Hi Shannon,
On 28/03/18 06:02, Shannon Zhao wrote:
>
>
> On 2018/3/27 22:15, Eric Auger wrote:
>> With KVM acceleration and if KVM VGICV3 supports to set multiple
>> redistributor regions, we now allow up to 512 vcpus.
>>
>> Signed-off-by: Eric Auger <eric.au...@redhat.com>
>> ---
>> hw/arm/virt.c | 17 ++++++++++++++++-
>> include/hw/arm/virt.h | 1 +
>> 2 files changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 8258f6f..cdb1a75 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -149,8 +149,10 @@ static const MemMapEntry a15memmap[] = {
>> [VIRT_PCIE_PIO] = { 0x3eff0000, 0x00010000 },
>> [VIRT_PCIE_ECAM] = { 0x3f000000, 0x01000000 },
>> [VIRT_MEM] = { 0x40000000, RAMLIMIT_BYTES },
>> + /* Allows 512 - 123 additional vcpus (each 2x64kB) */
>> + [VIRT_GIC_REDIST2] = { 0x4000000000ULL, 0x30A0000LL },
> One concern that this will limit the guest ram size to RAMLIMIT_BYTES.
> If we want to support larger ram size in the future, this may be a problem.
There is comment before #define RAMLIMIT_GB 255
saying that RAM extension should rather happen at 2TB base.
"../.. We don't want to fill all the way up to 512GB with RAM because
* we might want it for non-RAM purposes later"
This REDIST2 region could also be allocated at the top of the [256GB -
512GB] region.
I will start working on extending the RAM as suggested by this comment.
Thanks
Eric
>
>> /* Second PCIe window, 512GB wide at the 512GB boundary */
>> - [VIRT_PCIE_MMIO_HIGH] = { 0x8000000000ULL, 0x8000000000ULL },
>> + [VIRT_PCIE_MMIO_HIGH] = { 0x8000000000ULL, 0x8000000000ULL },
>> };
>>
>> static const int a15irqmap[] = {
>> @@ -553,6 +555,11 @@ static void create_gic(VirtMachineState *vms, qemu_irq
>> *pic)
>> agcc->register_redist_region((GICv3State *)gicdev,
>> vms->memmap[VIRT_GIC_REDIST].base,
>> vms->memmap[VIRT_GIC_REDIST].size >> 17);
>> + if (vms->smp_cpus > 123) {
>> + agcc->register_redist_region((GICv3State *)gicdev,
>> + vms->memmap[VIRT_GIC_REDIST2].base,
>> + vms->memmap[VIRT_GIC_REDIST2].size >> 17);
>> + }
>> } else {
>> sysbus_mmio_map(gicbusdev, 1, vms->memmap[VIRT_GIC_CPU].base);
>> }
>> @@ -1284,6 +1291,14 @@ static void machvirt_init(MachineState *machine)
>> */
>> if (vms->gic_version == 3) {
>> virt_max_cpus = vms->memmap[VIRT_GIC_REDIST].size / 0x20000;
>> + if (kvm_max_vcpus(kvm_state) > 255) {
>> + /*
>> + * VGICv3 KVM device capability to set multiple redistributor
>> + * was introduced at the same time KVM_MAX_VCPUS was bumped
>> + * from 255 to 512
>> + */
>> + virt_max_cpus += vms->memmap[VIRT_GIC_REDIST2].size / 0x20000;
>> + }
>> } else {
>> virt_max_cpus = GIC_NCPU;
>> }
>> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
>> index d168291..801a4ad 100644
>> --- a/include/hw/arm/virt.h
>> +++ b/include/hw/arm/virt.h
>> @@ -60,6 +60,7 @@ enum {
>> VIRT_GIC_V2M,
>> VIRT_GIC_ITS,
>> VIRT_GIC_REDIST,
>> + VIRT_GIC_REDIST2,
>> VIRT_UART,
>> VIRT_MMIO,
>> VIRT_RTC,
>>
>
