[kvm-unit-tests PATCH v2] x86: Test illegal LEA handling

[Michal Luczaj <mhal@rbox.co>]

Check if the emulator throws #UD on illegal LEA.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
v1 -> v2: Instead of racing decoder make use of force_emulation_prefix

 x86/emulator.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/x86/emulator.c b/x86/emulator.c
index cd78e3c..c3898f2 100644
--- a/x86/emulator.c
+++ b/x86/emulator.c
@@ -895,6 +895,24 @@ static void test_mov_dr(uint64_t *mem)
 		report(rax == DR6_ACTIVE_LOW, "mov_dr6");
 }
 
+static void illegal_lea_handler(struct ex_regs *regs)
+{
+	extern char illegal_lea_cont;
+
+	++exceptions;
+	regs->rip = (ulong)&illegal_lea_cont;
+}
+
+static void test_illegal_lea(uint64_t *mem)
+{
+	exceptions = 0;
+	handle_exception(UD_VECTOR, illegal_lea_handler);
+	asm(KVM_FEP ".byte 0x48; .byte 0x8d; .byte 0xc0\n\t"
+	    "illegal_lea_cont:" : : : "rax");
+	report(exceptions == 1, "illegal lea");
+	handle_exception(UD_VECTOR, 0);
+}
+
 static void test_push16(uint64_t *mem)
 {
 	uint64_t rsp1, rsp2;
@@ -1193,6 +1211,7 @@ int main(void)
 		test_smsw_reg(mem);
 		test_nop(mem);
 		test_mov_dr(mem);
+		test_illegal_lea(mem);
 	} else {
 		report_skip("skipping register-only tests, "
 			    "use kvm.force_emulation_prefix=1 to enable");
-- 
2.32.0