xref: /openbmc/qemu/include/exec/cpu-defs.h (revision 4b9fa0b4)
1 /*
2  * common defines for all CPUs
3  *
4  * Copyright (c) 2003 Fabrice Bellard
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18  */
19 #ifndef CPU_DEFS_H
20 #define CPU_DEFS_H
21 
22 #ifndef NEED_CPU_H
23 #error cpu.h included from common code
24 #endif
25 
26 #include "qemu/host-utils.h"
27 #include "qemu/thread.h"
28 #ifdef CONFIG_TCG
29 #include "tcg-target.h"
30 #endif
31 #ifndef CONFIG_USER_ONLY
32 #include "exec/hwaddr.h"
33 #endif
34 #include "exec/memattrs.h"
35 #include "hw/core/cpu.h"
36 
37 #include "cpu-param.h"
38 
39 #ifndef TARGET_LONG_BITS
40 # error TARGET_LONG_BITS must be defined in cpu-param.h
41 #endif
42 #ifndef NB_MMU_MODES
43 # error NB_MMU_MODES must be defined in cpu-param.h
44 #endif
45 #ifndef TARGET_PHYS_ADDR_SPACE_BITS
46 # error TARGET_PHYS_ADDR_SPACE_BITS must be defined in cpu-param.h
47 #endif
48 #ifndef TARGET_VIRT_ADDR_SPACE_BITS
49 # error TARGET_VIRT_ADDR_SPACE_BITS must be defined in cpu-param.h
50 #endif
51 #ifndef TARGET_PAGE_BITS
52 # ifdef TARGET_PAGE_BITS_VARY
53 #  ifndef TARGET_PAGE_BITS_MIN
54 #   error TARGET_PAGE_BITS_MIN must be defined in cpu-param.h
55 #  endif
56 # else
57 #  error TARGET_PAGE_BITS must be defined in cpu-param.h
58 # endif
59 #endif
60 
61 #define TARGET_LONG_SIZE (TARGET_LONG_BITS / 8)
62 
63 /* target_ulong is the type of a virtual address */
64 #if TARGET_LONG_SIZE == 4
65 typedef int32_t target_long;
66 typedef uint32_t target_ulong;
67 #define TARGET_FMT_lx "%08x"
68 #define TARGET_FMT_ld "%d"
69 #define TARGET_FMT_lu "%u"
70 #elif TARGET_LONG_SIZE == 8
71 typedef int64_t target_long;
72 typedef uint64_t target_ulong;
73 #define TARGET_FMT_lx "%016" PRIx64
74 #define TARGET_FMT_ld "%" PRId64
75 #define TARGET_FMT_lu "%" PRIu64
76 #else
77 #error TARGET_LONG_SIZE undefined
78 #endif
79 
80 #if !defined(CONFIG_USER_ONLY) && defined(CONFIG_TCG)
81 
82 /* use a fully associative victim tlb of 8 entries */
83 #define CPU_VTLB_SIZE 8
84 
85 #if HOST_LONG_BITS == 32 && TARGET_LONG_BITS == 32
86 #define CPU_TLB_ENTRY_BITS 4
87 #else
88 #define CPU_TLB_ENTRY_BITS 5
89 #endif
90 
91 #define CPU_TLB_DYN_MIN_BITS 6
92 #define CPU_TLB_DYN_DEFAULT_BITS 8
93 
94 # if HOST_LONG_BITS == 32
95 /* Make sure we do not require a double-word shift for the TLB load */
96 #  define CPU_TLB_DYN_MAX_BITS (32 - TARGET_PAGE_BITS)
97 # else /* HOST_LONG_BITS == 64 */
98 /*
99  * Assuming TARGET_PAGE_BITS==12, with 2**22 entries we can cover 2**(22+12) ==
100  * 2**34 == 16G of address space. This is roughly what one would expect a
101  * TLB to cover in a modern (as of 2018) x86_64 CPU. For instance, Intel
102  * Skylake's Level-2 STLB has 16 1G entries.
103  * Also, make sure we do not size the TLB past the guest's address space.
104  */
105 #  define CPU_TLB_DYN_MAX_BITS                                  \
106     MIN(22, TARGET_VIRT_ADDR_SPACE_BITS - TARGET_PAGE_BITS)
107 # endif
108 
109 typedef struct CPUTLBEntry {
110     /* bit TARGET_LONG_BITS to TARGET_PAGE_BITS : virtual address
111        bit TARGET_PAGE_BITS-1..4  : Nonzero for accesses that should not
112                                     go directly to ram.
113        bit 3                      : indicates that the entry is invalid
114        bit 2..0                   : zero
115     */
116     union {
117         struct {
118             target_ulong addr_read;
119             target_ulong addr_write;
120             target_ulong addr_code;
121             /* Addend to virtual address to get host address.  IO accesses
122                use the corresponding iotlb value.  */
123             uintptr_t addend;
124         };
125         /* padding to get a power of two size */
126         uint8_t dummy[1 << CPU_TLB_ENTRY_BITS];
127     };
128 } CPUTLBEntry;
129 
130 QEMU_BUILD_BUG_ON(sizeof(CPUTLBEntry) != (1 << CPU_TLB_ENTRY_BITS));
131 
132 /* The IOTLB is not accessed directly inline by generated TCG code,
133  * so the CPUIOTLBEntry layout is not as critical as that of the
134  * CPUTLBEntry. (This is also why we don't want to combine the two
135  * structs into one.)
136  */
137 typedef struct CPUIOTLBEntry {
138     /*
139      * @addr contains:
140      *  - in the lower TARGET_PAGE_BITS, a physical section number
141      *  - with the lower TARGET_PAGE_BITS masked off, an offset which
142      *    must be added to the virtual address to obtain:
143      *     + the ram_addr_t of the target RAM (if the physical section
144      *       number is PHYS_SECTION_NOTDIRTY or PHYS_SECTION_ROM)
145      *     + the offset within the target MemoryRegion (otherwise)
146      */
147     hwaddr addr;
148     MemTxAttrs attrs;
149 } CPUIOTLBEntry;
150 
151 /*
152  * Data elements that are per MMU mode, minus the bits accessed by
153  * the TCG fast path.
154  */
155 typedef struct CPUTLBDesc {
156     /*
157      * Describe a region covering all of the large pages allocated
158      * into the tlb.  When any page within this region is flushed,
159      * we must flush the entire tlb.  The region is matched if
160      * (addr & large_page_mask) == large_page_addr.
161      */
162     target_ulong large_page_addr;
163     target_ulong large_page_mask;
164     /* host time (in ns) at the beginning of the time window */
165     int64_t window_begin_ns;
166     /* maximum number of entries observed in the window */
167     size_t window_max_entries;
168     size_t n_used_entries;
169     /* The next index to use in the tlb victim table.  */
170     size_t vindex;
171     /* The tlb victim table, in two parts.  */
172     CPUTLBEntry vtable[CPU_VTLB_SIZE];
173     CPUIOTLBEntry viotlb[CPU_VTLB_SIZE];
174     /* The iotlb.  */
175     CPUIOTLBEntry *iotlb;
176 } CPUTLBDesc;
177 
178 /*
179  * Data elements that are per MMU mode, accessed by the fast path.
180  * The structure is aligned to aid loading the pair with one insn.
181  */
182 typedef struct CPUTLBDescFast {
183     /* Contains (n_entries - 1) << CPU_TLB_ENTRY_BITS */
184     uintptr_t mask;
185     /* The array of tlb entries itself. */
186     CPUTLBEntry *table;
187 } CPUTLBDescFast QEMU_ALIGNED(2 * sizeof(void *));
188 
189 /*
190  * Data elements that are shared between all MMU modes.
191  */
192 typedef struct CPUTLBCommon {
193     /* Serialize updates to f.table and d.vtable, and others as noted. */
194     QemuSpin lock;
195     /*
196      * Within dirty, for each bit N, modifications have been made to
197      * mmu_idx N since the last time that mmu_idx was flushed.
198      * Protected by tlb_c.lock.
199      */
200     uint16_t dirty;
201     /*
202      * Statistics.  These are not lock protected, but are read and
203      * written atomically.  This allows the monitor to print a snapshot
204      * of the stats without interfering with the cpu.
205      */
206     size_t full_flush_count;
207     size_t part_flush_count;
208     size_t elide_flush_count;
209 } CPUTLBCommon;
210 
211 /*
212  * The entire softmmu tlb, for all MMU modes.
213  * The meaning of each of the MMU modes is defined in the target code.
214  * Since this is placed within CPUNegativeOffsetState, the smallest
215  * negative offsets are at the end of the struct.
216  */
217 
218 typedef struct CPUTLB {
219     CPUTLBCommon c;
220     CPUTLBDesc d[NB_MMU_MODES];
221     CPUTLBDescFast f[NB_MMU_MODES];
222 } CPUTLB;
223 
224 /* This will be used by TCG backends to compute offsets.  */
225 #define TLB_MASK_TABLE_OFS(IDX) \
226     ((int)offsetof(ArchCPU, neg.tlb.f[IDX]) - (int)offsetof(ArchCPU, env))
227 
228 #else
229 
230 typedef struct CPUTLB { } CPUTLB;
231 
232 #endif  /* !CONFIG_USER_ONLY && CONFIG_TCG */
233 
234 /*
235  * This structure must be placed in ArchCPU immediately
236  * before CPUArchState, as a field named "neg".
237  */
238 typedef struct CPUNegativeOffsetState {
239     CPUTLB tlb;
240     IcountDecr icount_decr;
241 } CPUNegativeOffsetState;
242 
243 #endif
244