From patchwork Mon Dec 14 08:39:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 11971543 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=-18.8 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_GIT 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 A0BFCC2BB48 for ; Mon, 14 Dec 2020 08:40:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65130206C1 for ; Mon, 14 Dec 2020 08:40:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439401AbgLNIkj (ORCPT ); Mon, 14 Dec 2020 03:40:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2439374AbgLNIki (ORCPT ); Mon, 14 Dec 2020 03:40:38 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D68D6C0617A6 for ; Mon, 14 Dec 2020 00:39:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=SHy2+xDWEp3nAI2MDjVmGwD47Q0EuTz2//89CbFKm44=; b=vSo1UFV7ESLDmM8awvYZ1bDzXo Y0L+wpfgWGCPb+I+bX0iespurhZOvV9uovNc7inm1tsRbLYTU7fjW+ujp9mDGCxNgS4fHJXVnJSZ/ fNnXFVwTrB5yH/GT63JRqKV2vGEfj6zcHKYyzQf5qbHGmZ4R8Ibgc45LthAqRlJKV0R6mu9cgSbHv 348WcW8GQrD0GL/KLEFaytpUyTPXAhnjLsvBrztr9NtmWD6dO0134hqr42pn2U2CG8cYzSlELJaZm Ndk4uNbblBUZoGYOaPlOZwftbktKU2FDhUmj81ads78iSZxl8ALDz5FmlT7S7cTX2mp79G38SEfJC rmZg3dQA==; Received: from i7.infradead.org ([2001:8b0:10b:1:21e:67ff:fecb:7a92]) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kojNs-00028f-AB; Mon, 14 Dec 2020 08:39:08 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1kojNr-008SyF-SP; Mon, 14 Dec 2020 08:39:07 +0000 From: David Woodhouse To: kvm@vger.kernel.org Cc: Paolo Bonzini , Ankur Arora , Joao Martins , Boris Ostrovsky , Sean Christopherson , graf@amazon.com, iaslan@amazon.de, pdurrant@amazon.com, aagch@amazon.com, fandree@amazon.com Subject: [PATCH v3 16/17] KVM: Add documentation for Xen hypercall and shared_info updates Date: Mon, 14 Dec 2020 08:39:04 +0000 Message-Id: <20201214083905.2017260-17-dwmw2@infradead.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201214083905.2017260-1-dwmw2@infradead.org> References: <20201214083905.2017260-1-dwmw2@infradead.org> MIME-Version: 1.0 Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.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 | 123 +++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index e00a66d72372..d1c30105e6fd 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 +4814,71 @@ 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_id; + __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. Note that although Xen places vcpu_info for the first + 32 vCPUs in the shared_info page, KVM does not automatically do so + and requires that KVM_XEN_ATTR_TYPE_VCPU_INFO be used explicitly + even when the vcpu_info for a given vCPU resides at the "default" + location in the shared_info page. This is because KVM is not aware + of the Xen CPU id which is used as the index into the vcpu_info[] + array, so cannot know the correct default location. + +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 +5375,34 @@ 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 +6490,26 @@ 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.