Messages in this thread Patch in this message | | | Date | Tue, 16 Apr 2024 11:25:26 -0700 | From | Dan Williams <> | Subject | Re: [PATCH v3 12/14] fs/configfs: Add a callback to determine attribute visibility |
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Tom Lendacky wrote: > On 4/16/24 00:46, Dan Williams wrote: > > Tom Lendacky wrote: > >> In order to support dynamic decisions as to whether an attribute should be > >> created, add a callback that returns a bool to indicate whether the > >> attribute should be display. If no callback is registered, the attribute [..] > >> Cc: Joel Becker <jlbec@evilplan.org> > >> Cc: Christoph Hellwig <hch@lst.de> > >> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> > >> --- > >> fs/configfs/file.c | 7 +++ > >> include/linux/configfs.h | 111 +++++++++++++++++++++++++++------------ > >> 2 files changed, 84 insertions(+), 34 deletions(-) > >> [..] > >> diff --git a/include/linux/configfs.h b/include/linux/configfs.h > >> index 2606711adb18..c836d7bc7c9e 100644 > >> --- a/include/linux/configfs.h > >> +++ b/include/linux/configfs.h > >> @@ -116,35 +116,57 @@ struct configfs_attribute { > >> const char *ca_name; > >> struct module *ca_owner; > >> umode_t ca_mode; > >> + bool (*is_visible)(const struct config_item *, const struct configfs_attribute *); > >> ssize_t (*show)(struct config_item *, char *); > >> ssize_t (*store)(struct config_item *, const char *, size_t); > >> }; > >> > >> -#define CONFIGFS_ATTR(_pfx, _name) \ > >> +#define __CONFIGFS_ATTR(_pfx, _name, _vis) \ > >> static struct configfs_attribute _pfx##attr_##_name = { \ > >> .ca_name = __stringify(_name), \ > >> .ca_mode = S_IRUGO | S_IWUSR, \ > >> .ca_owner = THIS_MODULE, \ > >> + .is_visible = _vis, \ > >> .show = _pfx##_name##_show, \ > >> .store = _pfx##_name##_store, \ > > > > Shouldn't this operation live in configfs_group_operations? That would > > mirror the sysfs organization, and likely saves some memory. > > I suppose it can, but then you lose the grouping of attributes within > the same directory, right? A configfs group will result in moving the > entries into a subdirectory, right? If we go with the group level, then > we will be moving the existing TSM extra attributes and the new TSM SVSM > attributes into new, separate sub-directories.
I am not following the concern about "losing the grouping"? Here is what I was thinking with having the visibility routines in group operations. This is just the broard strokes, it compiles, but still needs the finer detail work to make tdx-guest skip all the attributes that do not apply to it. Might need to be broken up a bit more, but hopefully conveys the idea. Does this address your grouping concern?
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 87f241825bc3..39b8455f0ba5 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -968,7 +968,7 @@ static int __init sev_guest_probe(struct platform_device *pdev) snp_dev->input.resp_gpa = __pa(snp_dev->response); snp_dev->input.data_gpa = __pa(snp_dev->certs_data); - ret = tsm_register(&sev_tsm_ops, snp_dev, &tsm_report_extra_type); + ret = tsm_register(&sev_tsm_ops, snp_dev); if (ret) goto e_free_cert_data; diff --git a/drivers/virt/coco/tdx-guest/tdx-guest.c b/drivers/virt/coco/tdx-guest/tdx-guest.c index 1253bf76b570..654d20ea524a 100644 --- a/drivers/virt/coco/tdx-guest/tdx-guest.c +++ b/drivers/virt/coco/tdx-guest/tdx-guest.c @@ -301,7 +301,7 @@ static int __init tdx_guest_init(void) goto free_misc; } - ret = tsm_register(&tdx_tsm_ops, NULL, NULL); + ret = tsm_register(&tdx_tsm_ops, NULL); if (ret) goto free_quote; diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm.c index d1c2db83a8ca..b31be0e61728 100644 --- a/drivers/virt/coco/tsm.c +++ b/drivers/virt/coco/tsm.c @@ -14,7 +14,6 @@ static struct tsm_provider { const struct tsm_ops *ops; - const struct config_item_type *type; void *data; } provider; static DECLARE_RWSEM(tsm_rwsem); @@ -252,34 +251,18 @@ static ssize_t tsm_report_auxblob_read(struct config_item *cfg, void *buf, } CONFIGFS_BIN_ATTR_RO(tsm_report_, auxblob, NULL, TSM_OUTBLOB_MAX); -#define TSM_DEFAULT_ATTRS() \ - &tsm_report_attr_generation, \ - &tsm_report_attr_provider - static struct configfs_attribute *tsm_report_attrs[] = { - TSM_DEFAULT_ATTRS(), - NULL, -}; - -static struct configfs_attribute *tsm_report_extra_attrs[] = { - TSM_DEFAULT_ATTRS(), - &tsm_report_attr_privlevel, - &tsm_report_attr_privlevel_floor, + [TSM_REPORT_GENERATION] = &tsm_report_attr_generation, + [TSM_REPORT_PROVIDER] = &tsm_report_attr_provider, + [TSM_REPORT_PRIVLEVEL] = &tsm_report_attr_privlevel, + [TSM_REPORT_PRIVLEVEL_FLOOR] = &tsm_report_attr_privlevel_floor, NULL, }; -#define TSM_DEFAULT_BIN_ATTRS() \ - &tsm_report_attr_inblob, \ - &tsm_report_attr_outblob - static struct configfs_bin_attribute *tsm_report_bin_attrs[] = { - TSM_DEFAULT_BIN_ATTRS(), - NULL, -}; - -static struct configfs_bin_attribute *tsm_report_bin_extra_attrs[] = { - TSM_DEFAULT_BIN_ATTRS(), - &tsm_report_attr_auxblob, + [TSM_REPORT_INBLOB] = &tsm_report_attr_inblob, + [TSM_REPORT_OUTBLOB] = &tsm_report_attr_outblob, + [TSM_REPORT_AUXBLOB] = &tsm_report_attr_auxblob, NULL, }; @@ -297,21 +280,12 @@ static struct configfs_item_operations tsm_report_item_ops = { .release = tsm_report_item_release, }; -const struct config_item_type tsm_report_default_type = { +static const struct config_item_type tsm_report_type = { .ct_owner = THIS_MODULE, .ct_bin_attrs = tsm_report_bin_attrs, .ct_attrs = tsm_report_attrs, .ct_item_ops = &tsm_report_item_ops, }; -EXPORT_SYMBOL_GPL(tsm_report_default_type); - -const struct config_item_type tsm_report_extra_type = { - .ct_owner = THIS_MODULE, - .ct_bin_attrs = tsm_report_bin_extra_attrs, - .ct_attrs = tsm_report_extra_attrs, - .ct_item_ops = &tsm_report_item_ops, -}; -EXPORT_SYMBOL_GPL(tsm_report_extra_type); static struct config_item *tsm_report_make_item(struct config_group *group, const char *name) @@ -326,12 +300,38 @@ static struct config_item *tsm_report_make_item(struct config_group *group, if (!state) return ERR_PTR(-ENOMEM); - config_item_init_type_name(&state->cfg, name, provider.type); + config_item_init_type_name(&state->cfg, name, &tsm_report_type); return &state->cfg; } +static bool tsm_report_attr_visible(struct configfs_attribute *attr, int n) +{ + guard(rwsem_read)(&tsm_rwsem); + if (!provider.ops) + return false; + + if (!provider.ops->is_visible) + return true; + + return provider.ops->is_visible(n); +} + +static bool tsm_report_bin_attr_visible(struct configfs_bin_attribute *attr, + int n) +{ + if (!provider.ops) + return false; + + if (!provider.ops->is_bin_visible) + return true; + + return provider.ops->is_bin_visible(n); +} + static struct configfs_group_operations tsm_report_group_ops = { .make_item = tsm_report_make_item, + .is_visible = tsm_report_attr_visible, + .is_bin_visible = tsm_report_bin_attr_visible, }; static const struct config_item_type tsm_reports_type = { @@ -353,16 +353,10 @@ static struct configfs_subsystem tsm_configfs = { .su_mutex = __MUTEX_INITIALIZER(tsm_configfs.su_mutex), }; -int tsm_register(const struct tsm_ops *ops, void *priv, - const struct config_item_type *type) +int tsm_register(const struct tsm_ops *ops, void *priv) { const struct tsm_ops *conflict; - if (!type) - type = &tsm_report_default_type; - if (!(type == &tsm_report_default_type || type == &tsm_report_extra_type)) - return -EINVAL; - guard(rwsem_write)(&tsm_rwsem); conflict = provider.ops; if (conflict) { @@ -372,7 +366,6 @@ int tsm_register(const struct tsm_ops *ops, void *priv, provider.ops = ops; provider.data = priv; - provider.type = type; return 0; } EXPORT_SYMBOL_GPL(tsm_register); @@ -384,7 +377,6 @@ int tsm_unregister(const struct tsm_ops *ops) return -EBUSY; provider.ops = NULL; provider.data = NULL; - provider.type = NULL; return 0; } EXPORT_SYMBOL_GPL(tsm_unregister); diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 18677cd4e62f..213e88f4cec2 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -580,6 +580,7 @@ static void detach_attrs(struct config_item * item) static int populate_attrs(struct config_item *item) { const struct config_item_type *t = item->ci_type; + struct configfs_group_operations *ops = t->ct_group_ops; struct configfs_attribute *attr; struct configfs_bin_attribute *bin_attr; int error = 0; @@ -589,12 +590,17 @@ static int populate_attrs(struct config_item *item) return -EINVAL; if (t->ct_attrs) { for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { + if (ops && ops->is_visible && !ops->is_visible(attr, i)) + continue; if ((error = configfs_create_file(item, attr))) break; } } if (t->ct_bin_attrs) { for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) { + if (ops && ops->is_bin_visible && + !ops->is_bin_visible(bin_attr, i)) + continue; error = configfs_create_bin_file(item, bin_attr); if (error) break; diff --git a/fs/configfs/file.c b/fs/configfs/file.c index 0ad32150611e..356d23b6b9cf 100644 --- a/fs/configfs/file.c +++ b/fs/configfs/file.c @@ -444,7 +444,8 @@ const struct file_operations configfs_bin_file_operations = { * @attr: atrribute descriptor. */ -int configfs_create_file(struct config_item * item, const struct configfs_attribute * attr) +int configfs_create_file(struct config_item *item, + const struct configfs_attribute *attr) { struct dentry *dir = item->ci_dentry; struct configfs_dirent *parent_sd = dir->d_fsdata; diff --git a/include/linux/configfs.h b/include/linux/configfs.h index 2606711adb18..31553f12db7c 100644 --- a/include/linux/configfs.h +++ b/include/linux/configfs.h @@ -216,6 +216,8 @@ struct configfs_group_operations { struct config_group *(*make_group)(struct config_group *group, const char *name); void (*disconnect_notify)(struct config_group *group, struct config_item *item); void (*drop_item)(struct config_group *group, struct config_item *item); + bool (*is_visible)(struct configfs_attribute *attr, int n); + bool (*is_bin_visible)(struct configfs_bin_attribute *attr, int n); }; struct configfs_subsystem { diff --git a/include/linux/tsm.h b/include/linux/tsm.h index de8324a2223c..a45b12943223 100644 --- a/include/linux/tsm.h +++ b/include/linux/tsm.h @@ -42,6 +42,19 @@ struct tsm_report { u8 *auxblob; }; +enum tsm_attr_index { + TSM_REPORT_GENERATION, + TSM_REPORT_PROVIDER, + TSM_REPORT_PRIVLEVEL, + TSM_REPORT_PRIVLEVEL_FLOOR, +}; + +enum tsm_bin_attr_index { + TSM_REPORT_INBLOB, + TSM_REPORT_OUTBLOB, + TSM_REPORT_AUXBLOB, +}; + /** * struct tsm_ops - attributes and operations for tsm instances * @name: tsm id reflected in /sys/kernel/config/tsm/report/$report/provider @@ -55,15 +68,11 @@ struct tsm_report { struct tsm_ops { const char *name; const unsigned int privlevel_floor; + bool (*is_visible)(enum tsm_attr_index index); + bool (*is_bin_visible)(enum tsm_bin_attr_index index); int (*report_new)(struct tsm_report *report, void *data); }; -extern const struct config_item_type tsm_report_default_type; - -/* publish @privlevel, @privlevel_floor, and @auxblob attributes */ -extern const struct config_item_type tsm_report_extra_type; - -int tsm_register(const struct tsm_ops *ops, void *priv, - const struct config_item_type *type); +int tsm_register(const struct tsm_ops *ops, void *priv); int tsm_unregister(const struct tsm_ops *ops); #endif /* __TSM_H */
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