[PATCH 1/1] UBUNTU: SAUCE: kvm: fix push of wrong eip when doing softint

[Tim Gardner]

On 04/13/2011 08:28 AM, Andy Whitcroft wrote:
> From: Serge E. Hallyn<serge.hallyn at canonical.com>
>
> When doing a soft int, we need to bump eip before pushing it to
> the stack.  Otherwise we'll do the int a second time.
>
> [apw at canonical.com: merged eip update as per Jan's recommendation.]
> BugLink: http://bugs.launchpad.net/bugs/747090
> Signed-off-by: Serge E. Hallyn<serge.hallyn at ubuntu.com>
> Signed-off-by: Andy Whitcroft<apw at canonical.com>
> ---
>   arch/x86/kvm/vmx.c |   12 +++++++++---
>   arch/x86/kvm/x86.c |    5 +++--
>   arch/x86/kvm/x86.h |    2 +-
>   3 files changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index bf89ec2..3aad96c 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -1053,7 +1053,10 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
>   	}
>
>   	if (vmx->rmode.vm86_active) {
> -		if (kvm_inject_realmode_interrupt(vcpu, nr) != EMULATE_DONE)
> +		int inc_eip = 0;
> +		if (kvm_exception_is_soft(nr))
> +			inc_eip = vcpu->arch.event_exit_inst_len;
> +		if (kvm_inject_realmode_interrupt(vcpu, nr, inc_eip) != EMULATE_DONE)
>   			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
>   		return;
>   	}
> @@ -2871,7 +2874,10 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu)
>
>   	++vcpu->stat.irq_injections;
>   	if (vmx->rmode.vm86_active) {
> -		if (kvm_inject_realmode_interrupt(vcpu, irq) != EMULATE_DONE)
> +		int inc_eip = 0;
> +		if (vcpu->arch.interrupt.soft)
> +			inc_eip = vcpu->arch.event_exit_inst_len;
> +		if (kvm_inject_realmode_interrupt(vcpu, irq, inc_eip) != EMULATE_DONE)
>   			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
>   		return;
>   	}
> @@ -2905,7 +2911,7 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
>
>   	++vcpu->stat.nmi_injections;
>   	if (vmx->rmode.vm86_active) {
> -		if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR) != EMULATE_DONE)
> +		if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR, 0) != EMULATE_DONE)
>   			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
>   		return;
>   	}
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index bcc0efc..980317a 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4293,7 +4293,7 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
>   	memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
>   }
>
> -int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq)
> +int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
>   {
>   	struct decode_cache *c =&vcpu->arch.emulate_ctxt.decode;
>   	int ret;
> @@ -4302,7 +4302,8 @@ int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq)
>
>   	vcpu->arch.emulate_ctxt.decode.op_bytes = 2;
>   	vcpu->arch.emulate_ctxt.decode.ad_bytes = 2;
> -	vcpu->arch.emulate_ctxt.decode.eip = vcpu->arch.emulate_ctxt.eip;
> +	vcpu->arch.emulate_ctxt.decode.eip = vcpu->arch.emulate_ctxt.eip +
> +								 inc_eip;
>   	ret = emulate_int_real(&vcpu->arch.emulate_ctxt,&emulate_ops, irq);
>
>   	if (ret != X86EMUL_CONTINUE)
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index c600da8..e407ed3 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -77,7 +77,7 @@ static inline u32 bit(int bitno)
>
>   void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
>   void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
> -int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq);
> +int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
>
>   void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data);
>

ouch! Looks right to me, especially given the test results.

Acked-by: Tim Gardner <tim.gardner at canonical.com>

-- 
Tim Gardner tim.gardner at canonical.com