target/arm: Support PAuth extension for hvf

Currently we don't allow guests under hvf to use the PAuth extension,
because we didn't have any special code to handle that, and therefore
in arm_cpu_pauth_finalize() we will sanitize the ID_AA64ISAR1 value
the guest sees to clear the PAuth related fields.

Add support for this in the same way that KVM does it, by defaulting
to "PAuth enabled" if the host CPU has it and allowing the user to
disable it via '-cpu pauth=no' on the command line.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Alexander Graf <agraf@csgraf.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220204165506.2846058-7-peter.maydell@linaro.org

target/arm/cpu64.c

@@ -633,9 +633,10 @@ void arm_cpu_pauth_finalize(ARMCPU *cpu, Error **errp)
     uint64_t t;
 
     /* Exit early if PAuth is enabled, and fall through to disable it */
-    if (kvm_enabled() && cpu->prop_pauth) {
+    if ((kvm_enabled() || hvf_enabled()) && cpu->prop_pauth) {
         if (!cpu_isar_feature(aa64_pauth, cpu)) {
-            error_setg(errp, "'pauth' feature not supported by KVM on this host");
+            error_setg(errp, "'pauth' feature not supported by %s on this host",
+                       kvm_enabled() ? "KVM" : "hvf");
         }
 
         return;
@@ -672,10 +673,14 @@ void aarch64_add_pauth_properties(Object *obj)
 
     /* Default to PAUTH on, with the architected algorithm on TCG. */
     qdev_property_add_static(DEVICE(obj), &arm_cpu_pauth_property);
-    if (kvm_enabled()) {
+    if (kvm_enabled() || hvf_enabled()) {
         /*
          * Mirror PAuth support from the probed sysregs back into the
-         * property for KVM. Is it just a bit backward? Yes it is!
+         * property for KVM or hvf. Is it just a bit backward? Yes it is!
+         * Note that prop_pauth is true whether the host CPU supports the
+         * architected QARMA5 algorithm or the IMPDEF one. We don't
+         * provide the separate pauth-impdef property for KVM or hvf,
+         * only for TCG.
          */
         cpu->prop_pauth = cpu_isar_feature(aa64_pauth, cpu);
     } else {
@@ -695,6 +700,7 @@ static void aarch64_host_initfn(Object *obj)
 #elif defined(CONFIG_HVF)
     ARMCPU *cpu = ARM_CPU(obj);
     hvf_arm_set_cpu_features_from_host(cpu);
+    aarch64_add_pauth_properties(obj);
 #else
     g_assert_not_reached();
 #endif