[Qemu-devel] [PATCH 10/13] target/arm/monitor: kvm: only return valid sve vector sets

[Andrew Jones <drjones@redhat.com>]

While the TCG SVE implementation can implement all vector lengths
which are a quadword multiple, up to some maximum length, KVM can
only provide what the host supports, and not all multiples are
required to be supported by the architecture. With this patch
we extend the QMP query to ask KVM for the valid vectors when KVM
is enabled.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 target/arm/monitor.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/target/arm/monitor.c b/target/arm/monitor.c
index 8b2afa255c92..3e13dd7c7b7a 100644
--- a/target/arm/monitor.c
+++ b/target/arm/monitor.c
@@ -84,6 +84,41 @@ GICCapabilityList *qmp_query_gic_capabilities(Error **errp)
     return head;
 }
 
+#ifdef CONFIG_KVM
+static SVEVectorLengths *qmp_kvm_sve_vls_get(void)
+{
+    CPUArchState *env = mon_get_cpu_env();
+    ARMCPU *cpu = arm_env_get_cpu(env);
+    uint64_t sve_vls[KVM_ARM64_SVE_VLS_WORDS];
+    SVEVectorLengths *vls = g_new(SVEVectorLengths, 1);
+    intList **v = &vls->vls;
+    int ret, i;
+
+    ret = kvm_arm_get_sve_vls(CPU(cpu), sve_vls);
+    if (ret <= 0) {
+        *v = g_new0(intList, 1); /* one vl of 0 means none supported */
+        return vls;
+    }
+
+    for (i = KVM_ARM64_SVE_VQ_MIN; i <= ret; ++i) {
+        int bitval = (sve_vls[(i - KVM_ARM64_SVE_VQ_MIN) / 64] >>
+                      ((i - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1;
+        if (bitval) {
+            *v = g_new0(intList, 1);
+            (*v)->value = i;
+            v = &(*v)->next;
+        }
+    }
+
+    return vls;
+}
+#else
+static SVEVectorLengths *qmp_kvm_sve_vls_get(void)
+{
+    return NULL;
+}
+#endif
+
 static SVEVectorLengths *qmp_sve_vls_get(void)
 {
     CPUArchState *env = mon_get_cpu_env();
@@ -130,7 +165,13 @@ static SVEVectorLengths *qmp_sve_vls_dup_and_truncate(SVEVectorLengths *vls)
 SVEVectorLengthsList *qmp_query_sve_vector_lengths(Error **errp)
 {
     SVEVectorLengthsList *vls_list = g_new0(SVEVectorLengthsList, 1);
-    SVEVectorLengths *vls = qmp_sve_vls_get();
+    SVEVectorLengths *vls;
+
+    if (kvm_enabled()) {
+        vls = qmp_kvm_sve_vls_get();
+    } else {
+        vls = qmp_sve_vls_get();
+    }
 
     while (vls) {
         vls_list->value = vls;
-- 
2.20.1