tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * KVM dirty page logging test
   4  *
   5  * Copyright (C) 2018, Red Hat, Inc.
   6  */
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <linux/bitmap.h>
  10 #include <linux/bitops.h>
  11
  12 #include "test_util.h"
  13 #include "kvm_util.h"
  14 #include "processor.h"
  15 #include "vmx.h"
  16
  17 /* The memory slot index to track dirty pages */
  18 #define TEST_MEM_SLOT_INDEX             1
  19 #define TEST_MEM_PAGES                  3
  20
  21 /* L1 guest test virtual memory offset */
  22 #define GUEST_TEST_MEM                  0xc0000000
  23
  24 /* L2 guest test virtual memory offset */
  25 #define NESTED_TEST_MEM1                0xc0001000
  26 #define NESTED_TEST_MEM2                0xc0002000
  27
  28 static void l2_guest_code(u64 *a, u64 *b)
  29 {
  30         READ_ONCE(*a);
  31         WRITE_ONCE(*a, 1);
  32         GUEST_SYNC(true);
  33         GUEST_SYNC(false);
  34
  35         WRITE_ONCE(*b, 1);
  36         GUEST_SYNC(true);
  37         WRITE_ONCE(*b, 1);
  38         GUEST_SYNC(true);
  39         GUEST_SYNC(false);
  40
  41         /* Exit to L1 and never come back.  */
  42         vmcall();
  43 }
  44
  45 static void l2_guest_code_ept_enabled(void)
  46 {
  47         l2_guest_code((u64 *)NESTED_TEST_MEM1, (u64 *)NESTED_TEST_MEM2);
  48 }
  49
  50 static void l2_guest_code_ept_disabled(void)
  51 {
  52         /* Access the same L1 GPAs as l2_guest_code_ept_enabled() */
  53         l2_guest_code((u64 *)GUEST_TEST_MEM, (u64 *)GUEST_TEST_MEM);
  54 }
  55
  56 void l1_guest_code(struct vmx_pages *vmx)
  57 {
  58 #define L2_GUEST_STACK_SIZE 64
  59         unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
  60         void *l2_rip;
  61
  62         GUEST_ASSERT(vmx->vmcs_gpa);
  63         GUEST_ASSERT(prepare_for_vmx_operation(vmx));
  64         GUEST_ASSERT(load_vmcs(vmx));
  65
  66         if (vmx->eptp_gpa)
  67                 l2_rip = l2_guest_code_ept_enabled;
  68         else
  69                 l2_rip = l2_guest_code_ept_disabled;
  70
  71         prepare_vmcs(vmx, l2_rip, &l2_guest_stack[L2_GUEST_STACK_SIZE]);
  72
  73         GUEST_SYNC(false);
  74         GUEST_ASSERT(!vmlaunch());
  75         GUEST_SYNC(false);
  76         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
  77         GUEST_DONE();
  78 }
  79
  80 static void test_vmx_dirty_log(bool enable_ept)
  81 {
  82         vm_vaddr_t vmx_pages_gva = 0;
  83         struct vmx_pages *vmx;
  84         unsigned long *bmap;
  85         uint64_t *host_test_mem;
  86
  87         struct kvm_vcpu *vcpu;
  88         struct kvm_vm *vm;
  89         struct ucall uc;
  90         bool done = false;
  91
  92         pr_info("Nested EPT: %s\n", enable_ept ? "enabled" : "disabled");
  93
  94         /* Create VM */
  95         vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
  96         vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
  97         vcpu_args_set(vcpu, 1, vmx_pages_gva);
  98
  99         /* Add an extra memory slot for testing dirty logging */
 100         vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
 101                                     GUEST_TEST_MEM,
 102                                     TEST_MEM_SLOT_INDEX,
 103                                     TEST_MEM_PAGES,
 104                                     KVM_MEM_LOG_DIRTY_PAGES);
 105
 106         /*
 107          * Add an identity map for GVA range [0xc0000000, 0xc0002000).  This
 108          * affects both L1 and L2.  However...
 109          */
 110         virt_map(vm, GUEST_TEST_MEM, GUEST_TEST_MEM, TEST_MEM_PAGES);
 111
 112         /*
 113          * ... pages in the L2 GPA range [0xc0001000, 0xc0003000) will map to
 114          * 0xc0000000.
 115          *
 116          * Note that prepare_eptp should be called only L1's GPA map is done,
 117          * meaning after the last call to virt_map.
 118          *
 119          * When EPT is disabled, the L2 guest code will still access the same L1
 120          * GPAs as the EPT enabled case.
 121          */
 122         if (enable_ept) {
 123                 prepare_eptp(vmx, vm, 0);
 124                 nested_map_memslot(vmx, vm, 0);
 125                 nested_map(vmx, vm, NESTED_TEST_MEM1, GUEST_TEST_MEM, 4096);
 126                 nested_map(vmx, vm, NESTED_TEST_MEM2, GUEST_TEST_MEM, 4096);
 127         }
 128
 129         bmap = bitmap_zalloc(TEST_MEM_PAGES);
 130         host_test_mem = addr_gpa2hva(vm, GUEST_TEST_MEM);
 131
 132         while (!done) {
 133                 memset(host_test_mem, 0xaa, TEST_MEM_PAGES * 4096);
 134                 vcpu_run(vcpu);
 135                 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 136
 137                 switch (get_ucall(vcpu, &uc)) {
 138                 case UCALL_ABORT:
 139                         REPORT_GUEST_ASSERT(uc);
 140                         /* NOT REACHED */
 141                 case UCALL_SYNC:
 142                         /*
 143                          * The nested guest wrote at offset 0x1000 in the memslot, but the
 144                          * dirty bitmap must be filled in according to L1 GPA, not L2.
 145                          */
 146                         kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
 147                         if (uc.args[1]) {
 148                                 TEST_ASSERT(test_bit(0, bmap), "Page 0 incorrectly reported clean");
 149                                 TEST_ASSERT(host_test_mem[0] == 1, "Page 0 not written by guest");
 150                         } else {
 151                                 TEST_ASSERT(!test_bit(0, bmap), "Page 0 incorrectly reported dirty");
 152                                 TEST_ASSERT(host_test_mem[0] == 0xaaaaaaaaaaaaaaaaULL, "Page 0 written by guest");
 153                         }
 154
 155                         TEST_ASSERT(!test_bit(1, bmap), "Page 1 incorrectly reported dirty");
 156                         TEST_ASSERT(host_test_mem[4096 / 8] == 0xaaaaaaaaaaaaaaaaULL, "Page 1 written by guest");
 157                         TEST_ASSERT(!test_bit(2, bmap), "Page 2 incorrectly reported dirty");
 158                         TEST_ASSERT(host_test_mem[8192 / 8] == 0xaaaaaaaaaaaaaaaaULL, "Page 2 written by guest");
 159                         break;
 160                 case UCALL_DONE:
 161                         done = true;
 162                         break;
 163                 default:
 164                         TEST_FAIL("Unknown ucall %lu", uc.cmd);
 165                 }
 166         }
 167 }
 168
 169 int main(int argc, char *argv[])
 170 {
 171         TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
 172
 173         test_vmx_dirty_log(/*enable_ept=*/false);
 174
 175         if (kvm_cpu_has_ept())
 176                 test_vmx_dirty_log(/*enable_ept=*/true);
 177
 178         return 0;
 179 }