1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * tools/testing/selftests/kvm/lib/x86_64/svm.c
4 * Helpers used for nested SVM testing
5 * Largely inspired from KVM unit test svm.c
6 *
7 * Copyright (C) 2020, Red Hat, Inc.
8 */
9
10 #include "test_util.h"
11 #include "kvm_util.h"
12 #include "processor.h"
13 #include "svm_util.h"
14
15 #define SEV_DEV_PATH "/dev/sev"
16
17 struct gpr64_regs guest_regs;
18 u64 rflags;
19
20 /* Allocate memory regions for nested SVM tests.
21 *
22 * Input Args:
23 * vm - The VM to allocate guest-virtual addresses in.
24 *
25 * Output Args:
26 * p_svm_gva - The guest virtual address for the struct svm_test_data.
27 *
28 * Return:
29 * Pointer to structure with the addresses of the SVM areas.
30 */
31 struct svm_test_data *
32 vcpu_alloc_svm(struct kvm_vm *vm, vm_vaddr_t *p_svm_gva)
33 {
34 vm_vaddr_t svm_gva = vm_vaddr_alloc_page(vm);
35 struct svm_test_data *svm = addr_gva2hva(vm, svm_gva);
36
37 svm->vmcb = (void *)vm_vaddr_alloc_page(vm);
38 svm->vmcb_hva = addr_gva2hva(vm, (uintptr_t)svm->vmcb);
39 svm->vmcb_gpa = addr_gva2gpa(vm, (uintptr_t)svm->vmcb);
40
41 svm->save_area = (void *)vm_vaddr_alloc_page(vm);
42 svm->save_area_hva = addr_gva2hva(vm, (uintptr_t)svm->save_area);
43 svm->save_area_gpa = addr_gva2gpa(vm, (uintptr_t)svm->save_area);
44
45 svm->msr = (void *)vm_vaddr_alloc_page(vm);
46 svm->msr_hva = addr_gva2hva(vm, (uintptr_t)svm->msr);
47 svm->msr_gpa = addr_gva2gpa(vm, (uintptr_t)svm->msr);
48 memset(svm->msr_hva, 0, getpagesize());
49
50 *p_svm_gva = svm_gva;
51 return svm;
52 }
53
54 static void vmcb_set_seg(struct vmcb_seg *seg, u16 selector,
55 u64 base, u32 limit, u32 attr)
56 {
57 seg->selector = selector;
58 seg->attrib = attr;
59 seg->limit = limit;
60 seg->base = base;
61 }
62
63 void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_rsp)
64 {
65 struct vmcb *vmcb = svm->vmcb;
66 uint64_t vmcb_gpa = svm->vmcb_gpa;
67 struct vmcb_save_area *save = &vmcb->save;
68 struct vmcb_control_area *ctrl = &vmcb->control;
69 u32 data_seg_attr = 3 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK
70 | SVM_SELECTOR_DB_MASK | SVM_SELECTOR_G_MASK;
71 u32 code_seg_attr = 9 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK
72 | SVM_SELECTOR_L_MASK | SVM_SELECTOR_G_MASK;
73 uint64_t efer;
74
75 efer = rdmsr(MSR_EFER);
76 wrmsr(MSR_EFER, efer | EFER_SVME);
77 wrmsr(MSR_VM_HSAVE_PA, svm->save_area_gpa);
78
79 memset(vmcb, 0, sizeof(*vmcb));
80 asm volatile ("vmsave %0\n\t" : : "a" (vmcb_gpa) : "memory");
81 vmcb_set_seg(&save->es, get_es(), 0, -1U, data_seg_attr);
82 vmcb_set_seg(&save->cs, get_cs(), 0, -1U, code_seg_attr);
83 vmcb_set_seg(&save->ss, get_ss(), 0, -1U, data_seg_attr);
84 vmcb_set_seg(&save->ds, get_ds(), 0, -1U, data_seg_attr);
85 vmcb_set_seg(&save->gdtr, 0, get_gdt().address, get_gdt().size, 0);
86 vmcb_set_seg(&save->idtr, 0, get_idt().address, get_idt().size, 0);
87
88 ctrl->asid = 1;
89 save->cpl = 0;
90 save->efer = rdmsr(MSR_EFER);
91 asm volatile ("mov %%cr4, %0" : "=r"(save->cr4) : : "memory");
92 asm volatile ("mov %%cr3, %0" : "=r"(save->cr3) : : "memory");
93 asm volatile ("mov %%cr0, %0" : "=r"(save->cr0) : : "memory");
94 asm volatile ("mov %%dr7, %0" : "=r"(save->dr7) : : "memory");
95 asm volatile ("mov %%dr6, %0" : "=r"(save->dr6) : : "memory");
96 asm volatile ("mov %%cr2, %0" : "=r"(save->cr2) : : "memory");
97 save->g_pat = rdmsr(MSR_IA32_CR_PAT);
98 save->dbgctl = rdmsr(MSR_IA32_DEBUGCTLMSR);
99 ctrl->intercept = (1ULL << INTERCEPT_VMRUN) |
100 (1ULL << INTERCEPT_VMMCALL);
101 ctrl->msrpm_base_pa = svm->msr_gpa;
102
103 vmcb->save.rip = (u64)guest_rip;
104 vmcb->save.rsp = (u64)guest_rsp;
105 guest_regs.rdi = (u64)svm;
106 }
107
108 /*
109 * save/restore 64-bit general registers except rax, rip, rsp
110 * which are directly handed through the VMCB guest processor state
111 */
112 #define SAVE_GPR_C \
113 "xchg %%rbx, guest_regs+0x20\n\t" \
114 "xchg %%rcx, guest_regs+0x10\n\t" \
115 "xchg %%rdx, guest_regs+0x18\n\t" \
116 "xchg %%rbp, guest_regs+0x30\n\t" \
117 "xchg %%rsi, guest_regs+0x38\n\t" \
118 "xchg %%rdi, guest_regs+0x40\n\t" \
119 "xchg %%r8, guest_regs+0x48\n\t" \
120 "xchg %%r9, guest_regs+0x50\n\t" \
121 "xchg %%r10, guest_regs+0x58\n\t" \
122 "xchg %%r11, guest_regs+0x60\n\t" \
123 "xchg %%r12, guest_regs+0x68\n\t" \
124 "xchg %%r13, guest_regs+0x70\n\t" \
125 "xchg %%r14, guest_regs+0x78\n\t" \
126 "xchg %%r15, guest_regs+0x80\n\t"
127
128 #define LOAD_GPR_C SAVE_GPR_C
129
130 /*
131 * selftests do not use interrupts so we dropped clgi/sti/cli/stgi
132 * for now. registers involved in LOAD/SAVE_GPR_C are eventually
133 * unmodified so they do not need to be in the clobber list.
134 */
135 void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa)
136 {
137 asm volatile (
138 "vmload %[vmcb_gpa]\n\t"
139 "mov rflags, %%r15\n\t" // rflags
140 "mov %%r15, 0x170(%[vmcb])\n\t"
141 "mov guest_regs, %%r15\n\t" // rax
142 "mov %%r15, 0x1f8(%[vmcb])\n\t"
143 LOAD_GPR_C
144 "vmrun %[vmcb_gpa]\n\t"
145 SAVE_GPR_C
146 "mov 0x170(%[vmcb]), %%r15\n\t" // rflags
147 "mov %%r15, rflags\n\t"
148 "mov 0x1f8(%[vmcb]), %%r15\n\t" // rax
149 "mov %%r15, guest_regs\n\t"
150 "vmsave %[vmcb_gpa]\n\t"
151 : : [vmcb] "r" (vmcb), [vmcb_gpa] "a" (vmcb_gpa)
152 : "r15", "memory");
153 }
154
155 /*
156 * Open SEV_DEV_PATH if available, otherwise exit the entire program.
157 *
158 * Return:
159 * The opened file descriptor of /dev/sev.
160 */
161 int open_sev_dev_path_or_exit(void)
162 {
163 return open_path_or_exit(SEV_DEV_PATH, 0);
164 }
165
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.