From: Sean Christopherson <seanjc@google.com>
To: Jim Mattson <jmattson@google.com>
Cc: kvm@vger.kernel.org, pbonzini@redhat.com
Subject: Re: [PATCH v2 0/2] KVM: nVMX: Add IBPB between L2 and L1 to
Date: Fri, 2 Dec 2022 19:21:46 +0000 [thread overview]
Message-ID: <Y4pQSnFOQSoB80K1@google.com> (raw)
In-Reply-To: <20221019213620.1953281-1-jmattson@google.com>
On Wed, Oct 19, 2022, Jim Mattson wrote:
> Since L1 and L2 share branch prediction modes (guest {kernel,user}), the
> hardware will not protect indirect branches in L1 from steering by a
> malicious agent in L2. However, IBRS guarantees this protection. (For
> basic IBRS, a value of 1 must be written to IA32_SPEC_CTRL.IBRS after
> the transition from L2 to L1.)
>
> Fix the regression introduced in commit 5c911beff20a ("KVM: nVMX: Skip
> IBPB when switching between vmcs01 and vmcs02") by issuing an IBPB when
> emulating a VM-exit from L2 to L1.
>
> This is CVE-2022-2196.
>
> v2: Reworded some comments [Sean].
>
> Jim Mattson (2):
> KVM: VMX: Guest usage of IA32_SPEC_CTRL is likely
> KVM: VMX: Execute IBPB on emulated VM-exit when guest has IBRS
>
> arch/x86/kvm/vmx/nested.c | 11 +++++++++++
> arch/x86/kvm/vmx/vmx.c | 10 ++++++----
> 2 files changed, 17 insertions(+), 4 deletions(-)
>
> --
Merged to kvm/queue, thanks!
https://lore.kernel.org/all/Y4lHxds8pvBhxXFX@google.com
prev parent reply other threads:[~2022-12-02 19:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-19 21:36 [PATCH v2 0/2] KVM: nVMX: Add IBPB between L2 and L1 to Jim Mattson
2022-10-19 21:36 ` [PATCH v2 1/2] KVM: VMX: Guest usage of IA32_SPEC_CTRL is likely Jim Mattson
2022-11-01 19:23 ` Sean Christopherson
2022-10-19 21:36 ` [PATCH v2 2/2] KVM: VMX: Execute IBPB on emulated VM-exit when guest has IBRS Jim Mattson
2022-11-01 19:23 ` Sean Christopherson
2022-11-01 18:50 ` [PATCH v2 0/2] KVM: nVMX: Add IBPB between L2 and L1 to Jim Mattson
2022-12-02 19:21 ` Sean Christopherson [this message]
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