From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [RFC PATCH v3 2/2] add support for Hyper-V partition reference time enlightenment Date: Mon, 09 Dec 2013 15:32:55 +0100 Message-ID: <52A5D497.1070308@redhat.com> References: <1386502419-26614-1-git-send-email-vrozenfe@redhat.com> <1386502419-26614-3-git-send-email-vrozenfe@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, mtosatti@redhat.com, pl@dlhnet.de To: Vadim Rozenfeld Return-path: Received: from mail-qc0-f170.google.com ([209.85.216.170]:45943 "EHLO mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761057Ab3LIOdA (ORCPT ); Mon, 9 Dec 2013 09:33:00 -0500 Received: by mail-qc0-f170.google.com with SMTP id x13so2790675qcv.1 for ; Mon, 09 Dec 2013 06:32:59 -0800 (PST) In-Reply-To: <1386502419-26614-3-git-send-email-vrozenfe@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 08/12/2013 12:33, Vadim Rozenfeld ha scritto: > + tsc_ref.tsc_sequence = > + boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ? 1 : 0; > + tsc_ref.tsc_scale = > + ((10000LL << 32) / vcpu->arch.virtual_tsc_khz) << 32; > + tsc_ref.tsc_offset = 0; > if (__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref))) > return 1; > mark_page_dirty(kvm, gfn); > kvm->arch.hv_tsc_page = data; > + kvm->arch.hv_ref_count = 0; > break; > } > default: > @@ -3879,6 +3884,19 @@ long kvm_arch_vm_ioctl(struct file *filp, > local_irq_enable(); > kvm->arch.kvmclock_offset = delta; > kvm_gen_update_masterclock(kvm); > + > + if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) { > + HV_REFERENCE_TSC_PAGE* tsc_ref; > + u64 curr_time; > + tsc_ref = (HV_REFERENCE_TSC_PAGE*)gfn_to_hva(kvm, > + kvm->arch.hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT); > + tsc_ref->tsc_sequence = > + boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ? tsc_ref->tsc_sequence + 1 : 0; > + tsc_ref->tsc_scale = ((10000LL << 32) / __get_cpu_var(cpu_tsc_khz)) << 32; Why shouldn't this be vcpu->arch.virtual_tsc_khz? > + curr_time = (((tsc_ref->tsc_scale >> 32) * native_read_tsc()) >> 32) + > + tsc_ref->tsc_offset; > + tsc_ref->tsc_offset = kvm->arch.hv_ref_time - curr_time; > + } The difference in setting tsc_ref->tsc_scale is the only important change between the two occurrences. If you can avoid that difference and you move this to a separate function, you can reuse that new function in set_msr_hyperv_pw as well. Also, kvm_set_tsc_khz should recompute the reference page's values as well, so you'd have three uses. Paolo