On Wed, Feb 20, 2019 at 03:06:10PM +0100, Vitaly Kuznetsov wrote: > Yu Zhang <yu.c.zh...@linux.intel.com> writes: > > > 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 <yu.c.zh...@linux.intel.com> > > --- > > Cc: Paolo Bonzini <pbonz...@redhat.com> > > Cc: "Radim Krčmář" <rkrc...@redhat.com> > > Cc: Thomas Gleixner <t...@linutronix.de> > > Cc: Ingo Molnar <mi...@redhat.com> > > Cc: Borislav Petkov <b...@alien8.de> > > Cc: "H. Peter Anvin" <h...@zytor.com> > > 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; > > It seems that we can now drop 'valid' from role_ext as maxphyaddr can't > be 0.
Thanks, Vitaly. Yes, we can drop this field. :) > > Reviewed-by: Vitaly Kuznetsov <vkuzn...@redhat.com> > > -- > Vitaly > B.R. Yu