From 20754c2495a791b5b429c0da63394c86ade978e7 Mon Sep 17 00:00:00 2001 From: Hollis Blanchard Date: Fri, 25 Jul 2008 13:54:51 -0500 Subject: KVM: ppc: Stop saving host TLB state We're saving the host TLB state to memory on every exit, but never using it. Originally I had thought that we'd want to restore host TLB for heavyweight exits, but that could actually hurt when context switching to an unrelated host process (i.e. not qemu). Since this decreases the performance penalty of all exits, this patch improves guest boot time by about 15%. Signed-off-by: Hollis Blanchard Signed-off-by: Avi Kivity --- arch/powerpc/kernel/asm-offsets.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 92768d3006f7..594064953951 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -356,7 +356,6 @@ int main(void) DEFINE(VCPU_HOST_STACK, offsetof(struct kvm_vcpu, arch.host_stack)); DEFINE(VCPU_HOST_PID, offsetof(struct kvm_vcpu, arch.host_pid)); - DEFINE(VCPU_HOST_TLB, offsetof(struct kvm_vcpu, arch.host_tlb)); DEFINE(VCPU_SHADOW_TLB, offsetof(struct kvm_vcpu, arch.shadow_tlb)); DEFINE(VCPU_GPRS, offsetof(struct kvm_vcpu, arch.gpr)); DEFINE(VCPU_LR, offsetof(struct kvm_vcpu, arch.lr)); -- cgit v1.2.1 From 83aae4a8098eb8a40a2e9dab3714354182143b4f Mon Sep 17 00:00:00 2001 From: Hollis Blanchard Date: Fri, 25 Jul 2008 13:54:52 -0500 Subject: KVM: ppc: Write only modified shadow entries into the TLB on exit Track which TLB entries need to be written, instead of overwriting everything below the high water mark. Typically only a single guest TLB entry will be modified in a single exit. Guest boot time performance improvement: about 15%. Signed-off-by: Hollis Blanchard Signed-off-by: Avi Kivity --- arch/powerpc/kernel/asm-offsets.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 594064953951..1631d670b9ed 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -357,6 +357,7 @@ int main(void) DEFINE(VCPU_HOST_STACK, offsetof(struct kvm_vcpu, arch.host_stack)); DEFINE(VCPU_HOST_PID, offsetof(struct kvm_vcpu, arch.host_pid)); DEFINE(VCPU_SHADOW_TLB, offsetof(struct kvm_vcpu, arch.shadow_tlb)); + DEFINE(VCPU_SHADOW_MOD, offsetof(struct kvm_vcpu, arch.shadow_tlb_mod)); DEFINE(VCPU_GPRS, offsetof(struct kvm_vcpu, arch.gpr)); DEFINE(VCPU_LR, offsetof(struct kvm_vcpu, arch.lr)); DEFINE(VCPU_CR, offsetof(struct kvm_vcpu, arch.cr)); -- cgit v1.2.1 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/kernel/asm-offsets.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 1631d670b9ed..52649da344fb 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -369,7 +369,7 @@ int main(void) DEFINE(VCPU_SPRG5, offsetof(struct kvm_vcpu, arch.sprg5)); DEFINE(VCPU_SPRG6, offsetof(struct kvm_vcpu, arch.sprg6)); DEFINE(VCPU_SPRG7, offsetof(struct kvm_vcpu, arch.sprg7)); - DEFINE(VCPU_PID, offsetof(struct kvm_vcpu, arch.pid)); + DEFINE(VCPU_SHADOW_PID, offsetof(struct kvm_vcpu, arch.shadow_pid)); DEFINE(VCPU_LAST_INST, offsetof(struct kvm_vcpu, arch.last_inst)); DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear)); -- cgit v1.2.1