xref: /openbmc/qemu/include/exec/cpu-defs.h (revision 53c7c924)
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 2.1 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 #ifndef CONFIG_USER_ONLY
29 #include "exec/hwaddr.h"
30 #endif
31 #include "exec/memattrs.h"
32 #include "hw/core/cpu.h"
33 
34 #include "cpu-param.h"
35 
36 #ifndef TARGET_LONG_BITS
37 # error TARGET_LONG_BITS must be defined in cpu-param.h
38 #endif
39 #ifndef TARGET_PHYS_ADDR_SPACE_BITS
40 # error TARGET_PHYS_ADDR_SPACE_BITS must be defined in cpu-param.h
41 #endif
42 #ifndef TARGET_VIRT_ADDR_SPACE_BITS
43 # error TARGET_VIRT_ADDR_SPACE_BITS must be defined in cpu-param.h
44 #endif
45 #ifndef TARGET_PAGE_BITS
46 # ifdef TARGET_PAGE_BITS_VARY
47 #  ifndef TARGET_PAGE_BITS_MIN
48 #   error TARGET_PAGE_BITS_MIN must be defined in cpu-param.h
49 #  endif
50 # else
51 #  error TARGET_PAGE_BITS must be defined in cpu-param.h
52 # endif
53 #endif
54 
55 #include "exec/target_long.h"
56 
57 /*
58  * Fix the number of mmu modes to 16, which is also the maximum
59  * supported by the softmmu tlb api.
60  */
61 #define NB_MMU_MODES 16
62 
63 #if defined(CONFIG_SOFTMMU) && defined(CONFIG_TCG)
64 #include "exec/tlb-common.h"
65 
66 /* use a fully associative victim tlb of 8 entries */
67 #define CPU_VTLB_SIZE 8
68 
69 #define CPU_TLB_DYN_MIN_BITS 6
70 #define CPU_TLB_DYN_DEFAULT_BITS 8
71 
72 # if HOST_LONG_BITS == 32
73 /* Make sure we do not require a double-word shift for the TLB load */
74 #  define CPU_TLB_DYN_MAX_BITS (32 - TARGET_PAGE_BITS)
75 # else /* HOST_LONG_BITS == 64 */
76 /*
77  * Assuming TARGET_PAGE_BITS==12, with 2**22 entries we can cover 2**(22+12) ==
78  * 2**34 == 16G of address space. This is roughly what one would expect a
79  * TLB to cover in a modern (as of 2018) x86_64 CPU. For instance, Intel
80  * Skylake's Level-2 STLB has 16 1G entries.
81  * Also, make sure we do not size the TLB past the guest's address space.
82  */
83 #  ifdef TARGET_PAGE_BITS_VARY
84 #   define CPU_TLB_DYN_MAX_BITS                                  \
85     MIN(22, TARGET_VIRT_ADDR_SPACE_BITS - TARGET_PAGE_BITS)
86 #  else
87 #   define CPU_TLB_DYN_MAX_BITS                                  \
88     MIN_CONST(22, TARGET_VIRT_ADDR_SPACE_BITS - TARGET_PAGE_BITS)
89 #  endif
90 # endif
91 
92 #endif /* CONFIG_SOFTMMU && CONFIG_TCG */
93 
94 #if defined(CONFIG_SOFTMMU)
95 /*
96  * The full TLB entry, which is not accessed by generated TCG code,
97  * so the layout is not as critical as that of CPUTLBEntry. This is
98  * also why we don't want to combine the two structs.
99  */
100 typedef struct CPUTLBEntryFull {
101     /*
102      * @xlat_section contains:
103      *  - in the lower TARGET_PAGE_BITS, a physical section number
104      *  - with the lower TARGET_PAGE_BITS masked off, an offset which
105      *    must be added to the virtual address to obtain:
106      *     + the ram_addr_t of the target RAM (if the physical section
107      *       number is PHYS_SECTION_NOTDIRTY or PHYS_SECTION_ROM)
108      *     + the offset within the target MemoryRegion (otherwise)
109      */
110     hwaddr xlat_section;
111 
112     /*
113      * @phys_addr contains the physical address in the address space
114      * given by cpu_asidx_from_attrs(cpu, @attrs).
115      */
116     hwaddr phys_addr;
117 
118     /* @attrs contains the memory transaction attributes for the page. */
119     MemTxAttrs attrs;
120 
121     /* @prot contains the complete protections for the page. */
122     uint8_t prot;
123 
124     /* @lg_page_size contains the log2 of the page size. */
125     uint8_t lg_page_size;
126 
127     /*
128      * Additional tlb flags for use by the slow path. If non-zero,
129      * the corresponding CPUTLBEntry comparator must have TLB_FORCE_SLOW.
130      */
131     uint8_t slow_flags[MMU_ACCESS_COUNT];
132 
133     /*
134      * Allow target-specific additions to this structure.
135      * This may be used to cache items from the guest cpu
136      * page tables for later use by the implementation.
137      */
138 #ifdef TARGET_PAGE_ENTRY_EXTRA
139     TARGET_PAGE_ENTRY_EXTRA
140 #endif
141 } CPUTLBEntryFull;
142 #endif /* CONFIG_SOFTMMU */
143 
144 #if defined(CONFIG_SOFTMMU) && defined(CONFIG_TCG)
145 /*
146  * Data elements that are per MMU mode, minus the bits accessed by
147  * the TCG fast path.
148  */
149 typedef struct CPUTLBDesc {
150     /*
151      * Describe a region covering all of the large pages allocated
152      * into the tlb.  When any page within this region is flushed,
153      * we must flush the entire tlb.  The region is matched if
154      * (addr & large_page_mask) == large_page_addr.
155      */
156     vaddr large_page_addr;
157     vaddr large_page_mask;
158     /* host time (in ns) at the beginning of the time window */
159     int64_t window_begin_ns;
160     /* maximum number of entries observed in the window */
161     size_t window_max_entries;
162     size_t n_used_entries;
163     /* The next index to use in the tlb victim table.  */
164     size_t vindex;
165     /* The tlb victim table, in two parts.  */
166     CPUTLBEntry vtable[CPU_VTLB_SIZE];
167     CPUTLBEntryFull vfulltlb[CPU_VTLB_SIZE];
168     CPUTLBEntryFull *fulltlb;
169 } CPUTLBDesc;
170 
171 /*
172  * Data elements that are shared between all MMU modes.
173  */
174 typedef struct CPUTLBCommon {
175     /* Serialize updates to f.table and d.vtable, and others as noted. */
176     QemuSpin lock;
177     /*
178      * Within dirty, for each bit N, modifications have been made to
179      * mmu_idx N since the last time that mmu_idx was flushed.
180      * Protected by tlb_c.lock.
181      */
182     uint16_t dirty;
183     /*
184      * Statistics.  These are not lock protected, but are read and
185      * written atomically.  This allows the monitor to print a snapshot
186      * of the stats without interfering with the cpu.
187      */
188     size_t full_flush_count;
189     size_t part_flush_count;
190     size_t elide_flush_count;
191 } CPUTLBCommon;
192 
193 /*
194  * The entire softmmu tlb, for all MMU modes.
195  * The meaning of each of the MMU modes is defined in the target code.
196  * Since this is placed within CPUNegativeOffsetState, the smallest
197  * negative offsets are at the end of the struct.
198  */
199 
200 typedef struct CPUTLB {
201     CPUTLBCommon c;
202     CPUTLBDesc d[NB_MMU_MODES];
203     CPUTLBDescFast f[NB_MMU_MODES];
204 } CPUTLB;
205 
206 #else
207 
208 typedef struct CPUTLB { } CPUTLB;
209 
210 #endif /* CONFIG_SOFTMMU && CONFIG_TCG */
211 
212 /*
213  * This structure must be placed in ArchCPU immediately
214  * before CPUArchState, as a field named "neg".
215  */
216 typedef struct CPUNegativeOffsetState {
217     CPUTLB tlb;
218     IcountDecr icount_decr;
219 } CPUNegativeOffsetState;
220 
221 #endif
222