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

Zhang, Yang Z
2012-12-13T08:03:32Z

Gleb Natapov wrote on 2012-12-13:
> On Thu, Dec 13, 2012 at 07:54:35AM +0000, Zhang, Yang Z wrote:
>> Gleb Natapov wrote on 2012-12-13:
>>> 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?
>> I am not sure upstream guys will allow to export idt to a module. If it
>> is not a problem, then can do it as you suggested.
>>
> I replied to that before. No need to export idt to modules. Add function
> to entry_32/64.S that does dispatching and export it instead.
It still need to touch common code. Do you think upstream guys will buy-in this?

>>>> +
>>>> }
>>>>
>>>> static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
>>>> --
>>>> 1.7.1
>>>
>>> --
>>> Gleb.
>>> --
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>>
>>
>> Best regards,
>> Yang
>>
>
> --
> Gleb.

Best regards,
Yang