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-rw-r--r--target/arm/kvm64.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index dff85f6db9..37ceadd9a9 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -647,17 +647,26 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
 
     sve_supported = ioctl(fdarray[0], KVM_CHECK_EXTENSION, KVM_CAP_ARM_SVE) > 0;
 
-    kvm_arm_destroy_scratch_host_vcpu(fdarray);
-
-    if (err < 0) {
-        return false;
-    }
-
     /* Add feature bits that can't appear until after VCPU init. */
     if (sve_supported) {
         t = ahcf->isar.id_aa64pfr0;
         t = FIELD_DP64(t, ID_AA64PFR0, SVE, 1);
         ahcf->isar.id_aa64pfr0 = t;
+
+        /*
+         * Before v5.1, KVM did not support SVE and did not expose
+         * ID_AA64ZFR0_EL1 even as RAZ.  After v5.1, KVM still does
+         * not expose the register to "user" requests like this
+         * unless the host supports SVE.
+         */
+        err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64zfr0,
+                              ARM64_SYS_REG(3, 0, 0, 4, 4));
+    }
+
+    kvm_arm_destroy_scratch_host_vcpu(fdarray);
+
+    if (err < 0) {
+        return false;
     }
 
     /*