On Thu, Jan 17, 2013 at 01:36:36AM +0000, Zhang, Yang Z wrote: > Gleb Natapov wrote on 2013-01-16: > > On Wed, Jan 16, 2013 at 05:00:48PM +0800, Yang Zhang wrote: > >> From: Yang Zhang <yang.z.zhang@xxxxxxxxx> > >> > >> The "acknowledge interrupt on exit" feature controls processor behavior > >> for external interrupt acknowledgement. When this control is set, the > >> processor acknowledges the interrupt controller to acquire the > >> interrupt vector on VM exit. > >> > >> This feature is required by Posted Interrupt. It will be turnned on only > >> when posted interrupt is enabled. > >> > > Why? Always enable it. It is faster than current approach. > I don't think it will faster. It should be same. > Interrupt delivered->vmexit->interrupt enabled->interrupt redelivered->acked->dispatched through idt. vs Interrupt delivered->acked->vmexit->dispatched through idt. Anyway even if it is not slower it is better to use the same code path to make sure it is well tested. > >> Refer to Intel SDM volum 3, chapter 33.2. > >> > > Please CC H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> on the next version. > > > >> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx> > >> --- > >> arch/x86/kvm/vmx.c | 51 > >> +++++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, > >> 49 insertions(+), 2 deletions(-) > >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > >> index dd2a85c..d1ed9ae 100644 > >> --- a/arch/x86/kvm/vmx.c > >> +++ b/arch/x86/kvm/vmx.c > >> @@ -2565,7 +2565,7 @@ 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; @@ -3926,7 +3926,7 @@ static > >> int vmx_vcpu_setup(struct vcpu_vmx *vmx) ++vmx->nmsrs; } > >> - vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl); > >> + vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl & > >> ~VM_EXIT_ACK_INTR_ON_EXIT); > >> > >> /* 22.2.1, 20.8.1 */ > >> vmcs_write32(VM_ENTRY_CONTROLS, vmcs_config.vmentry_ctrl); > >> @@ -6096,6 +6096,52 @@ static void vmx_complete_atomic_exit(struct > > vcpu_vmx *vmx) > >> } > >> } > >> + +static noinline void vmx_handle_external_intr(struct kvm_vcpu *vcpu) > >> +{ + u32 exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO); + + if > >> ((exit_intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_EXT_INTR && > >> + (exit_intr_info & INTR_INFO_VALID_MASK) ) { > > if (exit_intr_info & (INTR_INFO_VALID_MASK | INTR_INFO_INTR_TYPE_MASK) > > == (INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR)) > > > >> + unsigned int vector; > >> + unsigned long entry; > >> + struct desc_ptr dt; > >> + gate_desc *desc; > >> + > >> + native_store_idt(&dt); > > This does not change. Store it in vcpu during vcpu creation instead of > > reading it each time. > Right. It will reduce the cost. > > >> + > >> + vector = exit_intr_info & INTR_INFO_VECTOR_MASK; > >> + desc = (void *)dt.address + vector * 16; > >> + > >> + entry = gate_offset(*desc); > >> + asm( > >> + "mov %0, %%" _ASM_DX "\n\t" > >> + "mov %%" _ASM_SP ", %%" _ASM_BX "\n\t" > >> +#ifdef CONFIG_X86_64 > >> + "and $0xfffffffffffffff0, %%" _ASM_SP "\n\t" > >> +#endif > >> + "mov %%ss, %%" _ASM_AX "\n\t" > >> + "push %%" _ASM_AX "\n\t" > >> + "push %%" _ASM_BX "\n\t" > > For 32bit you do not need to save ss:esp. > You are right. No need to save it for 32bit. > > >> + "pushf\n\t" > >> + "mov %%cs, %%" _ASM_AX "\n\t" > >> + "push %%" _ASM_AX "\n\t" > >> + "push intr_return\n\t" > >> + "jmp *%% " _ASM_DX "\n\t" > >> + ".pushsection .rodata \n\t" > >> + ".global intr_return \n\t" > >> + "intr_return: " _ASM_PTR " 1b \n\t" > >> + ".popsection\n\t" > >> + : :"m"(entry) : > >> +#ifdef CONFIG_X86_64 > >> + "rax", "rbx", "rdx" > >> +#else > >> + "eax", "ebx", "edx" > >> +#endif > >> + ); > >> + } > >> +} > >> + > >> static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx) > >> { > >> u32 exit_intr_info; > >> @@ -6431,6 +6477,7 @@ static void __noclone vmx_vcpu_run(struct > > kvm_vcpu *vcpu) > >> vmx_complete_atomic_exit(vmx); > >> vmx_recover_nmi_blocking(vmx); > >> vmx_complete_interrupts(vmx); > >> + vmx_handle_external_intr(vcpu); > > This should be done just before enabling interrupts, otherwise we are > > taking an interrupt before vmexit is fully complete. > How about to put it just after set vcpu->mode to OUTSIDE_GUEST_MODE? At that point, the vmexit is considered as fully complete. > As I said, right before local_irq_enable(). -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html