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Re: [Qemu-ppc] [PATCH v6 2/2] kvm: introduce KVM_MAX_VCPU_ID
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-ppc] [PATCH v6 2/2] kvm: introduce KVM_MAX_VCPU_ID |
Date: |
Tue, 10 May 2016 19:17:22 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.1 |
On 09/05/2016 18:23, Cornelia Huck wrote:
> On Mon, 09 May 2016 18:13:37 +0200
> Greg Kurz <address@hidden> wrote:
>
>> The KVM_MAX_VCPUS define provides the maximum number of vCPUs per guest, and
>> also the upper limit for vCPU ids. This is okay for all archs except PowerPC
>> which can have higher ids, depending on the cpu/core/thread topology. In the
>> worst case (single threaded guest, host with 8 threads per core), it limits
>> the maximum number of vCPUS to KVM_MAX_VCPUS / 8.
>>
>> This patch separates the vCPU numbering from the total number of vCPUs, with
>> the introduction of KVM_MAX_VCPU_ID, as the maximal valid value for vCPU ids
>> plus one.
>>
>> The corresponding KVM_CAP_MAX_VCPU_ID allows userspace to validate vCPU ids
>> before passing them to KVM_CREATE_VCPU.
>>
>> This patch only implements KVM_MAX_VCPU_ID with a specific value for PowerPC.
>> Other archs continue to return KVM_MAX_VCPUS instead.
>>
>> Suggested-by: Radim Krcmar <address@hidden>
>> Signed-off-by: Greg Kurz <address@hidden>
>> ---
>> v6: - provide cap in generic code (Cornelia)
>> - change PowerPC limit to threads_per_subcore * KVM_MAX_VCORES (Radim)
>> ---
>> Documentation/virtual/kvm/api.txt | 10 ++++++++--
>> arch/powerpc/include/asm/kvm_host.h | 3 +++
>> include/linux/kvm_host.h | 4 ++++
>> include/uapi/linux/kvm.h | 1 +
>> virt/kvm/kvm_main.c | 4 +++-
>> 5 files changed, 19 insertions(+), 3 deletions(-)
>
> Reviewed-by: Cornelia Huck <address@hidden>
>
Series pushed to kvm/queue, thanks.
Paolo