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

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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>
This commit is contained in:
Peter Maydell 2025-11-14 17:54:17 +00:00 • committed by Paolo Bonzini
parent 46b06eaeb4
commit ebd9ea2947
1 changed files with 1 additions and 1 deletions
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2
target/i386/tcg/decode-new.c.inc
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@ -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),