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    SubjectRe: [PATCH v4 13/15] x86/sev: Take advantage of configfs visibility support in TSM
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    On 4/24/24 8:58 AM, Tom Lendacky wrote:
    > The TSM attestation report support provides multiple configfs attribute
    > types (both for standard and binary attributes) to allow for additional
    > attributes to be displayed for SNP as compared to TDX. With the ability
    > to hide attributes via configfs, consoldate the multiple attribute groups
    > into a single standard attribute group and a single binary attribute
    > group. Modify the TDX support to hide the attributes that were previously
    > "hidden" as a result of registering the selective attribute groups.
    >
    > Co-developed-by: Dan Williams <dan.j.williams@intel.com>
    > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
    > Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
    > ---


    Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

    > drivers/virt/coco/sev-guest/sev-guest.c | 3 +-
    > drivers/virt/coco/tdx-guest/tdx-guest.c | 29 ++++++++-
    > drivers/virt/coco/tsm.c | 82 ++++++++++++-------------
    > include/linux/tsm.h | 41 ++++++++++---
    > 4 files changed, 102 insertions(+), 53 deletions(-)
    >
    > diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
    > index 2abb51bd034f..ec3d894cfe31 100644
    > --- a/drivers/virt/coco/sev-guest/sev-guest.c
    > +++ b/drivers/virt/coco/sev-guest/sev-guest.c
    > @@ -23,6 +23,7 @@
    > #include <linux/sockptr.h>
    > #include <linux/cleanup.h>
    > #include <linux/uuid.h>
    > +#include <linux/configfs.h>
    > #include <uapi/linux/sev-guest.h>
    > #include <uapi/linux/psp-sev.h>
    >
    > @@ -975,7 +976,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
    > /* Set the privlevel_floor attribute based on the vmpck_id */
    > sev_tsm_ops.privlevel_floor = vmpck_id;
    >
    > - 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..964af57f345c 100644
    > --- a/drivers/virt/coco/tdx-guest/tdx-guest.c
    > +++ b/drivers/virt/coco/tdx-guest/tdx-guest.c
    > @@ -17,6 +17,7 @@
    > #include <linux/delay.h>
    > #include <linux/tsm.h>
    > #include <linux/sizes.h>
    > +#include <linux/configfs.h>
    >
    > #include <uapi/linux/tdx-guest.h>
    >
    > @@ -249,6 +250,30 @@ static int tdx_report_new(struct tsm_report *report, void *data)
    > return ret;
    > }
    >
    > +static bool tdx_report_attr_visible(struct config_item *item,
    > + struct configfs_attribute *attr, int n)
    > +{
    > + switch (n) {
    > + case TSM_REPORT_GENERATION:
    > + case TSM_REPORT_PROVIDER:
    > + return true;
    > + }
    > +
    > + return false;
    > +}
    > +
    > +static bool tdx_report_bin_attr_visible(struct config_item *item,
    > + struct configfs_bin_attribute *attr, int n)
    > +{
    > + switch (n) {
    > + case TSM_REPORT_INBLOB:
    > + case TSM_REPORT_OUTBLOB:
    > + return true;
    > + }
    > +
    > + return false;
    > +}
    > +
    > static long tdx_guest_ioctl(struct file *file, unsigned int cmd,
    > unsigned long arg)
    > {
    > @@ -281,6 +306,8 @@ MODULE_DEVICE_TABLE(x86cpu, tdx_guest_ids);
    > static const struct tsm_ops tdx_tsm_ops = {
    > .name = KBUILD_MODNAME,
    > .report_new = tdx_report_new,
    > + .report_attr_visible = tdx_report_attr_visible,
    > + .report_bin_attr_visible = tdx_report_bin_attr_visible,
    > };
    >
    > static int __init tdx_guest_init(void)
    > @@ -301,7 +328,7 @@ 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..dedb4f582630 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(),
    > + [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,
    > };
    >
    > -static struct configfs_attribute *tsm_report_extra_attrs[] = {
    > - TSM_DEFAULT_ATTRS(),
    > - &tsm_report_attr_privlevel,
    > - &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 +300,40 @@ 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_is_visible(struct config_item *item,
    > + struct configfs_attribute *attr, int n)
    > +{
    > + guard(rwsem_read)(&tsm_rwsem);
    > + if (!provider.ops)
    > + return false;
    > +
    > + if (!provider.ops->report_attr_visible)
    > + return true;
    > +
    > + return provider.ops->report_attr_visible(item, attr, n);
    > +}
    > +
    > +static bool tsm_report_is_bin_visible(struct config_item *item,
    > + struct configfs_bin_attribute *attr, int n)
    > +{
    > + guard(rwsem_read)(&tsm_rwsem);
    > + if (!provider.ops)
    > + return false;
    > +
    > + if (!provider.ops->report_bin_attr_visible)
    > + return true;
    > +
    > + return provider.ops->report_bin_attr_visible(item, attr, n);
    > +}
    > +
    > static struct configfs_group_operations tsm_report_group_ops = {
    > .make_item = tsm_report_make_item,
    > + .is_visible = tsm_report_is_visible,
    > + .is_bin_visible = tsm_report_is_bin_visible,
    > };
    >
    > static const struct config_item_type tsm_reports_type = {
    > @@ -353,16 +355,10 @@ 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 +368,6 @@ 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 +379,6 @@ 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/include/linux/tsm.h b/include/linux/tsm.h
    > index 50c5769657d8..fa19291a9854 100644
    > --- a/include/linux/tsm.h
    > +++ b/include/linux/tsm.h
    > @@ -4,6 +4,7 @@
    >
    > #include <linux/sizes.h>
    > #include <linux/types.h>
    > +#include <linux/configfs.h>
    >
    > #define TSM_INBLOB_MAX 64
    > #define TSM_OUTBLOB_MAX SZ_32K
    > @@ -42,12 +43,40 @@ struct tsm_report {
    > u8 *auxblob;
    > };
    >
    > +/**
    > + * enum tsm_attr_index - index used to reference report attributes
    > + * @TSM_REPORT_GENERATION: index of the report generation number attribute
    > + * @TSM_REPORT_PROVIDER: index of the provider name attribute
    > + * @TSM_REPORT_PRIVLEVEL: index of the desired privilege level attribute
    > + * @TSM_REPORT_PRIVLEVEL_FLOOR: index of the minimum allowed privileg level attribute
    > + */
    > +enum tsm_attr_index {
    > + TSM_REPORT_GENERATION,
    > + TSM_REPORT_PROVIDER,
    > + TSM_REPORT_PRIVLEVEL,
    > + TSM_REPORT_PRIVLEVEL_FLOOR,
    > +};
    > +
    > +/**
    > + * enum tsm_bin_attr_index - index used to reference binary report attributes
    > + * @TSM_REPORT_INBLOB: index of the binary report input attribute
    > + * @TSM_REPORT_OUTBLOB: index of the binary report output attribute
    > + * @TSM_REPORT_AUXBLOB: index of the binary auxiliary data attribute
    > + */
    > +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
    > * @privlevel_floor: convey base privlevel for nested scenarios
    > * @report_new: Populate @report with the report blob and auxblob
    > * (optional), return 0 on successful population, or -errno otherwise
    > + * @report_attr_visible: show or hide a report attribute entry
    > + * @report_bin_attr_visible: show or hide a report binary attribute entry
    > *
    > * Implementation specific ops, only one is expected to be registered at
    > * a time i.e. only one of "sev-guest", "tdx-guest", etc.
    > @@ -56,14 +85,12 @@ struct tsm_ops {
    > const char *name;
    > unsigned int privlevel_floor;
    > int (*report_new)(struct tsm_report *report, void *data);
    > + bool (*report_attr_visible)(struct config_item *item,
    > + struct configfs_attribute *attr, int n);
    > + bool (*report_bin_attr_visible)(struct config_item *item,
    > + struct configfs_bin_attribute *attr, int n);
    > };
    >
    > -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 */

    --
    Sathyanarayanan Kuppuswamy
    Linux Kernel Developer


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