From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757540AbaIIQwo (ORCPT ); Tue, 9 Sep 2014 12:52:44 -0400 Received: from static.88-198-71-155.clients.your-server.de ([88.198.71.155]:51971 "EHLO socrates.bennee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757294AbaIIQwl (ORCPT ); Tue, 9 Sep 2014 12:52:41 -0400 X-Greylist: delayed 1496 seconds by postgrey-1.27 at vger.kernel.org; Tue, 09 Sep 2014 12:52:40 EDT From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: peter.maydell@linaro.org, christoffer.dall@linaro.org, jan.kiszka@siemens.com, dahi@linux.vnet.ibm.com, r65777@freescale.com, marc.zyngier@arm.com, bp@suse.de, pbonzini@redhat.com, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Gleb Natapov , Randy Dunlap , linux-doc@vger.kernel.org (open list:DOCUMENTATION), linux-kernel@vger.kernel.org (open list) 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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ------------------------ -- 2.1.0