Hi,
Ping. Please let me know if you have any feedback on this patch.
Thanks
On 4/29/21 12:07 PM, Brijesh Singh wrote:
> 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@xxxxxxxxxxxxx>
> Cc: Tom Lendacky <Thomas.Lendacky@xxxxxxx>
> Cc: Eric Blake <eblake@xxxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: kvm@xxxxxxxxxxxxxxx
> Reviewed-by: James Bottomley <jejb@xxxxxxxxxxxxx>
> Tested-by: James Bottomley <jejb@xxxxxxxxxxxxx>
> Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
> ---
> v3:
> * free the buffer in error path.
>
> v2:
> * add trace event.
> * fix the goto to return NULL on failure.
> * make the mnonce as a base64 encoded string
>
> 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 0c7491cd82..4b62f0ac05 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 72b9e2ab40..4b9d7d3bb9 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -491,6 +491,73 @@ 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 %ld bytes (got %ld)",
> + 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"
