From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43841) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1avbmt-0001C0-HR for qemu-devel@nongnu.org; Wed, 27 Apr 2016 22:34:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1avbms-0004Yw-DU for qemu-devel@nongnu.org; Wed, 27 Apr 2016 22:34:43 -0400 Message-ID: <5721768E.407@huawei.com> Date: Thu, 28 Apr 2016 10:33:50 +0800 From: Shannon Zhao MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [Query] Does Linux & Qemu support KVM for ARM32 guest on ARM64 host List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: r.sande@samsung.com, "kvmarm@lists.cs.columbia.edu" , qemu-arm@nongnu.org Cc: "kvm@vger.kernel.org" , Marc Zyngier , Andre Przywara , qemu-devel@nongnu.org, "linux-arm-kernel@lists.infradead.org" On 2016/4/28 9:50, RAVINDRA KUMAR SANDE wrote: > > What I did : > 1) Just for investigation, I took a ARMv8 ( OdroidC2 ) board > 2) I compiled Linux 3.14 with KVM support for this ARMv8 ( OdroidC2 ) > board, with modification replacing meson_timer by arm timer in its dts > file. > Why Linux 3.14 : I took Linux 3.14 because display drivers for this > board are officially for this version; and I am interested in seeing > some Linux guest booting with display on. > 3) I see from boot log of that KVM is initialized successfully, and I > can see /dev/kvm node. > 4) I built latest Qemu with --enable-kvm on this board natively. > > What I find : > 1) running "qemu-system-arm -enable-kvm -machine vexpress-a9 ...." > gives error : no accelerator found > 2) running "qemu-system-aarch64 -enable-kvm -machine vexpress-a9 ...." > gives error : kmv_init_vcpu (IOCtl on /dev/kvm) failed, guest not supported > ( I experimented some modifications as well to overcome above error, > such as replacing value assigned to cpu->kvm_target etc, but IOCtl call > is failing) > > Query: > 1) Does Arm64 Linux not enable KVM support for Arm32 guest ? > 2) Can qemu-system-arm not use the KVM feature on Arm64 host ? > 3) Can qemu-system-aarch64 not use KVM feature for Arm32 guest ? > You can use below command to boot a ARM32 guest on ARM64： qemu-system-aarch64 -enable-kvm -machine virt,kernel_irqchip=on -cpu host,aarch64=off .... -- Shannon