tools/testing/selftests/kvm/lib/x86_64/svm.c

   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 *
  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
  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
  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  */
 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
 151 void nested_svm_check_supported(void)
 152 {
 153         struct kvm_cpuid_entry2 *entry =
 154                 kvm_get_supported_cpuid_entry(0x80000001);
 155
 156         if (!(entry->ecx & CPUID_SVM)) {
 157                 fprintf(stderr, "nested SVM not enabled, skipping test\n");
 158                 exit(KSFT_SKIP);
 159         }
 160 }
 161