xref: /openbmc/qemu/include/exec/cpu-defs.h (revision 83a71719)
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 #include "qemu/queue.h"
29 #ifdef CONFIG_TCG
30 #include "tcg-target.h"
31 #endif
32 #ifndef CONFIG_USER_ONLY
33 #include "exec/hwaddr.h"
34 #endif
35 #include "exec/memattrs.h"
36 
37 #ifndef TARGET_LONG_BITS
38 #error TARGET_LONG_BITS must be defined before including this header
39 #endif
40 
41 #define TARGET_LONG_SIZE (TARGET_LONG_BITS / 8)
42 
43 /* target_ulong is the type of a virtual address */
44 #if TARGET_LONG_SIZE == 4
45 typedef int32_t target_long;
46 typedef uint32_t target_ulong;
47 #define TARGET_FMT_lx "%08x"
48 #define TARGET_FMT_ld "%d"
49 #define TARGET_FMT_lu "%u"
50 #elif TARGET_LONG_SIZE == 8
51 typedef int64_t target_long;
52 typedef uint64_t target_ulong;
53 #define TARGET_FMT_lx "%016" PRIx64
54 #define TARGET_FMT_ld "%" PRId64
55 #define TARGET_FMT_lu "%" PRIu64
56 #else
57 #error TARGET_LONG_SIZE undefined
58 #endif
59 
60 #if !defined(CONFIG_USER_ONLY) && defined(CONFIG_TCG)
61 /* use a fully associative victim tlb of 8 entries */
62 #define CPU_VTLB_SIZE 8
63 
64 #if HOST_LONG_BITS == 32 && TARGET_LONG_BITS == 32
65 #define CPU_TLB_ENTRY_BITS 4
66 #else
67 #define CPU_TLB_ENTRY_BITS 5
68 #endif
69 
70 #define CPU_TLB_DYN_MIN_BITS 6
71 #define CPU_TLB_DYN_DEFAULT_BITS 8
72 
73 # if HOST_LONG_BITS == 32
74 /* Make sure we do not require a double-word shift for the TLB load */
75 #  define CPU_TLB_DYN_MAX_BITS (32 - TARGET_PAGE_BITS)
76 # else /* HOST_LONG_BITS == 64 */
77 /*
78  * Assuming TARGET_PAGE_BITS==12, with 2**22 entries we can cover 2**(22+12) ==
79  * 2**34 == 16G of address space. This is roughly what one would expect a
80  * TLB to cover in a modern (as of 2018) x86_64 CPU. For instance, Intel
81  * Skylake's Level-2 STLB has 16 1G entries.
82  * Also, make sure we do not size the TLB past the guest's address space.
83  */
84 #  define CPU_TLB_DYN_MAX_BITS                                  \
85     MIN(22, TARGET_VIRT_ADDR_SPACE_BITS - TARGET_PAGE_BITS)
86 # endif
87 
88 typedef struct CPUTLBEntry {
89     /* bit TARGET_LONG_BITS to TARGET_PAGE_BITS : virtual address
90        bit TARGET_PAGE_BITS-1..4  : Nonzero for accesses that should not
91                                     go directly to ram.
92        bit 3                      : indicates that the entry is invalid
93        bit 2..0                   : zero
94     */
95     union {
96         struct {
97             target_ulong addr_read;
98             target_ulong addr_write;
99             target_ulong addr_code;
100             /* Addend to virtual address to get host address.  IO accesses
101                use the corresponding iotlb value.  */
102             uintptr_t addend;
103         };
104         /* padding to get a power of two size */
105         uint8_t dummy[1 << CPU_TLB_ENTRY_BITS];
106     };
107 } CPUTLBEntry;
108 
109 QEMU_BUILD_BUG_ON(sizeof(CPUTLBEntry) != (1 << CPU_TLB_ENTRY_BITS));
110 
111 /* The IOTLB is not accessed directly inline by generated TCG code,
112  * so the CPUIOTLBEntry layout is not as critical as that of the
113  * CPUTLBEntry. (This is also why we don't want to combine the two
114  * structs into one.)
115  */
116 typedef struct CPUIOTLBEntry {
117     /*
118      * @addr contains:
119      *  - in the lower TARGET_PAGE_BITS, a physical section number
120      *  - with the lower TARGET_PAGE_BITS masked off, an offset which
121      *    must be added to the virtual address to obtain:
122      *     + the ram_addr_t of the target RAM (if the physical section
123      *       number is PHYS_SECTION_NOTDIRTY or PHYS_SECTION_ROM)
124      *     + the offset within the target MemoryRegion (otherwise)
125      */
126     hwaddr addr;
127     MemTxAttrs attrs;
128 } CPUIOTLBEntry;
129 
130 /**
131  * struct CPUTLBWindow
132  * @begin_ns: host time (in ns) at the beginning of the time window
133  * @max_entries: maximum number of entries observed in the window
134  *
135  * See also: tlb_mmu_resize_locked()
136  */
137 typedef struct CPUTLBWindow {
138     int64_t begin_ns;
139     size_t max_entries;
140 } CPUTLBWindow;
141 
142 typedef struct CPUTLBDesc {
143     /*
144      * Describe a region covering all of the large pages allocated
145      * into the tlb.  When any page within this region is flushed,
146      * we must flush the entire tlb.  The region is matched if
147      * (addr & large_page_mask) == large_page_addr.
148      */
149     target_ulong large_page_addr;
150     target_ulong large_page_mask;
151     /* The next index to use in the tlb victim table.  */
152     size_t vindex;
153     CPUTLBWindow window;
154     size_t n_used_entries;
155 } CPUTLBDesc;
156 
157 /*
158  * Data elements that are shared between all MMU modes.
159  */
160 typedef struct CPUTLBCommon {
161     /* Serialize updates to tlb_table and tlb_v_table, and others as noted. */
162     QemuSpin lock;
163     /*
164      * Within dirty, for each bit N, modifications have been made to
165      * mmu_idx N since the last time that mmu_idx was flushed.
166      * Protected by tlb_c.lock.
167      */
168     uint16_t dirty;
169     /*
170      * Statistics.  These are not lock protected, but are read and
171      * written atomically.  This allows the monitor to print a snapshot
172      * of the stats without interfering with the cpu.
173      */
174     size_t full_flush_count;
175     size_t part_flush_count;
176     size_t elide_flush_count;
177 } CPUTLBCommon;
178 
179 # define CPU_TLB                                                        \
180     /* tlb_mask[i] contains (n_entries - 1) << CPU_TLB_ENTRY_BITS */    \
181     uintptr_t tlb_mask[NB_MMU_MODES];                                   \
182     CPUTLBEntry *tlb_table[NB_MMU_MODES];
183 # define CPU_IOTLB                              \
184     CPUIOTLBEntry *iotlb[NB_MMU_MODES];
185 
186 /*
187  * The meaning of each of the MMU modes is defined in the target code.
188  * Note that NB_MMU_MODES is not yet defined; we can only reference it
189  * within preprocessor defines that will be expanded later.
190  */
191 #define CPU_COMMON_TLB \
192     CPUTLBCommon tlb_c;                                                 \
193     CPUTLBDesc tlb_d[NB_MMU_MODES];                                     \
194     CPU_TLB                                                             \
195     CPUTLBEntry tlb_v_table[NB_MMU_MODES][CPU_VTLB_SIZE];               \
196     CPU_IOTLB                                                           \
197     CPUIOTLBEntry iotlb_v[NB_MMU_MODES][CPU_VTLB_SIZE];
198 
199 #else
200 
201 #define CPU_COMMON_TLB
202 
203 #endif
204 
205 
206 #define CPU_COMMON                                                      \
207     /* soft mmu support */                                              \
208     CPU_COMMON_TLB                                                      \
209 
210 #endif
211