target/i386/sev: add support to query the attestation report

The SEV FW >= 0.23 added a new command that can be used to query the
attestation report containing the SHA-256 digest of the guest memory
and VMSA encrypted with the LAUNCH_UPDATE and sign it with the PEK.

Note, we already have a command (LAUNCH_MEASURE) that can be used to
query the SHA-256 digest of the guest memory encrypted through the
LAUNCH_UPDATE. The main difference between previous and this command
is that the report is signed with the PEK and unlike the LAUNCH_MEASURE
command the ATTESATION_REPORT command can be called while the guest
is running.

Add a QMP interface "query-sev-attestation-report" that can be used
to get the report encoded in base64.

Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Tom Lendacky <Thomas.Lendacky@amd.com>
Cc: Eric Blake <eblake@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Reviewed-by: James Bottomley <jejb@linux.ibm.com>
Tested-by: James Bottomley <jejb@linux.ibm.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
Message-Id: <20210429170728.24322-1-brijesh.singh@amd.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
This commit is contained in:
Brijesh Singh 2021-04-29 12:07:28 -05:00 committed by Eduardo Habkost
parent 5aa9ef5e4b
commit 3ea1a80243
7 changed files with 129 additions and 0 deletions

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@ -1591,6 +1591,8 @@ enum sev_cmd_id {
KVM_SEV_DBG_ENCRYPT, KVM_SEV_DBG_ENCRYPT,
/* Guest certificates commands */ /* Guest certificates commands */
KVM_SEV_CERT_EXPORT, KVM_SEV_CERT_EXPORT,
/* Attestation report */
KVM_SEV_GET_ATTESTATION_REPORT,
KVM_SEV_NR_MAX, KVM_SEV_NR_MAX,
}; };
@ -1643,6 +1645,12 @@ struct kvm_sev_dbg {
__u32 len; __u32 len;
}; };
struct kvm_sev_attestation_report {
__u8 mnonce[16];
__u64 uaddr;
__u32 len;
};
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
#define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)
#define KVM_DEV_ASSIGN_MASK_INTX (1 << 2) #define KVM_DEV_ASSIGN_MASK_INTX (1 << 2)

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@ -285,3 +285,41 @@
## ##
{ 'command': 'query-gic-capabilities', 'returns': ['GICCapability'], { 'command': 'query-gic-capabilities', 'returns': ['GICCapability'],
'if': 'defined(TARGET_ARM)' } 'if': 'defined(TARGET_ARM)' }
##
# @SevAttestationReport:
#
# The struct describes attestation report for a Secure Encrypted Virtualization
# feature.
#
# @data: guest attestation report (base64 encoded)
#
#
# Since: 6.1
##
{ 'struct': 'SevAttestationReport',
'data': { 'data': 'str'},
'if': 'defined(TARGET_I386)' }
##
# @query-sev-attestation-report:
#
# This command is used to get the SEV attestation report, and is supported on AMD
# X86 platforms only.
#
# @mnonce: a random 16 bytes value encoded in base64 (it will be included in report)
#
# Returns: SevAttestationReport objects.
#
# Since: 6.1
#
# Example:
#
# -> { "execute" : "query-sev-attestation-report", "arguments": { "mnonce": "aaaaaaa" } }
# <- { "return" : { "data": "aaaaaaaabbbddddd"} }
#
##
{ 'command': 'query-sev-attestation-report', 'data': { 'mnonce': 'str' },
'returns': 'SevAttestationReport',
'if': 'defined(TARGET_I386)' }

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@ -757,3 +757,9 @@ void qmp_sev_inject_launch_secret(const char *packet_hdr,
sev_inject_launch_secret(packet_hdr, secret, gpa, errp); sev_inject_launch_secret(packet_hdr, secret, gpa, errp);
} }
SevAttestationReport *
qmp_query_sev_attestation_report(const char *mnonce, Error **errp)
{
return sev_get_attestation_report(mnonce, errp);
}

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@ -74,3 +74,10 @@ int sev_es_save_reset_vector(void *flash_ptr, uint64_t flash_size)
{ {
abort(); abort();
} }
SevAttestationReport *
sev_get_attestation_report(const char *mnonce, Error **errp)
{
error_setg(errp, "SEV is not available in this QEMU");
return NULL;
}

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@ -492,6 +492,73 @@ out:
return cap; return cap;
} }
SevAttestationReport *
sev_get_attestation_report(const char *mnonce, Error **errp)
{
struct kvm_sev_attestation_report input = {};
SevAttestationReport *report = NULL;
SevGuestState *sev = sev_guest;
guchar *data;
guchar *buf;
gsize len;
int err = 0, ret;
if (!sev_enabled()) {
error_setg(errp, "SEV is not enabled");
return NULL;
}
/* lets decode the mnonce string */
buf = g_base64_decode(mnonce, &len);
if (!buf) {
error_setg(errp, "SEV: failed to decode mnonce input");
return NULL;
}
/* verify the input mnonce length */
if (len != sizeof(input.mnonce)) {
error_setg(errp, "SEV: mnonce must be %zu bytes (got %" G_GSIZE_FORMAT ")",
sizeof(input.mnonce), len);
g_free(buf);
return NULL;
}
/* Query the report length */
ret = sev_ioctl(sev->sev_fd, KVM_SEV_GET_ATTESTATION_REPORT,
&input, &err);
if (ret < 0) {
if (err != SEV_RET_INVALID_LEN) {
error_setg(errp, "failed to query the attestation report length "
"ret=%d fw_err=%d (%s)", ret, err, fw_error_to_str(err));
g_free(buf);
return NULL;
}
}
data = g_malloc(input.len);
input.uaddr = (unsigned long)data;
memcpy(input.mnonce, buf, sizeof(input.mnonce));
/* Query the report */
ret = sev_ioctl(sev->sev_fd, KVM_SEV_GET_ATTESTATION_REPORT,
&input, &err);
if (ret) {
error_setg_errno(errp, errno, "Failed to get attestation report"
" ret=%d fw_err=%d (%s)", ret, err, fw_error_to_str(err));
goto e_free_data;
}
report = g_new0(SevAttestationReport, 1);
report->data = g_base64_encode(data, input.len);
trace_kvm_sev_attestation_report(mnonce, report->data);
e_free_data:
g_free(data);
g_free(buf);
return report;
}
static int static int
sev_read_file_base64(const char *filename, guchar **data, gsize *len) sev_read_file_base64(const char *filename, guchar **data, gsize *len)
{ {

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@ -35,5 +35,7 @@ extern uint32_t sev_get_cbit_position(void);
extern uint32_t sev_get_reduced_phys_bits(void); extern uint32_t sev_get_reduced_phys_bits(void);
extern char *sev_get_launch_measurement(void); extern char *sev_get_launch_measurement(void);
extern SevCapability *sev_get_capabilities(Error **errp); extern SevCapability *sev_get_capabilities(Error **errp);
extern SevAttestationReport *
sev_get_attestation_report(const char *mnonce, Error **errp);
#endif #endif

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@ -10,3 +10,4 @@ kvm_sev_launch_update_data(void *addr, uint64_t len) "addr %p len 0x%" PRIx64
kvm_sev_launch_measurement(const char *value) "data %s" kvm_sev_launch_measurement(const char *value) "data %s"
kvm_sev_launch_finish(void) "" kvm_sev_launch_finish(void) ""
kvm_sev_launch_secret(uint64_t hpa, uint64_t hva, uint64_t secret, int len) "hpa 0x%" PRIx64 " hva 0x%" PRIx64 " data 0x%" PRIx64 " len %d" kvm_sev_launch_secret(uint64_t hpa, uint64_t hva, uint64_t secret, int len) "hpa 0x%" PRIx64 " hva 0x%" PRIx64 " data 0x%" PRIx64 " len %d"
kvm_sev_attestation_report(const char *mnonce, const char *data) "mnonce %s data %s"