Re: [PATCH 3/4] KVM: VMX: Emulated real mode interrupt injection

Marcelo Tosatti
2010-09-20T17:35:50Z

On Sun, Sep 19, 2010 at 02:34:07PM +0200, Avi Kivity wrote:
> From: Mohammed Gamal <m.gamal005@gmail.com>
>
> Replace the inject-as-software-interrupt hack we currently have with
> emulated injection.
>
> Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
> arch/x86/kvm/vmx.c | 65 ++++-----------------------------------------------
> 1 files changed, 6 insertions(+), 59 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 8ef6199..2572153 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -155,11 +155,6 @@ struct vcpu_vmx {
> u32 limit;
> u32 ar;
> } tr, es, ds, fs, gs;
> - struct {
> - bool pending;
> - u8 vector;
> - unsigned rip;
> - } irq;
> } rmode;
> int vpid;
> bool emulation_required;
> @@ -1034,16 +1029,8 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
> }
>
> if (vmx->rmode.vm86_active) {
> - vmx->rmode.irq.pending = true;
> - vmx->rmode.irq.vector = nr;
> - vmx->rmode.irq.rip = kvm_rip_read(vcpu);
> - if (kvm_exception_is_soft(nr))
> - vmx->rmode.irq.rip +=
> - vmx->vcpu.arch.event_exit_inst_len;
> - intr_info |= INTR_TYPE_SOFT_INTR;
> - vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info);
> - vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
> - kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
> + if (kvm_inject_realmode_interrupt(vcpu, nr) != EMULATE_DONE)
> + kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
> return;
> }
>
> @@ -2822,16 +2809,8 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu)
>
> ++vcpu->stat.irq_injections;
> if (vmx->rmode.vm86_active) {
> - vmx->rmode.irq.pending = true;
> - vmx->rmode.irq.vector = irq;
> - vmx->rmode.irq.rip = kvm_rip_read(vcpu);
> - if (vcpu->arch.interrupt.soft)
> - vmx->rmode.irq.rip +=
> - vmx->vcpu.arch.event_exit_inst_len;
> - vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
> - irq | INTR_TYPE_SOFT_INTR | INTR_INFO_VALID_MASK);
> - vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
> - kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
> + if (kvm_inject_realmode_interrupt(vcpu, irq) != EMULATE_DONE)
> + kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
> return;
> }
> intr = irq | INTR_INFO_VALID_MASK;
> @@ -2863,14 +2842,8 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
>
> ++vcpu->stat.nmi_injections;
> if (vmx->rmode.vm86_active) {
> - vmx->rmode.irq.pending = true;
> - vmx->rmode.irq.vector = NMI_VECTOR;
> - vmx->rmode.irq.rip = kvm_rip_read(vcpu);
> - vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
> - NMI_VECTOR | INTR_TYPE_SOFT_INTR |
> - INTR_INFO_VALID_MASK);
> - vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
> - kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
> + if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR) != EMULATE_DONE)
> + kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
> return;
> }
> vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
> @@ -3832,29 +3805,6 @@ static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
> ktime_to_ns(ktime_sub(ktime_get(), vmx->entry_time));
> }
>
> -/*
> - * Failure to inject an interrupt should give us the information
> - * in IDT_VECTORING_INFO_FIELD. However, if the failure occurs
> - * when fetching the interrupt redirection bitmap in the real-mode
> - * tss, this doesn't happen. So we do it ourselves.
> - */
> -static void fixup_rmode_irq(struct vcpu_vmx *vmx, u32 *idt_vectoring_info)
> -{
> - vmx->rmode.irq.pending = 0;
> - if (kvm_rip_read(&vmx->vcpu) + 1 != vmx->rmode.irq.rip)
> - return;
> - kvm_rip_write(&vmx->vcpu, vmx->rmode.irq.rip);
> - if (*idt_vectoring_info & VECTORING_INFO_VALID_MASK) {
> - *idt_vectoring_info &= ~VECTORING_INFO_TYPE_MASK;
> - *idt_vectoring_info |= INTR_TYPE_EXT_INTR;
> - return;
> - }
> - *idt_vectoring_info =
> - VECTORING_INFO_VALID_MASK
> - | INTR_TYPE_EXT_INTR
> - | vmx->rmode.irq.vector;
> -}
> -
> static void __vmx_complete_interrupts(struct vcpu_vmx *vmx,
> u32 idt_vectoring_info,
> int instr_len_field,
> @@ -3864,9 +3814,6 @@ static void __vmx_complete_interrupts(struct vcpu_vmx *vmx,
> int type;
> bool idtv_info_valid;
>
> - if (vmx->rmode.irq.pending)
> - fixup_rmode_irq(vmx, &idt_vectoring_info);
> -

Don't you have to undo kvm_inject_realmode_interrupt if injection fails?

> idtv_info_valid = idt_vectoring_info & VECTORING_INFO_VALID_MASK;
>
> vmx->vcpu.arch.nmi_injected = false;
> --
> 1.7.2.3