target/i386: Mark VPERMILPS as not valid with prefix 0

There are a small set of binary SSE insns which have no MMX
equivalent, which we create the gen functions for with the
BINARY_INT_SSE() macro.  This forwards to gen_binary_int_sse() with a
NULL pointer for 'mmx'.

For almost all of these insns we correctly mark them in the decode
table as not permitting a zero prefix byte; however we got this wrong
for VPERMILPS, with the result that a bogus instruction would get
through the decode checks and end up in gen_binary_int_sse() trying
to call a NULL pointer.

Correct the decode table entry for VPERMILPS so that we get the
expected #UD exception.

In the x86 SDM, table A-4 "Three-byte Opcode Map: 08H-FFH
(First Two Bytes are 0F 38H)" confirms that there is no pfx 0
version of VPERMILPS.

Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3199
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Link: https://lore.kernel.org/r/20251114175417.2794804-1-peter.maydell@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.c.inc
index f4192f10068c65de5a5174a710ca6dad4e72bb76..805cfd08e83e193f3094e7a33d89c85481e1eb7f 100644 (file)
--- a/target/i386/tcg/decode-new.c.inc
+++ b/target/i386/tcg/decode-new.c.inc
@@ -643,7 +643,7 @@ static const X86OpEntry opcodes_0F38_00toEF[240] = {
     [0x0a] = X86_OP_ENTRY3(PSIGND,    V,x,        H,x,  W,x,  vex4 cpuid(SSSE3) mmx avx2_256 p_00_66),
     [0x0b] = X86_OP_ENTRY3(PMULHRSW,  V,x,        H,x,  W,x,  vex4 cpuid(SSSE3) mmx avx2_256 p_00_66),
     /* Listed incorrectly as type 4 */
-    [0x0c] = X86_OP_ENTRY3(VPERMILPS, V,x,        H,x,  W,x,  vex6 chk(W0) cpuid(AVX) p_00_66),
+    [0x0c] = X86_OP_ENTRY3(VPERMILPS, V,x,        H,x,  W,x,  vex6 chk(W0) cpuid(AVX) p_66),
     [0x0d] = X86_OP_ENTRY3(VPERMILPD, V,x,        H,x,  W,x,  vex6 chk(W0) cpuid(AVX) p_66),
     [0x0e] = X86_OP_ENTRY3(VTESTPS,   None,None,  V,x,  W,x,  vex6 chk(W0) cpuid(AVX) p_66),
     [0x0f] = X86_OP_ENTRY3(VTESTPD,   None,None,  V,x,  W,x,  vex6 chk(W0) cpuid(AVX) p_66),