xref: /openbmc/qemu/target/i386/tcg/sysemu/seg_helper.c (revision f6476697)
1 /*
2  *  x86 segmentation related helpers: (sysemu-only code)
3  *  TSS, interrupts, system calls, jumps and call/task gates, descriptors
4  *
5  *  Copyright (c) 2003 Fabrice Bellard
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * This library is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include "qemu/osdep.h"
22 #include "cpu.h"
23 #include "exec/helper-proto.h"
24 #include "exec/cpu_ldst.h"
25 #include "tcg/helper-tcg.h"
26 #include "../seg_helper.h"
27 
28 #ifdef TARGET_X86_64
29 void helper_syscall(CPUX86State *env, int next_eip_addend)
30 {
31     int selector;
32 
33     if (!(env->efer & MSR_EFER_SCE)) {
34         raise_exception_err_ra(env, EXCP06_ILLOP, 0, GETPC());
35     }
36     selector = (env->star >> 32) & 0xffff;
37     if (env->hflags & HF_LMA_MASK) {
38         int code64;
39 
40         env->regs[R_ECX] = env->eip + next_eip_addend;
41         env->regs[11] = cpu_compute_eflags(env) & ~RF_MASK;
42 
43         code64 = env->hflags & HF_CS64_MASK;
44 
45         env->eflags &= ~(env->fmask | RF_MASK);
46         cpu_load_eflags(env, env->eflags, 0);
47         cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
48                            0, 0xffffffff,
49                                DESC_G_MASK | DESC_P_MASK |
50                                DESC_S_MASK |
51                                DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK |
52                                DESC_L_MASK);
53         cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
54                                0, 0xffffffff,
55                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
56                                DESC_S_MASK |
57                                DESC_W_MASK | DESC_A_MASK);
58         if (code64) {
59             env->eip = env->lstar;
60         } else {
61             env->eip = env->cstar;
62         }
63     } else {
64         env->regs[R_ECX] = (uint32_t)(env->eip + next_eip_addend);
65 
66         env->eflags &= ~(IF_MASK | RF_MASK | VM_MASK);
67         cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
68                            0, 0xffffffff,
69                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
70                                DESC_S_MASK |
71                                DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK);
72         cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
73                                0, 0xffffffff,
74                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
75                                DESC_S_MASK |
76                                DESC_W_MASK | DESC_A_MASK);
77         env->eip = (uint32_t)env->star;
78     }
79 }
80 #endif /* TARGET_X86_64 */
81 
82 void handle_even_inj(CPUX86State *env, int intno, int is_int,
83                      int error_code, int is_hw, int rm)
84 {
85     CPUState *cs = env_cpu(env);
86     uint32_t event_inj = x86_ldl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
87                                                           control.event_inj));
88 
89     if (!(event_inj & SVM_EVTINJ_VALID)) {
90         int type;
91 
92         if (is_int) {
93             type = SVM_EVTINJ_TYPE_SOFT;
94         } else {
95             type = SVM_EVTINJ_TYPE_EXEPT;
96         }
97         event_inj = intno | type | SVM_EVTINJ_VALID;
98         if (!rm && exception_has_error_code(intno)) {
99             event_inj |= SVM_EVTINJ_VALID_ERR;
100             x86_stl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
101                                              control.event_inj_err),
102                      error_code);
103         }
104         x86_stl_phys(cs,
105                  env->vm_vmcb + offsetof(struct vmcb, control.event_inj),
106                  event_inj);
107     }
108 }
109 
110 void x86_cpu_do_interrupt(CPUState *cs)
111 {
112     X86CPU *cpu = X86_CPU(cs);
113     CPUX86State *env = &cpu->env;
114 
115     if (cs->exception_index == EXCP_VMEXIT) {
116         assert(env->old_exception == -1);
117         do_vmexit(env);
118     } else {
119         do_interrupt_all(cpu, cs->exception_index,
120                          env->exception_is_int,
121                          env->error_code,
122                          env->exception_next_eip, 0);
123         /* successfully delivered */
124         env->old_exception = -1;
125     }
126 }
127 
128 /* check if Port I/O is allowed in TSS */
129 void helper_check_io(CPUX86State *env, uint32_t addr, uint32_t size)
130 {
131     uintptr_t retaddr = GETPC();
132     uint32_t io_offset, val, mask;
133 
134     /* TSS must be a valid 32 bit one */
135     if (!(env->tr.flags & DESC_P_MASK) ||
136         ((env->tr.flags >> DESC_TYPE_SHIFT) & 0xf) != 9 ||
137         env->tr.limit < 103) {
138         goto fail;
139     }
140     io_offset = cpu_lduw_kernel_ra(env, env->tr.base + 0x66, retaddr);
141     io_offset += (addr >> 3);
142     /* Note: the check needs two bytes */
143     if ((io_offset + 1) > env->tr.limit) {
144         goto fail;
145     }
146     val = cpu_lduw_kernel_ra(env, env->tr.base + io_offset, retaddr);
147     val >>= (addr & 7);
148     mask = (1 << size) - 1;
149     /* all bits must be zero to allow the I/O */
150     if ((val & mask) != 0) {
151     fail:
152         raise_exception_err_ra(env, EXCP0D_GPF, 0, retaddr);
153     }
154 }
155