From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Longpeng(Mike)" Subject: [PATCH] kvm: x86: correct the misleading comment in vmx_handle_external_intr Date: Mon, 10 Oct 2016 08:23:43 +0800 Message-ID: <1476059023-33224-1-git-send-email-longpeng2@huawei.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , , "Longpeng(Mike)" To: , , , , , Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Since Paolo has removed irq-enable-operation in vmx_handle_external_intr (KVM: x86: use guest_exit_irqoff), the original comment about the IF bit in rflags is incorrect now. Signed-off-by: Longpeng(Mike) --- arch/x86/kvm/vmx.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index cf1b16d..9fa3c76 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -8647,9 +8647,12 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu) register void *__sp asm(_ASM_SP); /* - * If external interrupt exists, IF bit is set in rflags/eflags on the - * interrupt stack frame, and interrupt will be enabled on a return - * from interrupt handler. + * If external interrupt exists, fakes an interrupt stack and jump to + * idt table to let real handler to handle it. Because most of bits in + * rflags are cleared when VM exit(Intel SDM volum 3, chapter 27.5.3), + * the IF bit is 0 in rflags on the interrupt stack frame, so interrupt + * is still disabled when return from the irq handler, but it will be + * enabled later by the caller. */ if ((exit_intr_info & (INTR_INFO_VALID_MASK | INTR_INFO_INTR_TYPE_MASK)) == (INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR)) { -- 2.7.4