Re: [PATCH 1/2] x86: Enable ack interrupt on vmexit

Gleb Natapov
2012-12-13T07:51:22Z

On Thu, Dec 13, 2012 at 03:29:39PM +0800, Yang Zhang wrote:
> From: Yang Zhang <yang.z.zhang@Intel.com>
>
> Ack interrupt on vmexit is required by Posted Interrupt. With it,
> when external interrupt caused vmexit, the cpu will acknowledge the
> interrupt controller and save the interrupt's vector in vmcs. Only
> enable it when posted interrupt is enabled.
>
> There are several approaches to enable it. This patch uses a simply
> way: re-generate an interrupt via self ipi.
>
> Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
> ---
> arch/x86/kvm/vmx.c | 20 +++++++++++++++++---
> 1 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 8cd9eb7..6b6bd03 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2549,7 +2549,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
> #ifdef CONFIG_X86_64
> min |= VM_EXIT_HOST_ADDR_SPACE_SIZE;
> #endif
> - opt = VM_EXIT_SAVE_IA32_PAT | VM_EXIT_LOAD_IA32_PAT;
> + opt = VM_EXIT_SAVE_IA32_PAT | VM_EXIT_LOAD_IA32_PAT | VM_EXIT_ACK_INTR_ON_EXIT;
> if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_EXIT_CTLS,
> &_vmexit_control) < 0)
> return -EIO;
> @@ -3913,6 +3913,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
> unsigned long a;
> #endif
> int i;
> + u32 vmexit_ctrl = vmcs_config.vmexit_ctrl;
>
> /* I/O */
> vmcs_write64(IO_BITMAP_A, __pa(vmx_io_bitmap_a));
> @@ -3996,8 +3997,10 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
> vmx->guest_msrs[j].mask = -1ull;
> ++vmx->nmsrs;
> }
> -
> - vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl);
> +
> + if(!enable_apicv_pi)
> + vmexit_ctrl &= ~VM_EXIT_ACK_INTR_ON_EXIT;
> + vmcs_write32(VM_EXIT_CONTROLS, vmexit_ctrl);
>
> /* 22.2.1, 20.8.1 */
> vmcs_write32(VM_ENTRY_CONTROLS, vmcs_config.vmentry_ctrl);
> @@ -6267,6 +6270,17 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
> asm("int $2");
> kvm_after_handle_nmi(&vmx->vcpu);
> }
> + if ((exit_intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_EXT_INTR &&
> + (exit_intr_info & INTR_INFO_VALID_MASK) && enable_apicv_pi) {
> + unsigned int vector, tmr;
> +
> + vector = exit_intr_info & INTR_INFO_VECTOR_MASK;
> + tmr = apic_read(APIC_TMR + ((vector & ~0x1f) >> 1));
> + apic_eoi();
> + if ( !((1 << (vector % 32)) & tmr) )
> + apic->send_IPI_self(vector);
> + }
What happen with the idea to dispatch interrupt through idt without IPI?

> +
> }
>
> static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
> --
> 1.7.1

--
Gleb.