_scm_priv *p, struct nd_cmd_get_config_data_hdr *hdr) @@ -304,6 +364,65 @@ static inline int papr_scm_node(int node) return min_node; } +static ssize_t flags_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); + int rc; + u64 health; + + rc = drc_pmem_query_health(p, false); + if (rc) + return rc; + + /* + * Copy the LE byte-ordered health_bitmap locally, check for various + * masks and update the sysfs out buffer. + */ + health = p->health_bitmap; + + if (health & PAPR_SCM_DIMM_UNARMED_MASK) + rc += sprintf(buf, "not_armed "); + + if (health & PAPR_SCM_DIMM_BAD_SHUTDOWN_MASK) + rc += sprintf(buf + rc, "save_fail "); + + if (health & PAPR_SCM_DIMM_BAD_RESTORE_MASK) + rc += sprintf(buf + rc, "restore_fail "); + + if (health & PAPR_SCM_DIMM_ENCRYPTED) + rc += sprintf(buf + rc, "encrypted "); + + if (health & PAPR_SCM_DIMM_SMART_EVENT_MASK) + rc += sprintf(buf + rc, "smart_notify "); + + if (health & PAPR_SCM_DIMM_SCRUBBED_AND_LOCKED) + rc += sprintf(buf + rc, "scrubbed locked "); + + if (rc > 0) + rc += sprintf(buf + rc, "\n"); + + return rc; +} +DEVICE_ATTR_RO(flags); + +/* papr_scm specific dimm attributes */ +static struct attribute *papr_scm_nd_attributes[] = { + &dev_attr_flags.attr, + NULL, +}; + +static struct attribute_group papr_scm_nd_attribute_group = { + .name = "papr", + .attrs = papr_scm_nd_attributes, +}; + +static const struct attribute_group *papr_scm_dimm_attr_groups[] = { + &papr_scm_nd_attribute_group, + NULL, +}; + static int papr_scm_nvdimm_init(struct papr_scm_priv *p) { struct device *dev = &p->pdev->dev; @@ -330,8 +449,8 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p) dimm_flags = 0; set_bit(NDD_ALIASING, &dimm_flags); - p->nvdimm = nvdimm_create(p->bus, p, NULL, dimm_flags, - PAPR_SCM_DIMM_CMD_MASK, 0, NULL); + p->nvdimm = nvdimm_create(p->bus, p, papr_scm_dimm_attr_groups, + dimm_flags, PAPR_SCM_DIMM_CMD_MASK, 0, NULL); if (!p->nvdimm) { dev_err(dev, "Error creating DIMM object for %pOF\n", p->dn); goto err; @@ -415,6 +534,9 @@ static int papr_scm_probe(struct platform_device *pdev) if (!p) return -ENOMEM; + /* Initialize the dimm mutex */ + mutex_init(&p->dimm_mutex); + /* optional DT properties */ of_property_read_u32(dn, "ibm,metadata-size", &metadata_size); -- 2.25.3