xref: /openbmc/qemu/target/i386/tcg/sysemu/seg_helper.c (revision 28d5bfc0)
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 "qemu/log.h"
23 #include "qemu/main-loop.h"
24 #include "cpu.h"
25 #include "exec/helper-proto.h"
26 #include "exec/cpu_ldst.h"
27 #include "tcg/helper-tcg.h"
28 #include "../seg_helper.h"
29 
30 void helper_syscall(CPUX86State *env, int next_eip_addend)
31 {
32     int selector;
33 
34     if (!(env->efer & MSR_EFER_SCE)) {
35         raise_exception_err_ra(env, EXCP06_ILLOP, 0, GETPC());
36     }
37     selector = (env->star >> 32) & 0xffff;
38 #ifdef TARGET_X86_64
39     if (env->hflags & HF_LMA_MASK) {
40         int code64;
41 
42         env->regs[R_ECX] = env->eip + next_eip_addend;
43         env->regs[11] = cpu_compute_eflags(env) & ~RF_MASK;
44 
45         code64 = env->hflags & HF_CS64_MASK;
46 
47         env->eflags &= ~(env->fmask | RF_MASK);
48         cpu_load_eflags(env, env->eflags, 0);
49         cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
50                            0, 0xffffffff,
51                                DESC_G_MASK | DESC_P_MASK |
52                                DESC_S_MASK |
53                                DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK |
54                                DESC_L_MASK);
55         cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
56                                0, 0xffffffff,
57                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
58                                DESC_S_MASK |
59                                DESC_W_MASK | DESC_A_MASK);
60         if (code64) {
61             env->eip = env->lstar;
62         } else {
63             env->eip = env->cstar;
64         }
65     } else
66 #endif
67     {
68         env->regs[R_ECX] = (uint32_t)(env->eip + next_eip_addend);
69 
70         env->eflags &= ~(IF_MASK | RF_MASK | VM_MASK);
71         cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
72                            0, 0xffffffff,
73                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
74                                DESC_S_MASK |
75                                DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK);
76         cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
77                                0, 0xffffffff,
78                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
79                                DESC_S_MASK |
80                                DESC_W_MASK | DESC_A_MASK);
81         env->eip = (uint32_t)env->star;
82     }
83 }
84 
85 void handle_even_inj(CPUX86State *env, int intno, int is_int,
86                      int error_code, int is_hw, int rm)
87 {
88     CPUState *cs = env_cpu(env);
89     uint32_t event_inj = x86_ldl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
90                                                           control.event_inj));
91 
92     if (!(event_inj & SVM_EVTINJ_VALID)) {
93         int type;
94 
95         if (is_int) {
96             type = SVM_EVTINJ_TYPE_SOFT;
97         } else {
98             type = SVM_EVTINJ_TYPE_EXEPT;
99         }
100         event_inj = intno | type | SVM_EVTINJ_VALID;
101         if (!rm && exception_has_error_code(intno)) {
102             event_inj |= SVM_EVTINJ_VALID_ERR;
103             x86_stl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
104                                              control.event_inj_err),
105                      error_code);
106         }
107         x86_stl_phys(cs,
108                  env->vm_vmcb + offsetof(struct vmcb, control.event_inj),
109                  event_inj);
110     }
111 }
112 
113 void x86_cpu_do_interrupt(CPUState *cs)
114 {
115     X86CPU *cpu = X86_CPU(cs);
116     CPUX86State *env = &cpu->env;
117 
118     if (cs->exception_index == EXCP_VMEXIT) {
119         assert(env->old_exception == -1);
120         do_vmexit(env);
121     } else {
122         do_interrupt_all(cpu, cs->exception_index,
123                          env->exception_is_int,
124                          env->error_code,
125                          env->exception_next_eip, 0);
126         /* successfully delivered */
127         env->old_exception = -1;
128     }
129 }
130 
131 bool x86_cpu_exec_halt(CPUState *cpu)
132 {
133     if (cpu->interrupt_request & CPU_INTERRUPT_POLL) {
134         X86CPU *x86_cpu = X86_CPU(cpu);
135 
136         bql_lock();
137         apic_poll_irq(x86_cpu->apic_state);
138         cpu_reset_interrupt(cpu, CPU_INTERRUPT_POLL);
139         bql_unlock();
140     }
141     return cpu_has_work(cpu);
142 }
143 
144 bool x86_need_replay_interrupt(int interrupt_request)
145 {
146     /*
147      * CPU_INTERRUPT_POLL is a virtual event which gets converted into a
148      * "real" interrupt event later. It does not need to be recorded for
149      * replay purposes.
150      */
151     return !(interrupt_request & CPU_INTERRUPT_POLL);
152 }
153 
154 bool x86_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
155 {
156     X86CPU *cpu = X86_CPU(cs);
157     CPUX86State *env = &cpu->env;
158     int intno;
159 
160     interrupt_request = x86_cpu_pending_interrupt(cs, interrupt_request);
161     if (!interrupt_request) {
162         return false;
163     }
164 
165     /* Don't process multiple interrupt requests in a single call.
166      * This is required to make icount-driven execution deterministic.
167      */
168     switch (interrupt_request) {
169     case CPU_INTERRUPT_POLL:
170         cs->interrupt_request &= ~CPU_INTERRUPT_POLL;
171         apic_poll_irq(cpu->apic_state);
172         break;
173     case CPU_INTERRUPT_SIPI:
174         do_cpu_sipi(cpu);
175         break;
176     case CPU_INTERRUPT_SMI:
177         cpu_svm_check_intercept_param(env, SVM_EXIT_SMI, 0, 0);
178         cs->interrupt_request &= ~CPU_INTERRUPT_SMI;
179         do_smm_enter(cpu);
180         break;
181     case CPU_INTERRUPT_NMI:
182         cpu_svm_check_intercept_param(env, SVM_EXIT_NMI, 0, 0);
183         cs->interrupt_request &= ~CPU_INTERRUPT_NMI;
184         env->hflags2 |= HF2_NMI_MASK;
185         do_interrupt_x86_hardirq(env, EXCP02_NMI, 1);
186         break;
187     case CPU_INTERRUPT_MCE:
188         cs->interrupt_request &= ~CPU_INTERRUPT_MCE;
189         do_interrupt_x86_hardirq(env, EXCP12_MCHK, 0);
190         break;
191     case CPU_INTERRUPT_HARD:
192         cpu_svm_check_intercept_param(env, SVM_EXIT_INTR, 0, 0);
193         cs->interrupt_request &= ~(CPU_INTERRUPT_HARD |
194                                    CPU_INTERRUPT_VIRQ);
195         intno = cpu_get_pic_interrupt(env);
196         qemu_log_mask(CPU_LOG_INT,
197                       "Servicing hardware INT=0x%02x\n", intno);
198         do_interrupt_x86_hardirq(env, intno, 1);
199         break;
200     case CPU_INTERRUPT_VIRQ:
201         cpu_svm_check_intercept_param(env, SVM_EXIT_VINTR, 0, 0);
202         intno = x86_ldl_phys(cs, env->vm_vmcb
203                              + offsetof(struct vmcb, control.int_vector));
204         qemu_log_mask(CPU_LOG_INT,
205                       "Servicing virtual hardware INT=0x%02x\n", intno);
206         do_interrupt_x86_hardirq(env, intno, 1);
207         cs->interrupt_request &= ~CPU_INTERRUPT_VIRQ;
208         env->int_ctl &= ~V_IRQ_MASK;
209         break;
210     }
211 
212     /* Ensure that no TB jump will be modified as the program flow was changed.  */
213     return true;
214 }
215 
216 /* check if Port I/O is allowed in TSS */
217 void helper_check_io(CPUX86State *env, uint32_t addr, uint32_t size)
218 {
219     uintptr_t retaddr = GETPC();
220     uint32_t io_offset, val, mask;
221 
222     /* TSS must be a valid 32 bit one */
223     if (!(env->tr.flags & DESC_P_MASK) ||
224         ((env->tr.flags >> DESC_TYPE_SHIFT) & 0xf) != 9 ||
225         env->tr.limit < 103) {
226         goto fail;
227     }
228     io_offset = cpu_lduw_kernel_ra(env, env->tr.base + 0x66, retaddr);
229     io_offset += (addr >> 3);
230     /* Note: the check needs two bytes */
231     if ((io_offset + 1) > env->tr.limit) {
232         goto fail;
233     }
234     val = cpu_lduw_kernel_ra(env, env->tr.base + io_offset, retaddr);
235     val >>= (addr & 7);
236     mask = (1 << size) - 1;
237     /* all bits must be zero to allow the I/O */
238     if ((val & mask) != 0) {
239     fail:
240         raise_exception_err_ra(env, EXCP0D_GPF, 0, retaddr);
241     }
242 }
243