From 096d14a3b57e4a87d27be09cc64b4f84660acd08 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Fri, 22 Feb 2008 12:21:38 -0500
Subject: 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 <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
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 <linux/cpu.h>
#include <linux/mm.h>
#include <linux/highmem.h>
+#include <linux/hardirq.h>
+
+#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;
}
}
--
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