From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: [RFC PATCH v2 14/23] KVM: Allow 2048-bit register access via ioctl interface Date: Fri, 28 Sep 2018 14:39:18 +0100 Message-ID: <1538141967-15375-15-git-send-email-Dave.Martin@arm.com> References: <1538141967-15375-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id AE2164A210 for ; Fri, 28 Sep 2018 09:40:53 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DvqJEBcxLGWn for ; Fri, 28 Sep 2018 09:40:43 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 63AB34A1E5 for ; Fri, 28 Sep 2018 09:40:43 -0400 (EDT) In-Reply-To: <1538141967-15375-1-git-send-email-Dave.Martin@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: kvmarm@lists.cs.columbia.edu Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu The Arm SVE architecture defines registers that are up to 2048 bits in size (with some possibility of further future expansion). In order to avoid the need for an excessively large number of ioctls when saving and restoring a vcpu's registers, this patch adds a #define to make support for individual 2048-bit registers through the KVM_{GET,SET}_ONE_REG ioctl interface official. This will allow each SVE register to be accessed in a single call. There are sufficient spare bits in the register id size field for this change, so there is no ABI impact providing that KVM_GET_REG_LIST does not enumerate any 2048-bit register unless userspace explicitly opts in to the relevant architecture-specific features. Signed-off-by: Dave Martin --- include/uapi/linux/kvm.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 251be35..7c3c5cc 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1110,6 +1110,7 @@ struct kvm_dirty_tlb { #define KVM_REG_SIZE_U256 0x0050000000000000ULL #define KVM_REG_SIZE_U512 0x0060000000000000ULL #define KVM_REG_SIZE_U1024 0x0070000000000000ULL +#define KVM_REG_SIZE_U2048 0x0080000000000000ULL struct kvm_reg_list { __u64 n; /* number of regs */ -- 2.1.4