Merge branch 'for-linus' of git://linux-arm.org/linux-2.6
[linux-2.6] / arch / x86 / kernel / kvm.c
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>
28 #include <linux/highmem.h>
29 #include <linux/hardirq.h>
30 #include <asm/timer.h>
31
32 #define MMU_QUEUE_SIZE 1024
33
34 struct kvm_para_state {
35         u8 mmu_queue[MMU_QUEUE_SIZE];
36         int mmu_queue_len;
37         enum paravirt_lazy_mode mode;
38 };
39
40 static DEFINE_PER_CPU(struct kvm_para_state, para_state);
41
42 static struct kvm_para_state *kvm_para_state(void)
43 {
44         return &per_cpu(para_state, raw_smp_processor_id());
45 }
46
47 /*
48  * No need for any "IO delay" on KVM
49  */
50 static void kvm_io_delay(void)
51 {
52 }
53
54 static void kvm_mmu_op(void *buffer, unsigned len)
55 {
56         int r;
57         unsigned long a1, a2;
58
59         do {
60                 a1 = __pa(buffer);
61                 a2 = 0;   /* on i386 __pa() always returns <4G */
62                 r = kvm_hypercall3(KVM_HC_MMU_OP, len, a1, a2);
63                 buffer += r;
64                 len -= r;
65         } while (len);
66 }
67
68 static void mmu_queue_flush(struct kvm_para_state *state)
69 {
70         if (state->mmu_queue_len) {
71                 kvm_mmu_op(state->mmu_queue, state->mmu_queue_len);
72                 state->mmu_queue_len = 0;
73         }
74 }
75
76 static void kvm_deferred_mmu_op(void *buffer, int len)
77 {
78         struct kvm_para_state *state = kvm_para_state();
79
80         if (state->mode != PARAVIRT_LAZY_MMU) {
81                 kvm_mmu_op(buffer, len);
82                 return;
83         }
84         if (state->mmu_queue_len + len > sizeof state->mmu_queue)
85                 mmu_queue_flush(state);
86         memcpy(state->mmu_queue + state->mmu_queue_len, buffer, len);
87         state->mmu_queue_len += len;
88 }
89
90 static void kvm_mmu_write(void *dest, u64 val)
91 {
92         __u64 pte_phys;
93         struct kvm_mmu_op_write_pte wpte;
94
95 #ifdef CONFIG_HIGHPTE
96         struct page *page;
97         unsigned long dst = (unsigned long) dest;
98
99         page = kmap_atomic_to_page(dest);
100         pte_phys = page_to_pfn(page);
101         pte_phys <<= PAGE_SHIFT;
102         pte_phys += (dst & ~(PAGE_MASK));
103 #else
104         pte_phys = (unsigned long)__pa(dest);
105 #endif
106         wpte.header.op = KVM_MMU_OP_WRITE_PTE;
107         wpte.pte_val = val;
108         wpte.pte_phys = pte_phys;
109
110         kvm_deferred_mmu_op(&wpte, sizeof wpte);
111 }
112
113 /*
114  * We only need to hook operations that are MMU writes.  We hook these so that
115  * we can use lazy MMU mode to batch these operations.  We could probably
116  * improve the performance of the host code if we used some of the information
117  * here to simplify processing of batched writes.
118  */
119 static void kvm_set_pte(pte_t *ptep, pte_t pte)
120 {
121         kvm_mmu_write(ptep, pte_val(pte));
122 }
123
124 static void kvm_set_pte_at(struct mm_struct *mm, unsigned long addr,
125                            pte_t *ptep, pte_t pte)
126 {
127         kvm_mmu_write(ptep, pte_val(pte));
128 }
129
130 static void kvm_set_pmd(pmd_t *pmdp, pmd_t pmd)
131 {
132         kvm_mmu_write(pmdp, pmd_val(pmd));
133 }
134
135 #if PAGETABLE_LEVELS >= 3
136 #ifdef CONFIG_X86_PAE
137 static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte)
138 {
139         kvm_mmu_write(ptep, pte_val(pte));
140 }
141
142 static void kvm_pte_clear(struct mm_struct *mm,
143                           unsigned long addr, pte_t *ptep)
144 {
145         kvm_mmu_write(ptep, 0);
146 }
147
148 static void kvm_pmd_clear(pmd_t *pmdp)
149 {
150         kvm_mmu_write(pmdp, 0);
151 }
152 #endif
153
154 static void kvm_set_pud(pud_t *pudp, pud_t pud)
155 {
156         kvm_mmu_write(pudp, pud_val(pud));
157 }
158
159 #if PAGETABLE_LEVELS == 4
160 static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
161 {
162         kvm_mmu_write(pgdp, pgd_val(pgd));
163 }
164 #endif
165 #endif /* PAGETABLE_LEVELS >= 3 */
166
167 static void kvm_flush_tlb(void)
168 {
169         struct kvm_mmu_op_flush_tlb ftlb = {
170                 .header.op = KVM_MMU_OP_FLUSH_TLB,
171         };
172
173         kvm_deferred_mmu_op(&ftlb, sizeof ftlb);
174 }
175
176 static void kvm_release_pt(unsigned long pfn)
177 {
178         struct kvm_mmu_op_release_pt rpt = {
179                 .header.op = KVM_MMU_OP_RELEASE_PT,
180                 .pt_phys = (u64)pfn << PAGE_SHIFT,
181         };
182
183         kvm_mmu_op(&rpt, sizeof rpt);
184 }
185
186 static void kvm_enter_lazy_mmu(void)
187 {
188         struct kvm_para_state *state = kvm_para_state();
189
190         paravirt_enter_lazy_mmu();
191         state->mode = paravirt_get_lazy_mode();
192 }
193
194 static void kvm_leave_lazy_mmu(void)
195 {
196         struct kvm_para_state *state = kvm_para_state();
197
198         mmu_queue_flush(state);
199         paravirt_leave_lazy_mmu();
200         state->mode = paravirt_get_lazy_mode();
201 }
202
203 static void paravirt_ops_setup(void)
204 {
205         pv_info.name = "KVM";
206         pv_info.paravirt_enabled = 1;
207
208         if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
209                 pv_cpu_ops.io_delay = kvm_io_delay;
210
211         if (kvm_para_has_feature(KVM_FEATURE_MMU_OP)) {
212                 pv_mmu_ops.set_pte = kvm_set_pte;
213                 pv_mmu_ops.set_pte_at = kvm_set_pte_at;
214                 pv_mmu_ops.set_pmd = kvm_set_pmd;
215 #if PAGETABLE_LEVELS >= 3
216 #ifdef CONFIG_X86_PAE
217                 pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic;
218                 pv_mmu_ops.pte_clear = kvm_pte_clear;
219                 pv_mmu_ops.pmd_clear = kvm_pmd_clear;
220 #endif
221                 pv_mmu_ops.set_pud = kvm_set_pud;
222 #if PAGETABLE_LEVELS == 4
223                 pv_mmu_ops.set_pgd = kvm_set_pgd;
224 #endif
225 #endif
226                 pv_mmu_ops.flush_tlb_user = kvm_flush_tlb;
227                 pv_mmu_ops.release_pte = kvm_release_pt;
228                 pv_mmu_ops.release_pmd = kvm_release_pt;
229                 pv_mmu_ops.release_pud = kvm_release_pt;
230
231                 pv_mmu_ops.lazy_mode.enter = kvm_enter_lazy_mmu;
232                 pv_mmu_ops.lazy_mode.leave = kvm_leave_lazy_mmu;
233         }
234 #ifdef CONFIG_X86_IO_APIC
235         no_timer_check = 1;
236 #endif
237 }
238
239 void __init kvm_guest_init(void)
240 {
241         if (!kvm_para_available())
242                 return;
243
244         paravirt_ops_setup();
245 }