[PATCH 8/8] hw/arm/virt: Disable highmem when on hypervisor.framework

[Alexander Graf]

The Apple M1 only supports up to 36 bits of physical address space. That
means we can not fit the 64bit MMIO BAR region into our address space.

To fix this, let's not expose a 64bit MMIO BAR region when running on
Apple Silicon.

I have not been able to find a way to enumerate that easily, so let's
just assume we always have that little PA space on hypervisor.framework
systems.

Signed-off-by: Alexander Graf <agraf@csgraf.de>
---
 hw/arm/virt.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 27dbeb549e..d74053ecd4 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -45,6 +45,7 @@
 #include "hw/display/ramfb.h"
 #include "net/net.h"
 #include "sysemu/device_tree.h"
+#include "sysemu/hvf.h"
 #include "sysemu/numa.h"
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
@@ -1746,6 +1747,14 @@ static void machvirt_init(MachineState *machine)
     unsigned int smp_cpus = machine->smp.cpus;
     unsigned int max_cpus = machine->smp.max_cpus;
 
+    /*
+     * On Hypervisor.framework capable systems, we only have 36 bits of PA
+     * space, which is not enough to fit a 64bit BAR space
+     */
+    if (hvf_enabled()) {
+        vms->highmem = false;
+    }
+
     /*
      * In accelerated mode, the memory map is computed earlier in kvm_type()
      * to create a VM with the right number of IPA bits.
-- 
2.24.3 (Apple Git-128)