From a2d56020d1d91934e7bb3e7c8a5a3b5921ce121b Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Fri, 20 Sep 2013 14:52:43 +1000 Subject: KVM: PPC: Book3S PR: Keep volatile reg values in vcpu rather than shadow_vcpu Currently PR-style KVM keeps the volatile guest register values (R0 - R13, CR, LR, CTR, XER, PC) in a shadow_vcpu struct rather than the main kvm_vcpu struct. For 64-bit, the shadow_vcpu exists in two places, a kmalloc'd struct and in the PACA, and it gets copied back and forth in kvmppc_core_vcpu_load/put(), because the real-mode code can't rely on being able to access the kmalloc'd struct. This changes the code to copy the volatile values into the shadow_vcpu as one of the last things done before entering the guest. Similarly the values are copied back out of the shadow_vcpu to the kvm_vcpu immediately after exiting the guest. We arrange for interrupts to be still disabled at this point so that we can't get preempted on 64-bit and end up copying values from the wrong PACA. This means that the accessor functions in kvm_book3s.h for these registers are greatly simplified, and are same between PR and HV KVM. In places where accesses to shadow_vcpu fields are now replaced by accesses to the kvm_vcpu, we can also remove the svcpu_get/put pairs. Finally, on 64-bit, we don't need the kmalloc'd struct at all any more. With this, the time to read the PVR one million times in a loop went from 567.7ms to 575.5ms (averages of 6 values), an increase of about 1.4% for this worse-case test for guest entries and exits. The standard deviation of the measurements is about 11ms, so the difference is only marginally significant statistically. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/kernel/asm-offsets.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/asm-offsets.c') diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 5a285efba174..fda7f4020a33 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -520,6 +520,7 @@ int main(void) DEFINE(VCPU_PTID, offsetof(struct kvm_vcpu, arch.ptid)); DEFINE(VCPU_CFAR, offsetof(struct kvm_vcpu, arch.cfar)); DEFINE(VCPU_PPR, offsetof(struct kvm_vcpu, arch.ppr)); + DEFINE(VCPU_SHADOW_SRR1, offsetof(struct kvm_vcpu, arch.shadow_srr1)); DEFINE(VCORE_ENTRY_EXIT, offsetof(struct kvmppc_vcore, entry_exit_count)); DEFINE(VCORE_NAP_COUNT, offsetof(struct kvmppc_vcore, nap_count)); DEFINE(VCORE_IN_GUEST, offsetof(struct kvmppc_vcore, in_guest)); @@ -527,14 +528,13 @@ int main(void) DEFINE(VCORE_TB_OFFSET, offsetof(struct kvmppc_vcore, tb_offset)); DEFINE(VCORE_LPCR, offsetof(struct kvmppc_vcore, lpcr)); DEFINE(VCORE_PCR, offsetof(struct kvmppc_vcore, pcr)); - DEFINE(VCPU_SVCPU, offsetof(struct kvmppc_vcpu_book3s, shadow_vcpu) - - offsetof(struct kvmppc_vcpu_book3s, vcpu)); DEFINE(VCPU_SLB_E, offsetof(struct kvmppc_slb, orige)); DEFINE(VCPU_SLB_V, offsetof(struct kvmppc_slb, origv)); DEFINE(VCPU_SLB_SIZE, sizeof(struct kvmppc_slb)); #ifdef CONFIG_PPC_BOOK3S_64 #ifdef CONFIG_KVM_BOOK3S_PR + DEFINE(PACA_SVCPU, offsetof(struct paca_struct, shadow_vcpu)); # define SVCPU_FIELD(x, f) DEFINE(x, offsetof(struct paca_struct, shadow_vcpu.f)) #else # define SVCPU_FIELD(x, f) -- cgit v1.2.1