From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hollis Blanchard Subject: [PATCH 4 of 6] kvm: ppc: save and restore guest mappings on context switch Date: Tue, 02 Dec 2008 15:51:56 -0600 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org To: avi@redhat.com Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:35753 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751848AbYLBVwH (ORCPT ); Tue, 2 Dec 2008 16:52:07 -0500 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e33.co.us.ibm.com (8.13.1/8.13.1) with ESMTP id mB2LpTAr014903 for ; Tue, 2 Dec 2008 14:51:29 -0700 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id mB2Lpvtd199182 for ; Tue, 2 Dec 2008 14:51:59 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id mB2LpuM0024584 for ; Tue, 2 Dec 2008 14:51:57 -0700 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: Store shadow TLB entries in memory, but only use it on host context switch (instead of every guest entry). This improves performance for most workloads on 440 by reducing the guest TLB miss rate. Signed-off-by: Hollis Blanchard diff --git a/arch/powerpc/include/asm/kvm_44x.h b/arch/powerpc/include/asm/kvm_44x.h --- a/arch/powerpc/include/asm/kvm_44x.h +++ b/arch/powerpc/include/asm/kvm_44x.h @@ -42,6 +42,10 @@ struct kvmppc_vcpu_44x { /* References to guest pages in the hardware TLB. */ struct kvmppc_44x_shadow_ref shadow_refs[PPC44x_TLB_SIZE]; + /* State of the shadow TLB at guest context switch time. */ + struct kvmppc_44x_tlbe shadow_tlb[PPC44x_TLB_SIZE]; + u8 shadow_tlb_mod[PPC44x_TLB_SIZE]; + struct kvm_vcpu vcpu; }; @@ -51,5 +55,7 @@ static inline struct kvmppc_vcpu_44x *to } void kvmppc_set_pid(struct kvm_vcpu *vcpu, u32 new_pid); +void kvmppc_44x_tlb_put(struct kvm_vcpu *vcpu); +void kvmppc_44x_tlb_load(struct kvm_vcpu *vcpu); #endif /* __ASM_44X_H__ */ diff --git a/arch/powerpc/kvm/44x.c b/arch/powerpc/kvm/44x.c --- a/arch/powerpc/kvm/44x.c +++ b/arch/powerpc/kvm/44x.c @@ -96,15 +96,12 @@ void kvmppc_core_load_guest_debugstate(s void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { + kvmppc_44x_tlb_load(vcpu); } void kvmppc_core_vcpu_put(struct kvm_vcpu *vcpu) { - /* XXX Since every guest uses TS=1 TID=0/1 mappings, we can't leave any TLB - * entries around when we're descheduled, so we must completely flush the - * TLB of all guest mappings. On the other hand, if there is only one - * guest, this flush is completely unnecessary. */ - _tlbia(); + kvmppc_44x_tlb_put(vcpu); } int kvmppc_core_check_processor_compat(void) diff --git a/arch/powerpc/kvm/44x_tlb.c b/arch/powerpc/kvm/44x_tlb.c --- a/arch/powerpc/kvm/44x_tlb.c +++ b/arch/powerpc/kvm/44x_tlb.c @@ -73,6 +73,25 @@ static inline void kvmppc_44x_tlbie(unsi ); } +static inline void kvmppc_44x_tlbre(unsigned int index, + struct kvmppc_44x_tlbe *tlbe) +{ + asm volatile( + "tlbre %[word0], %[index], 0\n" + "mfspr %[tid], %[sprn_mmucr]\n" + "andi. %[tid], %[tid], 0xff\n" + "tlbre %[word1], %[index], 1\n" + "tlbre %[word2], %[index], 2\n" + : [word0] "=r"(tlbe->word0), + [word1] "=r"(tlbe->word1), + [word2] "=r"(tlbe->word2), + [tid] "=r"(tlbe->tid) + : [index] "r"(index), + [sprn_mmucr] "i"(SPRN_MMUCR) + : "cc" + ); +} + static inline void kvmppc_44x_tlbwe(unsigned int index, struct kvmppc_44x_tlbe *stlbe) { @@ -115,6 +134,44 @@ static u32 kvmppc_44x_tlb_shadow_attrib( return attrib; } + +/* Load shadow TLB back into hardware. */ +void kvmppc_44x_tlb_load(struct kvm_vcpu *vcpu) +{ + struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu); + int i; + + for (i = 0; i <= tlb_44x_hwater; i++) { + struct kvmppc_44x_tlbe *stlbe = &vcpu_44x->shadow_tlb[i]; + + if (get_tlb_v(stlbe) && get_tlb_ts(stlbe)) + kvmppc_44x_tlbwe(i, stlbe); + } +} + +static void kvmppc_44x_tlbe_set_modified(struct kvmppc_vcpu_44x *vcpu_44x, + unsigned int i) +{ + vcpu_44x->shadow_tlb_mod[i] = 1; +} + +/* Save hardware TLB to the vcpu, and invalidate all guest mappings. */ +void kvmppc_44x_tlb_put(struct kvm_vcpu *vcpu) +{ + struct kvmppc_vcpu_44x *vcpu_44x = to_44x(vcpu); + int i; + + for (i = 0; i <= tlb_44x_hwater; i++) { + struct kvmppc_44x_tlbe *stlbe = &vcpu_44x->shadow_tlb[i]; + + if (vcpu_44x->shadow_tlb_mod[i]) + kvmppc_44x_tlbre(i, stlbe); + + if (get_tlb_v(stlbe) && get_tlb_ts(stlbe)) + kvmppc_44x_tlbie(i); + } +} + /* Search the guest TLB for a matching entry. */ int kvmppc_44x_tlb_index(struct kvm_vcpu *vcpu, gva_t eaddr, unsigned int pid, @@ -283,6 +340,7 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcp ref->tid = stlbe.tid; /* Insert shadow mapping into hardware TLB. */ + kvmppc_44x_tlbe_set_modified(vcpu_44x, victim); kvmppc_44x_tlbwe(victim, &stlbe); KVMTRACE_5D(STLB_WRITE, vcpu, victim, stlbe.tid, stlbe.word0, stlbe.word1, stlbe.word2, handler);