We have seen that when kvm-unit-tests runs with kgdb enabled, the
kernel halts on the debugger during the KVM x86 instruction emulation
that performs a test of a division by zero, and also during fwait.
This patch adds calls that temporarily disable the debugger trap.
Signed-off-by: Dan Aloni <alonid@xxxxxxxxxxxxxxx>
Signed-off-by: Muli Ben-Yehuda <muli@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 07ffca0..05e8509 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -24,6 +24,7 @@
#include "kvm_cache_regs.h"
#include <linux/module.h>
#include <asm/kvm_emulate.h>
+#include <asm/kgdb.h>
#include <linux/stringify.h>
#include "x86.h"
@@ -4438,6 +4439,7 @@ static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt)
{
bool fault = false;
+ kgdb_ll_local_disable();
ctxt->ops->get_fpu(ctxt);
asm volatile("1: fwait \n\t"
"2: \n\t"
@@ -4449,6 +4451,7 @@ static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt)
_ASM_EXTABLE(1b, 3b)
: [fault]"+qm"(fault));
ctxt->ops->put_fpu(ctxt);
+ kgdb_ll_local_enable();
if (unlikely(fault))
return emulate_exception(ctxt, MF_VECTOR, 0, false);
@@ -4468,10 +4471,14 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *))
ulong flags = (ctxt->eflags & EFLAGS_MASK) | X86_EFLAGS_IF;
if (!(ctxt->d & ByteOp))
fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE;
+
+ kgdb_ll_local_disable();
asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n"
: "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags),
[fastop]"+S"(fop)
: "c"(ctxt->src2.val));
+ kgdb_ll_local_enable();
+
ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
if (!fop) /* exception is returned in fop variable */
return emulate_de(ctxt);
--
1.8.3.1
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