| Message ID | 1548950963-18414-1-git-send-email-yu.c.zhang@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: MMU: record maximum physical address width in kvm_mmu_extended_role | expand |
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 <yu.c.zhang@linux.intel.com> > --- > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: "Radim Krčmář" <rkrcmar@redhat.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Borislav Petkov <bp@alien8.de> > Cc: "H. Peter Anvin" <hpa@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; > > -- > 1.9.1 > Thanks Yu
Yu Zhang <yu.c.zhang@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.zhang@linux.intel.com> > --- > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: "Radim Krčmář" <rkrcmar@redhat.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Borislav Petkov <bp@alien8.de> > Cc: "H. Peter Anvin" <hpa@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. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
On Wed, Feb 20, 2019 at 03:06:10PM +0100, Vitaly Kuznetsov wrote: > Yu Zhang <yu.c.zhang@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.zhang@linux.intel.com> > > --- > > Cc: Paolo Bonzini <pbonzini@redhat.com> > > Cc: "Radim Krčmář" <rkrcmar@redhat.com> > > Cc: Thomas Gleixner <tglx@linutronix.de> > > Cc: Ingo Molnar <mingo@redhat.com> > > Cc: Borislav Petkov <bp@alien8.de> > > Cc: "H. Peter Anvin" <hpa@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 <vkuznets@redhat.com> > > -- > Vitaly > B.R. Yu
On 20/02/19 08:06, Yu Zhang wrote: > Hi Paolo, any comments on this patch? And the other one(kvm: x86: Return > LA57 feature based on hardware capability )? :-) Queued both, thanks. Paolo > 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 <yu.c.zhang@linux.intel.com> >> --- >> Cc: Paolo Bonzini <pbonzini@redhat.com> >> Cc: "Radim Krčmář" <rkrcmar@redhat.com> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: Borislav Petkov <bp@alien8.de> >> Cc: "H. Peter Anvin" <hpa@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; >> >> -- >> 1.9.1 >> > > Thanks > Yu >
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;
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.zhang@linux.intel.com> --- Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@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(+)