xref: /openbmc/qemu/target/i386/hvf/x86_task.c (revision d695918f)
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/error-report.h"
12 
13 #include "sysemu/hvf.h"
14 #include "hvf-i386.h"
15 #include "vmcs.h"
16 #include "vmx.h"
17 #include "x86.h"
18 #include "x86_descr.h"
19 #include "x86_mmu.h"
20 #include "x86_decode.h"
21 #include "x86_emu.h"
22 #include "x86_task.h"
23 #include "x86hvf.h"
24 
25 #include <Hypervisor/hv.h>
26 #include <Hypervisor/hv_vmx.h>
27 
28 #include "hw/i386/apic_internal.h"
29 #include "qemu/main-loop.h"
30 #include "qemu/accel.h"
31 #include "target/i386/cpu.h"
32 
33 // TODO: taskswitch handling
34 static void save_state_to_tss32(CPUState *cpu, struct x86_tss_segment32 *tss)
35 {
36     X86CPU *x86_cpu = X86_CPU(cpu);
37     CPUX86State *env = &x86_cpu->env;
38 
39     /* CR3 and ldt selector are not saved intentionally */
40     tss->eip = (uint32_t)env->eip;
41     tss->eflags = (uint32_t)env->eflags;
42     tss->eax = EAX(env);
43     tss->ecx = ECX(env);
44     tss->edx = EDX(env);
45     tss->ebx = EBX(env);
46     tss->esp = ESP(env);
47     tss->ebp = EBP(env);
48     tss->esi = ESI(env);
49     tss->edi = EDI(env);
50 
51     tss->es = vmx_read_segment_selector(cpu, R_ES).sel;
52     tss->cs = vmx_read_segment_selector(cpu, R_CS).sel;
53     tss->ss = vmx_read_segment_selector(cpu, R_SS).sel;
54     tss->ds = vmx_read_segment_selector(cpu, R_DS).sel;
55     tss->fs = vmx_read_segment_selector(cpu, R_FS).sel;
56     tss->gs = vmx_read_segment_selector(cpu, R_GS).sel;
57 }
58 
59 static void load_state_from_tss32(CPUState *cpu, struct x86_tss_segment32 *tss)
60 {
61     X86CPU *x86_cpu = X86_CPU(cpu);
62     CPUX86State *env = &x86_cpu->env;
63 
64     wvmcs(cpu->hvf->fd, VMCS_GUEST_CR3, tss->cr3);
65 
66     env->eip = tss->eip;
67     env->eflags = tss->eflags | 2;
68 
69     /* General purpose registers */
70     RAX(env) = tss->eax;
71     RCX(env) = tss->ecx;
72     RDX(env) = tss->edx;
73     RBX(env) = tss->ebx;
74     RSP(env) = tss->esp;
75     RBP(env) = tss->ebp;
76     RSI(env) = tss->esi;
77     RDI(env) = tss->edi;
78 
79     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ldt}}, R_LDTR);
80     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->es}}, R_ES);
81     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->cs}}, R_CS);
82     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ss}}, R_SS);
83     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ds}}, R_DS);
84     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->fs}}, R_FS);
85     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->gs}}, R_GS);
86 }
87 
88 static int task_switch_32(CPUState *cpu, x68_segment_selector tss_sel, x68_segment_selector old_tss_sel,
89                           uint64_t old_tss_base, struct x86_segment_descriptor *new_desc)
90 {
91     struct x86_tss_segment32 tss_seg;
92     uint32_t new_tss_base = x86_segment_base(new_desc);
93     uint32_t eip_offset = offsetof(struct x86_tss_segment32, eip);
94     uint32_t ldt_sel_offset = offsetof(struct x86_tss_segment32, ldt);
95 
96     vmx_read_mem(cpu, &tss_seg, old_tss_base, sizeof(tss_seg));
97     save_state_to_tss32(cpu, &tss_seg);
98 
99     vmx_write_mem(cpu, old_tss_base + eip_offset, &tss_seg.eip, ldt_sel_offset - eip_offset);
100     vmx_read_mem(cpu, &tss_seg, new_tss_base, sizeof(tss_seg));
101 
102     if (old_tss_sel.sel != 0xffff) {
103         tss_seg.prev_tss = old_tss_sel.sel;
104 
105         vmx_write_mem(cpu, new_tss_base, &tss_seg.prev_tss, sizeof(tss_seg.prev_tss));
106     }
107     load_state_from_tss32(cpu, &tss_seg);
108     return 0;
109 }
110 
111 void vmx_handle_task_switch(CPUState *cpu, x68_segment_selector tss_sel, int reason, bool gate_valid, uint8_t gate, uint64_t gate_type)
112 {
113     uint64_t rip = rreg(cpu->hvf->fd, HV_X86_RIP);
114     if (!gate_valid || (gate_type != VMCS_INTR_T_HWEXCEPTION &&
115                         gate_type != VMCS_INTR_T_HWINTR &&
116                         gate_type != VMCS_INTR_T_NMI)) {
117         int ins_len = rvmcs(cpu->hvf->fd, VMCS_EXIT_INSTRUCTION_LENGTH);
118         macvm_set_rip(cpu, rip + ins_len);
119         return;
120     }
121 
122     load_regs(cpu);
123 
124     struct x86_segment_descriptor curr_tss_desc, next_tss_desc;
125     int ret;
126     x68_segment_selector old_tss_sel = vmx_read_segment_selector(cpu, R_TR);
127     uint64_t old_tss_base = vmx_read_segment_base(cpu, R_TR);
128     uint32_t desc_limit;
129     struct x86_call_gate task_gate_desc;
130     struct vmx_segment vmx_seg;
131 
132     X86CPU *x86_cpu = X86_CPU(cpu);
133     CPUX86State *env = &x86_cpu->env;
134 
135     x86_read_segment_descriptor(cpu, &next_tss_desc, tss_sel);
136     x86_read_segment_descriptor(cpu, &curr_tss_desc, old_tss_sel);
137 
138     if (reason == TSR_IDT_GATE && gate_valid) {
139         int dpl;
140 
141         ret = x86_read_call_gate(cpu, &task_gate_desc, gate);
142 
143         dpl = task_gate_desc.dpl;
144         x68_segment_selector cs = vmx_read_segment_selector(cpu, R_CS);
145         if (tss_sel.rpl > dpl || cs.rpl > dpl)
146             ;//DPRINTF("emulate_gp");
147     }
148 
149     desc_limit = x86_segment_limit(&next_tss_desc);
150     if (!next_tss_desc.p || ((desc_limit < 0x67 && (next_tss_desc.type & 8)) || desc_limit < 0x2b)) {
151         VM_PANIC("emulate_ts");
152     }
153 
154     if (reason == TSR_IRET || reason == TSR_JMP) {
155         curr_tss_desc.type &= ~(1 << 1); /* clear busy flag */
156         x86_write_segment_descriptor(cpu, &curr_tss_desc, old_tss_sel);
157     }
158 
159     if (reason == TSR_IRET)
160         env->eflags &= ~NT_MASK;
161 
162     if (reason != TSR_CALL && reason != TSR_IDT_GATE)
163         old_tss_sel.sel = 0xffff;
164 
165     if (reason != TSR_IRET) {
166         next_tss_desc.type |= (1 << 1); /* set busy flag */
167         x86_write_segment_descriptor(cpu, &next_tss_desc, tss_sel);
168     }
169 
170     if (next_tss_desc.type & 8)
171         ret = task_switch_32(cpu, tss_sel, old_tss_sel, old_tss_base, &next_tss_desc);
172     else
173         //ret = task_switch_16(cpu, tss_sel, old_tss_sel, old_tss_base, &next_tss_desc);
174         VM_PANIC("task_switch_16");
175 
176     macvm_set_cr0(cpu->hvf->fd, rvmcs(cpu->hvf->fd, VMCS_GUEST_CR0) |
177                                 CR0_TS_MASK);
178     x86_segment_descriptor_to_vmx(cpu, tss_sel, &next_tss_desc, &vmx_seg);
179     vmx_write_segment_descriptor(cpu, &vmx_seg, R_TR);
180 
181     store_regs(cpu);
182 
183     hv_vcpu_invalidate_tlb(cpu->hvf->fd);
184 }
185