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

Gleb Natapov
2012-12-13T07:58:17Z

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.

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

--
Gleb.