From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yu Zhang Subject: Re: [PATCH] KVM: MMU: record maximum physical address width in kvm_mmu_extended_role Date: Wed, 20 Feb 2019 15:06:21 +0800 Message-ID: <20190220070621.meka6jyjpdreh2ed@linux.intel.com> References: <1548950963-18414-1-git-send-email-yu.c.zhang@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: kvm@vger.kernel.org, Radim =?utf-8?B?S3LEjW3DocWZ?= , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-kernel@vger.kernel.org To: Paolo Bonzini Return-path: Content-Disposition: inline In-Reply-To: <1548950963-18414-1-git-send-email-yu.c.zhang@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Hi Paolo, any comments on this patch? And the other one(kvm: x86: Return LA57 feature based on hardware capability )? :-) On Fri, Feb 01, 2019 at 12:09:23AM +0800, Yu Zhang wrote: > Previously, commit 7dcd57552008 ("x86/kvm/mmu: check if tdp/shadow > MMU reconfiguration is needed") offered some optimization to avoid > the unnecessary reconfiguration. Yet one scenario is broken - when > cpuid changes VM's maximum physical address width, reconfiguration > is needed to reset the reserved bits. Also, the TDP may need to > reset its shadow_root_level when this value is changed. > > To fix this, a new field, maxphyaddr, is introduced in the extended > role structure to keep track of the configured guest physical address > width. > > Signed-off-by: Yu Zhang > --- > Cc: Paolo Bonzini > Cc: "Radim Krčmář" > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: "H. Peter Anvin" > Cc: linux-kernel@vger.kernel.org > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/mmu.c | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 4660ce9..be87f71 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -299,6 +299,7 @@ struct kvm_mmu_memory_cache { > unsigned int cr4_smap:1; > unsigned int cr4_smep:1; > unsigned int cr4_la57:1; > + unsigned int maxphyaddr:6; > }; > }; > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c > index ce770b4..2b74505 100644 > --- a/arch/x86/kvm/mmu.c > +++ b/arch/x86/kvm/mmu.c > @@ -4769,6 +4769,7 @@ static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu) > ext.cr4_pse = !!is_pse(vcpu); > ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE); > ext.cr4_la57 = !!kvm_read_cr4_bits(vcpu, X86_CR4_LA57); > + ext.maxphyaddr = cpuid_maxphyaddr(vcpu); > > ext.valid = 1; > > -- > 1.9.1 > Thanks Yu