[PATCH 3/6] KVM: PPC: Book3E: Increase FPU laziness

[Alexander Graf]

On 03.07.2013, at 19:18, Scott Wood wrote:

> On 07/03/2013 07:42:36 AM, Mihai Caraman wrote:
>> Increase FPU laziness by calling kvmppc_load_guest_fp() just before
>> returning to guest instead of each sched in. Without this improvement
>> an interrupt may also claim floting point corrupting guest state.
>> Signed-off-by: Mihai Caraman <mihai.caraman at freescale.com>
>> ---
>> arch/powerpc/kvm/booke.c  |    1 +
>> arch/powerpc/kvm/e500mc.c |    2 --
>> 2 files changed, 1 insertions(+), 2 deletions(-)
>> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
>> index 113961f..3cae2e3 100644
>> --- a/arch/powerpc/kvm/booke.c
>> +++ b/arch/powerpc/kvm/booke.c
>> @@ -1204,6 +1204,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
>> 			r = (s << 2) | RESUME_HOST | (r & RESUME_FLAG_NV);
>> 		} else {
>> 			kvmppc_lazy_ee_enable();
>> +			kvmppc_load_guest_fp(vcpu);
>> 		}
> 
> This should go before the kvmppc_lazy_ee_enable().

Why? What difference does that make? We're running with interrupts disabled here, right?


Alex