[PATCH 4/7] x86/pv: Drop priv_op_ctxt.bpmatch and use pending_dbg instead

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

With a full pending_dbg field in x86_emulate_ctxt, use it rather than using a
local bpmatch field.

This simplifies the X86EMUL_OKAY path as singlestep is already accumulated by
x86_emulate() when appropriate.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Jinoh Kang <jinoh.kang.kr@xxxxxxxxx>

v2:
 * Tweak commit message to avoid referencing X86EMUL_DONE.
---
 xen/arch/x86/pv/emul-priv-op.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index 0d9f84f458ba..2f73ed0682e1 100644
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -34,7 +34,6 @@ struct priv_op_ctxt {
         unsigned long base, limit;
     } cs;
     char *io_emul_stub;
-    unsigned int bpmatch;
 };
 
 /* I/O emulation helpers.  Use non-standard calling conventions. */
@@ -367,7 +366,8 @@ static int cf_check read_io(
     if ( !guest_io_okay(port, bytes, curr, ctxt->regs) )
         return X86EMUL_UNHANDLEABLE;
 
-    poc->bpmatch = check_guest_io_breakpoint(curr, port, bytes);
+    poc->ctxt.retire.pending_dbg |=
+        check_guest_io_breakpoint(curr, port, bytes);
 
     if ( admin_io_okay(port, bytes, currd) )
     {
@@ -472,7 +472,8 @@ static int cf_check write_io(
     if ( !guest_io_okay(port, bytes, curr, ctxt->regs) )
         return X86EMUL_UNHANDLEABLE;
 
-    poc->bpmatch = check_guest_io_breakpoint(curr, port, bytes);
+    poc->ctxt.retire.pending_dbg |=
+        check_guest_io_breakpoint(curr, port, bytes);
 
     if ( admin_io_okay(port, bytes, currd) )
     {
@@ -636,7 +637,8 @@ static int cf_check rep_ins(
         return X86EMUL_EXCEPTION;
     }
 
-    poc->bpmatch = check_guest_io_breakpoint(curr, port, bytes_per_rep);
+    poc->ctxt.retire.pending_dbg |=
+        check_guest_io_breakpoint(curr, port, bytes_per_rep);
 
     while ( *reps < goal )
     {
@@ -658,7 +660,7 @@ static int cf_check rep_ins(
 
         ++*reps;
 
-        if ( poc->bpmatch || hypercall_preempt_check() )
+        if ( poc->ctxt.retire.pending_dbg || hypercall_preempt_check() )
             break;
 
         /* x86_emulate() clips the repetition count to ensure we don't wrap. */
@@ -703,7 +705,8 @@ static int cf_check rep_outs(
         return X86EMUL_EXCEPTION;
     }
 
-    poc->bpmatch = check_guest_io_breakpoint(curr, port, bytes_per_rep);
+    poc->ctxt.retire.pending_dbg |=
+        check_guest_io_breakpoint(curr, port, bytes_per_rep);
 
     while ( *reps < goal )
     {
@@ -726,7 +729,7 @@ static int cf_check rep_outs(
 
         ++*reps;
 
-        if ( poc->bpmatch || hypercall_preempt_check() )
+        if ( poc->ctxt.retire.pending_dbg || hypercall_preempt_check() )
             break;
 
         /* x86_emulate() clips the repetition count to ensure we don't wrap. */
@@ -1360,12 +1363,9 @@ int pv_emulate_privileged_op(struct cpu_user_regs *regs)
     case X86EMUL_OKAY:
         ASSERT(!curr->arch.pv.trap_bounce.flags);
 
-        if ( ctxt.ctxt.retire.singlestep )
-            ctxt.bpmatch |= DR_STEP;
-
-        if ( ctxt.bpmatch )
+        if ( ctxt.ctxt.retire.pending_dbg )
         {
-            curr->arch.dr6 |= ctxt.bpmatch | DR_STATUS_RESERVED_ONE;
+            curr->arch.dr6 |= ctxt.ctxt.retire.pending_dbg | 
DR_STATUS_RESERVED_ONE;
             pv_inject_hw_exception(X86_EXC_DB, X86_EVENT_NO_EC);
         }
 
-- 
2.30.2