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 "../kvm_util_internal.h"
13 #include "processor.h"
14 #include "svm_util.h"
15
16 struct gpr64_regs guest_regs;
17 u64 rflags;
18
19 /* Allocate memory regions for nested SVM tests.
20 *
21 * Input Args:
22 * vm - The VM to allocate guest-virtual addresses in.
23 *
24 * Output Args:
25 * p_svm_gva - The guest virtual address for the struct svm_test_data.
26 *
27 * Return:
28 * Pointer to structure with the addresses of the SVM areas.
29 */
30 struct svm_test_data *
vcpu_alloc_svm(struct kvm_vm * vm,vm_vaddr_t * p_svm_gva)31 vcpu_alloc_svm(struct kvm_vm *vm, vm_vaddr_t *p_svm_gva)
32 {
33 vm_vaddr_t svm_gva = vm_vaddr_alloc(vm, getpagesize(),
34 0x10000, 0, 0);
35 struct svm_test_data *svm = addr_gva2hva(vm, svm_gva);
36
37 svm->vmcb = (void *)vm_vaddr_alloc(vm, getpagesize(),
38 0x10000, 0, 0);
39 svm->vmcb_hva = addr_gva2hva(vm, (uintptr_t)svm->vmcb);
40 svm->vmcb_gpa = addr_gva2gpa(vm, (uintptr_t)svm->vmcb);
41
42 svm->save_area = (void *)vm_vaddr_alloc(vm, getpagesize(),
43 0x10000, 0, 0);
44 svm->save_area_hva = addr_gva2hva(vm, (uintptr_t)svm->save_area);
45 svm->save_area_gpa = addr_gva2gpa(vm, (uintptr_t)svm->save_area);
46
47 *p_svm_gva = svm_gva;
48 return svm;
49 }
50
vmcb_set_seg(struct vmcb_seg * seg,u16 selector,u64 base,u32 limit,u32 attr)51 static void vmcb_set_seg(struct vmcb_seg *seg, u16 selector,
52 u64 base, u32 limit, u32 attr)
53 {
54 seg->selector = selector;
55 seg->attrib = attr;
56 seg->limit = limit;
57 seg->base = base;
58 }
59
generic_svm_setup(struct svm_test_data * svm,void * guest_rip,void * guest_rsp)60 void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_rsp)
61 {
62 struct vmcb *vmcb = svm->vmcb;
63 uint64_t vmcb_gpa = svm->vmcb_gpa;
64 struct vmcb_save_area *save = &vmcb->save;
65 struct vmcb_control_area *ctrl = &vmcb->control;
66 u32 data_seg_attr = 3 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK
67 | SVM_SELECTOR_DB_MASK | SVM_SELECTOR_G_MASK;
68 u32 code_seg_attr = 9 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK
69 | SVM_SELECTOR_L_MASK | SVM_SELECTOR_G_MASK;
70 uint64_t efer;
71
72 efer = rdmsr(MSR_EFER);
73 wrmsr(MSR_EFER, efer | EFER_SVME);
74 wrmsr(MSR_VM_HSAVE_PA, svm->save_area_gpa);
75
76 memset(vmcb, 0, sizeof(*vmcb));
77 asm volatile ("vmsave\n\t" : : "a" (vmcb_gpa) : "memory");
78 vmcb_set_seg(&save->es, get_es(), 0, -1U, data_seg_attr);
79 vmcb_set_seg(&save->cs, get_cs(), 0, -1U, code_seg_attr);
80 vmcb_set_seg(&save->ss, get_ss(), 0, -1U, data_seg_attr);
81 vmcb_set_seg(&save->ds, get_ds(), 0, -1U, data_seg_attr);
82 vmcb_set_seg(&save->gdtr, 0, get_gdt().address, get_gdt().size, 0);
83 vmcb_set_seg(&save->idtr, 0, get_idt().address, get_idt().size, 0);
84
85 ctrl->asid = 1;
86 save->cpl = 0;
87 save->efer = rdmsr(MSR_EFER);
88 asm volatile ("mov %%cr4, %0" : "=r"(save->cr4) : : "memory");
89 asm volatile ("mov %%cr3, %0" : "=r"(save->cr3) : : "memory");
90 asm volatile ("mov %%cr0, %0" : "=r"(save->cr0) : : "memory");
91 asm volatile ("mov %%dr7, %0" : "=r"(save->dr7) : : "memory");
92 asm volatile ("mov %%dr6, %0" : "=r"(save->dr6) : : "memory");
93 asm volatile ("mov %%cr2, %0" : "=r"(save->cr2) : : "memory");
94 save->g_pat = rdmsr(MSR_IA32_CR_PAT);
95 save->dbgctl = rdmsr(MSR_IA32_DEBUGCTLMSR);
96 ctrl->intercept = (1ULL << INTERCEPT_VMRUN) |
97 (1ULL << INTERCEPT_VMMCALL);
98
99 vmcb->save.rip = (u64)guest_rip;
100 vmcb->save.rsp = (u64)guest_rsp;
101 guest_regs.rdi = (u64)svm;
102 }
103
104 /*
105 * save/restore 64-bit general registers except rax, rip, rsp
106 * which are directly handed through the VMCB guest processor state
107 */
108 #define SAVE_GPR_C \
109 "xchg %%rbx, guest_regs+0x20\n\t" \
110 "xchg %%rcx, guest_regs+0x10\n\t" \
111 "xchg %%rdx, guest_regs+0x18\n\t" \
112 "xchg %%rbp, guest_regs+0x30\n\t" \
113 "xchg %%rsi, guest_regs+0x38\n\t" \
114 "xchg %%rdi, guest_regs+0x40\n\t" \
115 "xchg %%r8, guest_regs+0x48\n\t" \
116 "xchg %%r9, guest_regs+0x50\n\t" \
117 "xchg %%r10, guest_regs+0x58\n\t" \
118 "xchg %%r11, guest_regs+0x60\n\t" \
119 "xchg %%r12, guest_regs+0x68\n\t" \
120 "xchg %%r13, guest_regs+0x70\n\t" \
121 "xchg %%r14, guest_regs+0x78\n\t" \
122 "xchg %%r15, guest_regs+0x80\n\t"
123
124 #define LOAD_GPR_C SAVE_GPR_C
125
126 /*
127 * selftests do not use interrupts so we dropped clgi/sti/cli/stgi
128 * for now. registers involved in LOAD/SAVE_GPR_C are eventually
129 * unmodified so they do not need to be in the clobber list.
130 */
run_guest(struct vmcb * vmcb,uint64_t vmcb_gpa)131 void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa)
132 {
133 asm volatile (
134 "vmload\n\t"
135 "mov rflags, %%r15\n\t" // rflags
136 "mov %%r15, 0x170(%[vmcb])\n\t"
137 "mov guest_regs, %%r15\n\t" // rax
138 "mov %%r15, 0x1f8(%[vmcb])\n\t"
139 LOAD_GPR_C
140 "vmrun\n\t"
141 SAVE_GPR_C
142 "mov 0x170(%[vmcb]), %%r15\n\t" // rflags
143 "mov %%r15, rflags\n\t"
144 "mov 0x1f8(%[vmcb]), %%r15\n\t" // rax
145 "mov %%r15, guest_regs\n\t"
146 "vmsave\n\t"
147 : : [vmcb] "r" (vmcb), [vmcb_gpa] "a" (vmcb_gpa)
148 : "r15", "memory");
149 }
150
nested_svm_supported(void)151 bool nested_svm_supported(void)
152 {
153 struct kvm_cpuid_entry2 *entry =
154 kvm_get_supported_cpuid_entry(0x80000001);
155
156 return entry->ecx & CPUID_SVM;
157 }
158
nested_svm_check_supported(void)159 void nested_svm_check_supported(void)
160 {
161 if (!nested_svm_supported()) {
162 print_skip("nested SVM not enabled");
163 exit(KSFT_SKIP);
164 }
165 }
166
