[PATCH] sev: allow capabilities to check for SEV-ES support

[Tyler Fanelli <tfanelli@redhat.com>]

Probe for SEV-ES and SEV-SNP capabilities to distinguish between Rome,
Naples, and Milan processors. Use the CPUID function to probe if a
processor is capable of running SEV-ES or SEV-SNP, rather than if it
actually is running SEV-ES or SEV-SNP.

Signed-off-by: Tyler Fanelli <tfanelli@redhat.com>
---
 qapi/misc-target.json | 11 +++++++++--
 target/i386/sev.c     |  6 ++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/qapi/misc-target.json b/qapi/misc-target.json
index 5aa2b95b7d..c3e9bce12b 100644
--- a/qapi/misc-target.json
+++ b/qapi/misc-target.json
@@ -182,13 +182,19 @@
 # @reduced-phys-bits: Number of physical Address bit reduction when SEV is
 #                     enabled
 #
+# @es: SEV-ES capability of the machine.
+#
+# @snp: SEV-SNP capability of the machine.
+#
 # Since: 2.12
 ##
 { 'struct': 'SevCapability',
   'data': { 'pdh': 'str',
             'cert-chain': 'str',
             'cbitpos': 'int',
-            'reduced-phys-bits': 'int'},
+            'reduced-phys-bits': 'int',
+            'es': 'bool',
+            'snp': 'bool'},
   'if': 'TARGET_I386' }
 
 ##
@@ -205,7 +211,8 @@
 #
 # -> { "execute": "query-sev-capabilities" }
 # <- { "return": { "pdh": "8CCDD8DDD", "cert-chain": "888CCCDDDEE",
-#                  "cbitpos": 47, "reduced-phys-bits": 5}}
+#                  "cbitpos": 47, "reduced-phys-bits": 5
+#                  "es": false, "snp": false}}
 #
 ##
 { 'command': 'query-sev-capabilities', 'returns': 'SevCapability',
diff --git a/target/i386/sev.c b/target/i386/sev.c
index eede07f11d..6d78dcd744 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -506,7 +506,7 @@ static SevCapability *sev_get_capabilities(Error **errp)
     guchar *pdh_data = NULL;
     guchar *cert_chain_data = NULL;
     size_t pdh_len = 0, cert_chain_len = 0;
-    uint32_t ebx;
+    uint32_t eax, ebx;
     int fd;
 
     if (!kvm_enabled()) {
@@ -534,8 +534,10 @@ static SevCapability *sev_get_capabilities(Error **errp)
     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);
+    host_cpuid(0x8000001F, 0, &eax, &ebx, NULL, NULL);
     cap->cbitpos = ebx & 0x3f;
+    cap->es = (eax & 0x8) ? true : false;
+    cap->snp = (eax & 0x10) ? true : false;
 
     /*
      * When SEV feature is enabled, we loose one bit in guest physical
-- 
2.31.1