From 096d14a3b57e4a87d27be09cc64b4f84660acd08 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Fri, 22 Feb 2008 12:21:38 -0500 Subject: [PATCH] x86: KVM guest: hypercall batching Batch pte updates and tlb flushes in lazy MMU mode. [avi: - adjust to mmu_op - helper for getting para_state without debug warnings] Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/kernel/kvm.c | 62 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 60 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index cbadc730496a..8b7a3cf37d2b 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -26,6 +26,22 @@ #include #include #include +#include + +#define MMU_QUEUE_SIZE 1024 + +struct kvm_para_state { + u8 mmu_queue[MMU_QUEUE_SIZE]; + int mmu_queue_len; + enum paravirt_lazy_mode mode; +}; + +static DEFINE_PER_CPU(struct kvm_para_state, para_state); + +static struct kvm_para_state *kvm_para_state(void) +{ + return &per_cpu(para_state, raw_smp_processor_id()); +} /* * No need for any "IO delay" on KVM @@ -48,6 +64,28 @@ static void kvm_mmu_op(void *buffer, unsigned len) } while (len); } +static void mmu_queue_flush(struct kvm_para_state *state) +{ + if (state->mmu_queue_len) { + kvm_mmu_op(state->mmu_queue, state->mmu_queue_len); + state->mmu_queue_len = 0; + } +} + +static void kvm_deferred_mmu_op(void *buffer, int len) +{ + struct kvm_para_state *state = kvm_para_state(); + + if (state->mode != PARAVIRT_LAZY_MMU) { + kvm_mmu_op(buffer, len); + return; + } + if (state->mmu_queue_len + len > sizeof state->mmu_queue) + mmu_queue_flush(state); + memcpy(state->mmu_queue + state->mmu_queue_len, buffer, len); + state->mmu_queue_len += len; +} + static void kvm_mmu_write(void *dest, u64 val) { __u64 pte_phys; @@ -68,7 +106,7 @@ static void kvm_mmu_write(void *dest, u64 val) wpte.pte_val = val; wpte.pte_phys = pte_phys; - kvm_mmu_op(&wpte, sizeof wpte); + kvm_deferred_mmu_op(&wpte, sizeof wpte); } /* @@ -137,7 +175,7 @@ static void kvm_flush_tlb(void) .header.op = KVM_MMU_OP_FLUSH_TLB, }; - kvm_mmu_op(&ftlb, sizeof ftlb); + kvm_deferred_mmu_op(&ftlb, sizeof ftlb); } static void kvm_release_pt(u32 pfn) @@ -150,6 +188,23 @@ static void kvm_release_pt(u32 pfn) kvm_mmu_op(&rpt, sizeof rpt); } +static void kvm_enter_lazy_mmu(void) +{ + struct kvm_para_state *state = kvm_para_state(); + + paravirt_enter_lazy_mmu(); + state->mode = paravirt_get_lazy_mode(); +} + +static void kvm_leave_lazy_mmu(void) +{ + struct kvm_para_state *state = kvm_para_state(); + + mmu_queue_flush(state); + paravirt_leave_lazy(paravirt_get_lazy_mode()); + state->mode = paravirt_get_lazy_mode(); +} + static void paravirt_ops_setup(void) { pv_info.name = "KVM"; @@ -178,6 +233,9 @@ static void paravirt_ops_setup(void) pv_mmu_ops.release_pte = kvm_release_pt; pv_mmu_ops.release_pmd = kvm_release_pt; pv_mmu_ops.release_pud = kvm_release_pt; + + pv_mmu_ops.lazy_mode.enter = kvm_enter_lazy_mmu; + pv_mmu_ops.lazy_mode.leave = kvm_leave_lazy_mmu; } }