From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liran Alon Subject: [PATCH v2 1/5] KVM: nVMX: Remove pi_pending as signal to process nested posted-interrupts Date: Tue, 5 Dec 2017 10:16:22 +0200 Message-ID: <1512461786-6465-2-git-send-email-liran.alon@oracle.com> References: <1512461786-6465-1-git-send-email-liran.alon@oracle.com> Cc: jmattson@google.com, wanpeng.li@hotmail.com, idan.brown@oracle.com, Liran Alon , Krish Sadhukhan , Konrad Rzeszutek Wilk To: pbonzini@redhat.com, rkrcmar@redhat.com, kvm@vger.kernel.org Return-path: Received: from aserp2130.oracle.com ([141.146.126.79]:45124 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752554AbdLEIQv (ORCPT ); Tue, 5 Dec 2017 03:16:51 -0500 In-Reply-To: <1512461786-6465-1-git-send-email-liran.alon@oracle.com> Sender: kvm-owner@vger.kernel.org List-ID: When L1 wants to send a posted-interrupt to another L1 CPU which runs L2, it does the following operations: 1. Sets the relevant bit in vmx->nested.pi_desc PIR. 2. Set ON bit in vmx->nested.pi_desc->control field. 3. Sends an IPI to dest L1 CPU by writing the the posted-interrupt notification-vector into the LAPIC ICR. Step (3) will exit to L0 on APIC_WRITE which will eventually reach vmx_deliver_nested_posted_interrupt(). If dest L0 CPU is in guest, then a physical IPI of notification-vector will be sent which will trigger evaluation of posted-interrupts and clear vmx->nested.pi_desc->control ON bit. Otherwise (or if dest L0 CPU exited from guest just before sending the physical IPI), the nested-posted-interrupts will be evaluated on next vmentry by vmx_complete_nested_posted_interrupt(). In order for vmx_complete_nested_posted_interrupt() to know if it should do any work, the flag vmx->nested.pi_pending was used which was set by vmx_deliver_nested_posted_interrupt(). However, this seems unnecessary because if posted-interrupts was not processed yet, vmx->nested.pi_desc->control ON bit should still be set. Therefore, it should suffice to use it in order to know if work should be done. Signed-off-by: Liran Alon Reviewed-by: Nikita Leshenko Reviewed-by: Krish Sadhukhan Signed-off-by: Krish Sadhukhan Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/kvm/vmx.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 714a0673ec3c..f5074ec5701b 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -453,7 +453,6 @@ struct nested_vmx { struct page *virtual_apic_page; struct page *pi_desc_page; struct pi_desc *pi_desc; - bool pi_pending; u16 posted_intr_nv; unsigned long *msr_bitmap; @@ -5050,10 +5049,9 @@ static void vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu) void *vapic_page; u16 status; - if (!vmx->nested.pi_desc || !vmx->nested.pi_pending) + if (!vmx->nested.pi_desc) return; - vmx->nested.pi_pending = false; if (!pi_test_and_clear_on(vmx->nested.pi_desc)) return; @@ -5126,7 +5124,6 @@ static int vmx_deliver_nested_posted_interrupt(struct kvm_vcpu *vcpu, * If a posted intr is not recognized by hardware, * we will accomplish it in the next vmentry. */ - vmx->nested.pi_pending = true; kvm_make_request(KVM_REQ_EVENT, vcpu); return 0; } @@ -10488,7 +10485,6 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, /* Posted interrupts setting is only taken from vmcs12. */ if (nested_cpu_has_posted_intr(vmcs12)) { vmx->nested.posted_intr_nv = vmcs12->posted_intr_nv; - vmx->nested.pi_pending = false; vmcs_write16(POSTED_INTR_NV, POSTED_INTR_NESTED_VECTOR); } else { exec_control &= ~PIN_BASED_POSTED_INTR; -- 1.9.1