From b7ab6d7d2cf7d5400592d1ff0448e8e0a09e5188 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 28 Sep 2022 23:36:50 +0000 Subject: KVM: selftests: Explicitly verify KVM doesn't patch hypercall if quirk==off 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 Message-Id: <20220928233652.783504-6-seanjc@google.com> Signed-off-by: Paolo Bonzini --- .../selftests/kvm/x86_64/fix_hypercall_test.c | 26 +++++++++++++++------- 1 file changed, 18 insertions(+), 8 deletions(-) (limited to 'tools/testing') 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(); } -- cgit v1.2.3