xref: /openbmc/qemu/target/i386/hvf/x86_task.c (revision 99d423e5)
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 "hw/i386/apic_internal.h"
30 #include "hw/boards.h"
31 #include "qemu/main-loop.h"
32 #include "sysemu/accel.h"
33 #include "sysemu/sysemu.h"
34 #include "target/i386/cpu.h"
35 
36 // TODO: taskswitch handling
37 static void save_state_to_tss32(CPUState *cpu, struct x86_tss_segment32 *tss)
38 {
39     X86CPU *x86_cpu = X86_CPU(cpu);
40     CPUX86State *env = &x86_cpu->env;
41 
42     /* CR3 and ldt selector are not saved intentionally */
43     tss->eip = EIP(env);
44     tss->eflags = EFLAGS(env);
45     tss->eax = EAX(env);
46     tss->ecx = ECX(env);
47     tss->edx = EDX(env);
48     tss->ebx = EBX(env);
49     tss->esp = ESP(env);
50     tss->ebp = EBP(env);
51     tss->esi = ESI(env);
52     tss->edi = EDI(env);
53 
54     tss->es = vmx_read_segment_selector(cpu, R_ES).sel;
55     tss->cs = vmx_read_segment_selector(cpu, R_CS).sel;
56     tss->ss = vmx_read_segment_selector(cpu, R_SS).sel;
57     tss->ds = vmx_read_segment_selector(cpu, R_DS).sel;
58     tss->fs = vmx_read_segment_selector(cpu, R_FS).sel;
59     tss->gs = vmx_read_segment_selector(cpu, R_GS).sel;
60 }
61 
62 static void load_state_from_tss32(CPUState *cpu, struct x86_tss_segment32 *tss)
63 {
64     X86CPU *x86_cpu = X86_CPU(cpu);
65     CPUX86State *env = &x86_cpu->env;
66 
67     wvmcs(cpu->hvf_fd, VMCS_GUEST_CR3, tss->cr3);
68 
69     RIP(env) = tss->eip;
70     EFLAGS(env) = tss->eflags | 2;
71 
72     /* General purpose registers */
73     RAX(env) = tss->eax;
74     RCX(env) = tss->ecx;
75     RDX(env) = tss->edx;
76     RBX(env) = tss->ebx;
77     RSP(env) = tss->esp;
78     RBP(env) = tss->ebp;
79     RSI(env) = tss->esi;
80     RDI(env) = tss->edi;
81 
82     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ldt}}, R_LDTR);
83     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->es}}, R_ES);
84     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->cs}}, R_CS);
85     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ss}}, R_SS);
86     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->ds}}, R_DS);
87     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->fs}}, R_FS);
88     vmx_write_segment_selector(cpu, (x68_segment_selector){{tss->gs}}, R_GS);
89 }
90 
91 static int task_switch_32(CPUState *cpu, x68_segment_selector tss_sel, x68_segment_selector old_tss_sel,
92                           uint64_t old_tss_base, struct x86_segment_descriptor *new_desc)
93 {
94     struct x86_tss_segment32 tss_seg;
95     uint32_t new_tss_base = x86_segment_base(new_desc);
96     uint32_t eip_offset = offsetof(struct x86_tss_segment32, eip);
97     uint32_t ldt_sel_offset = offsetof(struct x86_tss_segment32, ldt);
98 
99     vmx_read_mem(cpu, &tss_seg, old_tss_base, sizeof(tss_seg));
100     save_state_to_tss32(cpu, &tss_seg);
101 
102     vmx_write_mem(cpu, old_tss_base + eip_offset, &tss_seg.eip, ldt_sel_offset - eip_offset);
103     vmx_read_mem(cpu, &tss_seg, new_tss_base, sizeof(tss_seg));
104 
105     if (old_tss_sel.sel != 0xffff) {
106         tss_seg.prev_tss = old_tss_sel.sel;
107 
108         vmx_write_mem(cpu, new_tss_base, &tss_seg.prev_tss, sizeof(tss_seg.prev_tss));
109     }
110     load_state_from_tss32(cpu, &tss_seg);
111     return 0;
112 }
113 
114 void vmx_handle_task_switch(CPUState *cpu, x68_segment_selector tss_sel, int reason, bool gate_valid, uint8_t gate, uint64_t gate_type)
115 {
116     uint64_t rip = rreg(cpu->hvf_fd, HV_X86_RIP);
117     if (!gate_valid || (gate_type != VMCS_INTR_T_HWEXCEPTION &&
118                         gate_type != VMCS_INTR_T_HWINTR &&
119                         gate_type != VMCS_INTR_T_NMI)) {
120         int ins_len = rvmcs(cpu->hvf_fd, VMCS_EXIT_INSTRUCTION_LENGTH);
121         macvm_set_rip(cpu, rip + ins_len);
122         return;
123     }
124 
125     load_regs(cpu);
126 
127     struct x86_segment_descriptor curr_tss_desc, next_tss_desc;
128     int ret;
129     x68_segment_selector old_tss_sel = vmx_read_segment_selector(cpu, R_TR);
130     uint64_t old_tss_base = vmx_read_segment_base(cpu, R_TR);
131     uint32_t desc_limit;
132     struct x86_call_gate task_gate_desc;
133     struct vmx_segment vmx_seg;
134 
135     X86CPU *x86_cpu = X86_CPU(cpu);
136     CPUX86State *env = &x86_cpu->env;
137 
138     x86_read_segment_descriptor(cpu, &next_tss_desc, tss_sel);
139     x86_read_segment_descriptor(cpu, &curr_tss_desc, old_tss_sel);
140 
141     if (reason == TSR_IDT_GATE && gate_valid) {
142         int dpl;
143 
144         ret = x86_read_call_gate(cpu, &task_gate_desc, gate);
145 
146         dpl = task_gate_desc.dpl;
147         x68_segment_selector cs = vmx_read_segment_selector(cpu, R_CS);
148         if (tss_sel.rpl > dpl || cs.rpl > dpl)
149             ;//DPRINTF("emulate_gp");
150     }
151 
152     desc_limit = x86_segment_limit(&next_tss_desc);
153     if (!next_tss_desc.p || ((desc_limit < 0x67 && (next_tss_desc.type & 8)) || desc_limit < 0x2b)) {
154         VM_PANIC("emulate_ts");
155     }
156 
157     if (reason == TSR_IRET || reason == TSR_JMP) {
158         curr_tss_desc.type &= ~(1 << 1); /* clear busy flag */
159         x86_write_segment_descriptor(cpu, &curr_tss_desc, old_tss_sel);
160     }
161 
162     if (reason == TSR_IRET)
163         EFLAGS(env) &= ~RFLAGS_NT;
164 
165     if (reason != TSR_CALL && reason != TSR_IDT_GATE)
166         old_tss_sel.sel = 0xffff;
167 
168     if (reason != TSR_IRET) {
169         next_tss_desc.type |= (1 << 1); /* set busy flag */
170         x86_write_segment_descriptor(cpu, &next_tss_desc, tss_sel);
171     }
172 
173     if (next_tss_desc.type & 8)
174         ret = task_switch_32(cpu, tss_sel, old_tss_sel, old_tss_base, &next_tss_desc);
175     else
176         //ret = task_switch_16(cpu, tss_sel, old_tss_sel, old_tss_base, &next_tss_desc);
177         VM_PANIC("task_switch_16");
178 
179     macvm_set_cr0(cpu->hvf_fd, rvmcs(cpu->hvf_fd, VMCS_GUEST_CR0) | CR0_TS);
180     x86_segment_descriptor_to_vmx(cpu, tss_sel, &next_tss_desc, &vmx_seg);
181     vmx_write_segment_descriptor(cpu, &vmx_seg, R_TR);
182 
183     store_regs(cpu);
184 
185     hv_vcpu_invalidate_tlb(cpu->hvf_fd);
186     hv_vcpu_flush(cpu->hvf_fd);
187 }
188