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Wed, 26 May 2021 03:01:03 +0000 (GMT) Received: from vajain21.in.ibm.com (unknown [9.85.69.160]) by d06av21.portsmouth.uk.ibm.com (Postfix) with SMTP id 51B3C52065; Wed, 26 May 2021 03:00:59 +0000 (GMT) Received: by vajain21.in.ibm.com (sSMTP sendmail emulation); Wed, 26 May 2021 08:30:58 +0530 From: Vaibhav Jain To: qemu-devel@nongnu.org, kvm-ppc@vger.kernel.org, qemu-ppc@nongnu.org, david@gibson.dropbear.id.au, mst@redhat.com, imammedo@redhat.com, xiaoguangrong.eric@gmail.com Cc: Vaibhav Jain , shivaprasadbhat@gmail.com, bharata@linux.vnet.ibm.com, aneesh.kumar@linux.ibm.com, groug@kaod.org, ehabkost@redhat.com, marcel.apfelbaum@gmail.com Subject: [RFC PATCH v4] ppc/spapr: Add support for H_SCM_PERFORMANCE_STATS hcall Date: Wed, 26 May 2021 08:30:57 +0530 Message-Id: <20210526030057.395092-1-vaibhav@linux.ibm.com> X-Mailer: git-send-email 2.31.1 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: cmXW6mt9P6m8KyHcZl6n1juvI2PC0c_L X-Proofpoint-ORIG-GUID: uS42kuGdNWNpjljaNPUi2cYtutEItNkv X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-05-26_02:2021-05-25,2021-05-26 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 suspectscore=0 mlxscore=0 bulkscore=0 clxscore=1015 phishscore=0 lowpriorityscore=0 malwarescore=0 spamscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105260016 Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org Add support for H_SCM_PERFORMANCE_STATS described at [1] for spapr nvdimms. This enables guest to fetch performance stats[2] like expected life of an nvdimm ('MemLife ') etc and display them to the user. Linux kernel support for fetching these performance stats and exposing them to the user-space was done via [3]. The hcall semantics mandate that each nvdimm performance stats is uniquely identied by a 8-byte ascii string encoded as an unsigned integer (e.g 'MemLife ' == 0x4D656D4C69666520) and its value be a 8-byte unsigned integer. These performance-stats are exchanged with the guest in via a guest allocated buffer called 'requestAndResultBuffer' or rr-buffer for short. This buffer contains a header descibed by 'struct papr_scm_perf_stats' followed by an array of performance-stats described by 'struct papr_scm_perf_stat'. The hypervisor is expected to validate the rr-buffer header and then based on the request copy the needed performance-stats to the array of 'struct papr_scm_perf_stat' following the header. The patch proposes a new function h_scm_performance_stats() that services the H_SCM_PERFORMANCE_STATS hcall. After verifying the validity of the rr-buffer header via scm_perf_check_rr_buffer() it proceeds to fill the rr-buffer with requested performance-stats. The value of individual stats is retrived from individual accessor function for the stat which are indexed in the array 'nvdimm_perf_stats'. References: [1] "Hypercall Op-codes (hcalls)" https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/powerpc/papr_hcalls.rst#n269 [2] Sysfs attribute documentation for papr_scm https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/ABI/testing/sysfs-bus-papr-pmem#n36 [3] "powerpc/papr_scm: Fetch nvdimm performance stats from PHYP" https://lore.kernel.org/r/20200731064153.182203-2-vaibhav@linux.ibm.com Signed-off-by: Vaibhav Jain --- Changelog Since RFC-v3: * Introduced consistent types 'perf_stat_id/val' for handling perf-stats in code rather than switching between u64 and char[8]. [ David Gibson ] * Removed a redundant temporary variable 'stat_id' usage from nvdimm_stat_getval() [ David Gibson ] * Move the tests for buffer sizes around to a a central place in h_scm_performance_stats() [ David Gibson ] * Update the allocation size/type of rr-buffer in h_scm_performance_stats [ David Gibson, Groug ] * Reworked the loop for generating canned-response in h_scm_performance_stats(). * Reworked logic for returning an unknown stat-id in h_scm_performance_stats(). Since RFC-v2: * s/SCM_STATS_MAX_OUTPUT_BUFFER/SCM_STATS_MIN_OUTPUT_BUFFER/ thats the minimum size buffer needed to return all supported performance stats. Value for this is derived from size of array 'nvdimm_perf_stats' * Added SCM_STATS_MAX_OUTPUT_BUFFER to indicate maximum supported rr-buffer size from a guest. Value for this is derived from hard limit of SCM_STATS_MAX_STATS. * Updated scm_perf_check_rr_buffer() to add a check for max size of rr-buffer. [David] * Updated scm_perf_check_rr_buffer() to removed a reduntant check for min size of rr-buffer [David] * Updated h_scm_performance_stats() to have a single allocation for rr-buffer and copy it back to guest memory in a single shot. [David] Since RFC-v1: * Removed empty lines from code [ David ] * Updated struct papr_scm_perf_stat to use uint64_t for statistic_id. * Added a hard limit on max number of stats requested to 255 [ David ] * Updated scm_perf_check_rr_buffer() to check for rr-buffer header size [ David ] * Removed a redundant check from nvdimm_stat_getval() [ David ] * Removed a redundant call to address_space_access_valid() in scm_perf_check_rr_buffer() [ David ] * Instead of allocating a minimum size local buffer, allocate a max possible size local rr-buffer. [ David ] * Updated nvdimm_stat_getval() to set 'val' to '0' on error. [ David ] * Updated h_scm_performance_stats() to use a canned-response method for simplifying num_stats==0 case [ David ]. --- hw/ppc/spapr_nvdimm.c | 219 +++++++++++++++++++++++++++++++++++++++++ include/hw/ppc/spapr.h | 22 ++++- 2 files changed, 240 insertions(+), 1 deletion(-) diff --git a/hw/ppc/spapr_nvdimm.c b/hw/ppc/spapr_nvdimm.c index 252204e25f..81ab2811bc 100644 --- a/hw/ppc/spapr_nvdimm.c +++ b/hw/ppc/spapr_nvdimm.c @@ -35,6 +35,23 @@ /* SCM device is unable to persist memory contents */ #define PAPR_PMEM_UNARMED PPC_BIT(0) +/* Maximum number of stats that we can return back in a single stat request */ +#define SCM_STATS_MAX_STATS 255 + +/* Given _numstats_ != 0 calculate the size of RR buffer required */ +#define SCM_STATS_RR_BUFFER_SIZE(_numstats_) \ + (sizeof(struct papr_scm_perf_stats) + \ + sizeof(struct papr_scm_perf_stat) * \ + (_numstats_)) + +/* Maximum possible output buffer to fulfill a perf-stats request */ +#define SCM_STATS_MAX_OUTPUT_BUFFER \ + (SCM_STATS_RR_BUFFER_SIZE(SCM_STATS_MAX_STATS)) + +/* Minimum output buffer size needed to return all perf_stats except noopstat */ +#define SCM_STATS_MIN_OUTPUT_BUFFER (SCM_STATS_RR_BUFFER_SIZE\ + (ARRAY_SIZE(nvdimm_perf_stats) - 1)) + bool spapr_nvdimm_validate(HotplugHandler *hotplug_dev, NVDIMMDevice *nvdimm, uint64_t size, Error **errp) { @@ -502,6 +519,207 @@ static target_ulong h_scm_health(PowerPCCPU *cpu, SpaprMachineState *spapr, return H_SUCCESS; } +static int perf_stat_noop(SpaprDrc *drc, perf_stat_id unused, + perf_stat_val *val) +{ + *val = 0; + return H_SUCCESS; +} + +static int perf_stat_memlife(SpaprDrc *drc, perf_stat_id unused, + perf_stat_val *val) +{ + /* Assume full life available of an NVDIMM right now */ + *val = 100; + return H_SUCCESS; +} + +/* + * Holds all supported performance stats accessors. Each performance-statistic + * is uniquely identified by a 8-byte ascii string for example: 'MemLife ' + * which indicate in percentage how much usage life of an nvdimm is remaining. + * 'NoopStat' which is primarily used to test support for retriving performance + * stats and also to replace unknown stats present in the rr-buffer. + * + */ +static const struct { + perf_stat_id stat_id; + int (*stat_getval)(SpaprDrc *drc, perf_stat_id id, perf_stat_val *val); +} nvdimm_perf_stats[] = { + { "NoopStat", perf_stat_noop}, + { "MemLife ", perf_stat_memlife}, +}; + +/* + * Given a nvdimm drc and stat-name return its value. In case given stat-name + * isnt supported then return H_PARTIAL. + */ +static int nvdimm_stat_getval(SpaprDrc *drc, perf_stat_id id, + perf_stat_val *val) +{ + int index; + + *val = 0; + + /* Lookup the stats-id in the nvdimm_perf_stats table */ + for (index = 0; index < ARRAY_SIZE(nvdimm_perf_stats); ++index) { + if (!memcmp(&nvdimm_perf_stats[index].stat_id, id, + sizeof(perf_stat_id))) { + return nvdimm_perf_stats[index].stat_getval(drc, id, val); + } + } + return H_PARTIAL; +} + +/* + * Given a request & result buffer header verify its contents. Also + * buffer-size and number of stats requested are within our expected + * sane bounds. + */ +static int scm_perf_check_rr_buffer(struct papr_scm_perf_stats *header, + hwaddr addr, size_t size, + uint32_t *num_stats) +{ + size_t expected_buffsize; + + /* Verify the header eyecather and version */ + if (memcmp(&header->eye_catcher, SCM_STATS_EYECATCHER, + sizeof(header->eye_catcher))) { + return H_BAD_DATA; + } + if (be32_to_cpu(header->stats_version) != 0x1) { + return H_NOT_AVAILABLE; + } + + /* verify that rr buffer has enough space */ + *num_stats = be32_to_cpu(header->num_statistics); + if (*num_stats > SCM_STATS_MAX_STATS) { + /* Too many stats requested */ + return H_P3; + } + + expected_buffsize = *num_stats ? + SCM_STATS_RR_BUFFER_SIZE(*num_stats) : SCM_STATS_MIN_OUTPUT_BUFFER; + if (size < expected_buffsize) { + return H_P3; + } + + return H_SUCCESS; +} + +/* + * For a given DRC index (R3) return one ore more performance stats of an nvdimm + * device in guest allocated Request-and-result buffer (rr-buffer) (R4) of + * given 'size' (R5). The rr-buffer consists of a header described by + * 'struct papr_scm_perf_stats' that embeds the 'stats_version' and + * 'num_statistics' fields. This is followed by an array of + * 'struct papr_scm_perf_stat'. Based on the request type the writes the + * performance into the array of 'struct papr_scm_perf_stat' embedded inside + * the rr-buffer provided by the guest. + * Special cases handled are: + * 'size' == 0 : Return the maximum possible size of rr-buffer + * 'size' != 0 && 'num_statistics == 0' : Return all possible performance stats + * + * In case there was an error fetching a specific stats (e.g stat-id unknown or + * any other error) then return the stat-id in R4 and also replace its stat + * entry in rr-buffer with 'NoopStat' + */ +static target_ulong h_scm_performance_stats(PowerPCCPU *cpu, + SpaprMachineState *spapr, + target_ulong opcode, + target_ulong *args) +{ + SpaprDrc *drc = spapr_drc_by_index(args[0]); + const hwaddr addr = args[1]; + size_t size = args[2]; + g_autofree struct papr_scm_perf_stats *perfstats = NULL; + struct papr_scm_perf_stat *stats; + perf_stat_val stat_val; + uint32_t num_stats; + int index; + long rc; + + /* Ensure that the drc is valid & is valid PMEM dimm and is plugged in */ + if (!drc || !drc->dev || + spapr_drc_type(drc) != SPAPR_DR_CONNECTOR_TYPE_PMEM) { + return H_PARAMETER; + } + + /* Guest requested max buffer size for output buffer */ + if (size == 0) { + args[0] = SCM_STATS_MIN_OUTPUT_BUFFER; + return H_SUCCESS; + } + + /* verify size is enough to hold rr-buffer */ + if (size < sizeof(struct papr_scm_perf_stats)) { + return H_BAD_DATA; + } + + if (size > SCM_STATS_MAX_OUTPUT_BUFFER) { + return H_P3; + } + + /* allocate enough buffer space locally for holding max stats */ + perfstats = g_try_malloc0(size); + if (!perfstats) { + return H_NO_MEM; + } + stats = &perfstats->scm_statistics[0]; + + /* Read and verify rr-buffer */ + rc = address_space_read(&address_space_memory, addr, MEMTXATTRS_UNSPECIFIED, + perfstats, size); + if (rc != MEMTX_OK) { + return H_PRIVILEGE; + } + rc = scm_perf_check_rr_buffer(perfstats, addr, size, &num_stats); + if (rc != H_SUCCESS) { + return rc; + } + + /* when returning all stats generate a canned response first */ + if (num_stats == 0) { + /* Ignore 'noopstat' when generating canned response */ + for (num_stats = 0; num_stats < ARRAY_SIZE(nvdimm_perf_stats) - 1; + ++num_stats) { + memcpy(&stats[num_stats].statistic_id, + nvdimm_perf_stats[num_stats + 1].stat_id, + sizeof(perf_stat_id)); + } + } + + /* Populate the rr-buffer with stat values */ + for (args[0] = 0, index = 0; index < num_stats; ++index) { + rc = nvdimm_stat_getval(drc, stats[index].statistic_id, &stat_val); + + /* On error add noop stat to rr buffer & save last inval stat-id */ + if (rc != H_SUCCESS) { + if (!args[0]) { + memcpy(&args[0], stats[index].statistic_id, + sizeof(perf_stat_id)); + } + memcpy(&stats[index].statistic_id, nvdimm_perf_stats[0].stat_id, + sizeof(perf_stat_id)); + } + /* Caller expects stat values in BE encoding */ + stats[index].statistic_value = cpu_to_be64(stat_val); + } + + /* Update and copy the local rr-buffer back to guest */ + perfstats->num_statistics = cpu_to_be32(num_stats); + g_assert(size <= SCM_STATS_MAX_OUTPUT_BUFFER); + rc = address_space_write(&address_space_memory, addr, + MEMTXATTRS_UNSPECIFIED, perfstats, size); + + if (rc != MEMTX_OK) { + return H_PRIVILEGE; + } + + /* Check if there was a failure in fetching any stat */ + return args[0] ? H_PARTIAL : H_SUCCESS; +} + static void spapr_scm_register_types(void) { /* qemu/scm specific hcalls */ @@ -511,6 +729,7 @@ static void spapr_scm_register_types(void) spapr_register_hypercall(H_SCM_UNBIND_MEM, h_scm_unbind_mem); spapr_register_hypercall(H_SCM_UNBIND_ALL, h_scm_unbind_all); spapr_register_hypercall(H_SCM_HEALTH, h_scm_health); + spapr_register_hypercall(H_SCM_PERFORMANCE_STATS, h_scm_performance_stats); } type_init(spapr_scm_register_types) diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index bbf817af46..9e093b3a00 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -326,6 +326,7 @@ struct SpaprMachineState { #define H_P8 -61 #define H_P9 -62 #define H_OVERLAP -68 +#define H_BAD_DATA -70 #define H_UNSUPPORTED_FLAG -256 #define H_MULTI_THREADS_ACTIVE -9005 @@ -539,8 +540,9 @@ struct SpaprMachineState { #define H_SCM_UNBIND_MEM 0x3F0 #define H_SCM_UNBIND_ALL 0x3FC #define H_SCM_HEALTH 0x400 +#define H_SCM_PERFORMANCE_STATS 0x418 -#define MAX_HCALL_OPCODE H_SCM_HEALTH +#define MAX_HCALL_OPCODE H_SCM_PERFORMANCE_STATS /* The hcalls above are standardized in PAPR and implemented by pHyp * as well. @@ -793,6 +795,24 @@ OBJECT_DECLARE_SIMPLE_TYPE(SpaprTceTable, SPAPR_TCE_TABLE) DECLARE_INSTANCE_CHECKER(IOMMUMemoryRegion, SPAPR_IOMMU_MEMORY_REGION, TYPE_SPAPR_IOMMU_MEMORY_REGION) +/* Defs and structs exchanged with guest when reporting drc perf stats */ +#define SCM_STATS_EYECATCHER "SCMSTATS" + +typedef char perf_stat_id[8]; +typedef uint64_t perf_stat_val; + +struct QEMU_PACKED papr_scm_perf_stat { + perf_stat_id statistic_id; + perf_stat_val statistic_value; +}; + +struct QEMU_PACKED papr_scm_perf_stats { + uint8_t eye_catcher[8]; /* Should be “SCMSTATS” */ + uint32_t stats_version; /* Should be 0x01 */ + uint32_t num_statistics; /* Number of stats following */ + struct papr_scm_perf_stat scm_statistics[]; /* Performance matrics */ +}; + struct SpaprTceTable { DeviceState parent; uint32_t liobn;