* [PATCH] x86emul: defer injection of #DB
@ 2016-09-30 9:39 Jan Beulich
2016-09-30 10:10 ` Andrew Cooper
0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2016-09-30 9:39 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper
[-- Attachment #1: Type: text/plain, Size: 1472 bytes --]
Move the raising of the single step trap until after registers were
updated. This should probably have been that way from the beginning,
to allow the inject_hw_exception() hook to see updated register state
(in case it cares) - it's a trap, after all.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2267,6 +2267,7 @@ x86_emulate(
struct x86_emulate_state state;
int rc;
uint8_t b, d;
+ bool tf = ctxt->regs->eflags & EFLG_TF;
struct operand src = { .reg = REG_POISON };
struct operand dst = { .reg = REG_POISON };
enum x86_swint_type swint_type;
@@ -5161,11 +5162,6 @@ x86_emulate(
}
no_writeback:
- /* Inject #DB if single-step tracing was enabled at instruction start. */
- if ( (ctxt->regs->eflags & EFLG_TF) && (rc == X86EMUL_OKAY) &&
- (ops->inject_hw_exception != NULL) )
- rc = ops->inject_hw_exception(EXC_DB, -1, ctxt) ? : X86EMUL_EXCEPTION;
-
/* Commit shadow register state. */
_regs.eflags &= ~EFLG_RF;
@@ -5175,6 +5171,10 @@ x86_emulate(
*ctxt->regs = _regs;
+ /* Inject #DB if single-step tracing was enabled at instruction start. */
+ if ( tf && (rc == X86EMUL_OKAY) && ops->inject_hw_exception )
+ rc = ops->inject_hw_exception(EXC_DB, -1, ctxt) ? : X86EMUL_EXCEPTION;
+
done:
_put_fpu();
put_stub(stub);
[-- Attachment #2: x86emul-defer-DB-inject.patch --]
[-- Type: text/plain, Size: 1501 bytes --]
x86emul: defer injection of #DB
Move the raising of the single step trap until after registers were
updated. This should probably have been that way from the beginning,
to allow the inject_hw_exception() hook to see updated register state
(in case it cares) - it's a trap, after all.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2267,6 +2267,7 @@ x86_emulate(
struct x86_emulate_state state;
int rc;
uint8_t b, d;
+ bool tf = ctxt->regs->eflags & EFLG_TF;
struct operand src = { .reg = REG_POISON };
struct operand dst = { .reg = REG_POISON };
enum x86_swint_type swint_type;
@@ -5161,11 +5162,6 @@ x86_emulate(
}
no_writeback:
- /* Inject #DB if single-step tracing was enabled at instruction start. */
- if ( (ctxt->regs->eflags & EFLG_TF) && (rc == X86EMUL_OKAY) &&
- (ops->inject_hw_exception != NULL) )
- rc = ops->inject_hw_exception(EXC_DB, -1, ctxt) ? : X86EMUL_EXCEPTION;
-
/* Commit shadow register state. */
_regs.eflags &= ~EFLG_RF;
@@ -5175,6 +5171,10 @@ x86_emulate(
*ctxt->regs = _regs;
+ /* Inject #DB if single-step tracing was enabled at instruction start. */
+ if ( tf && (rc == X86EMUL_OKAY) && ops->inject_hw_exception )
+ rc = ops->inject_hw_exception(EXC_DB, -1, ctxt) ? : X86EMUL_EXCEPTION;
+
done:
_put_fpu();
put_stub(stub);
[-- Attachment #3: Type: text/plain, Size: 127 bytes --]
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2016-09-30 9:39 [PATCH] x86emul: defer injection of #DB Jan Beulich
2016-09-30 10:10 ` Andrew Cooper
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