[Xen-changelog] [xen master] x86emul: correct vzero{all, upper} for non-64-bit-mode

[patchbot@xxxxxxx]

commit 0de676d8e52d1995e551387642b00a2abf08b22d
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Mar 9 17:41:58 2017 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Mar 9 17:41:58 2017 +0100

    x86emul: correct vzero{all,upper} for non-64-bit-mode
    
    The registers only accessible in 64-bit mode need to be left alone in
    this case.
    
    Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 tools/tests/x86_emulator/test_x86_emulator.c | 39 ++++++++++++++++++++++++++++
 xen/arch/x86/x86_emulate/x86_emulate.c       | 39 ++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/tools/tests/x86_emulator/test_x86_emulator.c 
b/tools/tests/x86_emulator/test_x86_emulator.c
index 1e416fc..04332bb 100644
--- a/tools/tests/x86_emulator/test_x86_emulator.c
+++ b/tools/tests/x86_emulator/test_x86_emulator.c
@@ -2910,6 +2910,45 @@ int main(int argc, char **argv)
     else
         printf("skipped\n");
 
+#ifdef __x86_64__
+    printf("%-40s", "Testing vzeroupper (compat)...");
+    if ( cpu_has_avx )
+    {
+        decl_insn(vzeroupper);
+
+        ctxt.sp_size = ctxt.addr_size = 32;
+
+        asm volatile ( "vxorps %xmm2, %xmm2, %xmm3\n"
+                       "vcmpeqps %ymm3, %ymm3, %ymm4\n"
+                       "vmovaps %ymm4, %ymm9\n"
+                       put_insn(vzeroupper, "vzeroupper") );
+
+        set_insn(vzeroupper);
+        rc = x86_emulate(&ctxt, &emulops);
+        if ( rc != X86EMUL_OKAY || !check_eip(vzeroupper) )
+            goto fail;
+
+        /* XMM0...XMM7 should have their high parts cleared. */
+        asm ( "vextractf128 $1, %%ymm4, %%xmm0\n\t"
+              "vpmovmskb %%xmm4, %0\n\t"
+              "vpmovmskb %%xmm0, %1" : "=r" (rc), "=r" (i) );
+        if ( rc != 0xffff || i )
+            goto fail;
+
+        /* XMM8...XMM15 should have their high parts preserved. */
+        asm ( "vextractf128 $1, %%ymm9, %%xmm1\n\t"
+              "vpmovmskb %%xmm9, %0\n\t"
+              "vpmovmskb %%xmm1, %1" : "=r" (rc), "=r" (i) );
+        if ( rc != 0xffff || i != 0xffff )
+            goto fail;
+        printf("okay\n");
+
+        ctxt.sp_size = ctxt.addr_size = 64;
+    }
+    else
+        printf("skipped\n");
+#endif
+
 #undef decl_insn
 #undef put_insn
 #undef set_insn
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index e259546..0d4d345 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -6277,6 +6277,45 @@ x86_emulate(
             generate_exception_if(vex.reg != 0xf, EXC_UD);
             host_and_vcpu_must_have(avx);
             get_fpu(X86EMUL_FPU_ymm, &fic);
+
+#ifdef __x86_64__
+            if ( !mode_64bit() )
+            {
+                /*
+                 * Can't use the actual instructions here, as we must not
+                 * touch YMM8...YMM15.
+                 */
+                if ( vex.l )
+                {
+                    /* vpxor %xmmN, %xmmN, %xmmN */
+                    asm volatile ( ".byte 0xc5,0xf9,0xef,0xc0" );
+                    asm volatile ( ".byte 0xc5,0xf1,0xef,0xc9" );
+                    asm volatile ( ".byte 0xc5,0xe9,0xef,0xd2" );
+                    asm volatile ( ".byte 0xc5,0xe1,0xef,0xdb" );
+                    asm volatile ( ".byte 0xc5,0xd9,0xef,0xe4" );
+                    asm volatile ( ".byte 0xc5,0xd1,0xef,0xed" );
+                    asm volatile ( ".byte 0xc5,0xc9,0xef,0xf6" );
+                    asm volatile ( ".byte 0xc5,0xc1,0xef,0xff" );
+                }
+                else
+                {
+                    /* vpor %xmmN, %xmmN, %xmmN */
+                    asm volatile ( ".byte 0xc5,0xf9,0xeb,0xc0" );
+                    asm volatile ( ".byte 0xc5,0xf1,0xeb,0xc9" );
+                    asm volatile ( ".byte 0xc5,0xe9,0xeb,0xd2" );
+                    asm volatile ( ".byte 0xc5,0xe1,0xeb,0xdb" );
+                    asm volatile ( ".byte 0xc5,0xd9,0xeb,0xe4" );
+                    asm volatile ( ".byte 0xc5,0xd1,0xeb,0xed" );
+                    asm volatile ( ".byte 0xc5,0xc9,0xeb,0xf6" );
+                    asm volatile ( ".byte 0xc5,0xc1,0xeb,0xff" );
+                }
+
+                put_fpu(&fic);
+
+                ASSERT(!state->simd_size);
+                break;
+            }
+#endif
         }
         else
         {
--
generated by git-patchbot for /home/xen/git/xen.git#master

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