[Xen-changelog] [xen master] x86emul: suppress reads for unhandled 0f38/0f3a extension space insns

[patchbot@xxxxxxx]

commit 5d99933e6e3e54da3c7291a0f4bf6c89685b4d24
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Mar 9 17:42:55 2017 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Mar 9 17:42:55 2017 +0100

    x86emul: suppress reads for unhandled 0f38/0f3a extension space insns
    
    The way these extension spaces get handled we so far always end up
    going through the generic SrcMem operand fetch path for unused table
    entries. Suppress actual memory accesses happening by forcing op_bytes
    to zero in those cases.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 0d4d345..cbbfe5c 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2344,7 +2344,11 @@ x86_decode_0f38(
     switch ( ctxt->opcode & X86EMUL_OPC_MASK )
     {
     case 0x00 ... 0xef:
-    case 0xf2 ... 0xff:
+    case 0xf2 ... 0xf5:
+    case 0xf7 ... 0xff:
+        op_bytes = 0;
+        /* fall through */
+    case 0xf6: /* adcx / adox */
         ctxt->opcode |= MASK_INSR(vex.pfx, X86EMUL_OPC_PFX_MASK);
         break;
 
@@ -2360,6 +2364,22 @@ x86_decode_0f38(
         if ( rep_prefix() )
             ctxt->opcode |= MASK_INSR(vex.pfx, X86EMUL_OPC_PFX_MASK);
         break;
+
+    case X86EMUL_OPC_VEX(0, 0xf2):    /* andn */
+    case X86EMUL_OPC_VEX(0, 0xf3):    /* Grp 17 */
+    case X86EMUL_OPC_VEX(0, 0xf5):    /* bzhi */
+    case X86EMUL_OPC_VEX_F3(0, 0xf5): /* pext */
+    case X86EMUL_OPC_VEX_F2(0, 0xf5): /* pdep */
+    case X86EMUL_OPC_VEX_F2(0, 0xf6): /* mulx */
+    case X86EMUL_OPC_VEX(0, 0xf7):    /* bextr */
+    case X86EMUL_OPC_VEX_66(0, 0xf7): /* shlx */
+    case X86EMUL_OPC_VEX_F3(0, 0xf7): /* sarx */
+    case X86EMUL_OPC_VEX_F2(0, 0xf7): /* shrx */
+        break;
+
+    default:
+        op_bytes = 0;
+        break;
     }
 
     return X86EMUL_OKAY;
@@ -2376,6 +2396,13 @@ x86_decode_0f3a(
 
     switch ( ctxt->opcode & X86EMUL_OPC_MASK )
     {
+    case X86EMUL_OPC_66(0, 0x14)
+     ... X86EMUL_OPC_66(0, 0x17):     /* pextr*, extractps */
+    case X86EMUL_OPC_VEX_66(0, 0x14)
+     ... X86EMUL_OPC_VEX_66(0, 0x17): /* vpextr*, vextractps */
+    case X86EMUL_OPC_VEX_F2(0, 0xf0): /* rorx */
+        break;
+
     case X86EMUL_OPC_66(0, 0x20):     /* pinsrb */
     case X86EMUL_OPC_VEX_66(0, 0x20): /* vpinsrb */
         state->desc = DstImplicit | SrcMem;
@@ -2387,6 +2414,10 @@ x86_decode_0f3a(
     case X86EMUL_OPC_VEX_66(0, 0x22): /* vpinsr{d,q} */
         state->desc = DstImplicit | SrcMem;
         break;
+
+    default:
+        op_bytes = 0;
+        break;
     }
 
     return X86EMUL_OKAY;
--
generated by git-patchbot for /home/xen/git/xen.git#master

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