/*
* KVM paravirt_ops implementation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
* Copyright IBM Corporation, 2007
* Authors: Anthony Liguori <aliguori@us.ibm.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kvm_para.h>
#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
*/
static void kvm_io_delay(void)
{
}
static void kvm_mmu_op(void *buffer, unsigned len)
{
int r;
unsigned long a1, a2;
do {
a1 = __pa(buffer);
a2 = 0; /* on i386 __pa() always returns <4G */
r = kvm_hypercall3(KVM_HC_MMU_OP, len, a1, a2);
buffer += r;
len -= r;
} 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;
struct kvm_mmu_op_write_pte wpte;
#ifdef CONFIG_HIGHPTE
struct page *page;
unsigned long dst = (unsigned long) dest;
page = kmap_atomic_to_page(dest);
pte_phys = page_to_pfn(page);
pte_phys <<= PAGE_SHIFT;
pte_phys += (dst & ~(PAGE_MASK));
#else
pte_phys = (unsigned long)__pa(dest);
#endif
wpte.header.op = KVM_MMU_OP_WRITE_PTE;
wpte.pte_val = val;
wpte.pte_phys = pte_phys;
kvm_deferred_mmu_op(&wpte, sizeof wpte);
}
/*
* We only need to hook operations that are MMU writes. We hook these so that
* we can use lazy MMU mode to batch these operations. We could probably
* improve the performance of the host code if we used some of the information
* here to simplify processing of batched writes.
*/
static void kvm_set_pte(pte_t *ptep, pte_t pte)
{
kvm_mmu_write(ptep, pte_val(pte));
}
static void kvm_set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
kvm_mmu_write(ptep, pte_val(pte));
}
static void kvm_set_pmd(pmd_t *pmdp, pmd_t pmd)
{
kvm_mmu_write(pmdp, pmd_val(pmd));
}
#if PAGETABLE_LEVELS >= 3
#ifdef CONFIG_X86_PAE
static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte)
{
kvm_mmu_write(ptep, pte_val(pte));
}
static void kvm_pte_clear(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
kvm_mmu_write(ptep, 0);
}
static void kvm_pmd_clear(pmd_t *pmdp)
{
kvm_mmu_write(pmdp, 0);
}
#endif
static void kvm_set_pud(pud_t *pudp, pud_t pud)
{
kvm_mmu_write(pudp, pud_val(pud));
}
#if PAGETABLE_LEVELS == 4
static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
{
kvm_mmu_write(pgdp, pgd_val(pgd));
}
#endif
#endif /* PAGETABLE_LEVELS >= 3 */
static void kvm_flush_tlb(void)
{
struct kvm_mmu_op_flush_tlb ftlb = {
.header.op = KVM_MMU_OP_FLUSH_TLB,
};
kvm_deferred_mmu_op(&ftlb, sizeof ftlb);
}
static void kvm_release_pt(unsigned long pfn)
{
struct kvm_mmu_op_release_pt rpt = {
.header.op = KVM_MMU_OP_RELEASE_PT,
.pt_phys = (u64)pfn << PAGE_SHIFT,
};
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";
pv_info.paravirt_enabled = 1;
if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
pv_cpu_ops.io_delay = kvm_io_delay;
if (kvm_para_has_feature(KVM_FEATURE_MMU_OP)) {
pv_mmu_ops.set_pte = kvm_set_pte;
pv_mmu_ops.set_pte_at = kvm_set_pte_at;
pv_mmu_ops.set_pmd = kvm_set_pmd;
#if PAGETABLE_LEVELS >= 3
#ifdef CONFIG_X86_PAE
pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic;
pv_mmu_ops.pte_clear = kvm_pte_clear;
pv_mmu_ops.pmd_clear = kvm_pmd_clear;
#endif
pv_mmu_ops.set_pud = kvm_set_pud;
#if PAGETABLE_LEVELS == 4
pv_mmu_ops.set_pgd = kvm_set_pgd;
#endif
#endif
pv_mmu_ops.flush_tlb_user = kvm_flush_tlb;
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;
}
}
void __init kvm_guest_init(void)
{
if (!kvm_para_available())
return;
paravirt_ops_setup();
}
