[xen stable-4.15] x86emul: add memory operand low bits checks for ENQCMD{,S}

[patchbot@xxxxxxx]

commit 4799a202a9017360708c18aa8cd699bd8d6be08b
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jul 27 09:31:01 2022 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jul 27 09:31:01 2022 +0200

    x86emul: add memory operand low bits checks for ENQCMD{,S}
    
    Already ISE rev 044 added text to this effect; rev 045 further dropped
    leftover earlier text indicating the contrary:
    - ENQCMD requires the low 32 bits of the memory operand to be clear,
    - ENDCMDS requires bits 20...30 of the memory operand to be clear.
    
    Fixes: d27385968741 ("x86emul: support ENQCMD insns")
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: d620c66bdbe5510c3bae89be8cc7ca9a2a6cbaba
    master date: 2022-07-20 15:46:48 +0200
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 5e297f7971..247c14dc4e 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -10464,6 +10464,7 @@ x86_emulate(
             goto done;
         if ( vex.pfx == vex_f2 ) /* enqcmd */
         {
+            generate_exception_if(mmvalp->data32[0], EXC_GP, 0);
             fail_if(!ops->read_msr);
             if ( (rc = ops->read_msr(MSR_PASID, &msr_val,
                                      ctxt)) != X86EMUL_OKAY )
@@ -10471,7 +10472,8 @@ x86_emulate(
             generate_exception_if(!(msr_val & PASID_VALID), EXC_GP, 0);
             mmvalp->data32[0] = MASK_EXTR(msr_val, PASID_PASID_MASK);
         }
-        mmvalp->data32[0] &= ~0x7ff00000;
+        else
+            generate_exception_if(mmvalp->data32[0] & 0x7ff00000, EXC_GP, 0);
         state->blk = blk_enqcmd;
         if ( (rc = ops->blk(x86_seg_es, src.val, mmvalp, 64, &_regs.eflags,
                             state, ctxt)) != X86EMUL_OKAY )
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.15