Il 19/11/2013 15:53, Dan Aloni ha scritto:
> 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);
>
Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
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