From patchwork Tue Jan 17 10:29:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Usama Arif X-Patchwork-Id: 13104468 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 588D6C678D7 for ; Tue, 17 Jan 2023 10:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235982AbjAQKas (ORCPT ); Tue, 17 Jan 2023 05:30:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236181AbjAQKaV (ORCPT ); Tue, 17 Jan 2023 05:30:21 -0500 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 345A72FCE3 for ; Tue, 17 Jan 2023 02:29:38 -0800 (PST) Received: by mail-wr1-x433.google.com with SMTP id d2so9952631wrp.8 for ; Tue, 17 Jan 2023 02:29:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=tOVpxHZD0ZxVt/Val7yzJDOKpsPkSooq27SOBhqL+Kk=; b=g1p3ubnYwRTHrjE4Z2DfA/MH2EnDrh/8t2YbdFdGQ2RXS4HCOPoDRzLc6RbgsSk7EZ wiVV99cgkBmBSDrFgSxkSKw+h7LrY5waW8HRALrEO4NhQVKA4EY/LHdIOm6VAl6XxM5j 6kAgMinmi+lStYZQSun536mzqwEGcQzCWTyvlYeAm+8vuw+zX3dcBUapeO4+TO+IeXbQ v8uLeKNqsgFGn+WhKtX21orc6zZELYXdRHZriJFDI9/HVEBnxQ1M4eKmKJvopJHyg11g UcS8wqDaZUwVO9tvmMZXDTCTYQxa5DvYEMivbSqOc2MFSL1zycMGKA+dj4Yo1KeJvF+6 HecA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=tOVpxHZD0ZxVt/Val7yzJDOKpsPkSooq27SOBhqL+Kk=; b=Q/YvJS6EwQDpGfeBYOE2MeHwePMyrbasYlsRVKN9m/Ub0CJ9Q4PtEj8ru1+cFIcTS3 xfTWnG/0/fVrplmgHEMLxOWeIGiDyqBNuyCkKH0iERkVjFDl1qQbAw4QXCs96Oo6LOYJ NbkiZCq10/LxyN/Kv0Tq8oFzPbJ0JIuh0cRZfecA2kgwuIRfTHJ6g0EP/zm4pnlQ0eUJ srAkVDEYeaaDfBa0aX563NPbcn5JU2JUi5zUUWXNlqzX+2iVtAbbZchsowOM4pEQiHju TCSvOmbWzqx7DASvkdlCYCfum5AnWz4SezO9RT567j6W6UzDHH2uutGvkgXdAGSJc2md 57eQ== X-Gm-Message-State: AFqh2kqE47nUESfvjvRkxe67yu0GyDU9gY0Wziqb2m5tXko7WxgF4/PV zZxZ9qvKmFHGoVxp4ddIAVLVSGLGPedbiPI0Ims= X-Google-Smtp-Source: AMrXdXuy/hWkhxW9y7rCTLOqE/Nibr8MFx8zKk9jZqoyS1EmphFslhRskgoNwSz+fAiunB8+BlVPog== X-Received: by 2002:adf:fd83:0:b0:2bd:dbd8:d41e with SMTP id d3-20020adffd83000000b002bddbd8d41emr2309747wrr.57.1673951376751; Tue, 17 Jan 2023 02:29:36 -0800 (PST) Received: from usaari01.cust.communityfibre.co.uk ([2a02:6b6a:b566:0:17d8:e5ec:f870:7b46]) by smtp.gmail.com with ESMTPSA id j15-20020a5d452f000000b0028f9132e9ddsm28389844wra.39.2023.01.17.02.29.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Jan 2023 02:29:36 -0800 (PST) From: Usama Arif To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-doc@vger.kernel.org, virtualization@lists.linux-foundation.org, linux@armlinux.org.uk, yezengruan@huawei.com, catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, steven.price@arm.com, mark.rutland@arm.com, bagasdotme@gmail.com, pbonzini@redhat.com Cc: fam.zheng@bytedance.com, liangma@liangbit.com, punit.agrawal@bytedance.com, Usama Arif Subject: [v3 1/6] KVM: arm64: Document PV-lock interface Date: Tue, 17 Jan 2023 10:29:25 +0000 Message-Id: <20230117102930.1053337-2-usama.arif@bytedance.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230117102930.1053337-1-usama.arif@bytedance.com> References: <20230117102930.1053337-1-usama.arif@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Introduce a paravirtualization interface for KVM/arm64 to obtain whether the VCPU is currently running or not. The PV lock structure of the guest is allocated by user space. A hypercall interface is provided for the guest to interrogate the location of the shared memory structures. Signed-off-by: Zengruan Ye Signed-off-by: Usama Arif Reviewed-by: Bagas Sanjaya --- Documentation/virt/kvm/arm/index.rst | 1 + Documentation/virt/kvm/arm/pvlock.rst | 54 +++++++++++++++++++++++++ Documentation/virt/kvm/devices/vcpu.rst | 25 ++++++++++++ 3 files changed, 80 insertions(+) create mode 100644 Documentation/virt/kvm/arm/pvlock.rst diff --git a/Documentation/virt/kvm/arm/index.rst b/Documentation/virt/kvm/arm/index.rst index e84848432158..b8499dc00a6a 100644 --- a/Documentation/virt/kvm/arm/index.rst +++ b/Documentation/virt/kvm/arm/index.rst @@ -10,4 +10,5 @@ ARM hyp-abi hypercalls pvtime + pvlock ptp_kvm diff --git a/Documentation/virt/kvm/arm/pvlock.rst b/Documentation/virt/kvm/arm/pvlock.rst new file mode 100644 index 000000000000..1b9ff7d8a385 --- /dev/null +++ b/Documentation/virt/kvm/arm/pvlock.rst @@ -0,0 +1,54 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Paravirtualized lock support for arm64 +====================================== + +KVM/arm64 provides a hypervisor service call for paravirtualized guests to +determine whether a VCPU is currently running or not. + +A new SMCCC compatible hypercall is defined: + +* ARM_SMCCC_VENDOR_HYP_KVM_PV_LOCK_FUNC_ID: 0xC6000002 + +ARM_SMCCC_VENDOR_HYP_KVM_PV_LOCK_FUNC_ID + + ============= ======== ========================================== + Function ID: (uint32) 0xC6000002 + Return value: (int64) IPA of the pv lock data structure for this + VCPU. On failure: + NOT_SUPPORTED (-1) + ============= ======== ========================================== + +The IPA returned by PV_LOCK_PREEMPTED should be mapped by the guest as normal +memory with inner and outer write back caching attributes, in the inner +shareable domain. + +PV_LOCK_PREEMPTED returns the structure for the calling VCPU. + +PV lock state +------------- + +The structure pointed to by the PV_LOCK_PREEMPTED hypercall is as follows: + ++-----------+-------------+-------------+---------------------------------+ +| Field | Byte Length | Byte Offset | Description | ++===========+=============+=============+=================================+ +| preempted | 8 | 0 | Used to indicate if the VCPU | +| | | | which owns this struct is | +| | | | running or not. | +| | | | A non-zero value mean the VCPU | +| | | | has been scheduled out. A zero | +| | | | value means the VCPU has been | +| | | | scheduled in. | ++-----------+-------------+-------------+---------------------------------+ + +The preempted field will be updated to 0 by the hypervisor prior to scheduling +a VCPU. When the VCPU is scheduled out, the preempted field will be updated +to 1 by the hypervisor. + +The structure will be present within a reserved region of the normal memory +given to the guest. The guest should not attempt to write into this memory. +There is a structure per VCPU of the guest. + +For the user space interface see +:ref:`Documentation/virt/kvm/devices/vcpu.rst `. \ No newline at end of file diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst index 31f14ec4a65b..0f999919ba92 100644 --- a/Documentation/virt/kvm/devices/vcpu.rst +++ b/Documentation/virt/kvm/devices/vcpu.rst @@ -265,3 +265,28 @@ From the destination VMM process: 7. Write the KVM_VCPU_TSC_OFFSET attribute for every vCPU with the respective value derived in the previous step. + +.. _kvm_arm_vcpu_pvlock_ctrl: + +5. GROUP: KVM_ARM_VCPU_PVLOCK_CTRL +================================== + +:Architectures: ARM64 + +5.1 ATTRIBUTE: KVM_ARM_VCPU_PVLOCK_IPA +-------------------------------------- + +:Parameters: 64-bit base address + +Returns: + + ======= ====================================== + -ENXIO PV lock not implemented + -EEXIST Base address already set for this VCPU + -EINVAL Base address not 64 byte aligned + ======= ====================================== + +Specifies the base address of the pv lock structure for this VCPU. The +base address must be 64 byte aligned and exist within a valid guest memory +region. See Documentation/virt/kvm/arm/pvlock.rst for more information +including the layout of the pv lock structure.