From patchwork Fri Dec 4 09:11:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 11951161 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00738C4361A for ; Fri, 4 Dec 2020 09:12:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C3732255F for ; Fri, 4 Dec 2020 09:12:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726860AbgLDJMP (ORCPT ); Fri, 4 Dec 2020 04:12:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725969AbgLDJMO (ORCPT ); Fri, 4 Dec 2020 04:12:14 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07D05C061A4F for ; Fri, 4 Dec 2020 01:11:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Mime-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=rwD73xv1BxQiBy2g9od9iRiQskWTqOUNEcdlEWBPNF4=; b=zuh8E/IXrUyjjrlNZX33cTCZYb aBAa7S0QgY3msvTjXeArdmSRrp76jbKfxT0YMssxjMtNw9RDLZz2IzJ0hYHfRr3Jyur7BgouLvCNp OlLU/P28zVb4YM8Wy3J9LtV+myH66LMAFtrDUdYhkwRKa503Dkv6WdIDxlpFmKOLeyWyyqarG1Bn6 8kUngoG/TVYXFX5aiSrjj9ZlCen5OnZR1VBGSHfkO1NBurqZ/BnnnLi6+sEOalIy3snZ5C0I3KtSD xZOi0s9DOxW4r7FUCnX0GPK+G6LExN8tY+MJVnxHRyntGr8Wo9LsZckMlaObbMNTce+662/pNAkEs 8FZJIp7Q==; Received: from 54-240-197-230.amazon.com ([54.240.197.230] helo=freeip.amazon.com) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kl77i-0003iA-9z; Fri, 04 Dec 2020 09:11:30 +0000 Message-ID: <72dad534cf158fe70c0f98ba72c4b9cf476c7b62.camel@infradead.org> Subject: [PATCH 16/15] KVM: Add documentation for Xen hypercall and shared_info updates From: David Woodhouse To: kvm@vger.kernel.org Cc: Paolo Bonzini , Ankur Arora , Joao Martins , Boris Ostrovsky , Sean Christopherson Date: Fri, 04 Dec 2020 09:11:27 +0000 In-Reply-To: <20201204011848.2967588-1-dwmw2@infradead.org> References: <20201204011848.2967588-1-dwmw2@infradead.org> X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 Mime-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: David Woodhouse Signed-off-by: David Woodhouse --- Documentation/virt/kvm/api.rst | 119 +++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index e00a66d72372..d98c2ff90880 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -944,6 +944,13 @@ memory. __u8 pad2[30]; }; +If the KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag is returned from the +KVM_CAP_XEN_HVM check, it may be set in the flags field of this ioctl. +This requests KVM to generate the contents of the hypercall page +automatically, and also to intercept hypercalls with KVM_EXIT_XEN. +In this case, all of the blob size and address fields must be zero. + +No other flags are currently valid. 4.29 KVM_GET_CLOCK ------------------ @@ -4807,6 +4814,67 @@ into user space. If a vCPU is in running state while this ioctl is invoked, the vCPU may experience inconsistent filtering behavior on MSR accesses. +4.127 KVM_XEN_HVM_SET_ATTR +-------------------------- + +:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO +:Architectures: x86 +:Type: vm ioctl +:Parameters: struct kvm_xen_hvm_attr +:Returns: 0 on success, < 0 on error + +:: + + struct kvm_xen_hvm_attr { + __u16 type; + + union { + __u8 long_mode; + struct { + __u64 gfn; + } shared_info; + struct { + __u32 vcpu; + __u64 gpa; + } vcpu_attr; + __u64 pad[4]; + } u; + }; + +type values: + +KVM_XEN_ATTR_TYPE_LONG_MODE + Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This + determines the layout of the shared info pages exposed to the VM. + +KVM_XEN_ATTR_TYPE_SHARED_INFO + Sets the guest physical frame number at which the Xen "shared info" + page resides. It is the default location for the vcpu_info for the + first 32 vCPUs, and contains other VM-wide data structures shared + between the VM and the host. + +KVM_XEN_ATTR_TYPE_VCPU_INFO + Sets the guest physical address of the vcpu_info for a given vCPU. + +KVM_XEN_ATTR_TYPE_VCPU_TIME_INFO + Sets the guest physical address of an additional pvclock structure + for a given vCPU. This is typically used for guest vsyscall support. + +KVM_XEN_ATTR_TYPE_VCPU_RUNSTATE + Sets the guest physical address of the vcpu_runstate_info for a given + vCPU. This is how a Xen guest tracks CPU state such as steal time. + +4.128 KVM_XEN_HVM_GET_ATTR +-------------------------- + +:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO +:Architectures: x86 +:Type: vm ioctl +:Parameters: struct kvm_xen_hvm_attr +:Returns: 0 on success, < 0 on error + +Allows Xen VM attributes to be read. For the structure and types, +see KVM_XEN_HVM_SET_ATTR above. 5. The kvm_run structure ======================== @@ -5303,6 +5371,34 @@ wants to write. Once finished processing the event, user space must continue vCPU execution. If the MSR write was unsuccessful, user space also sets the "error" field to "1". +:: + + + struct kvm_xen_exit { + #define KVM_EXIT_XEN_HCALL 1 + __u32 type; + union { + struct { + __u32 longmode; + __u32 cpl; + __u64 input; + __u64 result; + __u64 params[6]; + } hcall; + } u; + }; + /* KVM_EXIT_XEN */ + struct kvm_hyperv_exit xen; + +Indicates that the VCPU exits into userspace to process some tasks +related to Xen emulation. + +Valid values for 'type' are: + + - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall. + Userspace is expected to place the hypercall result into the appropriate + field before invoking KVM_RUN again. + :: /* Fix the size of the union. */ @@ -6390,3 +6486,26 @@ When enabled, KVM will disable paravirtual features provided to the guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf (0x40000001). Otherwise, a guest may use the paravirtual features regardless of what has actually been exposed through the CPUID leaf. + +8.29 KVM_CAP_XEN_HVM +-------------------- + +:Architectures: x86 + +This capability indicates the features that Xen supports for hosting Xen +PVHVM guests. Valid flags are:: + + #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0) + #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1) + #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2) + +The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG +ioctl is available, for the guest to set its hypercall page. + +If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be +provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page +contents, to request that KVM generate hypercall page content automatically +and also enable interception of guest hypercalls with KVM_EXIT_XEN. + +The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the +KVM_XEN_HVM_SET_ATTR and KVM_XEN_HVM_GET_ATTR ioctls.