[Qemu-devel] [PATCH v7 08/17] 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 in passed though the KVM_CREATE_VM ioctl and
this allows KVM to set the stage2 tables dynamically.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

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         | 50 ++++++++++++++++++++++++++++++++++++++++++-
 include/hw/arm/virt.h |  2 ++
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 9db602457b..ad3a0ad73d 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1437,7 +1437,14 @@ 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 in kvm_type(),
+     * if set, to create a VM with the right number of IPA bits.
+     */
+
+    if (!mc->kvm_type || !kvm_enabled()) {
+        virt_set_memmap(vms);
+    }
 
     /* We can probe only here because during property set
      * KVM is not available yet
@@ -1814,6 +1821,36 @@ 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);
@@ -1838,6 +1875,7 @@ 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;
@@ -1909,6 +1947,12 @@ static void virt_instance_init(Object *obj)
                                     "Valid values are none and smmuv3",
                                     NULL);
 
+    if (vmc->no_extended_memmap) {
+        vms->extended_memmap = false;
+    } else {
+        vms->extended_memmap = true;
+    }
+
     vms->irqmap = a15irqmap;
 }
 
@@ -1939,8 +1983,12 @@ DEFINE_VIRT_MACHINE_AS_LATEST(4, 0)
 
 static void virt_machine_3_1_options(MachineClass *mc)
 {
+    VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
     virt_machine_4_0_options(mc);
     compat_props_add(mc->compat_props, hw_compat_3_1, hw_compat_3_1_len);
+
+    /* extended memory map is enabled from 4.0 onwards */
+    vmc->no_extended_memmap = true;
 }
 DEFINE_VIRT_MACHINE(3, 1)
 
diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index acad0400d8..7798462cb0 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -106,6 +106,7 @@ typedef struct {
     bool claim_edge_triggered_timers;
     bool smbios_old_sys_ver;
     bool no_highmem_ecam;
+    bool no_extended_memmap;
 } VirtMachineClass;
 
 typedef struct {
@@ -135,6 +136,7 @@ typedef struct {
     hwaddr highest_gpa;
     hwaddr device_memory_base;
     hwaddr device_memory_size;
+    bool extended_memmap;
 } VirtMachineState;
 
 #define VIRT_ECAM_ID(high) (high ? VIRT_HIGH_PCIE_ECAM : VIRT_PCIE_ECAM)
-- 
2.20.1