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

[Alexander Graf]

On 03.07.2013, at 14:42, 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.

Not sure I follow. Could you please describe exactly what's happening?


Alex

> 
> 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);
> 		}
> 	}
> 
> diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
> index 19c8379..09da1ac 100644
> --- a/arch/powerpc/kvm/e500mc.c
> +++ b/arch/powerpc/kvm/e500mc.c
> @@ -143,8 +143,6 @@ void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> 		kvmppc_e500_tlbil_all(vcpu_e500);
> 		__get_cpu_var(last_vcpu_on_cpu) = vcpu;
> 	}
> -
> -	kvmppc_load_guest_fp(vcpu);
> }
> 
> void kvmppc_core_vcpu_put(struct kvm_vcpu *vcpu)
> -- 
> 1.7.3.4
> 
> 
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