From: Dan Williams Date: Tue, 13 May 2025 18:28:25 +0000 (-0700) Subject: Merge branch 'for-6.16/tsm-mr' into tsm-next X-Git-Tag: ceph-for-6.17-rc6~732^2 X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=9d948b8804096d940022b1a3c483a5beb8b46574;p=ceph-client.git Merge branch 'for-6.16/tsm-mr' into tsm-next Pick up a couple fixes for issues noticed in linux-next (constification of bin_attrs and missing 'static'). --- 9d948b8804096d940022b1a3c483a5beb8b46574 diff --cc drivers/virt/coco/guest/tsm-mr.c index 1f0c43a516fb8,0000000000000..feb30af90a208 mode 100644,000000..100644 --- a/drivers/virt/coco/guest/tsm-mr.c +++ b/drivers/virt/coco/guest/tsm-mr.c @@@ -1,251 -1,0 +1,251 @@@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright(c) 2024-2025 Intel Corporation. All rights reserved. */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include + +#define CREATE_TRACE_POINTS +#include + +/* + * struct tm_context - contains everything necessary to implement sysfs + * attributes for MRs. + * @rwsem: protects the MR cache from concurrent access. + * @agrp: contains all MR attributes created by tsm_mr_create_attribute_group(). + * @tm: input to tsm_mr_create_attribute_group() containing MR definitions/ops. + * @in_sync: %true if MR cache is up-to-date. + * @mrs: array of &struct bin_attribute, one for each MR. + * + * This internal structure contains everything needed to implement + * tm_digest_read() and tm_digest_write(). + * + * Given tm->refresh() is potentially expensive, tm_digest_read() caches MR + * values and calls tm->refresh() only when necessary. Only live MRs (i.e., with + * %TSM_MR_F_LIVE set) can trigger tm->refresh(), while others are assumed to + * retain their values from the last tm->write(). @in_sync tracks if there have + * been tm->write() calls since the last tm->refresh(). That is, tm->refresh() + * will be called only when a live MR is being read and the cache is stale + * (@in_sync is %false). + * + * tm_digest_write() sets @in_sync to %false and calls tm->write(), whose + * semantics is arch and MR specific. Most (if not all) writable MRs support the + * extension semantics (i.e., tm->write() extends the input buffer into the MR). + */ +struct tm_context { + struct rw_semaphore rwsem; + struct attribute_group agrp; + const struct tsm_measurements *tm; + bool in_sync; + struct bin_attribute mrs[]; +}; + +static ssize_t tm_digest_read(struct file *filp, struct kobject *kobj, + const struct bin_attribute *attr, char *buffer, + loff_t off, size_t count) +{ + struct tm_context *ctx; + const struct tsm_measurement_register *mr; + int rc; + + ctx = attr->private; + rc = down_read_interruptible(&ctx->rwsem); + if (rc) + return rc; + + mr = &ctx->tm->mrs[attr - ctx->mrs]; + + /* + * @ctx->in_sync indicates if the MR cache is stale. It is a global + * instead of a per-MR flag for simplicity, as most (if not all) archs + * allow reading all MRs in oneshot. + * + * ctx->refresh() is necessary only for LIVE MRs, while others retain + * their values from their respective last ctx->write(). + */ + if ((mr->mr_flags & TSM_MR_F_LIVE) && !ctx->in_sync) { + up_read(&ctx->rwsem); + + rc = down_write_killable(&ctx->rwsem); + if (rc) + return rc; + + if (!ctx->in_sync) { + rc = ctx->tm->refresh(ctx->tm); + ctx->in_sync = !rc; + trace_tsm_mr_refresh(mr, rc); + } + + downgrade_write(&ctx->rwsem); + } + + memcpy(buffer, mr->mr_value + off, count); + trace_tsm_mr_read(mr); + + up_read(&ctx->rwsem); + return rc ?: count; +} + +static ssize_t tm_digest_write(struct file *filp, struct kobject *kobj, + const struct bin_attribute *attr, char *buffer, + loff_t off, size_t count) +{ + struct tm_context *ctx; + const struct tsm_measurement_register *mr; + ssize_t rc; + + /* partial writes are not supported */ + if (off != 0 || count != attr->size) + return -EINVAL; + + ctx = attr->private; + mr = &ctx->tm->mrs[attr - ctx->mrs]; + + rc = down_write_killable(&ctx->rwsem); + if (rc) + return rc; + + rc = ctx->tm->write(ctx->tm, mr, buffer); + + /* mark MR cache stale */ + if (!rc) { + ctx->in_sync = false; + trace_tsm_mr_write(mr, buffer); + } + + up_write(&ctx->rwsem); + return rc ?: count; +} + +/** + * tsm_mr_create_attribute_group() - creates an attribute group for measurement + * registers (MRs) + * @tm: pointer to &struct tsm_measurements containing the MR definitions. + * + * This function creates attributes corresponding to the MR definitions + * provided by @tm->mrs. + * + * The created attributes will reference @tm and its members. The caller must + * not free @tm until after tsm_mr_free_attribute_group() is called. + * + * Context: Process context. May sleep due to memory allocation. + * + * Return: + * * On success, the pointer to a an attribute group is returned; otherwise + * * %-EINVAL - Invalid MR definitions. + * * %-ENOMEM - Out of memory. + */ +const struct attribute_group * +tsm_mr_create_attribute_group(const struct tsm_measurements *tm) +{ + size_t nlen; + + if (!tm || !tm->mrs) + return ERR_PTR(-EINVAL); + + /* aggregated length of all MR names */ + nlen = 0; + for (size_t i = 0; i < tm->nr_mrs; ++i) { + if ((tm->mrs[i].mr_flags & TSM_MR_F_LIVE) && !tm->refresh) + return ERR_PTR(-EINVAL); + + if ((tm->mrs[i].mr_flags & TSM_MR_F_WRITABLE) && !tm->write) + return ERR_PTR(-EINVAL); + + if (!tm->mrs[i].mr_name) + return ERR_PTR(-EINVAL); + + if (tm->mrs[i].mr_flags & TSM_MR_F_NOHASH) + continue; + + if (tm->mrs[i].mr_hash >= HASH_ALGO__LAST) + return ERR_PTR(-EINVAL); + + /* MR sysfs attribute names have the form of MRNAME:HASH */ + nlen += strlen(tm->mrs[i].mr_name) + 1 + + strlen(hash_algo_name[tm->mrs[i].mr_hash]) + 1; + } + + /* + * @attrs and the MR name strings are combined into a single allocation + * so that we don't have to free MR names one-by-one in + * tsm_mr_free_attribute_group() + */ - const struct bin_attribute * const *attrs __free(kfree) = ++ const struct bin_attribute **attrs __free(kfree) = + kzalloc(sizeof(*attrs) * (tm->nr_mrs + 1) + nlen, GFP_KERNEL); + struct tm_context *ctx __free(kfree) = + kzalloc(struct_size(ctx, mrs, tm->nr_mrs), GFP_KERNEL); + char *name, *end; + + if (!ctx || !attrs) + return ERR_PTR(-ENOMEM); + + /* @attrs is followed immediately by MR name strings */ + name = (char *)&attrs[tm->nr_mrs + 1]; + end = name + nlen; + + for (size_t i = 0; i < tm->nr_mrs; ++i) { - /* break const for init */ - struct bin_attribute **bas = (struct bin_attribute **)attrs; ++ struct bin_attribute *bap = &ctx->mrs[i]; + - bas[i] = &ctx->mrs[i]; - sysfs_bin_attr_init(bas[i]); ++ sysfs_bin_attr_init(bap); + + if (tm->mrs[i].mr_flags & TSM_MR_F_NOHASH) - bas[i]->attr.name = tm->mrs[i].mr_name; ++ bap->attr.name = tm->mrs[i].mr_name; + else if (name < end) { - bas[i]->attr.name = name; ++ bap->attr.name = name; + name += snprintf(name, end - name, "%s:%s", + tm->mrs[i].mr_name, + hash_algo_name[tm->mrs[i].mr_hash]); + ++name; + } else + return ERR_PTR(-EINVAL); + + /* check for duplicated MR definitions */ + for (size_t j = 0; j < i; ++j) - if (!strcmp(bas[i]->attr.name, bas[j]->attr.name)) ++ if (!strcmp(bap->attr.name, attrs[j]->attr.name)) + return ERR_PTR(-EINVAL); + + if (tm->mrs[i].mr_flags & TSM_MR_F_READABLE) { - bas[i]->attr.mode |= 0444; - bas[i]->read_new = tm_digest_read; ++ bap->attr.mode |= 0444; ++ bap->read_new = tm_digest_read; + } + + if (tm->mrs[i].mr_flags & TSM_MR_F_WRITABLE) { - bas[i]->attr.mode |= 0200; - bas[i]->write_new = tm_digest_write; ++ bap->attr.mode |= 0200; ++ bap->write_new = tm_digest_write; + } + - bas[i]->size = tm->mrs[i].mr_size; - bas[i]->private = ctx; ++ bap->size = tm->mrs[i].mr_size; ++ bap->private = ctx; ++ ++ attrs[i] = bap; + } + + if (name != end) + return ERR_PTR(-EINVAL); + + init_rwsem(&ctx->rwsem); + ctx->agrp.name = "measurements"; + ctx->agrp.bin_attrs_new = no_free_ptr(attrs); + ctx->tm = tm; + return &no_free_ptr(ctx)->agrp; +} +EXPORT_SYMBOL_GPL(tsm_mr_create_attribute_group); + +/** + * tsm_mr_free_attribute_group() - frees the attribute group returned by + * tsm_mr_create_attribute_group() + * @attr_grp: attribute group returned by tsm_mr_create_attribute_group() + * + * Context: Process context. + */ +void tsm_mr_free_attribute_group(const struct attribute_group *attr_grp) +{ + if (!IS_ERR_OR_NULL(attr_grp)) { - kfree(attr_grp->bin_attrs); ++ kfree(attr_grp->bin_attrs_new); + kfree(container_of(attr_grp, struct tm_context, agrp)); + } +} +EXPORT_SYMBOL_GPL(tsm_mr_free_attribute_group);