sev/i386: add sev_get_capabilities()

The function can be used to get the current SEV capabilities.
The capabilities include platform diffie-hellman key (pdh) and certificate
chain. The key can be provided to the external entities which wants to
establish a trusted channel between SEV firmware and guest owner.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Brijesh Singh 2018-03-08 06:49:00 -06:00 committed by Paolo Bonzini
parent 31dd67f684
commit 9f75079498
4 changed files with 98 additions and 2 deletions

View File

@ -717,6 +717,13 @@ SevLaunchMeasureInfo *qmp_query_sev_launch_measure(Error **errp)
SevCapability *qmp_query_sev_capabilities(Error **errp)
{
SevCapability *data;
data = sev_get_capabilities();
if (!data) {
error_setg(errp, "SEV feature is not available");
return NULL;
}
return data;
}

View File

@ -44,3 +44,8 @@ char *sev_get_launch_measurement(void)
{
return NULL;
}
SevCapability *sev_get_capabilities(void)
{
return NULL;
}

View File

@ -426,6 +426,89 @@ sev_get_info(void)
return info;
}
static int
sev_get_pdh_info(int fd, guchar **pdh, size_t *pdh_len, guchar **cert_chain,
size_t *cert_chain_len)
{
guchar *pdh_data, *cert_chain_data;
struct sev_user_data_pdh_cert_export export = {};
int err, r;
/* query the certificate length */
r = sev_platform_ioctl(fd, SEV_PDH_CERT_EXPORT, &export, &err);
if (r < 0) {
if (err != SEV_RET_INVALID_LEN) {
error_report("failed to export PDH cert ret=%d fw_err=%d (%s)",
r, err, fw_error_to_str(err));
return 1;
}
}
pdh_data = g_new(guchar, export.pdh_cert_len);
cert_chain_data = g_new(guchar, export.cert_chain_len);
export.pdh_cert_address = (unsigned long)pdh_data;
export.cert_chain_address = (unsigned long)cert_chain_data;
r = sev_platform_ioctl(fd, SEV_PDH_CERT_EXPORT, &export, &err);
if (r < 0) {
error_report("failed to export PDH cert ret=%d fw_err=%d (%s)",
r, err, fw_error_to_str(err));
goto e_free;
}
*pdh = pdh_data;
*pdh_len = export.pdh_cert_len;
*cert_chain = cert_chain_data;
*cert_chain_len = export.cert_chain_len;
return 0;
e_free:
g_free(pdh_data);
g_free(cert_chain_data);
return 1;
}
SevCapability *
sev_get_capabilities(void)
{
SevCapability *cap;
guchar *pdh_data, *cert_chain_data;
size_t pdh_len = 0, cert_chain_len = 0;
uint32_t ebx;
int fd;
fd = open(DEFAULT_SEV_DEVICE, O_RDWR);
if (fd < 0) {
error_report("%s: Failed to open %s '%s'", __func__,
DEFAULT_SEV_DEVICE, strerror(errno));
return NULL;
}
if (sev_get_pdh_info(fd, &pdh_data, &pdh_len,
&cert_chain_data, &cert_chain_len)) {
return NULL;
}
cap = g_new0(SevCapability, 1);
cap->pdh = g_base64_encode(pdh_data, pdh_len);
cap->cert_chain = g_base64_encode(cert_chain_data, cert_chain_len);
host_cpuid(0x8000001F, 0, NULL, &ebx, NULL, NULL);
cap->cbitpos = ebx & 0x3f;
/*
* When SEV feature is enabled, we loose one bit in guest physical
* addressing.
*/
cap->reduced_phys_bits = 1;
g_free(pdh_data);
g_free(cert_chain_data);
close(fd);
return cap;
}
static int
sev_read_file_base64(const char *filename, guchar **data, gsize *len)
{

View File

@ -38,6 +38,7 @@ 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);
extern SevCapability *sev_get_capabilities(void);
typedef struct QSevGuestInfo QSevGuestInfo;
typedef struct QSevGuestInfoClass QSevGuestInfoClass;