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

On Wed, 20 Feb 2019 23:39:54 +0100
Eric Auger <eric.auger@redhat.com> wrote:

> 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;
That's probably was asked in v6,
do we really need this knob?

>  }
>  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)

Hi Igor,

On 2/22/19 1:45 PM, Igor Mammedov wrote:
> On Wed, 20 Feb 2019 23:39:54 +0100
> Eric Auger <eric.auger@redhat.com> wrote:
> 
>> 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;
> That's probably was asked in v6,
> do we really need this knob?
Yes the point was raised by Peter and I replied by another question ;-) "
But don't we want to forbid any pre-4.0 machvirt to run with more than
255GiB RAM?
"
without this knob:
- pre-4.0 machines will gain the capability to support more than 255GB
initial RAM if the kernel supports dynamic IPA setting
- pre-4.0 machines will gain PCDIMM/NVDIMM support
- another concern, maxmem and slots were not checked previously. If for
some reason - without instantiating the actual slots -, the user
specified it this was previously ignored. Now this is not anymore as
both parameters allow to compute the requested IPA range. So this may
fail now.
So I thought this was clearer to disable all the above for pre-4.0
machines. However if both of you agree, I will remove it.

thanks

Eric
> 
>>  }
>>  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)
> 

On Fri, 22 Feb 2019 15:01:25 +0100
Auger Eric <eric.auger@redhat.com> wrote:

> Hi Igor,
> 
> On 2/22/19 1:45 PM, Igor Mammedov wrote:
> > On Wed, 20 Feb 2019 23:39:54 +0100
> > Eric Auger <eric.auger@redhat.com> wrote:
> >   
> >> 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;  
> > That's probably was asked in v6,
> > do we really need this knob?  
> Yes the point was raised by Peter and I replied by another question ;-) "
> But don't we want to forbid any pre-4.0 machvirt to run with more than
> 255GiB RAM?
> "
> without this knob:
> - pre-4.0 machines will gain the capability to support more than 255GB
> initial RAM if the kernel supports dynamic IPA setting
should be fine, you shouldn't be able to start old QEMU with more than 255Gb

> - pre-4.0 machines will gain PCDIMM/NVDIMM support
ditto

> - another concern, maxmem and slots were not checked previously. If for
> some reason - without instantiating the actual slots -, the user
> specified it this was previously ignored. Now this is not anymore as
> both parameters allow to compute the requested IPA range. So this may
> fail now.
well that's in category of a broken setup even if QEMU didn't complain about
it before. User should fix it instead of QEMU supporting madness.
(I think that such invariant doesn't even deserve deprecation process)

> So I thought this was clearer to disable all the above for pre-4.0
> machines. However if both of you agree, I will remove it.
> 
> thanks
> 
> Eric
> >   
> >>  }
> >>  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)  
> >   
> 

Hi Igor,

On 2/22/19 3:39 PM, Igor Mammedov wrote:
> On Fri, 22 Feb 2019 15:01:25 +0100
> Auger Eric <eric.auger@redhat.com> wrote:
> 
>> Hi Igor,
>>
>> On 2/22/19 1:45 PM, Igor Mammedov wrote:
>>> On Wed, 20 Feb 2019 23:39:54 +0100
>>> Eric Auger <eric.auger@redhat.com> wrote:
>>>   
>>>> 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;  
>>> That's probably was asked in v6,
>>> do we really need this knob?  
>> Yes the point was raised by Peter and I replied by another question ;-) "
>> But don't we want to forbid any pre-4.0 machvirt to run with more than
>> 255GiB RAM?
>> "
>> without this knob:
>> - pre-4.0 machines will gain the capability to support more than 255GB
>> initial RAM if the kernel supports dynamic IPA setting
> should be fine, you shouldn't be able to start old QEMU with more than 255Gb
> 
>> - pre-4.0 machines will gain PCDIMM/NVDIMM support
> ditto
> 
>> - another concern, maxmem and slots were not checked previously. If for
>> some reason - without instantiating the actual slots -, the user
>> specified it this was previously ignored. Now this is not anymore as
>> both parameters allow to compute the requested IPA range. So this may
>> fail now.
> well that's in category of a broken setup even if QEMU didn't complain about
> it before. User should fix it instead of QEMU supporting madness.
> (I think that such invariant doesn't even deserve deprecation process)

OK. So I will remove the knob in the next release.

thanks

Eric
> 
>> So I thought this was clearer to disable all the above for pre-4.0
>> machines. However if both of you agree, I will remove it.
>>
>> thanks
>>
>> Eric
>>>   
>>>>  }
>>>>  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)  
>>>   
>>
>