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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020, Google LLC.
*
* Tests for KVM_CAP_EXIT_ON_EMULATION_FAILURE capability.
*/
#define _GNU_SOURCE /* for program_invocation_short_name */
#include "test_util.h"
#include "kvm_util.h"
#include "vmx.h"
#define VCPU_ID 1
#define PAGE_SIZE 4096
#define MAXPHYADDR 36
#define MEM_REGION_GVA 0x0000123456789000
#define MEM_REGION_GPA 0x0000000700000000
#define MEM_REGION_SLOT 10
#define MEM_REGION_SIZE PAGE_SIZE
static void guest_code(void)
{
__asm__ __volatile__("flds (%[addr])"
:: [addr]"r"(MEM_REGION_GVA));
GUEST_DONE();
}
static void run_guest(struct kvm_vm *vm)
{
int rc;
rc = _vcpu_run(vm, VCPU_ID);
TEST_ASSERT(rc == 0, "vcpu_run failed: %d\n", rc);
}
/*
* Accessors to get R/M, REG, and Mod bits described in the SDM vol 2,
* figure 2-2 "Table Interpretation of ModR/M Byte (C8H)".
*/
#define GET_RM(insn_byte) (insn_byte & 0x7)
#define GET_REG(insn_byte) ((insn_byte & 0x38) >> 3)
#define GET_MOD(insn_byte) ((insn_byte & 0xc) >> 6)
/* Ensure we are dealing with a simple 2-byte flds instruction. */
static bool is_flds(uint8_t *insn_bytes, uint8_t insn_size)
{
return insn_size >= 2 &&
insn_bytes[0] == 0xd9 &&
GET_REG(insn_bytes[1]) == 0x0 &&
GET_MOD(insn_bytes[1]) == 0x0 &&
/* Ensure there is no SIB byte. */
GET_RM(insn_bytes[1]) != 0x4 &&
/* Ensure there is no displacement byte. */
GET_RM(insn_bytes[1]) != 0x5;
}
static void process_exit_on_emulation_error(struct kvm_vm *vm)
{
struct kvm_run *run = vcpu_state(vm, VCPU_ID);
struct kvm_regs regs;
uint8_t *insn_bytes;
uint8_t insn_size;
uint64_t flags;
TEST_ASSERT(run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
"Unexpected exit reason: %u (%s)",
run->exit_reason,
exit_reason_str(run->exit_reason));
TEST_ASSERT(run->emulation_failure.suberror == KVM_INTERNAL_ERROR_EMULATION,
"Unexpected suberror: %u",
run->emulation_failure.suberror);
if (run->emulation_failure.ndata >= 1) {
flags = run->emulation_failure.flags;
if ((flags & KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES) &&
run->emulation_failure.ndata >= 3) {
insn_size = run->emulation_failure.insn_size;
insn_bytes = run->emulation_failure.insn_bytes;
TEST_ASSERT(insn_size <= 15 && insn_size > 0,
"Unexpected instruction size: %u",
insn_size);
TEST_ASSERT(is_flds(insn_bytes, insn_size),
"Unexpected instruction. Expected 'flds' (0xd9 /0)");
/*
* If is_flds() succeeded then the instruction bytes
* contained an flds instruction that is 2-bytes in
* length (ie: no prefix, no SIB, no displacement).
*/
vcpu_regs_get(vm, VCPU_ID, ®s);
regs.rip += 2;
vcpu_regs_set(vm, VCPU_ID, ®s);
}
}
}
static void do_guest_assert(struct kvm_vm *vm, struct ucall *uc)
{
TEST_FAIL("%s at %s:%ld", (const char *)uc->args[0], __FILE__,
uc->args[1]);
}
static void check_for_guest_assert(struct kvm_vm *vm)
{
struct kvm_run *run = vcpu_state(vm, VCPU_ID);
struct ucall uc;
if (run->exit_reason == KVM_EXIT_IO &&
get_ucall(vm, VCPU_ID, &uc) == UCALL_ABORT) {
do_guest_assert(vm, &uc);
}
}
static void process_ucall_done(struct kvm_vm *vm)
{
struct kvm_run *run = vcpu_state(vm, VCPU_ID);
struct ucall uc;
check_for_guest_assert(vm);
TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
"Unexpected exit reason: %u (%s)",
run->exit_reason,
exit_reason_str(run->exit_reason));
TEST_ASSERT(get_ucall(vm, VCPU_ID, &uc) == UCALL_DONE,
"Unexpected ucall command: %lu, expected UCALL_DONE (%d)",
uc.cmd, UCALL_DONE);
}
static uint64_t process_ucall(struct kvm_vm *vm)
{
struct kvm_run *run = vcpu_state(vm, VCPU_ID);
struct ucall uc;
TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
"Unexpected exit reason: %u (%s)",
run->exit_reason,
exit_reason_str(run->exit_reason));
switch (get_ucall(vm, VCPU_ID, &uc)) {
case UCALL_SYNC:
break;
case UCALL_ABORT:
do_guest_assert(vm, &uc);
break;
case UCALL_DONE:
process_ucall_done(vm);
break;
default:
TEST_ASSERT(false, "Unexpected ucall");
}
return uc.cmd;
}
int main(int argc, char *argv[])
{
struct kvm_enable_cap emul_failure_cap = {
.cap = KVM_CAP_EXIT_ON_EMULATION_FAILURE,
.args[0] = 1,
};
struct kvm_cpuid_entry2 *entry;
struct kvm_cpuid2 *cpuid;
struct kvm_vm *vm;
uint64_t gpa, pte;
uint64_t *hva;
int rc;
/* Tell stdout not to buffer its content */
setbuf(stdout, NULL);
vm = vm_create_default(VCPU_ID, 0, guest_code);
if (!kvm_check_cap(KVM_CAP_SMALLER_MAXPHYADDR)) {
printf("module parameter 'allow_smaller_maxphyaddr' is not set. Skipping test.\n");
return 0;
}
cpuid = kvm_get_supported_cpuid();
entry = kvm_get_supported_cpuid_index(0x80000008, 0);
entry->eax = (entry->eax & 0xffffff00) | MAXPHYADDR;
set_cpuid(cpuid, entry);
vcpu_set_cpuid(vm, VCPU_ID, cpuid);
rc = kvm_check_cap(KVM_CAP_EXIT_ON_EMULATION_FAILURE);
TEST_ASSERT(rc, "KVM_CAP_EXIT_ON_EMULATION_FAILURE is unavailable");
vm_enable_cap(vm, &emul_failure_cap);
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
MEM_REGION_GPA, MEM_REGION_SLOT,
MEM_REGION_SIZE / PAGE_SIZE, 0);
gpa = vm_phy_pages_alloc(vm, MEM_REGION_SIZE / PAGE_SIZE,
MEM_REGION_GPA, MEM_REGION_SLOT);
TEST_ASSERT(gpa == MEM_REGION_GPA, "Failed vm_phy_pages_alloc\n");
virt_map(vm, MEM_REGION_GVA, MEM_REGION_GPA, 1);
hva = addr_gpa2hva(vm, MEM_REGION_GPA);
memset(hva, 0, PAGE_SIZE);
pte = vm_get_page_table_entry(vm, VCPU_ID, MEM_REGION_GVA);
vm_set_page_table_entry(vm, VCPU_ID, MEM_REGION_GVA, pte | (1ull << 36));
run_guest(vm);
process_exit_on_emulation_error(vm);
run_guest(vm);
TEST_ASSERT(process_ucall(vm) == UCALL_DONE, "Expected UCALL_DONE");
kvm_vm_free(vm);
return 0;
}
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