From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: [RFC PATCH 13/16] KVM: Allow 2048-bit register access via KVM_{GET, SET}_ONE_REG Date: Thu, 21 Jun 2018 15:57:37 +0100 Message-ID: <1529593060-542-14-git-send-email-Dave.Martin@arm.com> References: <1529593060-542-1-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 AEBFE4A0DB for ; Thu, 21 Jun 2018 10:47:42 -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 p4bUKUBceG7r for ; Thu, 21 Jun 2018 10:47:14 -0400 (EDT) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id CBC0D4A0ED for ; Thu, 21 Jun 2018 10:47:03 -0400 (EDT) In-Reply-To: <1529593060-542-1-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 b6270a3..345be88 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1106,6 +1106,7 @@ 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