From patchwork Tue Aug 7 07:39:59 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Raghavendra K T X-Patchwork-Id: 1283971 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 0621A40B00 for ; Tue, 7 Aug 2012 07:43:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752186Ab2HGHnC (ORCPT ); Tue, 7 Aug 2012 03:43:02 -0400 Received: from e23smtp05.au.ibm.com ([202.81.31.147]:58052 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751124Ab2HGHmr (ORCPT ); Tue, 7 Aug 2012 03:42:47 -0400 Received: from /spool/local by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Peter Anvin" , KVM , Raghavendra K T , Avi Kivity , Gleb Natapov , Ingo Molnar , Marcelo Tosatti , Jan Kiszka , Thomas Gleixner , X86 Date: Tue, 07 Aug 2012 13:09:59 +0530 Message-Id: <20120807073959.20169.86246.sendpatchset@codeblue.in.ibm.com> In-Reply-To: <20120807073946.20169.72958.sendpatchset@codeblue.in.ibm.com> References: <20120807073946.20169.72958.sendpatchset@codeblue.in.ibm.com> Subject: [PATCH 1/3] Documentation/kvm : Add documentation on hypercalls x-cbid: 12080707-1396-0000-0000-000001AD15DF Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Raghavendra K T Thanks Alex for KVM_HC_FEATURES inputs and Jan for VAPIC_POLL_IRQ, and Peter (HPA) for suggesting hypercall ABI addition. Signed-off-by: Raghavendra K T --- TODO: We need to add history details of each hypercall as suggested by HPA, which I could not trace easily. Hope it is easy for hypercall authors Documentation/virtual/kvm/hypercalls.txt | 66 ++++++++++++++++++++++++++++++ 1 files changed, 66 insertions(+), 0 deletions(-) create mode 100644 Documentation/virtual/kvm/hypercalls.txt -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt new file mode 100644 index 0000000..ea113b5 --- /dev/null +++ b/Documentation/virtual/kvm/hypercalls.txt @@ -0,0 +1,66 @@ +Linux KVM Hypercall: +=================== +X86: + KVM Hypercalls have a three-byte sequence of either the vmcall or the vmmcall + instruction. The hypervisor can replace it with instructions that are + guaranteed to be supported. + + Up to four arguments may be passed in rbx, rcx, rdx, and rsi respectively. + The hypercall number should be placed in rax and the return value will be + placed in rax. No other registers will be clobbered unless explicitly stated + by the particular hypercall. + +S390: + R2-R7 are used for parameters 1-6. In addition, R1 is used for hypercall + number. The return value is written to R2. + + S390 uses diagnose instruction as hypercall (0x500) along with hypercall + number in R1. + + PowerPC: + It uses R3-R10 and hypercall number in R11. R4-R11 are used as output registers. + Return value is placed in R3. + + KVM hypercalls uses 4 byte opcode, that are patched with 'hypercall-instructions' + property inside the device tree's /hypervisor node. + For more information refer to Documentation/virtual/kvm/ppc-pv.txt + +KVM Hypercalls Documentation +=========================== +The template for each hypercall is: +1. Hypercall name. +2. Architecture(s) +3. Status (deprecated, obsolete, active) +4. Purpose + +1. KVM_HC_VAPIC_POLL_IRQ +------------------------ +Architecture: x86 +Status: active +Purpose: Trigger guest exit so that the host can check for pending +interrupts on reentry. + +2. KVM_HC_MMU_OP +------------------------ +Architecture: x86 +Status: deprecated. +Purpose: Support MMU operations such as writing to PTE, +flushing TLB, release PT. + +3. KVM_HC_FEATURES +------------------------ +Architecture: PPC +Status: active +Purpose: Expose hypercall availability to the guest. On x86 platforms, cpuid +used to enumerate which hypercalls are available. On PPC, either device tree +based lookup ( which is also what EPAPR dictates) OR KVM specific enumeration +mechanism (which is this hypercall) can be used. + +4. KVM_HC_PPC_MAP_MAGIC_PAGE +------------------------ +Architecture: PPC +Status: active +Purpose: To enable communication between the hypervisor and guest there is a +shared page that contains parts of supervisor visible register state. +The guest can map this shared page to access its supervisor register through +memory using this hypercall.