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

Zhang, Yang Z
2012-12-13T07:54:42Z

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.

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