From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71E7CC17440 for ; Tue, 12 Nov 2019 11:10:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E2642084E for ; Tue, 12 Nov 2019 11:10:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727196AbfKLLKu (ORCPT ); Tue, 12 Nov 2019 06:10:50 -0500 Received: from proxmox-new.maurer-it.com ([212.186.127.180]:33524 "EHLO proxmox-new.maurer-it.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727180AbfKLLKp (ORCPT ); Tue, 12 Nov 2019 06:10:45 -0500 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 3B811467A0; Tue, 12 Nov 2019 12:10:44 +0100 (CET) Subject: Re: [PATCH 4.19 STABLE] KVM: x86: introduce is_pae_paging To: Sean Christopherson , stable@vger.kernel.org, Greg Kroah-Hartman Cc: Paolo Bonzini , linux-kernel@vger.kernel.org References: <20191111225423.29309-1-sean.j.christopherson@intel.com> From: Thomas Lamprecht Message-ID: <4d382b90-34d8-5a4d-1f62-b9dcb479e2ed@proxmox.com> Date: Tue, 12 Nov 2019 12:10:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:71.0) Gecko/20100101 Thunderbird/71.0 MIME-Version: 1.0 In-Reply-To: <20191111225423.29309-1-sean.j.christopherson@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/11/19 11:54 PM, Sean Christopherson wrote: > From: Paolo Bonzini > > Upstream commit bf03d4f9334728bf7c8ffc7de787df48abd6340e. > > Checking for 32-bit PAE is quite common around code that fiddles with > the PDPTRs. Add a function to compress all checks into a single > invocation. > > Moving to the common helper also fixes a subtle bug in kvm_set_cr3() > where it fails to check is_long_mode() and results in KVM incorrectly > attempting to load PDPTRs for a 64-bit guest. > > Reviewed-by: Sean Christopherson > Signed-off-by: Paolo Bonzini > [sean: backport to 4.x; handle vmx.c split in 5.x, call out the bugfix] > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/vmx.c | 7 +++---- > arch/x86/kvm/x86.c | 8 ++++---- > arch/x86/kvm/x86.h | 5 +++++ > 3 files changed, 12 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 6f7b3acdab26..83acaed244ba 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -5181,7 +5181,7 @@ static void ept_load_pdptrs(struct kvm_vcpu *vcpu) > (unsigned long *)&vcpu->arch.regs_dirty)) > return; > > - if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) { > + if (is_pae_paging(vcpu)) { > vmcs_write64(GUEST_PDPTR0, mmu->pdptrs[0]); > vmcs_write64(GUEST_PDPTR1, mmu->pdptrs[1]); > vmcs_write64(GUEST_PDPTR2, mmu->pdptrs[2]); > @@ -5193,7 +5193,7 @@ static void ept_save_pdptrs(struct kvm_vcpu *vcpu) > { > struct kvm_mmu *mmu = vcpu->arch.walk_mmu; > > - if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) { > + if (is_pae_paging(vcpu)) { > mmu->pdptrs[0] = vmcs_read64(GUEST_PDPTR0); > mmu->pdptrs[1] = vmcs_read64(GUEST_PDPTR1); > mmu->pdptrs[2] = vmcs_read64(GUEST_PDPTR2); > @@ -12021,8 +12021,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne > * If PAE paging and EPT are both on, CR3 is not used by the CPU and > * must not be dereferenced. > */ > - if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu) && > - !nested_ept) { > + if (is_pae_paging(vcpu) && !nested_ept) { > if (!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) { > *entry_failure_code = ENTRY_FAIL_PDPTE; > return 1; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 6ae8a013af31..b9b87fb75ac0 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -633,7 +633,7 @@ bool pdptrs_changed(struct kvm_vcpu *vcpu) > gfn_t gfn; > int r; > > - if (is_long_mode(vcpu) || !is_pae(vcpu) || !is_paging(vcpu)) > + if (!is_pae_paging(vcpu)) > return false; > > if (!test_bit(VCPU_EXREG_PDPTR, > @@ -884,8 +884,8 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) > if (is_long_mode(vcpu) && > (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63))) > return 1; > - else if (is_pae(vcpu) && is_paging(vcpu) && > - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) > + else if (is_pae_paging(vcpu) && > + !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) > return 1; > > kvm_mmu_new_cr3(vcpu, cr3, skip_tlb_flush); > @@ -8312,7 +8312,7 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) > kvm_update_cpuid(vcpu); > > idx = srcu_read_lock(&vcpu->kvm->srcu); > - if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu)) { > + if (is_pae_paging(vcpu)) { > load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu)); > mmu_reset_needed = 1; > } > diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h > index 3a91ea760f07..608e5f8c5d0a 100644 > --- a/arch/x86/kvm/x86.h > +++ b/arch/x86/kvm/x86.h > @@ -139,6 +139,11 @@ static inline int is_paging(struct kvm_vcpu *vcpu) > return likely(kvm_read_cr0_bits(vcpu, X86_CR0_PG)); > } > > +static inline bool is_pae_paging(struct kvm_vcpu *vcpu) > +{ > + return !is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu); > +} > + > static inline u32 bit(int bitno) > { > return 1 << (bitno & 31); > Thanks for the fast and good answer and the backport, made things more clear here. Cannot reproduce the issues with that patch anymore Tested-by: Thomas Lamprecht