From 83aae4a8098eb8a40a2e9dab3714354182143b4f Mon Sep 17 00:00:00 2001 From: Hollis Blanchard Date: Fri, 25 Jul 2008 13:54:52 -0500 Subject: [PATCH] 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/include/asm/kvm_host.h | 3 ++ arch/powerpc/include/asm/kvm_ppc.h | 3 ++ arch/powerpc/kernel/asm-offsets.c | 1 + arch/powerpc/kvm/44x_tlb.c | 9 ++++- arch/powerpc/kvm/booke_interrupts.S | 51 +++++++++++++++++++---------- arch/powerpc/kvm/powerpc.c | 15 +++++++++ 6 files changed, 64 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index dc3a7562bae4..4338b03da8f9 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -82,6 +82,9 @@ struct kvm_vcpu_arch { /* Pages which are referenced in the shadow TLB. */ struct page *shadow_pages[PPC44x_TLB_SIZE]; + /* Track which TLB entries we've modified in the current exit. */ + u8 shadow_tlb_mod[PPC44x_TLB_SIZE]; + u32 host_stack; u32 host_pid; u32 host_dbcr0; diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index a8b068792260..8e7e42959903 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -65,6 +65,9 @@ extern void kvmppc_mmu_invalidate(struct kvm_vcpu *vcpu, gva_t eaddr, gva_t eend, u32 asid); extern void kvmppc_mmu_priv_switch(struct kvm_vcpu *vcpu, int usermode); +/* XXX Book E specific */ +extern void kvmppc_tlbe_set_modified(struct kvm_vcpu *vcpu, unsigned int i); + extern void kvmppc_check_and_deliver_interrupts(struct kvm_vcpu *vcpu); static inline void kvmppc_queue_exception(struct kvm_vcpu *vcpu, int exception) 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)); diff --git a/arch/powerpc/kvm/44x_tlb.c b/arch/powerpc/kvm/44x_tlb.c index a207d16b9dbb..06a5fcfc4d33 100644 --- a/arch/powerpc/kvm/44x_tlb.c +++ b/arch/powerpc/kvm/44x_tlb.c @@ -125,6 +125,11 @@ static void kvmppc_44x_shadow_release(struct kvm_vcpu *vcpu, } } +void kvmppc_tlbe_set_modified(struct kvm_vcpu *vcpu, unsigned int i) +{ + vcpu->arch.shadow_tlb_mod[i] = 1; +} + /* Caller must ensure that the specified guest TLB entry is safe to insert into * the shadow TLB. */ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid, @@ -172,10 +177,10 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid, * use host large pages in the future. */ stlbe->word0 = (gvaddr & PAGE_MASK) | PPC44x_TLB_VALID | PPC44x_TLB_TS | PPC44x_TLB_4K; - stlbe->word1 = (hpaddr & 0xfffffc00) | ((hpaddr >> 32) & 0xf); stlbe->word2 = kvmppc_44x_tlb_shadow_attrib(flags, vcpu->arch.msr & MSR_PR); + kvmppc_tlbe_set_modified(vcpu, victim); KVMTRACE_5D(STLB_WRITE, vcpu, victim, stlbe->tid, stlbe->word0, stlbe->word1, stlbe->word2, @@ -209,6 +214,7 @@ void kvmppc_mmu_invalidate(struct kvm_vcpu *vcpu, gva_t eaddr, kvmppc_44x_shadow_release(vcpu, i); stlbe->word0 = 0; + kvmppc_tlbe_set_modified(vcpu, i); KVMTRACE_5D(STLB_INVAL, vcpu, i, stlbe->tid, stlbe->word0, stlbe->word1, stlbe->word2, handler); @@ -229,6 +235,7 @@ void kvmppc_mmu_priv_switch(struct kvm_vcpu *vcpu, int usermode) kvmppc_44x_shadow_release(vcpu, i); stlbe->word0 = 0; + kvmppc_tlbe_set_modified(vcpu, i); KVMTRACE_5D(STLB_INVAL, vcpu, i, stlbe->tid, stlbe->word0, stlbe->word1, stlbe->word2, handler); diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S index 3e88dfa1dbe4..564ea32ecbac 100644 --- a/arch/powerpc/kvm/booke_interrupts.S +++ b/arch/powerpc/kvm/booke_interrupts.S @@ -335,7 +335,7 @@ lightweight_exit: lwz r3, VCPU_PID(r4) mtspr SPRN_PID, r3 - /* Prevent all TLB updates. */ + /* Prevent all asynchronous TLB updates. */ mfmsr r5 lis r6, (MSR_EE|MSR_CE|MSR_ME|MSR_DE)@h ori r6, r6, (MSR_EE|MSR_CE|MSR_ME|MSR_DE)@l @@ -344,28 +344,45 @@ lightweight_exit: /* Load the guest mappings, leaving the host's "pinned" kernel mappings * in place. */ - /* XXX optimization: load only modified guest entries. */ mfspr r10, SPRN_MMUCR /* Save host MMUCR. */ - lis r8, tlb_44x_hwater@ha - lwz r8, tlb_44x_hwater@l(r8) - addi r9, r4, VCPU_SHADOW_TLB - 4 - li r6, 0 + li r5, PPC44x_TLB_SIZE + lis r5, tlb_44x_hwater@ha + lwz r5, tlb_44x_hwater@l(r5) + mtctr r5 + addi r9, r4, VCPU_SHADOW_TLB + addi r5, r4, VCPU_SHADOW_MOD + li r3, 0 1: + lbzx r7, r3, r5 + cmpwi r7, 0 + beq 3f + /* Load guest entry. */ - lwzu r7, 4(r9) + mulli r11, r3, TLBE_BYTES + add r11, r11, r9 + lwz r7, 0(r11) mtspr SPRN_MMUCR, r7 - lwzu r7, 4(r9) - tlbwe r7, r6, PPC44x_TLB_PAGEID - lwzu r7, 4(r9) - tlbwe r7, r6, PPC44x_TLB_XLAT - lwzu r7, 4(r9) - tlbwe r7, r6, PPC44x_TLB_ATTRIB - /* Increment index. */ - addi r6, r6, 1 - cmpw r6, r8 - blt 1b + lwz r7, 4(r11) + tlbwe r7, r3, PPC44x_TLB_PAGEID + lwz r7, 8(r11) + tlbwe r7, r3, PPC44x_TLB_XLAT + lwz r7, 12(r11) + tlbwe r7, r3, PPC44x_TLB_ATTRIB +3: + addi r3, r3, 1 /* Increment index. */ + bdnz 1b + mtspr SPRN_MMUCR, r10 /* Restore host MMUCR. */ + /* Clear bitmap of modified TLB entries */ + li r5, PPC44x_TLB_SIZE>>2 + mtctr r5 + addi r5, r4, VCPU_SHADOW_MOD - 4 + li r6, 0 +1: + stwu r6, 4(r5) + bdnz 1b + iccci 0, 0 /* XXX hack */ /* Load some guest volatiles. */ diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index b75607180ddb..90a6fc422b23 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -27,6 +27,7 @@ #include #include #include +#include gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn) @@ -307,14 +308,28 @@ static void kvmppc_load_guest_debug_registers(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { + int i; + if (vcpu->guest_debug.enabled) kvmppc_load_guest_debug_registers(vcpu); + + /* Mark every guest entry in the shadow TLB entry modified, so that they + * will all be reloaded on the next vcpu run (instead of being + * demand-faulted). */ + for (i = 0; i <= tlb_44x_hwater; i++) + kvmppc_tlbe_set_modified(vcpu, i); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { if (vcpu->guest_debug.enabled) kvmppc_restore_host_debug_state(vcpu); + + /* Don't leave guest TLB entries resident when being de-scheduled. */ + /* XXX It would be nice to differentiate between heavyweight exit and + * sched_out here, since we could avoid the TLB flush for heavyweight + * exits. */ + _tlbia(); } int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu, -- 2.34.1