Currently, Apple doesn't support the nested virtualisation + SME combination.

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
---
 target/arm/hvf/hvf.c | 2 ++
 target/arm/hvf_arm.h | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index 03b174a8d4..8aa59a1f77 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -1189,6 +1189,8 @@ static bool hvf_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
 
     if (hvf_nested_virt_enabled()) {
         FIELD_DP64_IDREG(&host_isar, ID_AA64DFR0, PMUVER, 0x1);
+        /* SME is not implemented with nested virt on the Apple side */
+        FIELD_DP64_IDREG(&host_isar, ID_AA64PFR1, SME, 0);
     }
 
     ahcf->isar = host_isar;
diff --git a/target/arm/hvf_arm.h b/target/arm/hvf_arm.h
index 6b1c3b9792..9cb58ad9ab 100644
--- a/target/arm/hvf_arm.h
+++ b/target/arm/hvf_arm.h
@@ -11,6 +11,7 @@
 #ifndef QEMU_HVF_ARM_H
 #define QEMU_HVF_ARM_H
 
+#include "system/hvf.h"
 #include "target/arm/cpu-qom.h"
 
 /**
@@ -35,6 +36,10 @@ void hvf_arm_set_cpu_features_from_host(ARMCPU *cpu);
         if (__builtin_available(macOS 15.2, *)) {
             size_t svl_bytes;
             hv_return_t result = hv_sme_config_get_max_svl_bytes(&svl_bytes);
+            /* Nested virt not supported together with SME right now. */
+            if (hvf_nested_virt_enabled()) {
+                return false;
+            }
             if (result == HV_UNSUPPORTED) {
                 return false;
             }
-- 
2.50.1 (Apple Git-155)

On 7/3/26 16:31, Mohamed Mediouni wrote:
> Currently, Apple doesn't support the nested virtualisation + SME combination.
> 
> Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
> ---
>   target/arm/hvf/hvf.c | 2 ++
>   target/arm/hvf_arm.h | 5 +++++
>   2 files changed, 7 insertions(+)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>