Commit c6c89c97 authored by Brijesh Singh's avatar Brijesh Singh Committed by Paolo Bonzini
Browse files

sev/i386: add support to LAUNCH_MEASURE command 



During machine creation we encrypted the guest bios image, the
LAUNCH_MEASURE command can be used to retrieve the measurement of
the encrypted memory region. This measurement is a signature of
the memory contents that can be sent to the guest owner as an
attestation that the memory was encrypted correctly by the firmware.
VM management tools like libvirt can query the measurement using
query-sev-launch-measure QMP command.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 952e0668

target/i386/sev-stub.c

+5 −0
Original line number Diff line number Diff line
@@ -39,3 +39,8 @@ uint32_t sev_get_reduced_phys_bits(void) 
{

    return 0;

}



char *sev_get_launch_measurement(void)

{

    return NULL;

}

target/i386/sev.c

+63 −0
Original line number Diff line number Diff line
@@ -516,6 +516,68 @@ sev_launch_update_data(uint8_t *addr, uint64_t len) 
    return ret;

}



static void

sev_launch_get_measure(Notifier *notifier, void *unused)

{

    int ret, error;

    guchar *data;

    SEVState *s = sev_state;

    struct kvm_sev_launch_measure *measurement;



    if (!sev_check_state(SEV_STATE_LAUNCH_UPDATE)) {

        return;

    }



    measurement = g_new0(struct kvm_sev_launch_measure, 1);



    /* query the measurement blob length */

    ret = sev_ioctl(sev_state->sev_fd, KVM_SEV_LAUNCH_MEASURE,

                    measurement, &error);

    if (!measurement->len) {

        error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",

                     __func__, ret, error, fw_error_to_str(errno));

        goto free_measurement;

    }



    data = g_new0(guchar, measurement->len);

    measurement->uaddr = (unsigned long)data;



    /* get the measurement blob */

    ret = sev_ioctl(sev_state->sev_fd, KVM_SEV_LAUNCH_MEASURE,

                    measurement, &error);

    if (ret) {

        error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",

                     __func__, ret, error, fw_error_to_str(errno));

        goto free_data;

    }



    sev_set_guest_state(SEV_STATE_LAUNCH_SECRET);



    /* encode the measurement value and emit the event */

    s->measurement = g_base64_encode(data, measurement->len);

    trace_kvm_sev_launch_measurement(s->measurement);



free_data:

    g_free(data);

free_measurement:

    g_free(measurement);

}



char *

sev_get_launch_measurement(void)

{

    if (sev_state &&

        sev_state->state >= SEV_STATE_LAUNCH_SECRET) {

        return g_strdup(sev_state->measurement);

    }



    return NULL;

}



static Notifier sev_machine_done_notify = {

    .notify = sev_launch_get_measure,

};



void *

sev_guest_init(const char *id)

{
@@ -593,6 +655,7 @@ sev_guest_init(const char *id) 
    }



    ram_block_notifier_add(&sev_ram_notifier);

    qemu_add_machine_init_done_notifier(&sev_machine_done_notify);



    return s;

err:

target/i386/sev_i386.h

+2 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ extern uint64_t sev_get_me_mask(void); 
extern SevInfo *sev_get_info(void);

extern uint32_t sev_get_cbit_position(void);

extern uint32_t sev_get_reduced_phys_bits(void);

extern char *sev_get_launch_measurement(void);



typedef struct QSevGuestInfo QSevGuestInfo;

typedef struct QSevGuestInfoClass QSevGuestInfoClass;
@@ -78,6 +79,7 @@ struct SEVState { 
    uint32_t handle;

    int sev_fd;

    SevState state;

    gchar *measurement;

};



typedef struct SEVState SEVState;

target/i386/trace-events

+1 −0
Original line number Diff line number Diff line
@@ -13,3 +13,4 @@ kvm_memcrypt_unregister_region(void *addr, size_t len) "addr %p len 0x%zu" 
kvm_sev_change_state(const char *old, const char *new) "%s -> %s"

kvm_sev_launch_start(int policy, void *session, void *pdh) "policy 0x%x session %p pdh %p"

kvm_sev_launch_update_data(void *addr, uint64_t len) "addr %p len 0x%" PRIu64

kvm_sev_launch_measurement(const char *value) "data %s"