This commit extends the TSM core with support for CC measurement registers
(MRs).

The newly added APIs are:

- `tsm_register_measurement(struct tsm_measurement *)`
  This function allows a CC guest driver to register a set of measurement
  registers with the TSM core.
- `tsm_unregister_measurement(struct tsm_measurement *)`:
  This function enables a CC guest driver to unregister a previously registered
  set of measurement registers.

`struct tsm_measurement` has been defined to encapsulate the details of
CC-specific MRs. It includes an array of `struct tsm_measurement_register`s and
provides operations for reading and updating these registers. For a
comprehensive understanding of the structure and its usage, refer to the
detailed comments added in `include/linux/tsm.h`.

Upon successful registration of a measurement provider, the TSM core exposes
the MRs through a directory tree in the sysfs filesystem. The root of this tree
is located at `/sys/kernel/tsm/<MR provider>/`, with `<MR provider>` being the
name of the measurement provider. Each MR is made accessible as either a
file or a directory, named after the MR itself. In the former case, the file
content is the MR value, while in the latter case there will be two files in
the directory: `digest` and `hash_algo`. The purpose and content of these files
are self-explanatory.

Signed-off-by: Cedric Xing <cedric.xing@intel.com>
---
 drivers/virt/coco/Kconfig               |   3 +-
 drivers/virt/coco/Makefile              |   2 +
 drivers/virt/coco/{tsm.c => tsm-core.c} |  26 ++-
 drivers/virt/coco/tsm-mr.c              | 374 ++++++++++++++++++++++++++++++++
 4 files changed, 394 insertions(+), 11 deletions(-)

diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig
index d9ff676bf48d..0609622cbcb9 100644
--- a/drivers/virt/coco/Kconfig
+++ b/drivers/virt/coco/Kconfig
@@ -5,7 +5,8 @@
 
 config TSM_REPORTS
 	select CONFIGFS_FS
-	tristate
+	select CRYPTO_HASH_INFO
+	tristate "Trusted Security Module (TSM) sysfs/configfs support"
 
 source "drivers/virt/coco/efi_secret/Kconfig"
 
diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile
index b69c30c1c720..8192d78dff61 100644
--- a/drivers/virt/coco/Makefile
+++ b/drivers/virt/coco/Makefile
@@ -2,6 +2,8 @@
 #
 # Confidential computing related collateral
 #
+tsm-y				+= tsm-core.o tsm-mr.o
+
 obj-$(CONFIG_TSM_REPORTS)	+= tsm.o
 obj-$(CONFIG_EFI_SECRET)	+= efi_secret/
 obj-$(CONFIG_ARM_PKVM_GUEST)	+= pkvm-guest/
diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm-core.c
similarity index 95%
rename from drivers/virt/coco/tsm.c
rename to drivers/virt/coco/tsm-core.c
index 9432d4e303f1..92e961f21507 100644
--- a/drivers/virt/coco/tsm.c
+++ b/drivers/virt/coco/tsm-core.c
@@ -1,8 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2023 Intel Corporation. All rights reserved. */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
 #include <linux/tsm.h>
 #include <linux/err.h>
 #include <linux/slab.h>
@@ -166,8 +164,9 @@ static ssize_t tsm_report_service_guid_store(struct config_item *cfg,
 }
 CONFIGFS_ATTR_WO(tsm_report_, service_guid);
 
-static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg,
-							 const char *buf, size_t len)
+static ssize_t
+tsm_report_service_manifest_version_store(struct config_item *cfg,
+					  const char *buf, size_t len)
 {
 	struct tsm_report *report = to_tsm_report(cfg);
 	unsigned int val;
@@ -187,8 +186,8 @@ static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg
 }
 CONFIGFS_ATTR_WO(tsm_report_, service_manifest_version);
 
-static ssize_t tsm_report_inblob_write(struct config_item *cfg,
-				       const void *buf, size_t count)
+static ssize_t tsm_report_inblob_write(struct config_item *cfg, const void *buf,
+				       size_t count)
 {
 	struct tsm_report *report = to_tsm_report(cfg);
 	int rc;
@@ -341,7 +340,8 @@ static struct configfs_attribute *tsm_report_attrs[] = {
 	[TSM_REPORT_PRIVLEVEL_FLOOR] = &tsm_report_attr_privlevel_floor,
 	[TSM_REPORT_SERVICE_PROVIDER] = &tsm_report_attr_service_provider,
 	[TSM_REPORT_SERVICE_GUID] = &tsm_report_attr_service_guid,
-	[TSM_REPORT_SERVICE_MANIFEST_VER] = &tsm_report_attr_service_manifest_version,
+	[TSM_REPORT_SERVICE_MANIFEST_VER] =
+		&tsm_report_attr_service_manifest_version,
 	NULL,
 };
 
@@ -383,7 +383,8 @@ static bool tsm_report_is_visible(struct config_item *item,
 }
 
 static bool tsm_report_is_bin_visible(struct config_item *item,
-				      struct configfs_bin_attribute *attr, int n)
+				      struct configfs_bin_attribute *attr,
+				      int n)
 {
 	guard(rwsem_read)(&tsm_rwsem);
 	if (!provider.ops)
@@ -478,6 +479,9 @@ EXPORT_SYMBOL_GPL(tsm_unregister);
 
 static struct config_group *tsm_report_group;
 
+extern int tsm_mr_init(void);
+extern void tsm_mr_exit(void);
+
 static int __init tsm_init(void)
 {
 	struct config_group *root = &tsm_configfs.su_group;
@@ -497,16 +501,18 @@ static int __init tsm_init(void)
 	}
 	tsm_report_group = tsm;
 
-	return 0;
+	return tsm_mr_init();
 }
 module_init(tsm_init);
 
 static void __exit tsm_exit(void)
 {
+	tsm_mr_exit();
 	configfs_unregister_default_group(tsm_report_group);
 	configfs_unregister_subsystem(&tsm_configfs);
 }
 module_exit(tsm_exit);
 
 MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Provide Trusted Security Module attestation reports via configfs");
+MODULE_DESCRIPTION(
+	"Provide Trusted Security Module attestation reports via configfs");
diff --git a/drivers/virt/coco/tsm-mr.c b/drivers/virt/coco/tsm-mr.c
new file mode 100644
index 000000000000..a84e923a7782
--- /dev/null
+++ b/drivers/virt/coco/tsm-mr.c
@@ -0,0 +1,374 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
+
+#include <linux/tsm.h>
+#include <linux/shmem_fs.h>
+#include <linux/ctype.h>
+#include <crypto/hash_info.h>
+#include <crypto/hash.h>
+
+int tsm_mr_init(void);
+void tsm_mr_exit(void);
+
+enum _mrdir_bin_attr_index {
+	_MRDIR_BA_DIGEST,
+	_MRDIR_BA__COUNT,
+};
+
+struct _mrdir {
+	struct kobject kobj;
+	struct bin_attribute battrs[_MRDIR_BA__COUNT];
+};
+
+struct _mr_provider {
+	struct kset kset;
+	struct rw_semaphore rwsem;
+	struct bin_attribute *mrfiles;
+	struct tsm_measurement *tmr;
+	bool in_sync;
+};
+
+static inline const struct tsm_measurement_register *
+_mrdir_mr(const struct _mrdir *mrd)
+{
+	return (struct tsm_measurement_register *)mrd->battrs[_MRDIR_BA_DIGEST]
+		.private;
+}
+
+static inline struct _mr_provider *
+_mr_to_provider(const struct tsm_measurement_register *mr, struct kobject *kobj)
+{
+	if (mr->mr_flags & TSM_MR_F_F)
+		return container_of(kobj, struct _mr_provider, kset.kobj);
+	else
+		return container_of(kobj->kset, struct _mr_provider, kset);
+}
+
+static inline int _call_refresh(struct _mr_provider *pvd,
+				const struct tsm_measurement_register *mr)
+{
+	int rc = pvd->tmr->refresh(pvd->tmr, mr);
+	if (rc)
+		pr_warn(KBUILD_MODNAME ": %s.extend(%s) failed %d\n",
+			kobject_name(&pvd->kset.kobj), mr->mr_name, rc);
+	return rc;
+}
+
+static inline int _call_extend(struct _mr_provider *pvd,
+			       const struct tsm_measurement_register *mr,
+			       const u8 *data)
+{
+	int rc = pvd->tmr->extend(pvd->tmr, mr, data);
+	if (rc)
+		pr_warn(KBUILD_MODNAME ": %s.extend(%s) failed %d\n",
+			kobject_name(&pvd->kset.kobj), mr->mr_name, rc);
+	return rc;
+}
+
+static ssize_t hash_algo_show(struct kobject *kobj, struct kobj_attribute *attr,
+			      char *page)
+{
+	struct _mrdir *mrd;
+	mrd = container_of(kobj, typeof(*mrd), kobj);
+	return sysfs_emit(page, "%s", hash_algo_name[_mrdir_mr(mrd)->mr_hash]);
+}
+
+static ssize_t _mr_read(struct file *filp, struct kobject *kobj,
+			struct bin_attribute *attr, char *page, loff_t off,
+			size_t count)
+{
+	const struct tsm_measurement_register *mr;
+	struct _mr_provider *pvd;
+	int rc;
+
+	if (off < 0 || off > attr->size)
+		return -EINVAL;
+
+	count = min(count, attr->size - (size_t)off);
+	if (!count)
+		return count;
+
+	mr = (typeof(mr))attr->private;
+	BUG_ON(mr->mr_size != attr->size);
+
+	pvd = _mr_to_provider(mr, kobj);
+	rc = down_read_interruptible(&pvd->rwsem);
+	if (rc)
+		return rc;
+
+	if ((mr->mr_flags & TSM_MR_F_L) && !pvd->in_sync) {
+		up_read(&pvd->rwsem);
+
+		rc = down_write_killable(&pvd->rwsem);
+		if (rc)
+			return rc;
+
+		if (!pvd->in_sync) {
+			rc = _call_refresh(pvd, mr);
+			pvd->in_sync = !rc;
+		}
+
+		downgrade_write(&pvd->rwsem);
+	}
+
+	if (!rc)
+		memcpy(page, mr->mr_value + off, count);
+	else
+		pr_debug(KBUILD_MODNAME ": %s.refresh(%s)=%d\n",
+			 kobject_name(&pvd->kset.kobj), mr->mr_name, rc);
+
+	up_read(&pvd->rwsem);
+	return rc ?: count;
+}
+
+static ssize_t _mr_write(struct file *filp, struct kobject *kobj,
+			 struct bin_attribute *attr, char *page, loff_t off,
+			 size_t count)
+{
+	const struct tsm_measurement_register *mr;
+	struct _mr_provider *pvd;
+	ssize_t rc;
+
+	if (off != 0 || count != attr->size)
+		return -EINVAL;
+
+	mr = (typeof(mr))attr->private;
+	BUG_ON(mr->mr_size != attr->size);
+
+	pvd = _mr_to_provider(mr, kobj);
+	rc = down_write_killable(&pvd->rwsem);
+	if (rc)
+		return rc;
+
+	if (mr->mr_flags & TSM_MR_F_X)
+		rc = _call_extend(pvd, mr, page);
+	else
+		memcpy(mr->mr_value, page, count);
+
+	if (!rc)
+		pvd->in_sync = false;
+
+	up_write(&pvd->rwsem);
+	return rc ?: count;
+}
+
+static void _mrdir_release(struct kobject *kobj)
+{
+	struct _mrdir *mrd;
+	mrd = container_of(kobj, typeof(*mrd), kobj);
+	pr_debug("%s(%s)\n", __func__, kobject_name(kobj));
+	kfree(mrd);
+}
+
+static struct kobj_type _mrdir_ktype = {
+	.release = _mrdir_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+};
+
+static struct _mrdir *_mrdir_create(const struct tsm_measurement_register *mr,
+				    struct _mr_provider *pvd)
+{
+	struct _mrdir *mrd __free(kfree);
+	int rc;
+
+	BUG_ON(mr->mr_flags & TSM_MR_F_F);
+	mrd = kzalloc(sizeof(*mrd), GFP_KERNEL);
+	if (!mrd)
+		return ERR_PTR(-ENOMEM);
+
+	sysfs_bin_attr_init(&mrd->battrs[_MRDIR_BA_DIGEST]);
+	mrd->battrs[_MRDIR_BA_DIGEST].attr.name = "digest";
+	if (mr->mr_flags & TSM_MR_F_W)
+		mrd->battrs[_MRDIR_BA_DIGEST].attr.mode |= S_IWUSR | S_IWGRP;
+	if (mr->mr_flags & TSM_MR_F_R)
+		mrd->battrs[_MRDIR_BA_DIGEST].attr.mode |= S_IRUGO;
+
+	mrd->battrs[_MRDIR_BA_DIGEST].size = mr->mr_size;
+	mrd->battrs[_MRDIR_BA_DIGEST].read = _mr_read;
+	mrd->battrs[_MRDIR_BA_DIGEST].write = _mr_write;
+	mrd->battrs[_MRDIR_BA_DIGEST].private = (void *)mr;
+
+	mrd->kobj.kset = &pvd->kset;
+	rc = kobject_init_and_add(&mrd->kobj, &_mrdir_ktype, NULL, "%s",
+				  mr->mr_name);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return_ptr(mrd);
+}
+
+static void _mr_provider_release(struct kobject *kobj)
+{
+	struct _mr_provider *pvd;
+	pvd = container_of(kobj, typeof(*pvd), kset.kobj);
+	pr_debug("%s(%s)\n", __func__, kobject_name(kobj));
+	BUG_ON(!list_empty(&pvd->kset.list));
+	kfree(pvd->mrfiles);
+	kfree(pvd);
+}
+
+static struct kobj_type _mr_provider_ktype = {
+	.release = _mr_provider_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+};
+
+static struct kset *_sysfs_tsm;
+
+static struct _mr_provider *_mr_provider_create(struct tsm_measurement *tmr)
+{
+	struct _mr_provider *pvd __free(kfree);
+	int rc;
+
+	pvd = kzalloc(sizeof(*pvd), GFP_KERNEL);
+	if (!pvd)
+		return ERR_PTR(-ENOMEM);
+
+	if (!tmr->name || !tmr->mrs || !tmr->refresh || !tmr->extend)
+		return ERR_PTR(-EINVAL);
+
+	rc = kobject_set_name(&pvd->kset.kobj, "%s", tmr->name);
+	if (rc)
+		return ERR_PTR(rc);
+
+	pvd->kset.kobj.kset = _sysfs_tsm;
+	pvd->kset.kobj.ktype = &_mr_provider_ktype;
+	pvd->tmr = tmr;
+
+	init_rwsem(&pvd->rwsem);
+
+	rc = kset_register(&pvd->kset);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return_ptr(pvd);
+}
+
+DEFINE_FREE(_unregister_measurement, struct _mr_provider *,
+	    if (!IS_ERR_OR_NULL(_T)) tsm_unregister_measurement(_T->tmr));
+
+int tsm_register_measurement(struct tsm_measurement *tmr)
+{
+	static struct kobj_attribute _attr_hash = __ATTR_RO(hash_algo);
+
+	struct _mr_provider *pvd __free(_unregister_measurement);
+	int rc, nr;
+
+	pvd = _mr_provider_create(tmr);
+	if (IS_ERR(pvd))
+		return PTR_ERR(pvd);
+
+	nr = 0;
+	for (int i = 0; tmr->mrs[i].mr_name; ++i) {
+		// flat files are counted and skipped
+		if (tmr->mrs[i].mr_flags & TSM_MR_F_F) {
+			++nr;
+			continue;
+		}
+
+		struct _mrdir *mrd = _mrdir_create(&tmr->mrs[i], pvd);
+		if (IS_ERR(mrd))
+			return PTR_ERR(mrd);
+
+		struct attribute *attrs[] = {
+			&_attr_hash.attr,
+			NULL,
+		};
+		struct bin_attribute *battrs[_MRDIR_BA__COUNT + 1] = {};
+		for (int j = 0; j < _MRDIR_BA__COUNT; ++j)
+			battrs[j] = &mrd->battrs[j];
+		struct attribute_group agrp = {
+			.attrs = attrs,
+			.bin_attrs = battrs,
+		};
+		rc = sysfs_create_group(&mrd->kobj, &agrp);
+		if (rc)
+			return rc;
+	}
+
+	if (nr > 0) {
+		struct bin_attribute *mrfiles __free(kfree);
+		struct bin_attribute **battrs __free(kfree);
+
+		mrfiles = kcalloc(sizeof(*mrfiles), nr, GFP_KERNEL);
+		battrs = kcalloc(sizeof(*battrs), nr + 1, GFP_KERNEL);
+		if (!battrs || !mrfiles)
+			return -ENOMEM;
+
+		for (int i = 0, j = 0; tmr->mrs[i].mr_name; ++i) {
+			if (!(tmr->mrs[i].mr_flags & TSM_MR_F_F))
+				continue;
+
+			mrfiles[j].attr.name = tmr->mrs[i].mr_name;
+			mrfiles[j].read = _mr_read;
+			mrfiles[j].write = _mr_write;
+			mrfiles[j].size = tmr->mrs[i].mr_size;
+			mrfiles[j].private = (void *)&tmr->mrs[i];
+			if (tmr->mrs[i].mr_flags & TSM_MR_F_R)
+				mrfiles[j].attr.mode |= S_IRUGO;
+			if (tmr->mrs[i].mr_flags & TSM_MR_F_W)
+				mrfiles[j].attr.mode |= S_IWUSR | S_IWGRP;
+
+			battrs[j] = &mrfiles[j];
+			++j;
+
+			BUG_ON(j > nr);
+		}
+
+		struct attribute_group agrp = {
+			.bin_attrs = battrs,
+		};
+		rc = sysfs_create_group(&pvd->kset.kobj, &agrp);
+		if (rc)
+			return rc;
+
+		pvd->mrfiles = no_free_ptr(mrfiles);
+	}
+
+	pvd = NULL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tsm_register_measurement);
+
+static void _kset_put_children(struct kset *kset)
+{
+	struct kobject *p, *n;
+	spin_lock(&kset->list_lock);
+	list_for_each_entry_safe(p, n, &kset->list, entry) {
+		spin_unlock(&kset->list_lock);
+		kobject_put(p);
+		spin_lock(&kset->list_lock);
+	}
+	spin_unlock(&kset->list_lock);
+}
+
+int tsm_unregister_measurement(struct tsm_measurement *tmr)
+{
+	struct kobject *kobj = kset_find_obj(_sysfs_tsm, tmr->name);
+	if (!kobj)
+		return -ENOENT;
+
+	struct _mr_provider *pvd = container_of(kobj, typeof(*pvd), kset.kobj);
+	BUG_ON(pvd->tmr != tmr);
+
+	_kset_put_children(&pvd->kset);
+	kset_unregister(&pvd->kset);
+	kobject_put(kobj);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tsm_unregister_measurement);
+
+int tsm_mr_init(void)
+{
+	_sysfs_tsm = kset_create_and_add("tsm", NULL, kernel_kobj);
+	if (!_sysfs_tsm)
+		return -ENOMEM;
+	return 0;
+}
+
+void tsm_mr_exit(void)
+{
+	kset_unregister(_sysfs_tsm);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Provide Trusted Security Module measurements via sysfs");

-- 
2.43.0

On 1/11/24 03:50, Cedric Xing wrote:
> This commit extends the TSM core with support for CC measurement registers
> (MRs).
> 
> The newly added APIs are:
> 
> - `tsm_register_measurement(struct tsm_measurement *)`
>    This function allows a CC guest driver to register a set of measurement
>    registers with the TSM core.
> - `tsm_unregister_measurement(struct tsm_measurement *)`:
>    This function enables a CC guest driver to unregister a previously registered
>    set of measurement registers.
> 
> `struct tsm_measurement` has been defined to encapsulate the details of
> CC-specific MRs. It includes an array of `struct tsm_measurement_register`s and
> provides operations for reading and updating these registers. For a
> comprehensive understanding of the structure and its usage, refer to the
> detailed comments added in `include/linux/tsm.h`.
> 
> Upon successful registration of a measurement provider, the TSM core exposes
> the MRs through a directory tree in the sysfs filesystem. The root of this tree
> is located at `/sys/kernel/tsm/<MR provider>/`, with `<MR provider>` being the
> name of the measurement provider. Each MR is made accessible as either a
> file or a directory, named after the MR itself. In the former case, the file
> content is the MR value, while in the latter case there will be two files in
> the directory: `digest` and `hash_algo`. The purpose and content of these files
> are self-explanatory.
> 
> Signed-off-by: Cedric Xing <cedric.xing@intel.com>
> ---
>   drivers/virt/coco/Kconfig               |   3 +-
>   drivers/virt/coco/Makefile              |   2 +
>   drivers/virt/coco/{tsm.c => tsm-core.c} |  26 ++-
>   drivers/virt/coco/tsm-mr.c              | 374 ++++++++++++++++++++++++++++++++
>   4 files changed, 394 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig
> index d9ff676bf48d..0609622cbcb9 100644
> --- a/drivers/virt/coco/Kconfig
> +++ b/drivers/virt/coco/Kconfig
> @@ -5,7 +5,8 @@
>   
>   config TSM_REPORTS
>   	select CONFIGFS_FS
> -	tristate
> +	select CRYPTO_HASH_INFO
> +	tristate "Trusted Security Module (TSM) sysfs/configfs support"
>   
>   source "drivers/virt/coco/efi_secret/Kconfig"
>   
> diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile
> index b69c30c1c720..8192d78dff61 100644
> --- a/drivers/virt/coco/Makefile
> +++ b/drivers/virt/coco/Makefile
> @@ -2,6 +2,8 @@
>   #
>   # Confidential computing related collateral
>   #
> +tsm-y				+= tsm-core.o tsm-mr.o
> +
>   obj-$(CONFIG_TSM_REPORTS)	+= tsm.o
>   obj-$(CONFIG_EFI_SECRET)	+= efi_secret/
>   obj-$(CONFIG_ARM_PKVM_GUEST)	+= pkvm-guest/
> diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm-core.c
> similarity index 95%
> rename from drivers/virt/coco/tsm.c
> rename to drivers/virt/coco/tsm-core.c
> index 9432d4e303f1..92e961f21507 100644
> --- a/drivers/virt/coco/tsm.c
> +++ b/drivers/virt/coco/tsm-core.c
> @@ -1,8 +1,6 @@
>   // SPDX-License-Identifier: GPL-2.0-only
>   /* Copyright(c) 2023 Intel Corporation. All rights reserved. */
>   
> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> -

Why remove it?

>   #include <linux/tsm.h>
>   #include <linux/err.h>
>   #include <linux/slab.h>
> @@ -166,8 +164,9 @@ static ssize_t tsm_report_service_guid_store(struct config_item *cfg,
>   }
>   CONFIGFS_ATTR_WO(tsm_report_, service_guid);
>   
> -static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg,
> -							 const char *buf, size_t len)
> +static ssize_t
> +tsm_report_service_manifest_version_store(struct config_item *cfg,
> +					  const char *buf, size_t len)

Unrelated change usually goes to a separate preparation patch, otherwise 
too much noise.


>   {
>   	struct tsm_report *report = to_tsm_report(cfg);
>   	unsigned int val;
> @@ -187,8 +186,8 @@ static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg
>   }
>   CONFIGFS_ATTR_WO(tsm_report_, service_manifest_version);
>   
> -static ssize_t tsm_report_inblob_write(struct config_item *cfg,
> -				       const void *buf, size_t count)
> +static ssize_t tsm_report_inblob_write(struct config_item *cfg, const void *buf,
> +				       size_t count)

Unrelated change here and below.

>   {
>   	struct tsm_report *report = to_tsm_report(cfg);
>   	int rc;
> @@ -341,7 +340,8 @@ static struct configfs_attribute *tsm_report_attrs[] = {
>   	[TSM_REPORT_PRIVLEVEL_FLOOR] = &tsm_report_attr_privlevel_floor,
>   	[TSM_REPORT_SERVICE_PROVIDER] = &tsm_report_attr_service_provider,
>   	[TSM_REPORT_SERVICE_GUID] = &tsm_report_attr_service_guid,
> -	[TSM_REPORT_SERVICE_MANIFEST_VER] = &tsm_report_attr_service_manifest_version,
> +	[TSM_REPORT_SERVICE_MANIFEST_VER] =
> +		&tsm_report_attr_service_manifest_version,
>   	NULL,
>   };
>   
> @@ -383,7 +383,8 @@ static bool tsm_report_is_visible(struct config_item *item,
>   }
>   
>   static bool tsm_report_is_bin_visible(struct config_item *item,
> -				      struct configfs_bin_attribute *attr, int n)
> +				      struct configfs_bin_attribute *attr,
> +				      int n)
>   {
>   	guard(rwsem_read)(&tsm_rwsem);
>   	if (!provider.ops)
> @@ -478,6 +479,9 @@ EXPORT_SYMBOL_GPL(tsm_unregister);
>   
>   static struct config_group *tsm_report_group;
>   
> +extern int tsm_mr_init(void);
> +extern void tsm_mr_exit(void);
> +
>   static int __init tsm_init(void)
>   {
>   	struct config_group *root = &tsm_configfs.su_group;
> @@ -497,16 +501,18 @@ static int __init tsm_init(void)
>   	}
>   	tsm_report_group = tsm;
>   
> -	return 0;
> +	return tsm_mr_init();
>   }
>   module_init(tsm_init);
>   
>   static void __exit tsm_exit(void)
>   {
> +	tsm_mr_exit();
>   	configfs_unregister_default_group(tsm_report_group);
>   	configfs_unregister_subsystem(&tsm_configfs);
>   }
>   module_exit(tsm_exit);
>   
>   MODULE_LICENSE("GPL");
> -MODULE_DESCRIPTION("Provide Trusted Security Module attestation reports via configfs");
> +MODULE_DESCRIPTION(
> +	"Provide Trusted Security Module attestation reports via configfs");


Seems unrelated.

> diff --git a/drivers/virt/coco/tsm-mr.c b/drivers/virt/coco/tsm-mr.c
> new file mode 100644
> index 000000000000..a84e923a7782
> --- /dev/null
> +++ b/drivers/virt/coco/tsm-mr.c
> @@ -0,0 +1,374 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
> +
> +#include <linux/tsm.h>
> +#include <linux/shmem_fs.h>
> +#include <linux/ctype.h>
> +#include <crypto/hash_info.h>
> +#include <crypto/hash.h>
> +
> +int tsm_mr_init(void);
> +void tsm_mr_exit(void);

These two should go to drivers/virt/coco/tsm-mr.h, along with 
tsm_measurement_register and other TSM_MR_F_*.

> +
> +enum _mrdir_bin_attr_index {

Why do so many things have "_" prefix in this file?

> +	_MRDIR_BA_DIGEST,
> +	_MRDIR_BA__COUNT,

One underscore would do.

> +};
> +
> +struct _mrdir {
> +	struct kobject kobj;
> +	struct bin_attribute battrs[_MRDIR_BA__COUNT];
> +};
> +
> +struct _mr_provider {
> +	struct kset kset;
> +	struct rw_semaphore rwsem;
> +	struct bin_attribute *mrfiles;
> +	struct tsm_measurement *tmr;
> +	bool in_sync;
> +};
> +
> +static inline const struct tsm_measurement_register *
> +_mrdir_mr(const struct _mrdir *mrd)
> +{
> +	return (struct tsm_measurement_register *)mrd->battrs[_MRDIR_BA_DIGEST]
> +		.private;
> +}
> +
> +static inline struct _mr_provider *
> +_mr_to_provider(const struct tsm_measurement_register *mr, struct kobject *kobj)
> +{
> +	if (mr->mr_flags & TSM_MR_F_F)

No definition for TSM_MR_F_F (seems to come later in 2/2), how does this 
compile?


> +		return container_of(kobj, struct _mr_provider, kset.kobj);
> +	else
> +		return container_of(kobj->kset, struct _mr_provider, kset);
> +}
> +
> +static inline int _call_refresh(struct _mr_provider *pvd,
> +				const struct tsm_measurement_register *mr)
> +{
> +	int rc = pvd->tmr->refresh(pvd->tmr, mr);
> +	if (rc)
> +		pr_warn(KBUILD_MODNAME ": %s.extend(%s) failed %d\n",
> +			kobject_name(&pvd->kset.kobj), mr->mr_name, rc);
> +	return rc;
> +}
> +
> +static inline int _call_extend(struct _mr_provider *pvd,
> +			       const struct tsm_measurement_register *mr,
> +			       const u8 *data)
> +{
> +	int rc = pvd->tmr->extend(pvd->tmr, mr, data);
> +	if (rc)
> +		pr_warn(KBUILD_MODNAME ": %s.extend(%s) failed %d\n",
> +			kobject_name(&pvd->kset.kobj), mr->mr_name, rc);
> +	return rc;
> +}
> +
> +static ssize_t hash_algo_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			      char *page)
> +{
> +	struct _mrdir *mrd;
> +	mrd = container_of(kobj, typeof(*mrd), kobj);
> +	return sysfs_emit(page, "%s", hash_algo_name[_mrdir_mr(mrd)->mr_hash]);
> +}
> +
> +static ssize_t _mr_read(struct file *filp, struct kobject *kobj,
> +			struct bin_attribute *attr, char *page, loff_t off,
> +			size_t count)
> +{
> +	const struct tsm_measurement_register *mr;
> +	struct _mr_provider *pvd;
> +	int rc;
> +
> +	if (off < 0 || off > attr->size)
> +		return -EINVAL;
> +
> +	count = min(count, attr->size - (size_t)off);
> +	if (!count)
> +		return count;
> +
> +	mr = (typeof(mr))attr->private;
> +	BUG_ON(mr->mr_size != attr->size);
> +
> +	pvd = _mr_to_provider(mr, kobj);
> +	rc = down_read_interruptible(&pvd->rwsem);
> +	if (rc)
> +		return rc;
> +
> +	if ((mr->mr_flags & TSM_MR_F_L) && !pvd->in_sync) {
> +		up_read(&pvd->rwsem);
> +
> +		rc = down_write_killable(&pvd->rwsem);
> +		if (rc)
> +			return rc;
> +
> +		if (!pvd->in_sync) {
> +			rc = _call_refresh(pvd, mr);
> +			pvd->in_sync = !rc;
> +		}
> +
> +		downgrade_write(&pvd->rwsem);
> +	}
> +
> +	if (!rc)
> +		memcpy(page, mr->mr_value + off, count);
> +	else
> +		pr_debug(KBUILD_MODNAME ": %s.refresh(%s)=%d\n",
> +			 kobject_name(&pvd->kset.kobj), mr->mr_name, rc);
> +
> +	up_read(&pvd->rwsem);
> +	return rc ?: count;
> +}
> +
> +static ssize_t _mr_write(struct file *filp, struct kobject *kobj,
> +			 struct bin_attribute *attr, char *page, loff_t off,
> +			 size_t count)
> +{
> +	const struct tsm_measurement_register *mr;
> +	struct _mr_provider *pvd;
> +	ssize_t rc;
> +
> +	if (off != 0 || count != attr->size)
> +		return -EINVAL;
> +
> +	mr = (typeof(mr))attr->private;
> +	BUG_ON(mr->mr_size != attr->size);
> +
> +	pvd = _mr_to_provider(mr, kobj);
> +	rc = down_write_killable(&pvd->rwsem);
> +	if (rc)
> +		return rc;
> +
> +	if (mr->mr_flags & TSM_MR_F_X)
> +		rc = _call_extend(pvd, mr, page);
> +	else
> +		memcpy(mr->mr_value, page, count);
> +
> +	if (!rc)
> +		pvd->in_sync = false;
> +
> +	up_write(&pvd->rwsem);
> +	return rc ?: count;
> +}
> +
> +static void _mrdir_release(struct kobject *kobj)
> +{
> +	struct _mrdir *mrd;
> +	mrd = container_of(kobj, typeof(*mrd), kobj);
> +	pr_debug("%s(%s)\n", __func__, kobject_name(kobj));
> +	kfree(mrd);
> +}
> +
> +static struct kobj_type _mrdir_ktype = {
> +	.release = _mrdir_release,
> +	.sysfs_ops = &kobj_sysfs_ops,
> +};
> +
> +static struct _mrdir *_mrdir_create(const struct tsm_measurement_register *mr,
> +				    struct _mr_provider *pvd)
> +{
> +	struct _mrdir *mrd __free(kfree);
> +	int rc;
> +
> +	BUG_ON(mr->mr_flags & TSM_MR_F_F);
> +	mrd = kzalloc(sizeof(*mrd), GFP_KERNEL);
> +	if (!mrd)
> +		return ERR_PTR(-ENOMEM);
> +
> +	sysfs_bin_attr_init(&mrd->battrs[_MRDIR_BA_DIGEST]);
> +	mrd->battrs[_MRDIR_BA_DIGEST].attr.name = "digest";
> +	if (mr->mr_flags & TSM_MR_F_W)
> +		mrd->battrs[_MRDIR_BA_DIGEST].attr.mode |= S_IWUSR | S_IWGRP;
> +	if (mr->mr_flags & TSM_MR_F_R)
> +		mrd->battrs[_MRDIR_BA_DIGEST].attr.mode |= S_IRUGO;
> +
> +	mrd->battrs[_MRDIR_BA_DIGEST].size = mr->mr_size;
> +	mrd->battrs[_MRDIR_BA_DIGEST].read = _mr_read;
> +	mrd->battrs[_MRDIR_BA_DIGEST].write = _mr_write;
> +	mrd->battrs[_MRDIR_BA_DIGEST].private = (void *)mr;
> +
> +	mrd->kobj.kset = &pvd->kset;
> +	rc = kobject_init_and_add(&mrd->kobj, &_mrdir_ktype, NULL, "%s",
> +				  mr->mr_name);
> +	if (rc)
> +		return ERR_PTR(rc);
> +
> +	return_ptr(mrd);
> +}
> +
> +static void _mr_provider_release(struct kobject *kobj)
> +{
> +	struct _mr_provider *pvd;
> +	pvd = container_of(kobj, typeof(*pvd), kset.kobj);
> +	pr_debug("%s(%s)\n", __func__, kobject_name(kobj));
> +	BUG_ON(!list_empty(&pvd->kset.list));

Harsh. These days people do not like even WARN_ON :) None of these 
BUG_ONs seem bad enough to kill the system, dunno.

> +	kfree(pvd->mrfiles);
> +	kfree(pvd);
> +}
> +
> +static struct kobj_type _mr_provider_ktype = {
> +	.release = _mr_provider_release,
> +	.sysfs_ops = &kobj_sysfs_ops,
> +};
> +
> +static struct kset *_sysfs_tsm;
> +
> +static struct _mr_provider *_mr_provider_create(struct tsm_measurement *tmr)
> +{
> +	struct _mr_provider *pvd __free(kfree);
> +	int rc;
> +
> +	pvd = kzalloc(sizeof(*pvd), GFP_KERNEL);
> +	if (!pvd)
> +		return ERR_PTR(-ENOMEM);
> +
> +	if (!tmr->name || !tmr->mrs || !tmr->refresh || !tmr->extend)
> +		return ERR_PTR(-EINVAL);
> +
> +	rc = kobject_set_name(&pvd->kset.kobj, "%s", tmr->name);
> +	if (rc)
> +		return ERR_PTR(rc);
> +
> +	pvd->kset.kobj.kset = _sysfs_tsm;
> +	pvd->kset.kobj.ktype = &_mr_provider_ktype;
> +	pvd->tmr = tmr;
> +
> +	init_rwsem(&pvd->rwsem);
> +
> +	rc = kset_register(&pvd->kset);
> +	if (rc)
> +		return ERR_PTR(rc);
> +
> +	return_ptr(pvd);
> +}
> +
> +DEFINE_FREE(_unregister_measurement, struct _mr_provider *,
> +	    if (!IS_ERR_OR_NULL(_T)) tsm_unregister_measurement(_T->tmr));
> +
> +int tsm_register_measurement(struct tsm_measurement *tmr)
> +{
> +	static struct kobj_attribute _attr_hash = __ATTR_RO(hash_algo);
> +

Extra empty line not needed.

> +	struct _mr_provider *pvd __free(_unregister_measurement);
> +	int rc, nr;
> +
> +	pvd = _mr_provider_create(tmr);
> +	if (IS_ERR(pvd))
> +		return PTR_ERR(pvd);
> +
> +	nr = 0;
> +	for (int i = 0; tmr->mrs[i].mr_name; ++i) {
> +		// flat files are counted and skipped
> +		if (tmr->mrs[i].mr_flags & TSM_MR_F_F) {
> +			++nr;
> +			continue;
> +		}
> +
> +		struct _mrdir *mrd = _mrdir_create(&tmr->mrs[i], pvd);
> +		if (IS_ERR(mrd))
> +			return PTR_ERR(mrd);
> +
> +		struct attribute *attrs[] = {
> +			&_attr_hash.attr,
> +			NULL,
> +		};
> +		struct bin_attribute *battrs[_MRDIR_BA__COUNT + 1] = {};
> +		for (int j = 0; j < _MRDIR_BA__COUNT; ++j)
> +			battrs[j] = &mrd->battrs[j];

An empty line missing here.

> +		struct attribute_group agrp = {
> +			.attrs = attrs,
> +			.bin_attrs = battrs,
> +		};
> +		rc = sysfs_create_group(&mrd->kobj, &agrp);
> +		if (rc)
> +			return rc;
> +	}
> +
> +	if (nr > 0) {
> +		struct bin_attribute *mrfiles __free(kfree);
> +		struct bin_attribute **battrs __free(kfree);
> +
> +		mrfiles = kcalloc(sizeof(*mrfiles), nr, GFP_KERNEL);
> +		battrs = kcalloc(sizeof(*battrs), nr + 1, GFP_KERNEL);
> +		if (!battrs || !mrfiles)
> +			return -ENOMEM;
> +
> +		for (int i = 0, j = 0; tmr->mrs[i].mr_name; ++i) {
> +			if (!(tmr->mrs[i].mr_flags & TSM_MR_F_F))
> +				continue;
> +
> +			mrfiles[j].attr.name = tmr->mrs[i].mr_name;
> +			mrfiles[j].read = _mr_read;
> +			mrfiles[j].write = _mr_write;
> +			mrfiles[j].size = tmr->mrs[i].mr_size;
> +			mrfiles[j].private = (void *)&tmr->mrs[i];
> +			if (tmr->mrs[i].mr_flags & TSM_MR_F_R)
> +				mrfiles[j].attr.mode |= S_IRUGO;
> +			if (tmr->mrs[i].mr_flags & TSM_MR_F_W)
> +				mrfiles[j].attr.mode |= S_IWUSR | S_IWGRP;
> +
> +			battrs[j] = &mrfiles[j];
> +			++j;
> +
> +			BUG_ON(j > nr);
> +		}
> +
> +		struct attribute_group agrp = {
> +			.bin_attrs = battrs,
> +		};
> +		rc = sysfs_create_group(&pvd->kset.kobj, &agrp);
> +		if (rc)
> +			return rc;
> +
> +		pvd->mrfiles = no_free_ptr(mrfiles);
> +	}
> +
> +	pvd = NULL;

Is this needed for __free() machinery?


> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(tsm_register_measurement);
> +
> +static void _kset_put_children(struct kset *kset)
> +{
> +	struct kobject *p, *n;
> +	spin_lock(&kset->list_lock);
> +	list_for_each_entry_safe(p, n, &kset->list, entry) {
> +		spin_unlock(&kset->list_lock);
> +		kobject_put(p);
> +		spin_lock(&kset->list_lock);
> +	}
> +	spin_unlock(&kset->list_lock);
> +}
> +
> +int tsm_unregister_measurement(struct tsm_measurement *tmr)
> +{
> +	struct kobject *kobj = kset_find_obj(_sysfs_tsm, tmr->name);

Empty line missing. scripts/checkpatch.pl should have detected it. Thanks,

> +	if (!kobj)
> +		return -ENOENT;
> +
> +	struct _mr_provider *pvd = container_of(kobj, typeof(*pvd), kset.kobj);
> +	BUG_ON(pvd->tmr != tmr);
> +
> +	_kset_put_children(&pvd->kset);
> +	kset_unregister(&pvd->kset);
> +	kobject_put(kobj);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(tsm_unregister_measurement);
> +
> +int tsm_mr_init(void)
> +{
> +	_sysfs_tsm = kset_create_and_add("tsm", NULL, kernel_kobj);
> +	if (!_sysfs_tsm)
> +		return -ENOMEM;
> +	return 0;
> +}
> +
> +void tsm_mr_exit(void)
> +{
> +	kset_unregister(_sysfs_tsm);
> +}
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Provide Trusted Security Module measurements via sysfs");
> 

-- 
Alexey

On 11/3/2024 9:51 PM, Alexey Kardashevskiy wrote:
> On 1/11/24 03:50, Cedric Xing wrote:
>> diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm-core.c
>> similarity index 95%
>> rename from drivers/virt/coco/tsm.c
>> rename to drivers/virt/coco/tsm-core.c
>> index 9432d4e303f1..92e961f21507 100644
>> --- a/drivers/virt/coco/tsm.c
>> +++ b/drivers/virt/coco/tsm-core.c
>> @@ -1,8 +1,6 @@
>>   // SPDX-License-Identifier: GPL-2.0-only
>>   /* Copyright(c) 2023 Intel Corporation. All rights reserved. */
>> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> -
> 
> Why remove it?
> 
It's not used anywhere...

>>   #include <linux/tsm.h>
>>   #include <linux/err.h>
>>   #include <linux/slab.h>
>> @@ -166,8 +164,9 @@ static ssize_t 
>> tsm_report_service_guid_store(struct config_item *cfg,
>>   }
>>   CONFIGFS_ATTR_WO(tsm_report_, service_guid);
>> -static ssize_t tsm_report_service_manifest_version_store(struct 
>> config_item *cfg,
>> -                             const char *buf, size_t len)
>> +static ssize_t
>> +tsm_report_service_manifest_version_store(struct config_item *cfg,
>> +                      const char *buf, size_t len)
> 
> Unrelated change usually goes to a separate preparation patch, otherwise 
> too much noise.
> 
You are right. I'll capture all the "noise" in a single preparation commit.

>> -MODULE_DESCRIPTION("Provide Trusted Security Module attestation 
>> reports via configfs");
>> +MODULE_DESCRIPTION(
>> +    "Provide Trusted Security Module attestation reports via configfs");
> 
> 
> Seems unrelated.
> 
Are you suggesting an edit to the module description or simply 
complaining about unrelated changes in the same commit?

>> diff --git a/drivers/virt/coco/tsm-mr.c b/drivers/virt/coco/tsm-mr.c
>> new file mode 100644
>> index 000000000000..a84e923a7782
>> --- /dev/null
>> +++ b/drivers/virt/coco/tsm-mr.c
>> @@ -0,0 +1,374 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
>> +
>> +#include <linux/tsm.h>
>> +#include <linux/shmem_fs.h>
>> +#include <linux/ctype.h>
>> +#include <crypto/hash_info.h>
>> +#include <crypto/hash.h>
>> +
>> +int tsm_mr_init(void);
>> +void tsm_mr_exit(void);
> 
> These two should go to drivers/virt/coco/tsm-mr.h, along with 
> tsm_measurement_register and other TSM_MR_F_*.
> 
TSM_MR_F_* are part of the module interface and have been defined in 
include/linux/tsm.h

These 2 are internal functions called by the module entry/exit points 
only. Their prototypes appear here merely to avoid the compiler warning.

>> +
>> +enum _mrdir_bin_attr_index {
> 
> Why do so many things have "_" prefix in this file?
> 
All "_" prefixed symbols are file local. I should have used a more 
explicit prefix. I'll change this in the next revision.

>> +    _MRDIR_BA_DIGEST,
>> +    _MRDIR_BA__COUNT,
> 
> One underscore would do.
> 
Are you talking about the double "__" in _MRDIR_BA__COUNT? It isn't part 
of the enum logically, so I put an extra "_". A precedence is 
include/uapi/linux/hash_info.h:41 in the existing kernel source.

>> [...]
>> +static void _mr_provider_release(struct kobject *kobj)
>> +{
>> +    struct _mr_provider *pvd;
>> +    pvd = container_of(kobj, typeof(*pvd), kset.kobj);
>> +    pr_debug("%s(%s)\n", __func__, kobject_name(kobj));
>> +    BUG_ON(!list_empty(&pvd->kset.list));
> 
> Harsh. These days people do not like even WARN_ON :) None of these 
> BUG_ONs seem bad enough to kill the system, dunno.
> 
This BUG_ON has helped me catch kobject leaks in my code. I don't have 
problem removing it. But is there a guideline on what kinds of 
BUG_ON/WARN_ON should be kept/removed?

>> [...]
>> +int tsm_register_measurement(struct tsm_measurement *tmr)
>> +{
>> +    static struct kobj_attribute _attr_hash = __ATTR_RO(hash_algo);
>> +
> 
> Extra empty line not needed.
> 
>> [...]
>> +        for (int j = 0; j < _MRDIR_BA__COUNT; ++j)
>> +            battrs[j] = &mrd->battrs[j];
> 
> An empty line missing here.
> 
Thanks for pointing these out!

>> [...]
>> +    pvd = NULL;
> 
> Is this needed for __free() machinery?
> 
Yes. I should have put a comment here.

>> [...]
>> +    struct kobject *kobj = kset_find_obj(_sysfs_tsm, tmr->name);
> 
> Empty line missing. scripts/checkpatch.pl should have detected it. Thanks,
> 
Will run scripts/checkpatch.pl on the next revision before sending it out.

On 5/11/24 09:14, Xing, Cedric wrote:
> On 11/3/2024 9:51 PM, Alexey Kardashevskiy wrote:
>> On 1/11/24 03:50, Cedric Xing wrote:
>>> diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm-core.c
>>> similarity index 95%
>>> rename from drivers/virt/coco/tsm.c
>>> rename to drivers/virt/coco/tsm-core.c
>>> index 9432d4e303f1..92e961f21507 100644
>>> --- a/drivers/virt/coco/tsm.c
>>> +++ b/drivers/virt/coco/tsm-core.c
>>> @@ -1,8 +1,6 @@
>>>   // SPDX-License-Identifier: GPL-2.0-only
>>>   /* Copyright(c) 2023 Intel Corporation. All rights reserved. */
>>> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>> -
>>
>> Why remove it?
>>
> It's not used anywhere...
> 
>>>   #include <linux/tsm.h>
>>>   #include <linux/err.h>
>>>   #include <linux/slab.h>
>>> @@ -166,8 +164,9 @@ static ssize_t 
>>> tsm_report_service_guid_store(struct config_item *cfg,
>>>   }
>>>   CONFIGFS_ATTR_WO(tsm_report_, service_guid);
>>> -static ssize_t tsm_report_service_manifest_version_store(struct 
>>> config_item *cfg,
>>> -                             const char *buf, size_t len)
>>> +static ssize_t
>>> +tsm_report_service_manifest_version_store(struct config_item *cfg,
>>> +                      const char *buf, size_t len)
>>
>> Unrelated change usually goes to a separate preparation patch, 
>> otherwise too much noise.
>>
> You are right. I'll capture all the "noise" in a single preparation commit.


I am not even sure we want necessarily all of this changed, we can have 
100 char lines now.

> 
>>> -MODULE_DESCRIPTION("Provide Trusted Security Module attestation 
>>> reports via configfs");
>>> +MODULE_DESCRIPTION(
>>> +    "Provide Trusted Security Module attestation reports via 
>>> configfs");
>>
>>
>> Seems unrelated.
>>
> Are you suggesting an edit to the module description or simply 
> complaining about unrelated changes in the same commit?

The unrelated change complain.

> 
>>> diff --git a/drivers/virt/coco/tsm-mr.c b/drivers/virt/coco/tsm-mr.c
>>> new file mode 100644
>>> index 000000000000..a84e923a7782
>>> --- /dev/null
>>> +++ b/drivers/virt/coco/tsm-mr.c
>>> @@ -0,0 +1,374 @@
>>> +// SPDX-License-Identifier: GPL-2.0-only
>>> +/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
>>> +
>>> +#include <linux/tsm.h>
>>> +#include <linux/shmem_fs.h>
>>> +#include <linux/ctype.h>
>>> +#include <crypto/hash_info.h>
>>> +#include <crypto/hash.h>
>>> +
>>> +int tsm_mr_init(void);
>>> +void tsm_mr_exit(void);
>>
>> These two should go to drivers/virt/coco/tsm-mr.h, along with 
>> tsm_measurement_register and other TSM_MR_F_*.
>>
> TSM_MR_F_* are part of the module interface and have been defined in 
> include/linux/tsm.h
> 
> These 2 are internal functions called by the module entry/exit points 
> only. Their prototypes appear here merely to avoid the compiler warning.
> 
>>> +
>>> +enum _mrdir_bin_attr_index {
>>
>> Why do so many things have "_" prefix in this file?
>>
> All "_" prefixed symbols are file local. I should have used a more 
> explicit prefix. I'll change this in the next revision.

I do not think you need any prefix here (just mark those "static"), and 
"mr" is there already anyway, imho more than enough.


>>> +    _MRDIR_BA_DIGEST,
>>> +    _MRDIR_BA__COUNT,
>>
>> One underscore would do.
>>
> Are you talking about the double "__" in _MRDIR_BA__COUNT? It isn't part 
> of the enum logically, so I put an extra "_". A precedence is 
> include/uapi/linux/hash_info.h:41 in the existing kernel source.

okay :)

>>> [...]
>>> +static void _mr_provider_release(struct kobject *kobj)
>>> +{
>>> +    struct _mr_provider *pvd;
>>> +    pvd = container_of(kobj, typeof(*pvd), kset.kobj);
>>> +    pr_debug("%s(%s)\n", __func__, kobject_name(kobj));
>>> +    BUG_ON(!list_empty(&pvd->kset.list));
>>
>> Harsh. These days people do not like even WARN_ON :) None of these 
>> BUG_ONs seem bad enough to kill the system, dunno.
>>
> This BUG_ON has helped me catch kobject leaks in my code. I don't have 
> problem removing it. But is there a guideline on what kinds of 
> BUG_ON/WARN_ON should be kept/removed?

Sounds like only hardware faults are okay-ish to be guarded with BUG_ON.

https://www.kernel.org/doc/html/latest/process/deprecated.html#bug-and-bug-on

WARN_ON is considered as bad as many use panic_on_oops. Thanks,


>>> [...]
>>> +int tsm_register_measurement(struct tsm_measurement *tmr)
>>> +{
>>> +    static struct kobj_attribute _attr_hash = __ATTR_RO(hash_algo);
>>> +
>>
>> Extra empty line not needed.
>>
>>> [...]
>>> +        for (int j = 0; j < _MRDIR_BA__COUNT; ++j)
>>> +            battrs[j] = &mrd->battrs[j];
>>
>> An empty line missing here.
>>
> Thanks for pointing these out!
> 
>>> [...]
>>> +    pvd = NULL;
>>
>> Is this needed for __free() machinery?
>>
> Yes. I should have put a comment here.
> 
>>> [...]
>>> +    struct kobject *kobj = kset_find_obj(_sysfs_tsm, tmr->name);
>>
>> Empty line missing. scripts/checkpatch.pl should have detected it. 
>> Thanks,
>>
> Will run scripts/checkpatch.pl on the next revision before sending it out.

-- 
Alexey

On Mon, 2024-11-04 at 16:14 -0600, Xing, Cedric wrote:
> On 11/3/2024 9:51 PM, Alexey Kardashevskiy wrote:
> > On 1/11/24 03:50, Cedric Xing wrote:
> > > diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm-
> > > core.c
> > > similarity index 95%
> > > rename from drivers/virt/coco/tsm.c
> > > rename to drivers/virt/coco/tsm-core.c
> > > index 9432d4e303f1..92e961f21507 100644
> > > --- a/drivers/virt/coco/tsm.c
> > > +++ b/drivers/virt/coco/tsm-core.c
> > > @@ -1,8 +1,6 @@
> > >   // SPDX-License-Identifier: GPL-2.0-only
> > >   /* Copyright(c) 2023 Intel Corporation. All rights reserved. */
> > > -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > > -
> > 
> > Why remove it?
> > 
> It's not used anywhere...

Yes, it is; it's used in this line, which the patch doesn't appear to
remove:

int tsm_register(const struct tsm_ops *ops, void *priv)
{
	const struct tsm_ops *conflict;

	guard(rwsem_write)(&tsm_rwsem);
	conflict = provider.ops;
	if (conflict) {
		pr_err("\"%s\" ops already registered\n", conflict->name);
                ^^^^^^^

James

                

On 11/4/2024 4:22 PM, James Bottomley wrote:
> On Mon, 2024-11-04 at 16:14 -0600, Xing, Cedric wrote:
>> On 11/3/2024 9:51 PM, Alexey Kardashevskiy wrote:
>>> On 1/11/24 03:50, Cedric Xing wrote:
>>>> diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm-
>>>> core.c
>>>> similarity index 95%
>>>> rename from drivers/virt/coco/tsm.c
>>>> rename to drivers/virt/coco/tsm-core.c
>>>> index 9432d4e303f1..92e961f21507 100644
>>>> --- a/drivers/virt/coco/tsm.c
>>>> +++ b/drivers/virt/coco/tsm-core.c
>>>> @@ -1,8 +1,6 @@
>>>>    // SPDX-License-Identifier: GPL-2.0-only
>>>>    /* Copyright(c) 2023 Intel Corporation. All rights reserved. */
>>>> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>>> -
>>>
>>> Why remove it?
>>>
>> It's not used anywhere...
> 
> Yes, it is; it's used in this line, which the patch doesn't appear to
> remove:
> 
> int tsm_register(const struct tsm_ops *ops, void *priv)
> {
> 	const struct tsm_ops *conflict;
> 
> 	guard(rwsem_write)(&tsm_rwsem);
> 	conflict = provider.ops;
> 	if (conflict) {
> 		pr_err("\"%s\" ops already registered\n", conflict->name);
>                  ^^^^^^^
Now I remember. I had been seeing the module name somehow got printed 
twice in the log, so I removed it. Probably something wrong with my 
build env. I'll add that back. Thanks for pointing this out!