Explicitly verify that KVM doesn't patch in the native hypercall if the
FIX_HYPERCALL_INSN quirk is disabled. The test currently verifies that
a #UD occurred, but doesn't actually verify that no patching occurred.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
.../selftests/kvm/x86_64/fix_hypercall_test.c | 26 +++++++++++++------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/fix_hypercall_test.c b/tools/testing/selftests/kvm/x86_64/fix_hypercall_test.c
index cebc84b26352..10b9482fc4d7 100644
--- a/tools/testing/selftests/kvm/x86_64/fix_hypercall_test.c
+++ b/tools/testing/selftests/kvm/x86_64/fix_hypercall_test.c
@@ -21,8 +21,8 @@ static bool ud_expected;
static void guest_ud_handler(struct ex_regs *regs)
{
- GUEST_ASSERT(ud_expected);
- GUEST_DONE();
+ regs->rax = -EFAULT;
+ regs->rip += HYPERCALL_INSN_SIZE;
}
static const uint8_t vmx_vmcall[HYPERCALL_INSN_SIZE] = { 0x0f, 0x01, 0xc1 };
@@ -46,6 +46,7 @@ static void guest_main(void)
{
const uint8_t *native_hypercall_insn;
const uint8_t *other_hypercall_insn;
+ uint64_t ret;
if (is_intel_cpu()) {
native_hypercall_insn = vmx_vmcall;
@@ -61,15 +62,24 @@ static void guest_main(void)
memcpy(hypercall_insn, other_hypercall_insn, HYPERCALL_INSN_SIZE);
- do_sched_yield(GET_APIC_ID_FIELD(xapic_read_reg(APIC_ID)));
+ ret = do_sched_yield(GET_APIC_ID_FIELD(xapic_read_reg(APIC_ID)));
/*
- * The hypercall didn't #UD (guest_ud_handler() signals "done" if a #UD
- * occurs). Verify that a #UD is NOT expected and that KVM patched in
- * the native hypercall.
+ * If the quirk is disabled, verify that guest_ud_handler() "returned"
+ * -EFAULT and that KVM did NOT patch the hypercall. If the quirk is
+ * enabled, verify that the hypercall succeeded and that KVM patched in
+ * the "right" hypercall.
*/
- GUEST_ASSERT(!ud_expected);
- GUEST_ASSERT(!memcmp(native_hypercall_insn, hypercall_insn, HYPERCALL_INSN_SIZE));
+ if (ud_expected) {
+ GUEST_ASSERT(ret == (uint64_t)-EFAULT);
+ GUEST_ASSERT(!memcmp(other_hypercall_insn, hypercall_insn,
+ HYPERCALL_INSN_SIZE));
+ } else {
+ GUEST_ASSERT(!ret);
+ GUEST_ASSERT(!memcmp(native_hypercall_insn, hypercall_insn,
+ HYPERCALL_INSN_SIZE));
+ }
+
GUEST_DONE();
}
--
2.37.3.998.g577e59143f-goog
