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 /* 64 * Avoid using memset to clear the vmcb, since libc may not be 65 * available in L1 (and, even if it is, features that libc memset may 66 * want to use, like AVX, may not be enabled). 67 */ 68 static void clear_vmcb(struct vmcb *vmcb) 69 { 70 int n = sizeof(*vmcb) / sizeof(u32); 71 72 asm volatile ("rep stosl" : "+c"(n), "+D"(vmcb) : "a"(0) : "memory"); 73 } 74 75 void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_rsp) 76 { 77 struct vmcb *vmcb = svm->vmcb; 78 uint64_t vmcb_gpa = svm->vmcb_gpa; 79 struct vmcb_save_area *save = &vmcb->save; 80 struct vmcb_control_area *ctrl = &vmcb->control; 81 u32 data_seg_attr = 3 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK 82 | SVM_SELECTOR_DB_MASK | SVM_SELECTOR_G_MASK; 83 u32 code_seg_attr = 9 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK 84 | SVM_SELECTOR_L_MASK | SVM_SELECTOR_G_MASK; 85 uint64_t efer; 86 87 efer = rdmsr(MSR_EFER); 88 wrmsr(MSR_EFER, efer | EFER_SVME); 89 wrmsr(MSR_VM_HSAVE_PA, svm->save_area_gpa); 90 91 clear_vmcb(vmcb); 92 asm volatile ("vmsave %0\n\t" : : "a" (vmcb_gpa) : "memory"); 93 vmcb_set_seg(&save->es, get_es(), 0, -1U, data_seg_attr); 94 vmcb_set_seg(&save->cs, get_cs(), 0, -1U, code_seg_attr); 95 vmcb_set_seg(&save->ss, get_ss(), 0, -1U, data_seg_attr); 96 vmcb_set_seg(&save->ds, get_ds(), 0, -1U, data_seg_attr); 97 vmcb_set_seg(&save->gdtr, 0, get_gdt().address, get_gdt().size, 0); 98 vmcb_set_seg(&save->idtr, 0, get_idt().address, get_idt().size, 0); 99 100 ctrl->asid = 1; 101 save->cpl = 0; 102 save->efer = rdmsr(MSR_EFER); 103 asm volatile ("mov %%cr4, %0" : "=r"(save->cr4) : : "memory"); 104 asm volatile ("mov %%cr3, %0" : "=r"(save->cr3) : : "memory"); 105 asm volatile ("mov %%cr0, %0" : "=r"(save->cr0) : : "memory"); 106 asm volatile ("mov %%dr7, %0" : "=r"(save->dr7) : : "memory"); 107 asm volatile ("mov %%dr6, %0" : "=r"(save->dr6) : : "memory"); 108 asm volatile ("mov %%cr2, %0" : "=r"(save->cr2) : : "memory"); 109 save->g_pat = rdmsr(MSR_IA32_CR_PAT); 110 save->dbgctl = rdmsr(MSR_IA32_DEBUGCTLMSR); 111 ctrl->intercept = (1ULL << INTERCEPT_VMRUN) | 112 (1ULL << INTERCEPT_VMMCALL); 113 ctrl->msrpm_base_pa = svm->msr_gpa; 114 115 vmcb->save.rip = (u64)guest_rip; 116 vmcb->save.rsp = (u64)guest_rsp; 117 guest_regs.rdi = (u64)svm; 118 } 119 120 /* 121 * save/restore 64-bit general registers except rax, rip, rsp 122 * which are directly handed through the VMCB guest processor state 123 */ 124 #define SAVE_GPR_C \ 125 "xchg %%rbx, guest_regs+0x20\n\t" \ 126 "xchg %%rcx, guest_regs+0x10\n\t" \ 127 "xchg %%rdx, guest_regs+0x18\n\t" \ 128 "xchg %%rbp, guest_regs+0x30\n\t" \ 129 "xchg %%rsi, guest_regs+0x38\n\t" \ 130 "xchg %%rdi, guest_regs+0x40\n\t" \ 131 "xchg %%r8, guest_regs+0x48\n\t" \ 132 "xchg %%r9, guest_regs+0x50\n\t" \ 133 "xchg %%r10, guest_regs+0x58\n\t" \ 134 "xchg %%r11, guest_regs+0x60\n\t" \ 135 "xchg %%r12, guest_regs+0x68\n\t" \ 136 "xchg %%r13, guest_regs+0x70\n\t" \ 137 "xchg %%r14, guest_regs+0x78\n\t" \ 138 "xchg %%r15, guest_regs+0x80\n\t" 139 140 #define LOAD_GPR_C SAVE_GPR_C 141 142 /* 143 * selftests do not use interrupts so we dropped clgi/sti/cli/stgi 144 * for now. registers involved in LOAD/SAVE_GPR_C are eventually 145 * unmodified so they do not need to be in the clobber list. 146 */ 147 void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa) 148 { 149 asm volatile ( 150 "vmload %[vmcb_gpa]\n\t" 151 "mov rflags, %%r15\n\t" // rflags 152 "mov %%r15, 0x170(%[vmcb])\n\t" 153 "mov guest_regs, %%r15\n\t" // rax 154 "mov %%r15, 0x1f8(%[vmcb])\n\t" 155 LOAD_GPR_C 156 "vmrun %[vmcb_gpa]\n\t" 157 SAVE_GPR_C 158 "mov 0x170(%[vmcb]), %%r15\n\t" // rflags 159 "mov %%r15, rflags\n\t" 160 "mov 0x1f8(%[vmcb]), %%r15\n\t" // rax 161 "mov %%r15, guest_regs\n\t" 162 "vmsave %[vmcb_gpa]\n\t" 163 : : [vmcb] "r" (vmcb), [vmcb_gpa] "a" (vmcb_gpa) 164 : "r15", "memory"); 165 } 166 167 /* 168 * Open SEV_DEV_PATH if available, otherwise exit the entire program. 169 * 170 * Return: 171 * The opened file descriptor of /dev/sev. 172 */ 173 int open_sev_dev_path_or_exit(void) 174 { 175 return open_path_or_exit(SEV_DEV_PATH, 0); 176 } 177