Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752621AbdLLQDC (ORCPT ); Tue, 12 Dec 2017 11:03:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50972 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752584AbdLLQC4 (ORCPT ); Tue, 12 Dec 2017 11:02:56 -0500 Subject: Re: [PATCH v2] KVM: VMX: drop I/O permission bitmaps To: Quan Xu , kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, rkrcmar@redhat.com, jmattson@google.com, david@redhat.com References: <1513068261-2019-1-git-send-email-quan.xu0@gmail.com> From: Paolo Bonzini Message-ID: <73c19457-52ec-3807-940a-4a38defd6849@redhat.com> Date: Tue, 12 Dec 2017 17:02:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <1513068261-2019-1-git-send-email-quan.xu0@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 12 Dec 2017 16:02:56 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3326 Lines: 95 On 12/12/2017 09:44, Quan Xu wrote: > From: Quan Xu > > Since KVM removes the only I/O port 0x80 bypass on Intel hosts, > clear CPU_BASED_USE_IO_BITMAPS and set CPU_BASED_UNCOND_IO_EXITING > bit. Then these I/O permission bitmaps are not used at all, so > drop I/O permission bitmaps. > > Signed-off-by: Jim Mattson > Signed-off-by: Radim Krčmář > Signed-off-by: Quan Xu > --- > arch/x86/kvm/vmx.c | 15 +-------------- > 1 files changed, 1 insertions(+), 14 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 2fd9a8c..41aaf5e 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -943,8 +943,6 @@ static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12, > static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock); > > enum { > - VMX_IO_BITMAP_A, > - VMX_IO_BITMAP_B, > VMX_MSR_BITMAP_LEGACY, > VMX_MSR_BITMAP_LONGMODE, > VMX_MSR_BITMAP_LEGACY_X2APIC_APICV, > @@ -958,8 +956,6 @@ enum { > > static unsigned long *vmx_bitmap[VMX_BITMAP_NR]; > > -#define vmx_io_bitmap_a (vmx_bitmap[VMX_IO_BITMAP_A]) > -#define vmx_io_bitmap_b (vmx_bitmap[VMX_IO_BITMAP_B]) > #define vmx_msr_bitmap_legacy (vmx_bitmap[VMX_MSR_BITMAP_LEGACY]) > #define vmx_msr_bitmap_longmode (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE]) > #define vmx_msr_bitmap_legacy_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC_APICV]) > @@ -3632,7 +3628,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf) > #endif > CPU_BASED_CR3_LOAD_EXITING | > CPU_BASED_CR3_STORE_EXITING | > - CPU_BASED_USE_IO_BITMAPS | > + CPU_BASED_UNCOND_IO_EXITING | > CPU_BASED_MOV_DR_EXITING | > CPU_BASED_USE_TSC_OFFSETING | > CPU_BASED_INVLPG_EXITING | > @@ -5445,10 +5441,6 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx) > #endif > int i; > > - /* I/O */ > - vmcs_write64(IO_BITMAP_A, __pa(vmx_io_bitmap_a)); > - vmcs_write64(IO_BITMAP_B, __pa(vmx_io_bitmap_b)); > - > if (enable_shadow_vmcs) { > vmcs_write64(VMREAD_BITMAP, __pa(vmx_vmread_bitmap)); > vmcs_write64(VMWRITE_BITMAP, __pa(vmx_vmwrite_bitmap)); > @@ -6751,14 +6743,9 @@ static __init int hardware_setup(void) > goto out; > } > > - vmx_io_bitmap_b = (unsigned long *)__get_free_page(GFP_KERNEL); > memset(vmx_vmread_bitmap, 0xff, PAGE_SIZE); > memset(vmx_vmwrite_bitmap, 0xff, PAGE_SIZE); > > - memset(vmx_io_bitmap_a, 0xff, PAGE_SIZE); > - > - memset(vmx_io_bitmap_b, 0xff, PAGE_SIZE); > - > memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE); > memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE); > > Squashing this for documentation: diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 51967236486e..b016cf1b9f77 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -10551,8 +10551,8 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, } /* - * Merging of IO bitmap not currently supported. - * Rather, exit every time. + * A vmexit (to either L1 hypervisor or L0 userspace) is always needed + * for I/O port accesses. */ exec_control &= ~CPU_BASED_USE_IO_BITMAPS; exec_control |= CPU_BASED_UNCOND_IO_EXITING; Thanks, Paolo