[Xen-changelog] [xen stable-4.7] x86/emul: Fix the emulation of invlpga

[patchbot@xxxxxxx]

commit f89c26c60a92452069f9ed1691e5341549866451
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Mar 6 16:17:48 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Mar 6 16:17:48 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 | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 51d4dddfeb..256604c17c 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -362,6 +362,7 @@ typedef union {
 #define MSR_EFER         0xc0000080
 #define EFER_SCE         (1u<<0)
 #define EFER_LMA         (1u<<10)
+#define EFER_SVME        (1u<<12)
 #define MSR_STAR         0xc0000081
 #define MSR_LSTAR        0xc0000082
 #define MSR_CSTAR        0xc0000083
@@ -3989,14 +3990,24 @@ x86_emulate(
 
         switch( modrm )
         {
-        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;
             goto no_writeback;
+        }
         case 0xf9: /* rdtscp */ {
             uint64_t tsc_aux;
             fail_if(ops->read_msr == NULL);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.7

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