[PATCH v8 06/12] x86/HVM: make hvmemul_blk() capable of handling r/o operations

[Jan Beulich <jbeulich@xxxxxxxx>]

In preparation for handling e.g. FLDENV or {F,FX,X}RSTOR here as well.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v8: New (could be folded into "x86emul: support MOVDIR{I,64B} insns",
    but would invalidate Paul's R-b there).

--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1453,7 +1453,7 @@ static int hvmemul_blk(
     struct hvm_emulate_ctxt *hvmemul_ctxt =
         container_of(ctxt, struct hvm_emulate_ctxt, ctxt);
     unsigned long addr;
-    uint32_t pfec = PFEC_page_present | PFEC_write_access;
+    uint32_t pfec = PFEC_page_present;
     int rc;
     void *mapping = NULL;
 
@@ -1462,6 +1462,9 @@ static int hvmemul_blk(
     if ( rc != X86EMUL_OKAY || !bytes )
         return rc;
 
+    if ( x86_insn_is_mem_write(state, ctxt) )
+        pfec |= PFEC_write_access;
+
     if ( is_x86_system_segment(seg) )
         pfec |= PFEC_implicit;
     else if ( hvmemul_ctxt->seg_reg[x86_seg_ss].dpl == 3 )