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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * xen_vmcall_test
   4  *
   5  * Copyright © 2020 Amazon.com, Inc. or its affiliates.
   6  *
   7  * Userspace hypercall testing
   8  */
   9
  10 #include "test_util.h"
  11 #include "kvm_util.h"
  12 #include "processor.h"
  13
  14 #define VCPU_ID         5
  15
  16 #define HCALL_REGION_GPA        0xc0000000ULL
  17 #define HCALL_REGION_SLOT       10
  18 #define PAGE_SIZE               4096
  19
  20 static struct kvm_vm *vm;
  21
  22 #define INPUTVALUE 17
  23 #define ARGVALUE(x) (0xdeadbeef5a5a0000UL + x)
  24 #define RETVALUE 0xcafef00dfbfbffffUL
  25
  26 #define XEN_HYPERCALL_MSR       0x40000200
  27 #define HV_GUEST_OS_ID_MSR      0x40000000
  28 #define HV_HYPERCALL_MSR        0x40000001
  29
  30 #define HVCALL_SIGNAL_EVENT             0x005d
  31 #define HV_STATUS_INVALID_ALIGNMENT     4
  32
  33 static void guest_code(void)
  34 {
  35         unsigned long rax = INPUTVALUE;
  36         unsigned long rdi = ARGVALUE(1);
  37         unsigned long rsi = ARGVALUE(2);
  38         unsigned long rdx = ARGVALUE(3);
  39         unsigned long rcx;
  40         register unsigned long r10 __asm__("r10") = ARGVALUE(4);
  41         register unsigned long r8 __asm__("r8") = ARGVALUE(5);
  42         register unsigned long r9 __asm__("r9") = ARGVALUE(6);
  43
  44         /* First a direct invocation of 'vmcall' */
  45         __asm__ __volatile__("vmcall" :
  46                              "=a"(rax) :
  47                              "a"(rax), "D"(rdi), "S"(rsi), "d"(rdx),
  48                              "r"(r10), "r"(r8), "r"(r9));
  49         GUEST_ASSERT(rax == RETVALUE);
  50
  51         /* Fill in the Xen hypercall page */
  52         __asm__ __volatile__("wrmsr" : : "c" (XEN_HYPERCALL_MSR),
  53                              "a" (HCALL_REGION_GPA & 0xffffffff),
  54                              "d" (HCALL_REGION_GPA >> 32));
  55
  56         /* Set Hyper-V Guest OS ID */
  57         __asm__ __volatile__("wrmsr" : : "c" (HV_GUEST_OS_ID_MSR),
  58                              "a" (0x5a), "d" (0));
  59
  60         /* Hyper-V hypercall page */
  61         u64 msrval = HCALL_REGION_GPA + PAGE_SIZE + 1;
  62         __asm__ __volatile__("wrmsr" : : "c" (HV_HYPERCALL_MSR),
  63                              "a" (msrval & 0xffffffff),
  64                              "d" (msrval >> 32));
  65
  66         /* Invoke a Xen hypercall */
  67         __asm__ __volatile__("call *%1" : "=a"(rax) :
  68                              "r"(HCALL_REGION_GPA + INPUTVALUE * 32),
  69                              "a"(rax), "D"(rdi), "S"(rsi), "d"(rdx),
  70                              "r"(r10), "r"(r8), "r"(r9));
  71         GUEST_ASSERT(rax == RETVALUE);
  72
  73         /* Invoke a Hyper-V hypercall */
  74         rax = 0;
  75         rcx = HVCALL_SIGNAL_EVENT;      /* code */
  76         rdx = 0x5a5a5a5a;               /* ingpa (badly aligned) */
  77         __asm__ __volatile__("call *%1" : "=a"(rax) :
  78                              "r"(HCALL_REGION_GPA + PAGE_SIZE),
  79                              "a"(rax), "c"(rcx), "d"(rdx),
  80                              "r"(r8));
  81         GUEST_ASSERT(rax == HV_STATUS_INVALID_ALIGNMENT);
  82
  83         GUEST_DONE();
  84 }
  85
  86 int main(int argc, char *argv[])
  87 {
  88         if (!(kvm_check_cap(KVM_CAP_XEN_HVM) &
  89               KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) ) {
  90                 print_skip("KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL not available");
  91                 exit(KSFT_SKIP);
  92         }
  93
  94         vm = vm_create_default(VCPU_ID, 0, (void *) guest_code);
  95         vcpu_set_hv_cpuid(vm, VCPU_ID);
  96
  97         struct kvm_xen_hvm_config hvmc = {
  98                 .flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL,
  99                 .msr = XEN_HYPERCALL_MSR,
 100         };
 101         vm_ioctl(vm, KVM_XEN_HVM_CONFIG, &hvmc);
 102
 103         /* Map a region for the hypercall pages */
 104         vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
 105                                     HCALL_REGION_GPA, HCALL_REGION_SLOT, 2, 0);
 106         virt_map(vm, HCALL_REGION_GPA, HCALL_REGION_GPA, 2);
 107
 108         for (;;) {
 109                 volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
 110                 struct ucall uc;
 111
 112                 vcpu_run(vm, VCPU_ID);
 113
 114                 if (run->exit_reason == KVM_EXIT_XEN) {
 115                         ASSERT_EQ(run->xen.type, KVM_EXIT_XEN_HCALL);
 116                         ASSERT_EQ(run->xen.u.hcall.cpl, 0);
 117                         ASSERT_EQ(run->xen.u.hcall.longmode, 1);
 118                         ASSERT_EQ(run->xen.u.hcall.input, INPUTVALUE);
 119                         ASSERT_EQ(run->xen.u.hcall.params[0], ARGVALUE(1));
 120                         ASSERT_EQ(run->xen.u.hcall.params[1], ARGVALUE(2));
 121                         ASSERT_EQ(run->xen.u.hcall.params[2], ARGVALUE(3));
 122                         ASSERT_EQ(run->xen.u.hcall.params[3], ARGVALUE(4));
 123                         ASSERT_EQ(run->xen.u.hcall.params[4], ARGVALUE(5));
 124                         ASSERT_EQ(run->xen.u.hcall.params[5], ARGVALUE(6));
 125                         run->xen.u.hcall.result = RETVALUE;
 126                         continue;
 127                 }
 128
 129                 TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
 130                             "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
 131                             run->exit_reason,
 132                             exit_reason_str(run->exit_reason));
 133
 134                 switch (get_ucall(vm, VCPU_ID, &uc)) {
 135                 case UCALL_ABORT:
 136                         TEST_FAIL("%s", (const char *)uc.args[0]);
 137                         /* NOT REACHED */
 138                 case UCALL_SYNC:
 139                         break;
 140                 case UCALL_DONE:
 141                         goto done;
 142                 default:
 143                         TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd);
 144                 }
 145         }
 146 done:
 147         kvm_vm_free(vm);
 148         return 0;
 149 }