From patchwork Tue Sep 9 16:27:18 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Alex_Benn=C3=A9e?= X-Patchwork-Id: 4871611 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id DF1FA9F371 for ; Tue, 9 Sep 2014 16:30:11 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F1A0820179 for ; Tue, 9 Sep 2014 16:30:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AB03F20166 for ; Tue, 9 Sep 2014 16:30:05 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XROHF-0005om-O6; Tue, 09 Sep 2014 16:28:21 +0000 Received: from static.88-198-71-155.clients.your-server.de ([88.198.71.155] helo=socrates.bennee.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XROH6-0005ep-Hy for linux-arm-kernel@lists.infradead.org; Tue, 09 Sep 2014 16:28:13 +0000 Received: from localhost ([127.0.0.1] helo=zen.linaro.local) by socrates.bennee.com with esmtp (Exim 4.80) (envelope-from ) id 1XROaE-0007mw-GQ; Tue, 09 Sep 2014 18:47:58 +0200 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/2] KVM: document KVM_SET_GUEST_DEBUG api Date: Tue, 9 Sep 2014 17:27:18 +0100 Message-Id: <1410280039-2823-2-git-send-email-alex.bennee@linaro.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1410280039-2823-1-git-send-email-alex.bennee@linaro.org> References: <1410280039-2823-1-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 127.0.0.1 X-SA-Exim-Mail-From: alex.bennee@linaro.org X-SA-Exim-Scanned: No (on socrates.bennee.com); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140909_092812_771596_A74FDBFB X-CRM114-Status: GOOD ( 12.71 ) X-Spam-Score: 0.0 (/) Cc: peter.maydell@linaro.org, Randy Dunlap , "open list:DOCUMENTATION" , marc.zyngier@arm.com, jan.kiszka@siemens.com, Gleb Natapov , open list , dahi@linux.vnet.ibm.com, r65777@freescale.com, pbonzini@redhat.com, bp@suse.de, =?UTF-8?q?Alex=20Benn=C3=A9e?= , christoffer.dall@linaro.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In preparation for working on the ARM implementation I noticed the debug interface was missing from the API document. I've pieced together the expected behaviour from the code and commit messages written it up as best I can. Signed-off-by: Alex Bennée diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index d3dde61..723d3f3 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2575,6 +2575,50 @@ associated with the service will be forgotten, and subsequent RTAS calls by the guest for that service will be passed to userspace to be handled. +4.87 KVM_SET_GUEST_DEBUG + +Capability: KVM_CAP_SET_GUEST_DEBUG +Architectures: x86, s390, ppc +Type: vcpu ioctl +Parameters: struct kvm_guest_debug (in) +Returns: 0 on success; -1 on error + +struct kvm_guest_debug { + __u32 control; + __u32 pad; + struct kvm_guest_debug_arch arch; +}; + +Set up the processor specific debug registers and configure vcpu for +handling guest debug events. There are two parts to the structure, the +first a control bitfield indicates the type of debug events to handle +when running. Common control bits are: + + - KVM_GUESTDBG_ENABLE: guest debugging is enabled + - KVM_GUESTDBG_SINGLESTEP: the next run should single-step + +The top 16 bits of the control field are architecture specific control +flags which can include the following: + + - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86] + - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390] + - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] + - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] + - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390] + +For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints +are enabled in memory so we need to ensure breakpoint exceptions are +correctly trapped and the KVM run loop exits at the breakpoint and not +running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP +we need to ensure the guest vCPUs architecture specific registers are +updated to the correct (supplied) values. + +The second part of the structure is architecture specific and +typically contains a set of debug registers. + +When debug events exit the main run loop with the reason +KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run +structure containing architecture specific debug information. 5. The kvm_run structure ------------------------