[Xen-changelog] [xen master] x86emul: add XOP decoding

[patchbot@xxxxxxx]

commit f09902c456d091e405cfce8d8788b535b01bf88e
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Sep 29 12:04:05 2016 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Sep 29 12:04:05 2016 +0200

    x86emul: add XOP decoding
    
    This way we can at least size (and e.g. skip) them if needed, and we
    also won't raise the wrong fault due to not having read all relevant
    bytes.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 62 ++++++++++++++++++++++++++--------
 1 file changed, 48 insertions(+), 14 deletions(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index aa2fdb5..1053d2d 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -279,6 +279,12 @@ static const opcode_desc_t twobyte_table[256] = {
     ModRM, ModRM, ModRM, ModRM, ModRM, ModRM, ModRM, ModRM
 };
 
+static const opcode_desc_t xop_table[] = {
+    DstReg|SrcImmByte|ModRM,
+    DstReg|SrcMem|ModRM,
+    DstReg|SrcImm|ModRM,
+};
+
 #define REX_PREFIX 0x40
 #define REX_B 0x01
 #define REX_X 0x02
@@ -1591,6 +1597,13 @@ struct x86_emulate_state {
         ext_0f   = vex_0f,
         ext_0f38 = vex_0f38,
         ext_0f3a = vex_0f3a,
+        /*
+         * For XOP use values such that the respective instruction field
+         * can be used without adjustment.
+         */
+        ext_8f08 = 8,
+        ext_8f09,
+        ext_8f0a,
     } ext;
     uint8_t opcode;
     uint8_t modrm, modrm_mod, modrm_reg, modrm_rm;
@@ -1813,7 +1826,7 @@ x86_decode(
         modrm = insn_fetch_type(uint8_t);
         modrm_mod = (modrm & 0xc0) >> 6;
 
-        if ( !ext && ((b & ~1) == 0xc4) )
+        if ( !ext && ((b & ~1) == 0xc4 || (b == 0x8f && (modrm & 0x18))) )
             switch ( def_ad_bytes )
             {
             default:
@@ -1827,11 +1840,11 @@ x86_decode(
                     break;
                 /* fall through */
             case 8:
-                /* VEX */
+                /* VEX / XOP */
                 generate_exception_if(rex_prefix || vex.pfx, EXC_UD, -1);
 
                 vex.raw[0] = modrm;
-                if ( b & 1 )
+                if ( b == 0xc5 )
                 {
                     vex.raw[1] = modrm;
                     vex.opcx = vex_0f;
@@ -1859,18 +1872,30 @@ x86_decode(
                     rex_prefix |= REX_R;
 
                 b = insn_fetch_type(uint8_t);
-                switch ( ext = vex.opcx )
+                ext = vex.opcx;
+                if ( b != 0x8f )
+                {
+                    switch ( ext )
+                    {
+                    case vex_0f:
+                        d = twobyte_table[b];
+                        break;
+                    case vex_0f38:
+                        d = twobyte_table[0x38];
+                        break;
+                    case vex_0f3a:
+                        d = twobyte_table[0x3a];
+                        break;
+                    default:
+                        rc = X86EMUL_UNHANDLEABLE;
+                        goto done;
+                    }
+                }
+                else if ( ext < ext_8f08 +
+                                sizeof(xop_table) / sizeof(*xop_table) )
+                    d = xop_table[ext - ext_8f08];
+                else
                 {
-                case vex_0f:
-                    d = twobyte_table[b];
-                    break;
-                case vex_0f38:
-                    d = twobyte_table[0x38];
-                    break;
-                case vex_0f3a:
-                    d = twobyte_table[0x3a];
-                    break;
-                default:
                     rc = X86EMUL_UNHANDLEABLE;
                     goto done;
                 }
@@ -1932,6 +1957,9 @@ x86_decode(
 
         case ext_0f:
         case ext_0f3a:
+        case ext_8f08:
+        case ext_8f09:
+        case ext_8f0a:
             break;
 
         case ext_0f38:
@@ -2121,6 +2149,9 @@ x86_decode(
 
     case ext_0f38:
     case ext_0f3a:
+    case ext_8f08:
+    case ext_8f09:
+    case ext_8f0a:
         break;
 
     default:
@@ -2337,6 +2368,9 @@ x86_emulate(
     default:
         ASSERT_UNREACHABLE();
     case ext_0f3a:
+    case ext_8f08:
+    case ext_8f09:
+    case ext_8f0a:
         goto cannot_emulate;
     }
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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