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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>
This commit is contained in:
Marcelo Tosatti 2008-02-22 12:21:38 -05:00 committed by Avi Kivity
parent 1da8a77bdc
commit 096d14a3b5
1 changed files with 60 additions and 2 deletions
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62
arch/x86/kernel/kvm.c
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@ -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;
}
}