accel, hw/arm, include/system/hvf: infrastructure changes for HVF vGIC

Misc changes needed for HVF vGIC enablement.

Note: x86_64 macOS exposes interrupt controller virtualisation since macOS 12.
Keeping an #ifdef here in case we end up supporting that...

However, given that x86_64 macOS is on its way out, it'll probably (?)
not be supported in QEMU.

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
Message-id: 20260429190532.26538-4-mohamed@unpredictable.fr
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

accel/hvf/hvf-all.c

@@ -10,6 +10,8 @@
 
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
+#include "qapi/error.h"
+#include "qapi/qapi-visit-common.h"
 #include "accel/accel-ops.h"
 #include "exec/cpu-common.h"
 #include "system/address-spaces.h"
@@ -21,6 +23,7 @@
 #include "trace.h"
 
 bool hvf_allowed;
+bool hvf_kernel_irqchip;
 
 const char *hvf_return_string(hv_return_t ret)
 {
@@ -216,6 +219,43 @@ static int hvf_gdbstub_sstep_flags(AccelState *as)
     return SSTEP_ENABLE | SSTEP_NOIRQ;
 }
 
+static void hvf_set_kernel_irqchip(Object *obj, Visitor *v,
+                                   const char *name, void *opaque,
+                                   Error **errp)
+{
+    OnOffSplit mode;
+    if (!visit_type_OnOffSplit(v, name, &mode, errp)) {
+        return;
+    }
+
+    switch (mode) {
+    case ON_OFF_SPLIT_ON:
+#ifdef HOST_X86_64
+        /* macOS 12 onwards exposes an HVF virtual APIC. */
+        error_setg(errp, "HVF: kernel irqchip is not currently implemented for x86.");
+        break;
+#else
+        hvf_kernel_irqchip = true;
+        break;
+#endif
+
+    case ON_OFF_SPLIT_OFF:
+        hvf_kernel_irqchip = false;
+        break;
+
+    case ON_OFF_SPLIT_SPLIT:
+        error_setg(errp, "HVF: split irqchip is not supported on HVF.");
+        break;
+
+    default:
+        /*
+         * The value was checked in visit_type_OnOffSplit() above. If
+         * we get here, then something is wrong in QEMU.
+         */
+        abort();
+    }
+}
+
 static void hvf_accel_class_init(ObjectClass *oc, const void *data)
 {
     AccelClass *ac = ACCEL_CLASS(oc);
@@ -223,6 +263,12 @@ static void hvf_accel_class_init(ObjectClass *oc, const void *data)
     ac->init_machine = hvf_accel_init;
     ac->allowed = &hvf_allowed;
     ac->gdbstub_supported_sstep_flags = hvf_gdbstub_sstep_flags;
+    hvf_kernel_irqchip = false;
+    object_class_property_add(oc, "kernel-irqchip", "on|off|split",
+        NULL, hvf_set_kernel_irqchip,
+        NULL, NULL);
+    object_class_property_set_description(oc, "kernel-irqchip",
+        "Configure HVF irqchip");
 }
 
 static const TypeInfo hvf_accel_type = {

accel/stubs/hvf-stub.c

@@ -10,3 +10,4 @@
 #include "system/hvf.h"
 
 bool hvf_allowed;
+bool hvf_kernel_irqchip;

hw/arm/virt.c

@@ -1163,7 +1163,7 @@ static void create_gic(VirtMachineState *vms, MemoryRegion *mem)
      * interrupts; there are always 32 of the former (mandated by GIC spec).
      */
     qdev_prop_set_uint32(vms->gic, "num-irq", NUM_IRQS + 32);
-    if (!kvm_irqchip_in_kernel()) {
+    if (!kvm_irqchip_in_kernel() && !hvf_irqchip_in_kernel()) {
         qdev_prop_set_bit(vms->gic, "has-security-extensions", vms->secure);
     }
 
@@ -1186,7 +1186,8 @@ static void create_gic(VirtMachineState *vms, MemoryRegion *mem)
         qdev_prop_set_array(vms->gic, "redist-region-count",
                             redist_region_count);
 
-        if (!kvm_irqchip_in_kernel()) {
+        if (!kvm_irqchip_in_kernel() &&
+         !(hvf_enabled() && hvf_irqchip_in_kernel())) {
             if (vms->tcg_its) {
                 object_property_set_link(OBJECT(vms->gic), "sysmem",
                                          OBJECT(mem), &error_fatal);
@@ -1197,7 +1198,7 @@ static void create_gic(VirtMachineState *vms, MemoryRegion *mem)
                                  ARCH_GIC_MAINT_IRQ);
         }
     } else {
-        if (!kvm_irqchip_in_kernel()) {
+        if (!kvm_irqchip_in_kernel() && !hvf_irqchip_in_kernel()) {
             qdev_prop_set_bit(vms->gic, "has-virtualization-extensions",
                               vms->virt);
         }
@@ -2444,7 +2445,15 @@ static void finalize_gic_version(VirtMachineState *vms)
         accel_name = "KVM with kernel-irqchip=off";
     } else if (whpx_enabled()) {
         gics_supported |= VIRT_GIC_VERSION_3_MASK;
-    } else if (tcg_enabled() || hvf_enabled() || qtest_enabled())  {
+    } else if (hvf_enabled()) {
+        if (!hvf_irqchip_in_kernel()) {
+            gics_supported |= VIRT_GIC_VERSION_2_MASK;
+        }
+        /* Hypervisor.framework doesn't expose EL2<->1 transition notifiers */
+        if (!(!hvf_irqchip_in_kernel() && vms->virt)) {
+            gics_supported |= VIRT_GIC_VERSION_3_MASK;
+        }
+    } else if (tcg_enabled() || qtest_enabled())  {
         gics_supported |= VIRT_GIC_VERSION_2_MASK;
         if (module_object_class_by_name("arm-gicv3")) {
             gics_supported |= VIRT_GIC_VERSION_3_MASK;
@@ -2486,6 +2495,8 @@ static void finalize_msi_controller(VirtMachineState *vms)
             vms->msi_controller = VIRT_MSI_CTRL_GICV2M;
         } else if (whpx_enabled()) {
             vms->msi_controller = VIRT_MSI_CTRL_GICV2M;
+        }  else if (hvf_enabled() && hvf_irqchip_in_kernel()) {
+            vms->msi_controller = VIRT_MSI_CTRL_GICV2M;
         } else {
             vms->msi_controller = VIRT_MSI_CTRL_ITS;
         }
@@ -2505,6 +2516,10 @@ static void finalize_msi_controller(VirtMachineState *vms)
             error_report("ITS not supported on WHPX.");
             exit(1);
         }
+        if (hvf_enabled() && hvf_irqchip_in_kernel()) {
+            error_report("ITS not supported on HVF when using the hardware vGIC.");
+            exit(1);
+        }
     }
 
     assert(vms->msi_controller != VIRT_MSI_CTRL_AUTO);

hw/intc/arm_gicv3_common.c

@@ -33,6 +33,7 @@
 #include "hw/arm/linux-boot-if.h"
 #include "system/kvm.h"
 #include "system/whpx.h"
+#include "system/hvf.h"
 
 
 static void gicv3_gicd_no_migration_shift_bug_post_load(GICv3State *cs)
@@ -659,6 +660,8 @@ const char *gicv3_class_name(void)
         return "kvm-arm-gicv3";
     } else if (whpx_enabled()) {
         return TYPE_WHPX_GICV3;
+    } else if (hvf_enabled() && hvf_irqchip_in_kernel()) {
+        return TYPE_HVF_GICV3;
     } else {
         if (kvm_enabled()) {
             error_report("Userspace GICv3 is not supported with KVM");

include/system/hvf.h

@@ -26,8 +26,11 @@
 #ifdef CONFIG_HVF_IS_POSSIBLE
 extern bool hvf_allowed;
 #define hvf_enabled() (hvf_allowed)
+extern bool hvf_kernel_irqchip;
+#define hvf_irqchip_in_kernel()  (hvf_kernel_irqchip)
 #else /* !CONFIG_HVF_IS_POSSIBLE */
 #define hvf_enabled() 0
+#define hvf_irqchip_in_kernel() 0
 #endif /* !CONFIG_HVF_IS_POSSIBLE */
 
 #define TYPE_HVF_ACCEL ACCEL_CLASS_NAME("hvf")

system/vl.c

@@ -1781,6 +1781,8 @@ static void qemu_apply_legacy_machine_options(QDict *qdict)
                                    false);
         object_register_sugar_prop(ACCEL_CLASS_NAME("whpx"), "kernel-irqchip", value,
                                    false);
+        object_register_sugar_prop(ACCEL_CLASS_NAME("hvf"), "kernel-irqchip", value,
+                                   false);
         qdict_del(qdict, "kernel-irqchip");
     }