Merge commit 'v2.6.28-rc2' into x86/pci-ioapic-boot-irq-quirks
[deliverable/linux.git] / arch / x86 / kernel / kvm.c
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1/*
2 * KVM paravirt_ops implementation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17 *
18 * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
19 * Copyright IBM Corporation, 2007
20 * Authors: Anthony Liguori <aliguori@us.ibm.com>
21 */
22
23#include <linux/module.h>
24#include <linux/kernel.h>
25#include <linux/kvm_para.h>
26#include <linux/cpu.h>
27#include <linux/mm.h>
1da8a77b 28#include <linux/highmem.h>
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29#include <linux/hardirq.h>
30
31#define MMU_QUEUE_SIZE 1024
32
33struct kvm_para_state {
34 u8 mmu_queue[MMU_QUEUE_SIZE];
35 int mmu_queue_len;
36 enum paravirt_lazy_mode mode;
37};
38
39static DEFINE_PER_CPU(struct kvm_para_state, para_state);
40
41static struct kvm_para_state *kvm_para_state(void)
42{
43 return &per_cpu(para_state, raw_smp_processor_id());
44}
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45
46/*
47 * No need for any "IO delay" on KVM
48 */
49static void kvm_io_delay(void)
50{
51}
52
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53static void kvm_mmu_op(void *buffer, unsigned len)
54{
55 int r;
56 unsigned long a1, a2;
57
58 do {
59 a1 = __pa(buffer);
60 a2 = 0; /* on i386 __pa() always returns <4G */
61 r = kvm_hypercall3(KVM_HC_MMU_OP, len, a1, a2);
62 buffer += r;
63 len -= r;
64 } while (len);
65}
66
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67static void mmu_queue_flush(struct kvm_para_state *state)
68{
69 if (state->mmu_queue_len) {
70 kvm_mmu_op(state->mmu_queue, state->mmu_queue_len);
71 state->mmu_queue_len = 0;
72 }
73}
74
75static void kvm_deferred_mmu_op(void *buffer, int len)
76{
77 struct kvm_para_state *state = kvm_para_state();
78
79 if (state->mode != PARAVIRT_LAZY_MMU) {
80 kvm_mmu_op(buffer, len);
81 return;
82 }
83 if (state->mmu_queue_len + len > sizeof state->mmu_queue)
84 mmu_queue_flush(state);
85 memcpy(state->mmu_queue + state->mmu_queue_len, buffer, len);
86 state->mmu_queue_len += len;
87}
88
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89static void kvm_mmu_write(void *dest, u64 val)
90{
91 __u64 pte_phys;
92 struct kvm_mmu_op_write_pte wpte;
93
94#ifdef CONFIG_HIGHPTE
95 struct page *page;
96 unsigned long dst = (unsigned long) dest;
97
98 page = kmap_atomic_to_page(dest);
99 pte_phys = page_to_pfn(page);
100 pte_phys <<= PAGE_SHIFT;
101 pte_phys += (dst & ~(PAGE_MASK));
102#else
103 pte_phys = (unsigned long)__pa(dest);
104#endif
105 wpte.header.op = KVM_MMU_OP_WRITE_PTE;
106 wpte.pte_val = val;
107 wpte.pte_phys = pte_phys;
108
096d14a3 109 kvm_deferred_mmu_op(&wpte, sizeof wpte);
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110}
111
112/*
113 * We only need to hook operations that are MMU writes. We hook these so that
114 * we can use lazy MMU mode to batch these operations. We could probably
115 * improve the performance of the host code if we used some of the information
116 * here to simplify processing of batched writes.
117 */
118static void kvm_set_pte(pte_t *ptep, pte_t pte)
119{
120 kvm_mmu_write(ptep, pte_val(pte));
121}
122
123static void kvm_set_pte_at(struct mm_struct *mm, unsigned long addr,
124 pte_t *ptep, pte_t pte)
125{
126 kvm_mmu_write(ptep, pte_val(pte));
127}
128
129static void kvm_set_pmd(pmd_t *pmdp, pmd_t pmd)
130{
131 kvm_mmu_write(pmdp, pmd_val(pmd));
132}
133
134#if PAGETABLE_LEVELS >= 3
135#ifdef CONFIG_X86_PAE
136static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte)
137{
138 kvm_mmu_write(ptep, pte_val(pte));
139}
140
141static void kvm_set_pte_present(struct mm_struct *mm, unsigned long addr,
142 pte_t *ptep, pte_t pte)
143{
144 kvm_mmu_write(ptep, pte_val(pte));
145}
146
147static void kvm_pte_clear(struct mm_struct *mm,
148 unsigned long addr, pte_t *ptep)
149{
150 kvm_mmu_write(ptep, 0);
151}
152
153static void kvm_pmd_clear(pmd_t *pmdp)
154{
155 kvm_mmu_write(pmdp, 0);
156}
157#endif
158
159static void kvm_set_pud(pud_t *pudp, pud_t pud)
160{
161 kvm_mmu_write(pudp, pud_val(pud));
162}
163
164#if PAGETABLE_LEVELS == 4
165static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
166{
167 kvm_mmu_write(pgdp, pgd_val(pgd));
168}
169#endif
170#endif /* PAGETABLE_LEVELS >= 3 */
171
172static void kvm_flush_tlb(void)
173{
174 struct kvm_mmu_op_flush_tlb ftlb = {
175 .header.op = KVM_MMU_OP_FLUSH_TLB,
176 };
177
096d14a3 178 kvm_deferred_mmu_op(&ftlb, sizeof ftlb);
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179}
180
f8639939 181static void kvm_release_pt(unsigned long pfn)
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182{
183 struct kvm_mmu_op_release_pt rpt = {
184 .header.op = KVM_MMU_OP_RELEASE_PT,
185 .pt_phys = (u64)pfn << PAGE_SHIFT,
186 };
187
188 kvm_mmu_op(&rpt, sizeof rpt);
189}
190
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191static void kvm_enter_lazy_mmu(void)
192{
193 struct kvm_para_state *state = kvm_para_state();
194
195 paravirt_enter_lazy_mmu();
196 state->mode = paravirt_get_lazy_mode();
197}
198
199static void kvm_leave_lazy_mmu(void)
200{
201 struct kvm_para_state *state = kvm_para_state();
202
203 mmu_queue_flush(state);
204 paravirt_leave_lazy(paravirt_get_lazy_mode());
205 state->mode = paravirt_get_lazy_mode();
206}
207
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208static void paravirt_ops_setup(void)
209{
210 pv_info.name = "KVM";
211 pv_info.paravirt_enabled = 1;
212
213 if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
214 pv_cpu_ops.io_delay = kvm_io_delay;
215
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216 if (kvm_para_has_feature(KVM_FEATURE_MMU_OP)) {
217 pv_mmu_ops.set_pte = kvm_set_pte;
218 pv_mmu_ops.set_pte_at = kvm_set_pte_at;
219 pv_mmu_ops.set_pmd = kvm_set_pmd;
220#if PAGETABLE_LEVELS >= 3
221#ifdef CONFIG_X86_PAE
222 pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic;
223 pv_mmu_ops.set_pte_present = kvm_set_pte_present;
224 pv_mmu_ops.pte_clear = kvm_pte_clear;
225 pv_mmu_ops.pmd_clear = kvm_pmd_clear;
226#endif
227 pv_mmu_ops.set_pud = kvm_set_pud;
228#if PAGETABLE_LEVELS == 4
229 pv_mmu_ops.set_pgd = kvm_set_pgd;
230#endif
231#endif
232 pv_mmu_ops.flush_tlb_user = kvm_flush_tlb;
233 pv_mmu_ops.release_pte = kvm_release_pt;
234 pv_mmu_ops.release_pmd = kvm_release_pt;
235 pv_mmu_ops.release_pud = kvm_release_pt;
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236
237 pv_mmu_ops.lazy_mode.enter = kvm_enter_lazy_mmu;
238 pv_mmu_ops.lazy_mode.leave = kvm_leave_lazy_mmu;
1da8a77b 239 }
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240}
241
242void __init kvm_guest_init(void)
243{
244 if (!kvm_para_available())
245 return;
246
247 paravirt_ops_setup();
248}
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