x86emul: fix FMA scalar operand sizes

FMA insns, unlike the earlier AVX additions, don't use the low opcode
bit to distinguish between single and double vector elements. While the
difference is benign for packed flavors, the scalar ones need to use
VEX.W here. Oddly enough the table entries didn't even use
simd_scalar_fp, but uniformly used simd_packed_fp (implying the
distinction was by [VEX-encoded] opcode prefix).

Split simd_scalar_fp into simd_scalar_opc and simd_scalar_vexw, and
correct FMA scalar table entries to use the latter.

Also correct the scalar insn comments (they only ever use XMM registers
as operands).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c
index e372c4bb033c37dac8af4f6013c763cd0315161d..4afc3f6ca3d6d7f87c36057a8e321decbd0e392e 100644 (file)
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -224,7 +224,13 @@ enum simd_opsize {
      * - 32 bits with low opcode bit clear (scalar single)
      * - 64 bits with low opcode bit set (scalar double)
      */
-    simd_scalar_fp,
+    simd_scalar_opc,
+
+    /*
+     * Scalar floating point:
+     * - 32/64 bits depending on VEX.W
+     */
+    simd_scalar_vexw,
 
     /*
      * 128 bits of integer or floating point data, with no further
@@ -407,7 +413,7 @@ static const struct ext0f38_table {
     [0x13] = { .simd_size = simd_other, .two_op = 1 },
     [0x14 ... 0x16] = { .simd_size = simd_packed_fp },
     [0x17] = { .simd_size = simd_packed_int, .two_op = 1 },
-    [0x18 ... 0x19] = { .simd_size = simd_scalar_fp, .two_op = 1 },
+    [0x18 ... 0x19] = { .simd_size = simd_scalar_opc, .two_op = 1 },
     [0x1a] = { .simd_size = simd_128, .two_op = 1 },
     [0x1c ... 0x1e] = { .simd_size = simd_packed_int, .two_op = 1 },
     [0x20 ... 0x25] = { .simd_size = simd_other, .two_op = 1 },
@@ -427,9 +433,30 @@ static const struct ext0f38_table {
     [0x8c] = { .simd_size = simd_other },
     [0x8e] = { .simd_size = simd_other, .to_mem = 1 },
     [0x90 ... 0x93] = { .simd_size = simd_other, .vsib = 1 },
-    [0x96 ... 0x9f] = { .simd_size = simd_packed_fp },
-    [0xa6 ... 0xaf] = { .simd_size = simd_packed_fp },
-    [0xb6 ... 0xbf] = { .simd_size = simd_packed_fp },
+    [0x96 ... 0x98] = { .simd_size = simd_packed_fp },
+    [0x99] = { .simd_size = simd_scalar_vexw },
+    [0x9a] = { .simd_size = simd_packed_fp },
+    [0x9b] = { .simd_size = simd_scalar_vexw },
+    [0x9c] = { .simd_size = simd_packed_fp },
+    [0x9d] = { .simd_size = simd_scalar_vexw },
+    [0x9e] = { .simd_size = simd_packed_fp },
+    [0x9f] = { .simd_size = simd_scalar_vexw },
+    [0xa6 ... 0xa8] = { .simd_size = simd_packed_fp },
+    [0xa9] = { .simd_size = simd_scalar_vexw },
+    [0xaa] = { .simd_size = simd_packed_fp },
+    [0xab] = { .simd_size = simd_scalar_vexw },
+    [0xac] = { .simd_size = simd_packed_fp },
+    [0xad] = { .simd_size = simd_scalar_vexw },
+    [0xae] = { .simd_size = simd_packed_fp },
+    [0xaf] = { .simd_size = simd_scalar_vexw },
+    [0xb6 ... 0xb8] = { .simd_size = simd_packed_fp },
+    [0xb9] = { .simd_size = simd_scalar_vexw },
+    [0xba] = { .simd_size = simd_packed_fp },
+    [0xbb] = { .simd_size = simd_scalar_vexw },
+    [0xbc] = { .simd_size = simd_packed_fp },
+    [0xbd] = { .simd_size = simd_scalar_vexw },
+    [0xbe] = { .simd_size = simd_packed_fp },
+    [0xbf] = { .simd_size = simd_scalar_vexw },
     [0xc8 ... 0xcd] = { .simd_size = simd_other },
     [0xdb] = { .simd_size = simd_packed_int, .two_op = 1 },
     [0xdc ... 0xdf] = { .simd_size = simd_packed_int },
@@ -454,7 +481,7 @@ static const struct ext0f3a_table {
     [0x04 ... 0x05] = { .simd_size = simd_packed_fp, .two_op = 1 },
     [0x06] = { .simd_size = simd_packed_fp },
     [0x08 ... 0x09] = { .simd_size = simd_packed_fp, .two_op = 1 },
-    [0x0a ... 0x0b] = { .simd_size = simd_scalar_fp },
+    [0x0a ... 0x0b] = { .simd_size = simd_scalar_opc },
     [0x0c ... 0x0d] = { .simd_size = simd_packed_fp },
     [0x0e ... 0x0f] = { .simd_size = simd_packed_int },
     [0x14 ... 0x17] = { .simd_size = simd_none, .to_mem = 1, .two_op = 1 },
@@ -476,13 +503,13 @@ static const struct ext0f3a_table {
     [0x5c ... 0x5f] = { .simd_size = simd_packed_fp, .four_op = 1 },
     [0x60 ... 0x63] = { .simd_size = simd_packed_int, .two_op = 1 },
     [0x68 ... 0x69] = { .simd_size = simd_packed_fp, .four_op = 1 },
-    [0x6a ... 0x6b] = { .simd_size = simd_scalar_fp, .four_op = 1 },
+    [0x6a ... 0x6b] = { .simd_size = simd_scalar_opc, .four_op = 1 },
     [0x6c ... 0x6d] = { .simd_size = simd_packed_fp, .four_op = 1 },
-    [0x6e ... 0x6f] = { .simd_size = simd_scalar_fp, .four_op = 1 },
+    [0x6e ... 0x6f] = { .simd_size = simd_scalar_opc, .four_op = 1 },
     [0x78 ... 0x79] = { .simd_size = simd_packed_fp, .four_op = 1 },
-    [0x7a ... 0x7b] = { .simd_size = simd_scalar_fp, .four_op = 1 },
+    [0x7a ... 0x7b] = { .simd_size = simd_scalar_opc, .four_op = 1 },
     [0x7c ... 0x7d] = { .simd_size = simd_packed_fp, .four_op = 1 },
-    [0x7e ... 0x7f] = { .simd_size = simd_scalar_fp, .four_op = 1 },
+    [0x7e ... 0x7f] = { .simd_size = simd_scalar_opc, .four_op = 1 },
     [0xcc] = { .simd_size = simd_other },
     [0xdf] = { .simd_size = simd_packed_int, .two_op = 1 },
     [0xf0] = {},
@@ -518,7 +545,7 @@ static const struct ext8f09_table {
 } ext8f09_table[256] = {
     [0x01 ... 0x02] = { .two_op = 1 },
     [0x80 ... 0x81] = { .simd_size = simd_packed_fp, .two_op = 1 },
-    [0x82 ... 0x83] = { .simd_size = simd_scalar_fp, .two_op = 1 },
+    [0x82 ... 0x83] = { .simd_size = simd_scalar_opc, .two_op = 1 },
     [0x90 ... 0x9b] = { .simd_size = simd_packed_int },
     [0xc1 ... 0xc3] = { .simd_size = simd_packed_int, .two_op = 1 },
     [0xc6 ... 0xc7] = { .simd_size = simd_packed_int, .two_op = 1 },
@@ -3132,10 +3159,14 @@ x86_decode(
         }
         break;
 
-    case simd_scalar_fp:
+    case simd_scalar_opc:
         op_bytes = 4 << (ctxt->opcode & 1);
         break;
 
+    case simd_scalar_vexw:
+        op_bytes = 4 << vex.w;
+        break;
+
     case simd_128:
         op_bytes = 16;
         break;
@@ -7747,33 +7778,33 @@ x86_emulate(
     case X86EMUL_OPC_VEX_66(0x0f38, 0x96): /* vfmaddsub132p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0x97): /* vfmsubadd132p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0x98): /* vfmadd132p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0x99): /* vfmadd132s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0x99): /* vfmadd132s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0x9a): /* vfmsub132p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0x9b): /* vfmsub132s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0x9b): /* vfmsub132s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0x9c): /* vfnmadd132p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0x9d): /* vfnmadd132s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0x9d): /* vfnmadd132s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0x9e): /* vfnmsub132p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0x9f): /* vfnmsub132s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0x9f): /* vfnmsub132s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xa6): /* vfmaddsub213p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xa7): /* vfmsubadd213p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xa8): /* vfmadd213p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xa9): /* vfmadd213s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xa9): /* vfmadd213s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xaa): /* vfmsub213p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xab): /* vfmsub213s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xab): /* vfmsub213s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xac): /* vfnmadd213p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xad): /* vfnmadd213s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xad): /* vfnmadd213s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xae): /* vfnmsub213p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xaf): /* vfnmsub213s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xaf): /* vfnmsub213s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xb6): /* vfmaddsub231p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xb7): /* vfmsubadd231p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xb8): /* vfmadd231p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xb9): /* vfmadd231s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xb9): /* vfmadd231s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xba): /* vfmsub231p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xbb): /* vfmsub231s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xbb): /* vfmsub231s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xbc): /* vfnmadd231p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xbd): /* vfnmadd231s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xbd): /* vfnmadd231s{s,d} xmm/mem,xmm,xmm */
     case X86EMUL_OPC_VEX_66(0x0f38, 0xbe): /* vfnmsub231p{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
-    case X86EMUL_OPC_VEX_66(0x0f38, 0xbf): /* vfnmsub231s{s,d} {x,y}mm/mem,{x,y}mm,{x,y}mm */
+    case X86EMUL_OPC_VEX_66(0x0f38, 0xbf): /* vfnmsub231s{s,d} xmm/mem,xmm,xmm */
         host_and_vcpu_must_have(fma);
         goto simd_0f_ymm;