From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756634AbbCMAr6 (ORCPT ); Thu, 12 Mar 2015 20:47:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39222 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756588AbbCMArz (ORCPT ); Thu, 12 Mar 2015 20:47:55 -0400 Date: Thu, 12 Mar 2015 21:47:09 -0300 From: Marcelo Tosatti To: Joel Schopp Cc: Gleb Natapov , Paolo Bonzini , kvm@vger.kernel.org, David Kaplan , rkrcmar@redhat.com, Joerg Roedel , linux-kernel@vger.kernel.org, Borislav Petkov Subject: Re: [PATCH v3] x86: svm: use kvm_fast_pio_in() Message-ID: <20150313004709.GA16530@amt.cnet> References: <20150302210202.2951.56810.stgit@joelvmguard2.amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150302210202.2951.56810.stgit@joelvmguard2.amd.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 02, 2015 at 03:02:02PM -0600, Joel Schopp wrote: > From: David Kaplan > > We can make the in instruction go faster the same way the out instruction is > already. > > Changes from v2[Joel]: > * changed rax from u32 to unsigned long > * changed a couple return 0 to BUG_ON() > * changed 8 to sizeof(new_rax) > * added trace hook > * removed redundant clearing of count > Changes from v1[Joel] > * Added kvm_fast_pio_in() implementation that was left out of v1 > > Signed-off-by: David Kaplan > [extracted from larger unlrelated patch, forward ported, addressed reviews, tested] > Signed-off-by: Joel Schopp > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/svm.c | 4 +++- > arch/x86/kvm/x86.c | 30 ++++++++++++++++++++++++++++++ > 3 files changed, 34 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index a236e39..b976824 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -931,6 +931,7 @@ int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr); > struct x86_emulate_ctxt; > > int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size, unsigned short port); > +int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size, unsigned short port); > void kvm_emulate_cpuid(struct kvm_vcpu *vcpu); > int kvm_emulate_halt(struct kvm_vcpu *vcpu); > int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu); > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index d319e0c..f8c906b 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -1899,7 +1899,7 @@ static int io_interception(struct vcpu_svm *svm) > ++svm->vcpu.stat.io_exits; > string = (io_info & SVM_IOIO_STR_MASK) != 0; > in = (io_info & SVM_IOIO_TYPE_MASK) != 0; > - if (string || in) > + if (string) > return emulate_instruction(vcpu, 0) == EMULATE_DONE; > > port = io_info >> 16; > @@ -1907,6 +1907,8 @@ static int io_interception(struct vcpu_svm *svm) > svm->next_rip = svm->vmcb->control.exit_info_2; > skip_emulated_instruction(&svm->vcpu); > > + if (in) > + return kvm_fast_pio_in(vcpu, size, port); > return kvm_fast_pio_out(vcpu, size, port); > } > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index bd7a70b..d05efaf 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -5463,6 +5463,36 @@ int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size, unsigned short port) > } > EXPORT_SYMBOL_GPL(kvm_fast_pio_out); > > +static int complete_fast_pio(struct kvm_vcpu *vcpu) > +{ > + unsigned long new_rax = kvm_register_read(vcpu, VCPU_REGS_RAX); > + > + BUG_ON(!vcpu->arch.pio.count); > + BUG_ON(vcpu->arch.pio.count * vcpu->arch.pio.size > sizeof(new_rax)); > + > + memcpy(&new_rax, vcpu, sizeof(new_rax)); Weird. > + trace_kvm_pio(KVM_PIO_IN, vcpu->arch.pio.port, vcpu->arch.pio.size, > + vcpu->arch.pio.count, vcpu->arch.pio_data); > + kvm_register_write(vcpu, VCPU_REGS_RAX, new_rax); > + vcpu->arch.pio.count = 0; > + return 1; > +} > + > +int kvm_fast_pio_in(struct kvm_vcpu *vcpu, int size, unsigned short port) > +{ > + unsigned long val; Please zero initialize val. Please check sanity of size.