From 49dd2c492895828a90ecdf889e7fe9cfb40a82a7 Mon Sep 17 00:00:00 2001 From: Hollis Blanchard Date: Fri, 25 Jul 2008 13:54:53 -0500 Subject: KVM: powerpc: Map guest userspace with TID=0 mappings When we use TID=N userspace mappings, we must ensure that kernel mappings have been destroyed when entering userspace. Using TID=1/TID=0 for kernel/user mappings and running userspace with PID=0 means that userspace can't access the kernel mappings, but the kernel can directly access userspace. The net is that we don't need to flush the TLB on privilege switches, but we do on guest context switches (which are far more infrequent). Guest boot time performance improvement: about 30%. Signed-off-by: Hollis Blanchard Signed-off-by: Avi Kivity --- arch/powerpc/kvm/booke_interrupts.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/kvm/booke_interrupts.S') diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S index 564ea32ecbac..95e165baf85f 100644 --- a/arch/powerpc/kvm/booke_interrupts.S +++ b/arch/powerpc/kvm/booke_interrupts.S @@ -332,7 +332,7 @@ lightweight_exit: mfspr r3, SPRN_PID stw r3, VCPU_HOST_PID(r4) - lwz r3, VCPU_PID(r4) + lwz r3, VCPU_SHADOW_PID(r4) mtspr SPRN_PID, r3 /* Prevent all asynchronous TLB updates. */ -- cgit v1.2.3