xref: /openbmc/qemu/target/i386/hvf/x86_task.c (revision 8f0a3716)
1 // This software is licensed under the terms of the GNU General Public
2 // License version 2, as published by the Free Software Foundation, and
3 // may be copied, distributed, and modified under those terms.
4 //
5 // This program is distributed in the hope that it will be useful,
6 // but WITHOUT ANY WARRANTY; without even the implied warranty of
7 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
8 // GNU General Public License for more details.
9 #include "qemu/osdep.h"
10 #include "panic.h"
11 #include "qemu-common.h"
12 #include "qemu/error-report.h"
13 
14 #include "sysemu/hvf.h"
15 #include "hvf-i386.h"
16 #include "vmcs.h"
17 #include "vmx.h"
18 #include "x86.h"
19 #include "x86_descr.h"
20 #include "x86_mmu.h"
21 #include "x86_decode.h"
22 #include "x86_emu.h"
23 #include "x86_task.h"
24 #include "x86hvf.h"
25 
26 #include <Hypervisor/hv.h>
27 #include <Hypervisor/hv_vmx.h>
28 
29 #include "exec/address-spaces.h"
30 #include "exec/exec-all.h"
31 #include "exec/ioport.h"
32 #include "hw/i386/apic_internal.h"
33 #include "hw/boards.h"
34 #include "qemu/main-loop.h"
35 #include "sysemu/accel.h"
36 #include "sysemu/sysemu.h"
37 #include "target/i386/cpu.h"
38 
39 // TODO: taskswitch handling
40 static void save_state_to_tss32(CPUState *cpu, struct x86_tss_segment32 *tss)
41 {
42     X86CPU *x86_cpu = X86_CPU(cpu);
43     CPUX86State *env = &x86_cpu->env;
44 
45     /* CR3 and ldt selector are not saved intentionally */
46     tss->eip = EIP(env);
47     tss->eflags = EFLAGS(env);
48     tss->eax = EAX(env);
49     tss->ecx = ECX(env);
50     tss->edx = EDX(env);
51     tss->ebx = EBX(env);
52     tss->esp = ESP(env);
53     tss->ebp = EBP(env);
54     tss->esi = ESI(env);
55     tss->edi = EDI(env);
56 
57     tss->es = vmx_read_segment_selector(cpu, R_ES).sel;
58     tss->cs = vmx_read_segment_selector(cpu, R_CS).sel;
59     tss->ss = vmx_read_segment_selector(cpu, R_SS).sel;
60     tss->ds = vmx_read_segment_selector(cpu, R_DS).sel;
61     tss->fs = vmx_read_segment_selector(cpu, R_FS).sel;
62     tss->gs = vmx_read_segment_selector(cpu, R_GS).sel;
63 }
64 
65 static void load_state_from_tss32(CPUState *cpu, struct x86_tss_segment32 *tss)
66 {
67     X86CPU *x86_cpu = X86_CPU(cpu);
68     CPUX86State *env = &x86_cpu->env;
69 
70     wvmcs(cpu->hvf_fd, VMCS_GUEST_CR3, tss->cr3);
71 
72     RIP(env) = tss->eip;
73     EFLAGS(env) = tss->eflags | 2;
74 
75     /* General purpose registers */
76     RAX(env) = tss->eax;
77     RCX(env) = tss->ecx;
78     RDX(env) = tss->edx;
79     RBX(env) = tss->ebx;
80     RSP(env) = tss->esp;
81     RBP(env) = tss->ebp;
82     RSI(env) = tss->esi;
83     RDI(env) = tss->edi;
84 
85     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ldt}}, R_LDTR);
86     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->es}}, R_ES);
87     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->cs}}, R_CS);
88     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ss}}, R_SS);
89     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ds}}, R_DS);
90     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->fs}}, R_FS);
91     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->gs}}, R_GS);
92 }
93 
94 static int task_switch_32(CPUState *cpu, x68_segment_selector tss_sel, x68_segment_selector old_tss_sel,
95                           uint64_t old_tss_base, struct x86_segment_descriptor *new_desc)
96 {
97     struct x86_tss_segment32 tss_seg;
98     uint32_t new_tss_base = x86_segment_base(new_desc);
99     uint32_t eip_offset = offsetof(struct x86_tss_segment32, eip);
100     uint32_t ldt_sel_offset = offsetof(struct x86_tss_segment32, ldt);
101 
102     vmx_read_mem(cpu, &tss_seg, old_tss_base, sizeof(tss_seg));
103     save_state_to_tss32(cpu, &tss_seg);
104 
105     vmx_write_mem(cpu, old_tss_base + eip_offset, &tss_seg.eip, ldt_sel_offset - eip_offset);
106     vmx_read_mem(cpu, &tss_seg, new_tss_base, sizeof(tss_seg));
107 
108     if (old_tss_sel.sel != 0xffff) {
109         tss_seg.prev_tss = old_tss_sel.sel;
110 
111         vmx_write_mem(cpu, new_tss_base, &tss_seg.prev_tss, sizeof(tss_seg.prev_tss));
112     }
113     load_state_from_tss32(cpu, &tss_seg);
114     return 0;
115 }
116 
117 void vmx_handle_task_switch(CPUState *cpu, x68_segment_selector tss_sel, int reason, bool gate_valid, uint8_t gate, uint64_t gate_type)
118 {
119     uint64_t rip = rreg(cpu->hvf_fd, HV_X86_RIP);
120     if (!gate_valid || (gate_type != VMCS_INTR_T_HWEXCEPTION &&
121                         gate_type != VMCS_INTR_T_HWINTR &&
122                         gate_type != VMCS_INTR_T_NMI)) {
123         int ins_len = rvmcs(cpu->hvf_fd, VMCS_EXIT_INSTRUCTION_LENGTH);
124         macvm_set_rip(cpu, rip + ins_len);
125         return;
126     }
127 
128     load_regs(cpu);
129 
130     struct x86_segment_descriptor curr_tss_desc, next_tss_desc;
131     int ret;
132     x68_segment_selector old_tss_sel = vmx_read_segment_selector(cpu, R_TR);
133     uint64_t old_tss_base = vmx_read_segment_base(cpu, R_TR);
134     uint32_t desc_limit;
135     struct x86_call_gate task_gate_desc;
136     struct vmx_segment vmx_seg;
137 
138     X86CPU *x86_cpu = X86_CPU(cpu);
139     CPUX86State *env = &x86_cpu->env;
140 
141     x86_read_segment_descriptor(cpu, &next_tss_desc, tss_sel);
142     x86_read_segment_descriptor(cpu, &curr_tss_desc, old_tss_sel);
143 
144     if (reason == TSR_IDT_GATE && gate_valid) {
145         int dpl;
146 
147         ret = x86_read_call_gate(cpu, &task_gate_desc, gate);
148 
149         dpl = task_gate_desc.dpl;
150         x68_segment_selector cs = vmx_read_segment_selector(cpu, R_CS);
151         if (tss_sel.rpl > dpl || cs.rpl > dpl)
152             ;//DPRINTF("emulate_gp");
153     }
154 
155     desc_limit = x86_segment_limit(&next_tss_desc);
156     if (!next_tss_desc.p || ((desc_limit < 0x67 && (next_tss_desc.type & 8)) || desc_limit < 0x2b)) {
157         VM_PANIC("emulate_ts");
158     }
159 
160     if (reason == TSR_IRET || reason == TSR_JMP) {
161         curr_tss_desc.type &= ~(1 << 1); /* clear busy flag */
162         x86_write_segment_descriptor(cpu, &curr_tss_desc, old_tss_sel);
163     }
164 
165     if (reason == TSR_IRET)
166         EFLAGS(env) &= ~RFLAGS_NT;
167 
168     if (reason != TSR_CALL && reason != TSR_IDT_GATE)
169         old_tss_sel.sel = 0xffff;
170 
171     if (reason != TSR_IRET) {
172         next_tss_desc.type |= (1 << 1); /* set busy flag */
173         x86_write_segment_descriptor(cpu, &next_tss_desc, tss_sel);
174     }
175 
176     if (next_tss_desc.type & 8)
177         ret = task_switch_32(cpu, tss_sel, old_tss_sel, old_tss_base, &next_tss_desc);
178     else
179         //ret = task_switch_16(cpu, tss_sel, old_tss_sel, old_tss_base, &next_tss_desc);
180         VM_PANIC("task_switch_16");
181 
182     macvm_set_cr0(cpu->hvf_fd, rvmcs(cpu->hvf_fd, VMCS_GUEST_CR0) | CR0_TS);
183     x86_segment_descriptor_to_vmx(cpu, tss_sel, &next_tss_desc, &vmx_seg);
184     vmx_write_segment_descriptor(cpu, &vmx_seg, R_TR);
185 
186     store_regs(cpu);
187 
188     hv_vcpu_invalidate_tlb(cpu->hvf_fd);
189     hv_vcpu_flush(cpu->hvf_fd);
190 }
191