Messages in this thread | | | Date | Fri, 12 Apr 2024 10:52:40 -0500 | Subject | Re: [PATCH v3 13/14] x86/sev: Hide SVSM attestation entries if not running under an SVSM | From | Tom Lendacky <> |
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On 4/9/24 13:12, Kuppuswamy Sathyanarayanan wrote: > > 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/
If you don't think TDX will be able to make use of the SVSM attribute I can look at adding a callback. But I was waiting to see if anyone else had comments, for or against, before re-doing it all.
Thanks, Tom
> >> 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 >
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