[Qemu-devel] [PATCH v12 08/10] hw/arm/virt: Implement kvm_type function for 4.0 machine

[Eric Auger <eric.auger@redhat.com>]

This patch implements the machine class kvm_type() callback.
It returns the number of bits requested to implement the whole GPA
range including the RAM and IO regions located beyond.
The returned value is passed though the KVM_CREATE_VM ioctl and
this allows KVM to set the stage2 tables dynamically.

To compute the highest GPA used in the memory map, kvm_type()
must freeze the memory map by calling virt_set_memmap().

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

---
v11 -> v12:
- added Igor's R-b

v10 -> v11:
- replace !kvm_enabled check by !vms->memmap

v7 -> v8:
- remove vmc->no_extended_memmap and vms->extended_memmap

v6 -> v7:
- Introduce RAMBASE and rename add LEGACY_ prefix in that patch
- use local variables with explicit names in virt_set_memmap:
  device_memory_base, device_memory_size
- add an extended_memmap field in the class

v5 -> v6:
- add some comments
- high IO region cannot start before 256GiB
---
 hw/arm/virt.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 2e788a0361..3ac6b152f5 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1440,7 +1440,13 @@ static void machvirt_init(MachineState *machine)
     bool firmware_loaded = bios_name || drive_get(IF_PFLASH, 0, 0);
     bool aarch64 = true;
 
-    virt_set_memmap(vms);
+    /*
+     * In accelerated mode, the memory map is computed earlier in kvm_type()
+     * to create a VM with the right number of IPA bits.
+     */
+    if (!vms->memmap) {
+        virt_set_memmap(vms);
+    }
 
     /* We can probe only here because during property set
      * KVM is not available yet
@@ -1829,6 +1835,36 @@ static HotplugHandler *virt_machine_get_hotplug_handler(MachineState *machine,
     return NULL;
 }
 
+/*
+ * for arm64 kvm_type [7-0] encodes the requested number of bits
+ * in the IPA address space
+ */
+static int virt_kvm_type(MachineState *ms, const char *type_str)
+{
+    VirtMachineState *vms = VIRT_MACHINE(ms);
+    int max_vm_pa_size = kvm_arm_get_max_vm_ipa_size(ms);
+    int requested_pa_size;
+
+    /* we freeze the memory map to compute the highest gpa */
+    virt_set_memmap(vms);
+
+    requested_pa_size = 64 - clz64(vms->highest_gpa);
+
+    if (requested_pa_size > max_vm_pa_size) {
+        error_report("-m and ,maxmem option values "
+                     "require an IPA range (%d bits) larger than "
+                     "the one supported by the host (%d bits)",
+                     requested_pa_size, max_vm_pa_size);
+       exit(1);
+    }
+    /*
+     * By default we return 0 which corresponds to an implicit legacy
+     * 40b IPA setting. Otherwise we return the actual requested PA
+     * logsize
+     */
+    return requested_pa_size > 40 ? requested_pa_size : 0;
+}
+
 static void virt_machine_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
@@ -1853,6 +1889,7 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
     mc->cpu_index_to_instance_props = virt_cpu_index_to_props;
     mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-a15");
     mc->get_default_cpu_node_id = virt_get_default_cpu_node_id;
+    mc->kvm_type = virt_kvm_type;
     assert(!mc->get_hotplug_handler);
     mc->get_hotplug_handler = virt_machine_get_hotplug_handler;
     hc->plug = virt_machine_device_plug_cb;
-- 
2.20.1