From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750942AbaHTHN4 (ORCPT ); Wed, 20 Aug 2014 03:13:56 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:37997 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750789AbaHTHNy (ORCPT ); Wed, 20 Aug 2014 03:13:54 -0400 Message-ID: <53F44AAD.5020203@redhat.com> Date: Wed, 20 Aug 2014 09:13:49 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.7.0 MIME-Version: 1.0 To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org CC: linux-kernel@vger.kernel.org, Gleb Natapov , Raghavendra KT , Vinod Chegu , Hui-Zhi Subject: Re: [PATCH 3/9] KVM: VMX: make PLE window per-vcpu References: <1408480536-8240-1-git-send-email-rkrcmar@redhat.com> <1408480536-8240-4-git-send-email-rkrcmar@redhat.com> In-Reply-To: <1408480536-8240-4-git-send-email-rkrcmar@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 19/08/2014 22:35, Radim Krčmář ha scritto: > Change PLE window into per-vcpu variable, seeded from module parameter, > to allow greater flexibility. > > Brings in a small overhead on every vmentry. > > Signed-off-by: Radim Krčmář > --- > I've been thinking about a general hierarchical per-vcpu variable model, > but it's hard to have current performance and sane code. > > arch/x86/kvm/vmx.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 2b306f9..eaa5574 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -484,6 +484,9 @@ struct vcpu_vmx { > > /* Support for a guest hypervisor (nested VMX) */ > struct nested_vmx nested; > + > + /* Dynamic PLE window. */ > + int ple_window; > }; > > enum segment_cache_field { > @@ -4403,6 +4406,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) > if (ple_gap) { > vmcs_write32(PLE_GAP, ple_gap); > vmcs_write32(PLE_WINDOW, ple_window); Is this necessary? > + vmx->ple_window = ple_window; > } > > vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, 0); > @@ -7387,6 +7391,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) > if (vmx->emulation_required) > return; > > + if (ple_gap) > + vmcs_write32(PLE_WINDOW, vmx->ple_window); > + > if (vmx->nested.sync_shadow_vmcs) { > copy_vmcs12_to_shadow(vmx); > vmx->nested.sync_shadow_vmcs = false; >