From patchwork Sat Sep 15 15:36:05 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoffer Dall X-Patchwork-Id: 1461941 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 6D819DF264 for ; Sat, 15 Sep 2012 15:36:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754217Ab2IOPgJ (ORCPT ); Sat, 15 Sep 2012 11:36:09 -0400 Received: from mail-qa0-f46.google.com ([209.85.216.46]:34570 "EHLO mail-qa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753939Ab2IOPgH (ORCPT ); Sat, 15 Sep 2012 11:36:07 -0400 Received: by mail-qa0-f46.google.com with SMTP id s11so600729qaa.19 for ; Sat, 15 Sep 2012 08:36:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=subject:to:from:date:message-id:in-reply-to:references:user-agent :mime-version:content-type:content-transfer-encoding :x-gm-message-state; bh=JIVOr+0i2C7gW6BOZMDGRXnyFgPN3B0EYD7ZrpV3EKU=; b=LNiO01iyswARXiVckTdo33X2LfCc+HnnE50Qq4NjH1d/1jQzY0BzEThL/y5vyaIXwV TAv5jRGgdBpd4+xT/ezdsFtk40leWiGF8o+1+OMswaqQpurwMub2BtFDcBQ7zd8QyZsy DVTr8e0G2rkbeikJ4oSjDTmE1YeWCddUdRujfcf10dMk7JqZukf79pgHSVpI2LXH8CZZ FWMGvd2w1sgVCnOUsNq91wvwJnlyhMDm3an3H5zwiXEXWXAhkTsuUp11UjqEvukZ21GM GHYNlFOT8/ADmOBlHI1YcViUm8eE/Gk7wlI6iuukU31FvMpaq1w/nvdF64wdErC4Q+ON gvBA== Received: by 10.224.213.198 with SMTP id gx6mr15585665qab.9.1347723366773; Sat, 15 Sep 2012 08:36:06 -0700 (PDT) Received: from [127.0.1.1] (pool-72-80-83-148.nycmny.fios.verizon.net. [72.80.83.148]) by mx.google.com with ESMTPS id ca8sm6996736qab.20.2012.09.15.08.36.06 (version=TLSv1/SSLv3 cipher=OTHER); Sat, 15 Sep 2012 08:36:06 -0700 (PDT) Subject: [PATCH 15/15] KVM: ARM: Guest wait-for-interrupts (WFI) support To: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu From: Christoffer Dall Date: Sat, 15 Sep 2012 11:36:05 -0400 Message-ID: <20120915153605.21241.75455.stgit@ubuntu> In-Reply-To: <20120915153359.21241.86002.stgit@ubuntu> References: <20120915153359.21241.86002.stgit@ubuntu> User-Agent: StGit/0.15 MIME-Version: 1.0 X-Gm-Message-State: ALoCoQn52joetNeh4hZwVe6WrVQMPJPlrDBPanOnehmi22pdq6Ivoc4KLMzftlt9oiQd3EiKxgsj Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Christoffer Dall When the guest executes a WFI instruction the operation is trapped to KVM, which emulates the instruction in software. There is no correlation between a guest executing a WFI instruction and actually putting the hardware into a low-power mode, since a KVM guest is essentially a process and the WFI instruction can be seen as 'sleep' call from this process. Therefore, we block the vcpu when the guest excecutes a wfi instruction and the IRQ or FIQ lines are not raised. When an interrupt comes in through KVM_IRQ_LINE (see previous patch) we signal the VCPU thread and unflag the VCPU to no longer wait for interrupts. Signed-off-by: Christoffer Dall --- arch/arm/kvm/arm.c | 10 ++++++++-- arch/arm/kvm/emulate.c | 13 ++++++++++++- arch/arm/kvm/trace.h | 16 ++++++++++++++++ 3 files changed, 36 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 06a3368..64fbec7 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -318,9 +318,16 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, return -EINVAL; } +/** + * kvm_arch_vcpu_runnable - determine if the vcpu can be scheduled + * @v: The VCPU pointer + * + * If the guest CPU is not waiting for interrupts or an interrupt line is + * asserted, the CPU is by definition runnable. + */ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v) { - return 0; + return !!v->arch.irq_lines; } int kvm_arch_vcpu_in_guest_mode(struct kvm_vcpu *v) @@ -586,7 +593,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) * Check conditions before entering the guest */ cond_resched(); - update_vttbr(vcpu->kvm); local_irq_disable(); diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c index 2670679..fc0fcd3 100644 --- a/arch/arm/kvm/emulate.c +++ b/arch/arm/kvm/emulate.c @@ -154,9 +154,20 @@ static int kvm_instr_index(u32 instr, u32 table[][2], int table_entries) return INSTR_NONE; } +/** + * kvm_handle_wfi - handle a wait-for-interrupts instruction executed by a guest + * @vcpu: the vcpu pointer + * @run: the kvm_run structure pointer + * + * Simply sets the wait_for_interrupts flag on the vcpu structure, which will + * halt execution of world-switches and schedule other host processes until + * there is an incoming IRQ or FIQ to the VM. + */ int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run) { - return 0; + trace_kvm_wfi(vcpu->arch.regs.pc); + kvm_vcpu_block(vcpu); + return 1; } diff --git a/arch/arm/kvm/trace.h b/arch/arm/kvm/trace.h index 7199b58..b371138 100644 --- a/arch/arm/kvm/trace.h +++ b/arch/arm/kvm/trace.h @@ -143,6 +143,22 @@ TRACE_EVENT(kvm_emulate_cp15_imp, __entry->CRm, __entry->Op2) ); +TRACE_EVENT(kvm_wfi, + TP_PROTO(unsigned long vcpu_pc), + TP_ARGS(vcpu_pc), + + TP_STRUCT__entry( + __field( unsigned long, vcpu_pc ) + ), + + TP_fast_assign( + __entry->vcpu_pc = vcpu_pc; + ), + + TP_printk("guest executed wfi at: 0x%08lx", __entry->vcpu_pc) +); + + #endif /* _TRACE_KVM_H */ #undef TRACE_INCLUDE_PATH