diff mbox series

[3/7] x86/pv: Fix the determiniation of whether to inject #DB

Message ID 20230915203628.837732-4-andrew.cooper3@citrix.com (mailing list archive)
State New, archived
Headers show
Series x86/pv: #DB vs %dr6 fixes, part 2 | expand

Commit Message

Andrew Cooper Sept. 15, 2023, 8:36 p.m. UTC 
We long ago fixed the emulator to not inject exceptions behind our back.
Therefore, assert that that a PV event (including interrupts, because that
would be buggy too) isn't pending, rather than skipping the #DB injection if
one is.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Wei Liu <wl@xen.org>
CC: Jinoh Kang <jinoh.kang.kr@gmail.com>

v2:
 * Drop X86EMUL_DONE adjustment.
---
 xen/arch/x86/pv/emul-priv-op.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index 142bc4818cb5..0d9f84f458ba 100644
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -1358,14 +1358,17 @@  int pv_emulate_privileged_op(struct cpu_user_regs *regs)
     switch ( rc )
     {
     case X86EMUL_OKAY:
+        ASSERT(!curr->arch.pv.trap_bounce.flags);
+
         if ( ctxt.ctxt.retire.singlestep )
             ctxt.bpmatch |= DR_STEP;
+
         if ( ctxt.bpmatch )
         {
             curr->arch.dr6 |= ctxt.bpmatch | DR_STATUS_RESERVED_ONE;
-            if ( !(curr->arch.pv.trap_bounce.flags & TBF_EXCEPTION) )
-                pv_inject_hw_exception(X86_EXC_DB, X86_EVENT_NO_EC);
+            pv_inject_hw_exception(X86_EXC_DB, X86_EVENT_NO_EC);
         }
+
         /* fall through */
     case X86EMUL_RETRY:
         return EXCRET_fault_fixed;