Drop the last user of the one-off exception handler by making use of
ASM_TRY() for the #MF test.
Also streamline the multiple scattered asm() statements into a single
one making use of a real output value instead of hard-coding rax and
relying on the instruction to generate an exception (instead of
clobbering rax and not making gcc aware of it).
As this removes the last user of advance_rip_and_note_exception() we can
remove it for good!
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
---
x86/emulator64.c | 39 ++++++++++++++++-----------------------
1 file changed, 16 insertions(+), 23 deletions(-)
diff --git a/x86/emulator64.c b/x86/emulator64.c
index 50a02bca6ac8..f8ff99fc39cc 100644
--- a/x86/emulator64.c
+++ b/x86/emulator64.c
@@ -1,14 +1,6 @@
#define MAGIC_NUM 0xdeadbeefdeadbeefUL
#define GS_BASE 0x400000
-static unsigned long rip_advance;
-
-static void advance_rip_and_note_exception(struct ex_regs *regs)
-{
- ++exceptions;
- regs->rip += rip_advance;
-}
-
static void test_cr8(void)
{
unsigned long src, dst;
@@ -313,23 +305,24 @@ static void test_cmov(u32 *mem)
static void test_mmx_movq_mf(uint64_t *mem)
{
- /* movq %mm0, (%rax) */
- extern char movq_start, movq_end;
- handler old;
-
uint16_t fcw = 0; /* all exceptions unmasked */
- write_cr0(read_cr0() & ~6); /* TS, EM */
- exceptions = 0;
- old = handle_exception(MF_VECTOR, advance_rip_and_note_exception);
- asm volatile("fninit; fldcw %0" : : "m"(fcw));
- asm volatile("fldz; fldz; fdivp"); /* generate exception */
+ uint64_t val;
- rip_advance = &movq_end - &movq_start;
- asm(KVM_FEP "movq_start: movq %mm0, (%rax); movq_end:");
- /* exit MMX mode */
- asm volatile("fnclex; emms");
- report(exceptions == 1, "movq mmx generates #MF");
- handle_exception(MF_VECTOR, old);
+ write_cr0(read_cr0() & ~(X86_CR0_TS | X86_CR0_EM));
+ asm volatile("fninit\n\t"
+ "fldcw %[fcw]\n\t"
+ "fldz\n\t"
+ "fldz\n\t"
+ /* generate exception (0.0 / 0.0) */
+ "fdivp\n\t"
+ /* trigger #MF */
+ ASM_TRY_FEP("1f") "movq %%mm0, %[val]\n\t"
+ /* exit MMX mode */
+ "1: fnclex\n\t"
+ "emms\n\t"
+ : [val]"=m"(val)
+ : [fcw]"m"(fcw));
+ report(exception_vector() == MF_VECTOR, "movq mmx generates #MF");
}
static void test_jmp_noncanonical(uint64_t *mem)
--
2.39.2
