[PATCH qemu-server v1 1/2] query-machine-capabilities: amd-sev: add max-asid and min-asid-std-sev

[Markus Frank <m.frank@proxmox.com>]

Read two more AMD SEV values with CPUID that are currently only visible
in the BIOS and dmesg.

max-asid: maximum number of Address Space Identifiers (ASID) for all AMD
SEV VMs = maximum number of SEV guests that can run at the same time

min-asid-std-sev: minimum ASID value for standard SEV guests

AMD SEV ASID Ranges:
* 1 .. (min-asid-std-sev - 1): SEV-ES, SEV-SNP guests
* min-asid-std-sev .. max-asid: standard SEV guests

This could be used to prevent SEV VMs from starting and to display a
more informative error message if all ASIDs are already in use by other
SEV VMs.

Signed-off-by: Markus Frank <m.frank@proxmox.com>
---
 .../query-machine-capabilities.c                          | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/query-machine-capabilities/query-machine-capabilities.c b/src/query-machine-capabilities/query-machine-capabilities.c
index 0a9ab805..cf5f5252 100644
--- a/src/query-machine-capabilities/query-machine-capabilities.c
+++ b/src/query-machine-capabilities/query-machine-capabilities.c
@@ -31,6 +31,8 @@ typedef struct {
 
     uint8_t cbitpos;
     uint8_t reduced_phys_bits;
+    uint32_t max_asid;
+    uint32_t min_asid_std_sev;
 } cpu_caps_amd_sev_t;
 
 typedef struct {
@@ -138,6 +140,8 @@ void query_cpu_capabilities_sev(cpu_caps_amd_sev_t *res) {
 
     res->cbitpos = ebx & 0x3f;
     res->reduced_phys_bits = (ebx >> 6) & 0x3f;
+    res->max_asid = ecx;
+    res->min_asid_std_sev = edx;
 #else
     memset(res, 0, sizeof(*res));
 #endif
@@ -213,12 +217,16 @@ int main() {
             " \"amd-sev\": {"
             " \"cbitpos\": %u,"
             " \"reduced-phys-bits\": %u,"
+            " \"max-asid\": %u,"
+            " \"min-asid-std-sev\": %u,"
             " \"sev-support\": %s,"
             " \"sev-support-es\": %s,"
             " \"sev-support-snp\": %s"
             " }",
             caps_sev.cbitpos,
             caps_sev.reduced_phys_bits,
+            caps_sev.max_asid,
+            caps_sev.min_asid_std_sev,
             caps_sev.sev_support ? "true" : "false",
             caps_sev.sev_es_support ? "true" : "false",
             caps_sev.sev_snp_support ? "true" : "false"
-- 
2.47.3