From: Yu Zhang <yu.c.zhang@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, "Radim Krčmář" <rkrcmar@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: MMU: record maximum physical address width in kvm_mmu_extended_role
Date: Wed, 20 Feb 2019 15:06:21 +0800 [thread overview]
Message-ID: <20190220070621.meka6jyjpdreh2ed@linux.intel.com> (raw)
In-Reply-To: <1548950963-18414-1-git-send-email-yu.c.zhang@linux.intel.com>
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
next prev parent reply other threads:[~2019-02-20 7:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-31 16:09 [PATCH] KVM: MMU: record maximum physical address width in kvm_mmu_extended_role Yu Zhang
2019-02-20 7:06 ` Yu Zhang [this message]
2019-02-22 18:24 ` Paolo Bonzini
2019-02-20 14:06 ` Vitaly Kuznetsov
2019-02-21 6:58 ` Yu Zhang
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