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Re: [Qemu-arm] [Qemu-devel] [PATCH v7 08/17] hw/arm/virt: Implement kvm_
From: |
Auger Eric |
Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH v7 08/17] hw/arm/virt: Implement kvm_type function for 4.0 machine |
Date: |
Fri, 22 Feb 2019 15:53:23 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
Hi Igor,
On 2/22/19 3:39 PM, Igor Mammedov wrote:
> On Fri, 22 Feb 2019 15:01:25 +0100
> Auger Eric <address@hidden> wrote:
>
>> Hi Igor,
>>
>> On 2/22/19 1:45 PM, Igor Mammedov wrote:
>>> On Wed, 20 Feb 2019 23:39:54 +0100
>>> Eric Auger <address@hidden> 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 <address@hidden>
>>>>
>>>> ---
>>>>
>>>> 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)
>>>
>>
>
[Qemu-arm] [PATCH v7 09/17] hw/arm/virt: Bump the 255GB initial RAM limit, Eric Auger, 2019/02/20
[Qemu-arm] [PATCH v7 11/17] hw/arm/boot: Expose the PC-DIMM nodes in the DT, Eric Auger, 2019/02/20
[Qemu-arm] [PATCH v7 10/17] hw/arm/virt: Add memory hotplug framework, Eric Auger, 2019/02/20
[Qemu-arm] [PATCH v7 12/17] hw/arm/virt-acpi-build: Add PC-DIMM in SRAT, Eric Auger, 2019/02/20
[Qemu-arm] [PATCH v7 13/17] hw/arm/virt: Allocate device_memory, Eric Auger, 2019/02/20