From: Michal Privoznik <mprivozn@redhat.com>

Pretty straightforward. The only "weird" thing here is that
'hv-time' enlightenment is exposed as a <timer/> under <clock/>
element. Since it's required by 'hv-stimer' and
'hv-stimer-direct' it needs to be enabled too.

Resolves: https://issues.redhat.com/browse/RHEL-114003
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_command.c                       |  2 +-
 src/qemu/qemu_process.c                       | 72 +++++++++++++++++++
 .../hyperv-host-model.x86_64-latest.args      |  2 +-
 3 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 609d0677df..fcf5fc1935 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6461,13 +6461,13 @@ qemuBuildCpuHypervCommandLine(virBuffer *buf,
 
     switch ((virDomainHyperVMode) def->features[VIR_DOMAIN_FEATURE_HYPERV]) {
     case VIR_DOMAIN_HYPERV_MODE_CUSTOM:
-    case VIR_DOMAIN_HYPERV_MODE_HOST_MODEL:
         break;
 
     case VIR_DOMAIN_HYPERV_MODE_PASSTHROUGH:
         virBufferAddLit(buf, ",hv-passthrough=on");
         break;
 
+    case VIR_DOMAIN_HYPERV_MODE_HOST_MODEL:
     case VIR_DOMAIN_HYPERV_MODE_NONE:
     case VIR_DOMAIN_HYPERV_MODE_LAST:
     default:
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index d42e3f612b..9926998f85 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -6835,6 +6835,75 @@ qemuProcessPrepareChardevSource(virDomainDef *def,
 }
 
 
+static void
+qemuProcessMaybeAddHypervTimer(virDomainDef *def)
+{
+    g_autofree virDomainTimerDef *timer = NULL;
+
+    if (virDomainDefHasTimer(def, VIR_DOMAIN_TIMER_NAME_HYPERVCLOCK))
+        return;
+
+    timer = g_new0(virDomainTimerDef, 1);
+    timer->name = VIR_DOMAIN_TIMER_NAME_HYPERVCLOCK;
+    timer->present = VIR_TRISTATE_BOOL_YES;
+
+    VIR_APPEND_ELEMENT(def->clock.timers, def->clock.ntimers, timer);
+}
+
+
+static int
+qemuProcessEnableDomainFeatures(virDomainObj *vm)
+{
+    virDomainCapsFeatureHyperv *hv = NULL;
+    qemuDomainObjPrivate *priv = vm->privateData;
+    size_t i;
+
+    if (vm->def->features[VIR_DOMAIN_FEATURE_HYPERV] != VIR_DOMAIN_HYPERV_MODE_HOST_MODEL)
+        return 0;
+
+    hv = virQEMUCapsGetHypervCapabilities(priv->qemuCaps);
+    if (!hv || hv->supported != VIR_TRISTATE_BOOL_YES) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("host-model hyperv mode unsupported, no hyperv capabilities found"));
+        return -1;
+    }
+
+    for (i = 0; i < VIR_DOMAIN_HYPERV_LAST; i++) {
+        if (!VIR_DOMAIN_CAPS_ENUM_IS_SET(hv->features, i))
+            continue;
+
+        vm->def->hyperv.features[i] = VIR_TRISTATE_SWITCH_ON;
+
+        if (i == VIR_DOMAIN_HYPERV_SPINLOCKS) {
+            if (hv->spinlocks != 0) {
+                vm->def->hyperv.spinlocks = hv->spinlocks;
+            } else {
+                vm->def->hyperv.features[i] = VIR_TRISTATE_SWITCH_ABSENT;
+            }
+        } else if (i == VIR_DOMAIN_HYPERV_STIMER) {
+            vm->def->hyperv.stimer_direct = hv->stimer_direct;
+            /* Both hv-stimer and hv-stimer-direct require hv-time which is
+             * expose as a timer. Enable it. */
+            qemuProcessMaybeAddHypervTimer(vm->def);
+        } else if (i == VIR_DOMAIN_HYPERV_TLBFLUSH) {
+            vm->def->hyperv.tlbflush_direct = hv->tlbflush_direct;
+            vm->def->hyperv.tlbflush_extended = hv->tlbflush_extended;
+        } else if (i == VIR_DOMAIN_HYPERV_VENDOR_ID) {
+            if (hv->vendor_id) {
+                vm->def->hyperv.vendor_id = g_strdup(hv->vendor_id);
+            } else {
+                vm->def->hyperv.features[i] = VIR_TRISTATE_SWITCH_ABSENT;
+            }
+        }
+    }
+
+    vm->def->features[VIR_DOMAIN_FEATURE_HYPERV] = VIR_DOMAIN_HYPERV_MODE_CUSTOM;
+
+    return 0;
+}
+
+
+
 /**
  * qemuProcessPrepareDomain:
  * @driver: qemu driver
@@ -6948,6 +7017,9 @@ qemuProcessPrepareDomain(virQEMUDriver *driver,
         VIR_DEBUG("Aligning guest memory");
         if (qemuDomainAlignMemorySizes(vm->def) < 0)
             return -1;
+
+        if (qemuProcessEnableDomainFeatures(vm) < 0)
+            return -1;
     }
 
     for (i = 0; i < vm->def->nchannels; i++) {
diff --git a/tests/qemuxmlconfdata/hyperv-host-model.x86_64-latest.args b/tests/qemuxmlconfdata/hyperv-host-model.x86_64-latest.args
index 2ed72fcd1b..58502ff51e 100644
--- a/tests/qemuxmlconfdata/hyperv-host-model.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/hyperv-host-model.x86_64-latest.args
@@ -12,7 +12,7 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.config \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-QEMUGuest1/master-key.aes"}' \
 -machine pc,usb=off,dump-guest-core=off,memory-backend=pc.ram,acpi=on \
 -accel tcg \
--cpu qemu64 \
+-cpu 'qemu64,hv-time=on,hv-relaxed=on,hv-vapic=on,hv-spinlocks=0xfff,hv-vpindex=on,hv-runtime=on,hv-synic=on,hv-stimer=on,hv-stimer-direct=on,hv-reset=on,hv-vendor-id=Linux KVM Hv,hv-frequencies=on,hv-reenlightenment=on,hv-tlbflush=on,hv-tlbflush-direct=on,hv-tlbflush-ext=on,hv-ipi=on,hv-avic=on,hv-emsr-bitmap=on,hv-xmm-input=on' \
 -m size=219136k \
 -object '{"qom-type":"memory-backend-ram","id":"pc.ram","size":224395264}' \
 -overcommit mem-lock=off \
-- 
2.49.1