[Xen-changelog] [xen stable-4.8] x86/emul: Fix the emulation of invlpga

[patchbot@xxxxxxx]

commit 22d2146e9b15d2b728f449e969d84cc4ae025258
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Mar 6 16:08:54 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Mar 6 16:08:54 2018 +0100

    x86/emul: Fix the emulation of invlpga
    
    The instruction requires EFER.SVME set to be usable in the first place.
    
    Furthermore, the emulation doesn't handle ASIDs, so avoid giving the
    impression that they work.  Permit ASID 0 which is reserved for non-root
    mode (in which case the instruction is identical to invlpg), but raise #UD 
for
    any other ASID.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    master commit: a91b2ec337a45d5d98e5a4387aa6563bc5cdc4c9
    master date: 2018-02-05 18:17:22 +0000
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index bfabec06ba..5340d5c5d5 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -4419,14 +4419,24 @@ x86_emulate(
             _regs.eflags |= EFLG_ZF;
             break;
 
-        case 0xdf: /* invlpga */
-            generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, -1);
+        case 0xdf: /* invlpga */ {
+            uint64_t msr_val;
+
+            fail_if(!ops->read_msr);
+            if ( (rc = ops->read_msr(MSR_EFER,
+                                     &msr_val, ctxt)) != X86EMUL_OKAY )
+                goto done;
+            /* Finding SVME set implies vcpu_has_svm(). */
+            generate_exception_if(!(msr_val & EFER_SVME) ||
+                                  !in_protmode(ctxt, ops), EXC_UD, -1);
             generate_exception_if(!mode_ring0(), EXC_GP, 0);
+            generate_exception_if((uint32_t)_regs.ecx, EXC_UD, -1); /* TODO: 
Support ASIDs. */
             fail_if(ops->invlpg == NULL);
             if ( (rc = ops->invlpg(x86_seg_none, truncate_ea(_regs.eax),
                                    ctxt)) )
                 goto done;
             break;
+        }
 
         case 0xf9: /* rdtscp */
         {
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/xen-changelog