From: Paolo Bonzini <pbonzini@redhat.com>
To: Emanuele Giuseppe Esposito <eesposit@redhat.com>, kvm@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/4] KVM: nSVM: avoid TOC/TOU race when checking vmcb12
Date: Tue, 28 Sep 2021 18:52:47 +0200 [thread overview]
Message-ID: <41b9a6c6-37b0-5d23-ebfb-134af360ebf9@redhat.com> (raw)
In-Reply-To: <20210917120329.2013766-1-eesposit@redhat.com>
On 17/09/21 14:03, Emanuele Giuseppe Esposito wrote:
> Currently there is a TOC/TOU race between the check of vmcb12's
> efer, cr0 and cr4 registers and the later save of their values in
> svm_set_*, because the guest could modify the values in the meanwhile.
>
> To solve this issue, this serie introuces and uses svm->nested.save
> structure in enter_svm_guest_mode to save the current value of efer,
> cr0 and cr4 and later use these to set the vcpu->arch.* state.
>
> Patch 1 just refactor the code to simplify the next two patches,
> patch 2 introduces svm->nested.save to cache the efer, cr0 and cr4 fields
> and in patch 3 and 4 we use it to avoid TOC/TOU races.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Most of my remarks from the RFC still apply, so I will wait for v3.
Thanks, and sorry for the time between send and review.
Paolo
prev parent reply other threads:[~2021-09-28 16:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-17 12:03 Emanuele Giuseppe Esposito
2021-09-17 12:03 ` [PATCH v2 1/4] KVM: nSVM: move nested_vmcb_check_cr3_cr4 logic in nested_vmcb_valid_sregs Emanuele Giuseppe Esposito
2021-09-17 12:03 ` [PATCH v2 2/4] nSVM: introduce smv->nested.save to cache save area fields Emanuele Giuseppe Esposito
2021-09-28 16:51 ` Paolo Bonzini
2021-09-17 12:03 ` [PATCH v2 3/4] nSVM: use vmcb_save_area_cached in nested_vmcb_valid_sregs() Emanuele Giuseppe Esposito
2021-09-17 12:03 ` [PATCH v2 4/4] nSVM: use svm->nested.save to load vmcb12 registers and avoid TOC/TOU races Emanuele Giuseppe Esposito
2021-09-28 16:52 ` Paolo Bonzini [this message]
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