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@xxxxxxxxxxxxxxx>
>> ---
>> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Cc: Borislav Petkov <bp@xxxxxxxxx>
>> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> ---
>> 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
>
