Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753624Ab1BMPNZ (ORCPT ); Sun, 13 Feb 2011 10:13:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:3454 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750907Ab1BMPNT (ORCPT ); Sun, 13 Feb 2011 10:13:19 -0500 Message-ID: <4D57F4CE.2090804@redhat.com> Date: Sun, 13 Feb 2011 17:12:14 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.7 MIME-Version: 1.0 To: Joerg Roedel CC: Marcelo Tosatti , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Zachary Amsden Subject: Re: [PATCH 6/6] KVM: X86: Implement userspace interface to set virtual_tsc_khz References: <1297272584-22689-1-git-send-email-joerg.roedel@amd.com> <1297272584-22689-7-git-send-email-joerg.roedel@amd.com> In-Reply-To: <1297272584-22689-7-git-send-email-joerg.roedel@amd.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2471 Lines: 95 On 02/09/2011 07:29 PM, Joerg Roedel wrote: > This patch implements two new vm-ioctls to get and set the > virtual_tsc_khz if the machine supports tsc-scaling. Setting > the tsc-frequency is only possible before userspace creates > any vcpu. > > Signed-off-by: Joerg Roedel > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/svm.c | 3 +++ > arch/x86/kvm/x86.c | 38 ++++++++++++++++++++++++++++++++++++++ > include/linux/kvm.h | 4 ++++ > 4 files changed, 46 insertions(+), 0 deletions(-) > Documentation/kvm/api.txt +++++++++++++ > @@ -633,6 +633,7 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes, > u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn); > > extern bool tdp_enabled; > +extern int kvm_has_tsc_control; bool > + case KVM_SET_TSC_KHZ: { > + u32 user_tsc_khz; > + > + if (!kvm_has_tsc_control) > + break; > + > + /* > + * We force the tsc frequency to be set before any > + * vcpu is created > + */ > + if (atomic_read(&kvm->online_vcpus)> 0) > + goto out; What if a vcpu is created here? No locking AFAICS. > + > + user_tsc_khz = arg; > + > + kvm_arch_set_tsc_khz(kvm, user_tsc_khz); > + Error check for impossible values (0, values the tsc multiplier can't reach)? > + r = 0; > + goto out; > + } > + case KVM_GET_TSC_KHZ: { > + > + if (!kvm_has_tsc_control) > + break; > + > + r = -EFAULT; > + if (copy_to_user(argp,&kvm->arch.virtual_tsc_khz, sizeof(__u32))) > + goto out; Should be the return value, no? > + > + r = 0; > + goto out; > + } > > default: > ; > > > @@ -677,6 +678,9 @@ struct kvm_clock_data { > #define KVM_SET_PIT2 _IOW(KVMIO, 0xa0, struct kvm_pit_state2) > /* Available with KVM_CAP_PPC_GET_PVINFO */ > #define KVM_PPC_GET_PVINFO _IOW(KVMIO, 0xa1, struct kvm_ppc_pvinfo) > +/* Available with KVM_CAP_TSC_CONTROL */ > +#define KVM_SET_TSC_KHZ _IOW(KVMIO, 0xa2, __u32) > +#define KVM_GET_TSC_KHZ _IOR(KVMIO, 0xa3, __u32) > _IO() - use arg or return value _IOW/_IOR - copy_to/from_user() pick one, but don't mix. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/