From 3ea1a80243d5b5ba23d8c2b7d3a86034ea0ade22 Mon Sep 17 00:00:00 2001 From: Brijesh Singh Date: Thu, 29 Apr 2021 12:07:28 -0500 Subject: [PATCH] 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 Cc: Tom Lendacky Cc: Eric Blake Cc: Paolo Bonzini Cc: kvm@vger.kernel.org Reviewed-by: James Bottomley Tested-by: James Bottomley Signed-off-by: Brijesh Singh Reviewed-by: Connor Kuehl Message-Id: <20210429170728.24322-1-brijesh.singh@amd.com> Signed-off-by: Eduardo Habkost --- linux-headers/linux/kvm.h | 8 +++++ qapi/misc-target.json | 38 ++++++++++++++++++++++ target/i386/monitor.c | 6 ++++ target/i386/sev-stub.c | 7 ++++ target/i386/sev.c | 67 +++++++++++++++++++++++++++++++++++++++ target/i386/sev_i386.h | 2 ++ target/i386/trace-events | 1 + 7 files changed, 129 insertions(+) diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h index 020b62a619..897f831374 100644 --- a/linux-headers/linux/kvm.h +++ b/linux-headers/linux/kvm.h @@ -1591,6 +1591,8 @@ enum sev_cmd_id { KVM_SEV_DBG_ENCRYPT, /* Guest certificates commands */ KVM_SEV_CERT_EXPORT, + /* Attestation report */ + KVM_SEV_GET_ATTESTATION_REPORT, KVM_SEV_NR_MAX, }; @@ -1643,6 +1645,12 @@ struct kvm_sev_dbg { __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_PCI_2_3 (1 << 1) #define KVM_DEV_ASSIGN_MASK_INTX (1 << 2) diff --git a/qapi/misc-target.json b/qapi/misc-target.json index 6200c671be..5573dcf8f0 100644 --- a/qapi/misc-target.json +++ b/qapi/misc-target.json @@ -285,3 +285,41 @@ ## { 'command': 'query-gic-capabilities', 'returns': ['GICCapability'], '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)' } diff --git a/target/i386/monitor.c b/target/i386/monitor.c index 5994408bee..119211f0b0 100644 --- a/target/i386/monitor.c +++ b/target/i386/monitor.c @@ -757,3 +757,9 @@ void qmp_sev_inject_launch_secret(const char *packet_hdr, 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); +} diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c index 0207f1c5aa..0227cb5177 100644 --- a/target/i386/sev-stub.c +++ b/target/i386/sev-stub.c @@ -74,3 +74,10 @@ int sev_es_save_reset_vector(void *flash_ptr, uint64_t flash_size) { abort(); } + +SevAttestationReport * +sev_get_attestation_report(const char *mnonce, Error **errp) +{ + error_setg(errp, "SEV is not available in this QEMU"); + return NULL; +} diff --git a/target/i386/sev.c b/target/i386/sev.c index 41f7800b5f..1a88f12703 100644 --- a/target/i386/sev.c +++ b/target/i386/sev.c @@ -492,6 +492,73 @@ out: 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 sev_read_file_base64(const char *filename, guchar **data, gsize *len) { diff --git a/target/i386/sev_i386.h b/target/i386/sev_i386.h index ae221d4c72..ae6d840478 100644 --- a/target/i386/sev_i386.h +++ b/target/i386/sev_i386.h @@ -35,5 +35,7 @@ extern uint32_t sev_get_cbit_position(void); extern uint32_t sev_get_reduced_phys_bits(void); extern char *sev_get_launch_measurement(void); extern SevCapability *sev_get_capabilities(Error **errp); +extern SevAttestationReport * +sev_get_attestation_report(const char *mnonce, Error **errp); #endif diff --git a/target/i386/trace-events b/target/i386/trace-events index a22ab24e21..8d6437404d 100644 --- a/target/i386/trace-events +++ b/target/i386/trace-events @@ -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_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_attestation_report(const char *mnonce, const char *data) "mnonce %s data %s"