Hello! > > The access is done similar to vGICv2, using KVM_DEV_ARM_VGIC_GRP_DIST_REGS > > and KVM_DEV_ARM_VGIC_GRP_REDIST_REGS with KVM_SET_DEVICE_ATTR and > > KVM_GET_DEVICE_ATTR ioctls. Since GICv3 can handle large number of CPUs, > > KVM_DEV_ARM_VGIC_CPUID_MASK has been extended to 20 bits. This is enough > > for 1048576 CPUs. > > I guess the 20 bits come from 8 bits for Aff2 and Aff1 and 4-bits for > Aff0? If so, please mention this. But I am not sure we should limit the > cpu index in this public API
The documentation is confusing. It is actually not the affinity ID, but just number from 0 to N. See http://lxr.free-electrons.com/source/include/linux/kvm_host.h#L427 - this is the function which gets this "id" and returns vcpu structure. So, we can have up to 1 << 20 = 1048576 CPUs. Enough? If you are OK with this, i can post a separate patch to fix the documentation, or include it in respin. > we could push the size bit into offset and use the > full upper 32 bits for cpuid, or at least 28 bits plus 4 reserved. Actually 20 bits comes from ARM64_SYS_REG() macro, which i reuse for KVM_DEV_ARM_VGIC_GRP_CPU_REGS: --- cut --- bits: | 63 .. 56 | 55 .. 48 | 47 ... 40 | 39 .. 32 | 31 .. 0 | values: | arch | size | reserved | cpu id | reg id | --- cut --- arch = KVM_REG_ARM64 and size = KVM_REG_SIZE_U64. I decided not to invent own macro. Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
