Messages in this thread | | | Date | Tue, 9 Apr 2024 11:12:52 -0700 | Subject | Re: [PATCH v3 13/14] x86/sev: Hide SVSM attestation entries if not running under an SVSM | From | Kuppuswamy Sathyanarayanan <> |
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On 3/25/24 3:26 PM, Tom Lendacky wrote: > Config-fs provides support to hide individual attribute entries. Using > this support, base the display of the SVSM related entries on the presence > of an SVSM. > > Cc: Joel Becker <jlbec@evilplan.org> > Cc: Christoph Hellwig <hch@lst.de> > Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> > --- > arch/x86/coco/core.c | 4 ++++ > drivers/virt/coco/tsm.c | 14 ++++++++++---- > include/linux/cc_platform.h | 8 ++++++++ > 3 files changed, 22 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c > index d07be9d05cd0..efa0f648f754 100644 > --- a/arch/x86/coco/core.c > +++ b/arch/x86/coco/core.c > @@ -12,6 +12,7 @@ > > #include <asm/coco.h> > #include <asm/processor.h> > +#include <asm/sev.h> > > enum cc_vendor cc_vendor __ro_after_init = CC_VENDOR_NONE; > u64 cc_mask __ro_after_init; > @@ -78,6 +79,9 @@ static bool noinstr amd_cc_platform_has(enum cc_attr attr) > case CC_ATTR_GUEST_STATE_ENCRYPT: > return sev_status & MSR_AMD64_SEV_ES_ENABLED; > > + case CC_ATTR_GUEST_SVSM_PRESENT: > + return snp_get_vmpl(); > + > /* > * With SEV, the rep string I/O instructions need to be unrolled > * but SEV-ES supports them through the #VC handler. > diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm.c > index 46f230bf13ac..d30471874e87 100644 > --- a/drivers/virt/coco/tsm.c > +++ b/drivers/virt/coco/tsm.c > @@ -64,6 +64,12 @@ static struct tsm_report_state *to_state(struct tsm_report *report) > return container_of(report, struct tsm_report_state, report); > } > > +static bool provider_visibility(const struct config_item *item, > + const struct configfs_attribute *attr) > +{ > + return cc_platform_has(CC_ATTR_GUEST_SVSM_PRESENT); > +} > +
Any comment about the following query? I think introducing a CC flag for this use case is over kill.
https://lore.kernel.org/lkml/6b90b223-46e0-4e6d-a17c-5caf72e3c949@linux.intel.com/
> static int try_advance_write_generation(struct tsm_report *report) > { > struct tsm_report_state *state = to_state(report); > @@ -144,7 +150,7 @@ static ssize_t tsm_report_service_provider_store(struct config_item *cfg, > > return len; > } > -CONFIGFS_ATTR_WO(tsm_report_, service_provider); > +CONFIGFS_ATTR_VISIBLE_WO(tsm_report_, service_provider, provider_visibility); > > static ssize_t tsm_report_service_guid_store(struct config_item *cfg, > const char *buf, size_t len) > @@ -165,7 +171,7 @@ static ssize_t tsm_report_service_guid_store(struct config_item *cfg, > > return len; > } > -CONFIGFS_ATTR_WO(tsm_report_, service_guid); > +CONFIGFS_ATTR_VISIBLE_WO(tsm_report_, service_guid, provider_visibility); > > static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg, > const char *buf, size_t len) > @@ -186,7 +192,7 @@ static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg > > return len; > } > -CONFIGFS_ATTR_WO(tsm_report_, service_manifest_version); > +CONFIGFS_ATTR_VISIBLE_WO(tsm_report_, service_manifest_version, provider_visibility); > > static ssize_t tsm_report_inblob_write(struct config_item *cfg, > const void *buf, size_t count) > @@ -333,7 +339,7 @@ static ssize_t tsm_report_manifestblob_read(struct config_item *cfg, void *buf, > > return tsm_report_read(report, buf, count, TSM_MANIFEST); > } > -CONFIGFS_BIN_ATTR_RO(tsm_report_, manifestblob, NULL, TSM_OUTBLOB_MAX); > +CONFIGFS_BIN_ATTR_VISIBLE_RO(tsm_report_, manifestblob, NULL, TSM_OUTBLOB_MAX, provider_visibility); > > #define TSM_DEFAULT_ATTRS() \ > &tsm_report_attr_generation, \ > diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h > index cb0d6cd1c12f..f1b4266c1484 100644 > --- a/include/linux/cc_platform.h > +++ b/include/linux/cc_platform.h > @@ -90,6 +90,14 @@ enum cc_attr { > * Examples include TDX Guest. > */ > CC_ATTR_HOTPLUG_DISABLED, > + > + /** > + * @CC_ATTR_GUEST_SVSM_PRESENT: Guest is running under an SVSM > + * > + * The platform/OS is running as a guest/virtual machine and is > + * running under a Secure VM Service Module (SVSM). > + */ > + CC_ATTR_GUEST_SVSM_PRESENT, > }; > > #ifdef CONFIG_ARCH_HAS_CC_PLATFORM
-- Sathyanarayanan Kuppuswamy Linux Kernel Developer
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