xref: /openbmc/qemu/target/i386/tcg/sysemu/seg_helper.c (revision bad5cfcd)
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 "cpu.h"
24 #include "exec/helper-proto.h"
25 #include "exec/cpu_ldst.h"
26 #include "tcg/helper-tcg.h"
27 #include "../seg_helper.h"
28 
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 #ifdef TARGET_X86_64
38     if (env->hflags & HF_LMA_MASK) {
39         int code64;
40 
41         env->regs[R_ECX] = env->eip + next_eip_addend;
42         env->regs[11] = cpu_compute_eflags(env) & ~RF_MASK;
43 
44         code64 = env->hflags & HF_CS64_MASK;
45 
46         env->eflags &= ~(env->fmask | RF_MASK);
47         cpu_load_eflags(env, env->eflags, 0);
48         cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
49                            0, 0xffffffff,
50                                DESC_G_MASK | DESC_P_MASK |
51                                DESC_S_MASK |
52                                DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK |
53                                DESC_L_MASK);
54         cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
55                                0, 0xffffffff,
56                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
57                                DESC_S_MASK |
58                                DESC_W_MASK | DESC_A_MASK);
59         if (code64) {
60             env->eip = env->lstar;
61         } else {
62             env->eip = env->cstar;
63         }
64     } else
65 #endif
66     {
67         env->regs[R_ECX] = (uint32_t)(env->eip + next_eip_addend);
68 
69         env->eflags &= ~(IF_MASK | RF_MASK | VM_MASK);
70         cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
71                            0, 0xffffffff,
72                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
73                                DESC_S_MASK |
74                                DESC_CS_MASK | DESC_R_MASK | DESC_A_MASK);
75         cpu_x86_load_seg_cache(env, R_SS, (selector + 8) & 0xfffc,
76                                0, 0xffffffff,
77                                DESC_G_MASK | DESC_B_MASK | DESC_P_MASK |
78                                DESC_S_MASK |
79                                DESC_W_MASK | DESC_A_MASK);
80         env->eip = (uint32_t)env->star;
81     }
82 }
83 
84 void handle_even_inj(CPUX86State *env, int intno, int is_int,
85                      int error_code, int is_hw, int rm)
86 {
87     CPUState *cs = env_cpu(env);
88     uint32_t event_inj = x86_ldl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
89                                                           control.event_inj));
90 
91     if (!(event_inj & SVM_EVTINJ_VALID)) {
92         int type;
93 
94         if (is_int) {
95             type = SVM_EVTINJ_TYPE_SOFT;
96         } else {
97             type = SVM_EVTINJ_TYPE_EXEPT;
98         }
99         event_inj = intno | type | SVM_EVTINJ_VALID;
100         if (!rm && exception_has_error_code(intno)) {
101             event_inj |= SVM_EVTINJ_VALID_ERR;
102             x86_stl_phys(cs, env->vm_vmcb + offsetof(struct vmcb,
103                                              control.event_inj_err),
104                      error_code);
105         }
106         x86_stl_phys(cs,
107                  env->vm_vmcb + offsetof(struct vmcb, control.event_inj),
108                  event_inj);
109     }
110 }
111 
112 void x86_cpu_do_interrupt(CPUState *cs)
113 {
114     X86CPU *cpu = X86_CPU(cs);
115     CPUX86State *env = &cpu->env;
116 
117     if (cs->exception_index == EXCP_VMEXIT) {
118         assert(env->old_exception == -1);
119         do_vmexit(env);
120     } else {
121         do_interrupt_all(cpu, cs->exception_index,
122                          env->exception_is_int,
123                          env->error_code,
124                          env->exception_next_eip, 0);
125         /* successfully delivered */
126         env->old_exception = -1;
127     }
128 }
129 
130 bool x86_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
131 {
132     X86CPU *cpu = X86_CPU(cs);
133     CPUX86State *env = &cpu->env;
134     int intno;
135 
136     interrupt_request = x86_cpu_pending_interrupt(cs, interrupt_request);
137     if (!interrupt_request) {
138         return false;
139     }
140 
141     /* Don't process multiple interrupt requests in a single call.
142      * This is required to make icount-driven execution deterministic.
143      */
144     switch (interrupt_request) {
145     case CPU_INTERRUPT_POLL:
146         cs->interrupt_request &= ~CPU_INTERRUPT_POLL;
147         apic_poll_irq(cpu->apic_state);
148         break;
149     case CPU_INTERRUPT_SIPI:
150         do_cpu_sipi(cpu);
151         break;
152     case CPU_INTERRUPT_SMI:
153         cpu_svm_check_intercept_param(env, SVM_EXIT_SMI, 0, 0);
154         cs->interrupt_request &= ~CPU_INTERRUPT_SMI;
155         do_smm_enter(cpu);
156         break;
157     case CPU_INTERRUPT_NMI:
158         cpu_svm_check_intercept_param(env, SVM_EXIT_NMI, 0, 0);
159         cs->interrupt_request &= ~CPU_INTERRUPT_NMI;
160         env->hflags2 |= HF2_NMI_MASK;
161         do_interrupt_x86_hardirq(env, EXCP02_NMI, 1);
162         break;
163     case CPU_INTERRUPT_MCE:
164         cs->interrupt_request &= ~CPU_INTERRUPT_MCE;
165         do_interrupt_x86_hardirq(env, EXCP12_MCHK, 0);
166         break;
167     case CPU_INTERRUPT_HARD:
168         cpu_svm_check_intercept_param(env, SVM_EXIT_INTR, 0, 0);
169         cs->interrupt_request &= ~(CPU_INTERRUPT_HARD |
170                                    CPU_INTERRUPT_VIRQ);
171         intno = cpu_get_pic_interrupt(env);
172         qemu_log_mask(CPU_LOG_INT,
173                       "Servicing hardware INT=0x%02x\n", intno);
174         do_interrupt_x86_hardirq(env, intno, 1);
175         break;
176     case CPU_INTERRUPT_VIRQ:
177         cpu_svm_check_intercept_param(env, SVM_EXIT_VINTR, 0, 0);
178         intno = x86_ldl_phys(cs, env->vm_vmcb
179                              + offsetof(struct vmcb, control.int_vector));
180         qemu_log_mask(CPU_LOG_INT,
181                       "Servicing virtual hardware INT=0x%02x\n", intno);
182         do_interrupt_x86_hardirq(env, intno, 1);
183         cs->interrupt_request &= ~CPU_INTERRUPT_VIRQ;
184         env->int_ctl &= ~V_IRQ_MASK;
185         break;
186     }
187 
188     /* Ensure that no TB jump will be modified as the program flow was changed.  */
189     return true;
190 }
191 
192 /* check if Port I/O is allowed in TSS */
193 void helper_check_io(CPUX86State *env, uint32_t addr, uint32_t size)
194 {
195     uintptr_t retaddr = GETPC();
196     uint32_t io_offset, val, mask;
197 
198     /* TSS must be a valid 32 bit one */
199     if (!(env->tr.flags & DESC_P_MASK) ||
200         ((env->tr.flags >> DESC_TYPE_SHIFT) & 0xf) != 9 ||
201         env->tr.limit < 103) {
202         goto fail;
203     }
204     io_offset = cpu_lduw_kernel_ra(env, env->tr.base + 0x66, retaddr);
205     io_offset += (addr >> 3);
206     /* Note: the check needs two bytes */
207     if ((io_offset + 1) > env->tr.limit) {
208         goto fail;
209     }
210     val = cpu_lduw_kernel_ra(env, env->tr.base + io_offset, retaddr);
211     val >>= (addr & 7);
212     mask = (1 << size) - 1;
213     /* all bits must be zero to allow the I/O */
214     if ((val & mask) != 0) {
215     fail:
216         raise_exception_err_ra(env, EXCP0D_GPF, 0, retaddr);
217     }
218 }
219