Hi Marc, Christoffer - to clarify - this series may be causing a conflict with the arm64 basic approach, and arm32 exit code touch ups. The intent for this series is more of an RFC or preview, to get some feedback - if this approach is sensible (I guess later applied to arm64 as well if it is). Thanks, - Mario On 06/24/2015 08:30 PM, Mario Smarduch wrote: > Currently we do a lazy VFP switch in Hyp mode, but once we exit and re-enter hyp > mode we trap again on VFP access. This mode has shown around 30-50% improvement > running hackbench and lmbench. > > This patch series extends lazy VFP switch beyond Hyp mode to KVM host mode. > > 1 - On guest access we switch from host to guest and set a flag accessible to > host > 2 - On exit to KVM host, VFP state is restored on vcpu_put if flag is marked (1) > 3 - Otherwise guest is resumed and continues to use its VFP registers. > 4 - In case of 2 on VM entry we set VFP trap flag to repeat 1. > > If guest does not access VFP registers them implemenation remains the same. > > Executing hackbench on Fast Models and Exynos arm32 board shows good > results. Considering all exits 2% of the time KVM host lazy vfp switch is > invoked. > > Howeverr this patch set requires more burn in time and testing under various > loads. > > Currently ARM32 is addressed later ARM64. > > Mario Smarduch (3): > define headers and offsets to mange VFP state > Implement lazy VFP switching outside of Hyp Mode > Add VFP lazy switch hooks in Host KVM > > arch/arm/include/asm/kvm_asm.h | 1 + > arch/arm/include/asm/kvm_host.h | 3 +++ > arch/arm/kernel/asm-offsets.c | 1 + > arch/arm/kvm/arm.c | 15 ++++++++++++ > arch/arm/kvm/interrupts.S | 49 +++++++++++++++++++++++++-------------- > 5 files changed, 51 insertions(+), 18 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
