Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753458AbdDKXfX (ORCPT ); Tue, 11 Apr 2017 19:35:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33078 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752010AbdDKXfU (ORCPT ); Tue, 11 Apr 2017 19:35:20 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 886AA61D28 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=bsd@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 886AA61D28 From: Bandan Das To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, david@redhat.com Subject: Re: [PATCH 4/6] kvm: nVMX: support EPT accessed/dirty bits References: <1490867732-16743-1-git-send-email-pbonzini@redhat.com> <1490867732-16743-5-git-send-email-pbonzini@redhat.com> Date: Tue, 11 Apr 2017 19:35:16 -0400 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 11 Apr 2017 23:35:19 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3751 Lines: 107 Paolo Bonzini writes: ... > accessed_dirty = have_ad ? PT_GUEST_ACCESSED_MASK : 0; > + > + /* > + * FIXME: on Intel processors, loads of the PDPTE registers for PAE paging > + * by the MOV to CR instruction are treated as reads and do not cause the > + * processor to set the dirty flag in tany EPT paging-structure entry. > + */ Minor typo: "in any EPT paging-structure entry". > + nested_access = (have_ad ? PFERR_WRITE_MASK : 0) | PFERR_USER_MASK; > + > pt_access = pte_access = ACC_ALL; > ++walker->level; > > @@ -338,7 +337,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, > walker->pte_gpa[walker->level - 1] = pte_gpa; > > real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn), > - PFERR_USER_MASK|PFERR_WRITE_MASK, > + nested_access, > &walker->fault); I can't seem to understand the significance of this change (or for that matter what was before this change). mmu->translate_gpa() just returns gfn_to_gpa(table_gfn), right ? Bandan > /* > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 1c372600a962..6aaecc78dd71 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -2767,6 +2767,8 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx) > vmx->nested.nested_vmx_ept_caps |= VMX_EPT_EXTENT_GLOBAL_BIT | > VMX_EPT_EXTENT_CONTEXT_BIT | VMX_EPT_2MB_PAGE_BIT | > VMX_EPT_1GB_PAGE_BIT; > + if (enable_ept_ad_bits) > + vmx->nested.nested_vmx_ept_caps |= VMX_EPT_AD_BIT; > } else > vmx->nested.nested_vmx_ept_caps = 0; > > @@ -6211,6 +6213,18 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) > > exit_qualification = vmcs_readl(EXIT_QUALIFICATION); > > + if (is_guest_mode(vcpu) > + && !(exit_qualification & EPT_VIOLATION_GVA_TRANSLATED)) { > + /* > + * Fix up exit_qualification according to whether guest > + * page table accesses are reads or writes. > + */ > + u64 eptp = nested_ept_get_cr3(vcpu); > + exit_qualification &= ~EPT_VIOLATION_ACC_WRITE; > + if (eptp & VMX_EPT_AD_ENABLE_BIT) > + exit_qualification |= EPT_VIOLATION_ACC_WRITE; > + } > + > /* > * EPT violation happened while executing iret from NMI, > * "blocked by NMI" bit has to be set before next VM entry. > @@ -9416,17 +9430,26 @@ static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu) > return get_vmcs12(vcpu)->ept_pointer; > } > > -static void nested_ept_init_mmu_context(struct kvm_vcpu *vcpu) > +static int nested_ept_init_mmu_context(struct kvm_vcpu *vcpu) > { > + u64 eptp; > + > WARN_ON(mmu_is_nested(vcpu)); > + eptp = nested_ept_get_cr3(vcpu); > + if ((eptp & VMX_EPT_AD_ENABLE_BIT) && !enable_ept_ad_bits) > + return 1; > + > + kvm_mmu_unload(vcpu); > kvm_init_shadow_ept_mmu(vcpu, > to_vmx(vcpu)->nested.nested_vmx_ept_caps & > - VMX_EPT_EXECUTE_ONLY_BIT); > + VMX_EPT_EXECUTE_ONLY_BIT, > + eptp & VMX_EPT_AD_ENABLE_BIT); > vcpu->arch.mmu.set_cr3 = vmx_set_cr3; > vcpu->arch.mmu.get_cr3 = nested_ept_get_cr3; > vcpu->arch.mmu.inject_page_fault = nested_ept_inject_page_fault; > > vcpu->arch.walk_mmu = &vcpu->arch.nested_mmu; > + return 0; > } > > static void nested_ept_uninit_mmu_context(struct kvm_vcpu *vcpu) > @@ -10188,8 +10211,10 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, > } > > if (nested_cpu_has_ept(vmcs12)) { > - kvm_mmu_unload(vcpu); > - nested_ept_init_mmu_context(vcpu); > + if (nested_ept_init_mmu_context(vcpu)) { > + *entry_failure_code = ENTRY_FAIL_DEFAULT; > + return 1; > + } > } else if (nested_cpu_has2(vmcs12, > SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) { > vmx_flush_tlb_ept_only(vcpu);