Re: [RFC PATCH v2 2/4] x86: Add inject_realmode_interrupt() wrapper

[Gleb Natapov <gleb@redhat.com>]

On Sat, Aug 14, 2010 at 03:19:39AM +0300, Mohammed Gamal wrote:
> This adds a wrapper function inject_realmode_interrupt() around the
> emulator function emulate_int_real() to allow real mode interrupt injection.
> 
> Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
> ---
>  arch/x86/kvm/x86.c |   33 +++++++++++++++++++++++++++++++++
>  arch/x86/kvm/x86.h |    1 +
>  2 files changed, 34 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 1722d37..d3ba1c3 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3936,6 +3936,39 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu)
>  		kvm_queue_exception(vcpu, ctxt->exception);
>  }
>  
> +int inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq)
> +{       
> +	struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
> +	int cs_db, cs_l, ret;
> +	cache_all_regs(vcpu);
> +
> +	kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
> +
> +	vcpu->arch.emulate_ctxt.vcpu = vcpu;
> +	vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
> +	vcpu->arch.emulate_ctxt.eip = kvm_rip_read(vcpu);
> +	vcpu->arch.emulate_ctxt.mode =
> +		(!is_protmode(vcpu)) ? X86EMUL_MODE_REAL :
> +		(vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM)
> +		? X86EMUL_MODE_VM86 : cs_l
> +		? X86EMUL_MODE_PROT64 : cs_db
> +		? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
> +	memset(c, 0, sizeof(struct decode_cache));
> +	memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
> +
We have this code in 2 places already: kvm_task_switch() and emulate_instruction().
This will be the third one. Should be moved to separate function.

> +	ret = emulate_int_real(&vcpu->arch.emulate_ctxt, &emulate_ops, irq);
> +
> +	if (ret != X86EMUL_CONTINUE)
> +		return EMULATE_FAIL;
> +
> +	memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
> +	kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
> +	kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
> +
> +	return EMULATE_DONE;
> +}
> +EXPORT_SYMBOL_GPL(inject_realmode_interrupt);
> +
>  static int handle_emulation_failure(struct kvm_vcpu *vcpu)
>  {
>  	++vcpu->stat.insn_emulation_fail;
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index b7a4047..c6e8a4d 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -67,5 +67,6 @@ static inline int is_paging(struct kvm_vcpu *vcpu)
>  
>  void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
>  void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
> +int inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq);
>  
>  #endif
> -- 
> 1.7.0.4
> 
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--
			Gleb.