Re: [PATCH v2 2/7] KVM-HDR: KVM Steal time implementation

[Glauber Costa <glommer@redhat.com>]

On 06/19/2011 06:49 AM, Avi Kivity wrote:
> On 06/17/2011 01:20 AM, Glauber Costa wrote:
>> To implement steal time, we need the hypervisor to pass the guest
>> information
>> about how much time was spent running other processes outside the VM.
>> This is per-vcpu, and using the kvmclock structure for that is an abuse
>> we decided not to make.
>>
>> In this patchset, I am introducing a new msr, KVM_MSR_STEAL_TIME, that
>> holds the memory area address containing information about steal time
>>
>> This patch contains the headers for it. I am keeping it separate to
>> facilitate
>> backports to people who wants to backport the kernel part but not the
>> hypervisor, or the other way around.
>>
>>
>> index d079aed..79c12a7 100644
>> --- a/Documentation/virtual/kvm/msr.txt
>> +++ b/Documentation/virtual/kvm/msr.txt
>> @@ -185,3 +185,36 @@ MSR_KVM_ASYNC_PF_EN: 0x4b564d02
>>
>> Currently type 2 APF will be always delivered on the same vcpu as
>> type 1 was, but guest should not rely on that.
>> +
>> +MSR_KVM_STEAL_TIME: 0x4b564d03
>> +
>> + data: 64-byte alignment physical address of a memory area which must be
>> + in guest RAM, plus an enable bit in bit 0. This memory is expected to
>> + hold a copy of the following structure:
>> +
>> + struct kvm_steal_time {
>> + __u64 steal;
>> + __u32 version;
>> + __u32 flags;
>> + __u32 pad[6];
>
> Should be 12 to be a 64-byte structure, no?
Avi, you should understand this is a discussion between 3 people: One of 
them can do math, the other can't.