From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935202AbcIPO4r (ORCPT ); Fri, 16 Sep 2016 10:56:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37526 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756048AbcIPO4j (ORCPT ); Fri, 16 Sep 2016 10:56:39 -0400 Subject: Re: [PATCH v2 0/6] kvm: x86: export TSC information to user-space To: Luiz Capitulino , kvm@vger.kernel.org References: <1474036056-21270-1-git-send-email-lcapitulino@redhat.com> Cc: linux-kernel@vger.kernel.org, rkrcmar@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, mtosatti@redhat.com From: Paolo Bonzini Message-ID: Date: Fri, 16 Sep 2016 16:56:34 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1474036056-21270-1-git-send-email-lcapitulino@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Fri, 16 Sep 2016 14:56:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/09/2016 16:27, Luiz Capitulino wrote: > [Introduction will follow] > > Changelog > --------- > > v2 > > - add tsc_offset field to struct kvm_vcpu_arch > - drop read_tsc_offset() > - add per-vcpu dir entries in debugfs > - export TSC scaling info (besides TSC offset) > - export the TSC offset as a signed number > - drop patch that wrongly tried to improve error > handling in kvm_create_vm_debugfs() I've tested this patch on an AMD machine with TSC scaling, so I'm pushing it shortly to kvm/queue. Paolo > Intro > ----- > > This series exports a VM's TSC offset and TSC scaling > information to user-space via a new per-vcpu directory > in debugfs. For example: > > /sys/kernel/debug/kvm/66828-10/vcpu0/tsc-offset > /sys/kernel/debug/kvm/66828-10/vcpu0/tsc-scaling-ratio > /sys/kernel/debug/kvm/66828-10/vcpu0/tsc-scaling-ratio-frac-bits > > The TSC offset in particular is needed in user-space > in order for tracing tools, such as trace-cmd, to be > able to merge the host and guest traces using the > host TSC. This is explained in detail in this thread: > > [Qemu-devel] [RFC] host and guest kernel trace merging > https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg00887.html > > Luiz Capitulino (6): > kvm: x86: add tsc_offset field to struct kvm_vcpu_arch > kvm: x86: drop read_tsc_offset() > kvm: kvm_destroy_vm_debugfs(): check debugfs_stat_data pointer > kvm: add stubs for arch specific debugfs support > kvm: create per-vcpu dirs in debugfs > kvm: x86: export TSC information to user-space > > arch/arm/kvm/arm.c | 10 ++++++ > arch/mips/kvm/mips.c | 10 ++++++ > arch/powerpc/kvm/powerpc.c | 10 ++++++ > arch/s390/kvm/kvm-s390.c | 10 ++++++ > arch/x86/include/asm/kvm_host.h | 2 +- > arch/x86/kvm/Makefile | 2 +- > arch/x86/kvm/debugfs.c | 69 +++++++++++++++++++++++++++++++++++++++++ > arch/x86/kvm/svm.c | 8 ----- > arch/x86/kvm/vmx.c | 6 ---- > arch/x86/kvm/x86.c | 12 +++++-- > include/linux/kvm_host.h | 4 +++ > virt/kvm/kvm_main.c | 40 ++++++++++++++++++++++-- > 12 files changed, 161 insertions(+), 22 deletions(-) > create mode 100644 arch/x86/kvm/debugfs.c >