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Commit 096d14a3 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
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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: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 1da8a77b

arch/x86/kernel/kvm.c

+60 −2
Original line number Diff line number Diff line
@@ -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;

	}

}