Messages in this thread | | | Date | Tue, 3 Oct 2023 10:17:53 +0700 | Subject | Re: [PATCH v2 1/4] x86: KVM: SVM: always update the x2avic msr interception | From | "Suthikulpanit, Suravee" <> |
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Maxim,
Thanks for finding and fixing this.
On 9/29/2023 7:24 AM, Sean Christopherson wrote: > On Thu, Sep 28, 2023, Maxim Levitsky wrote: >> The following problem exists since x2avic was enabled in the KVM: >> >> svm_set_x2apic_msr_interception is called to enable the interception of > > Nit, svm_set_x2apic_msr_interception(). > > Definitely not worth another version though. > >> the x2apic msrs. >> >> In particular it is called at the moment the guest resets its apic. >> >> Assuming that the guest's apic was in x2apic mode, the reset will bring >> it back to the xapic mode. >> >> The svm_set_x2apic_msr_interception however has an erroneous check for >> '!apic_x2apic_mode()' which prevents it from doing anything in this case. >> >> As a result of this, all x2apic msrs are left unintercepted, and that >> exposes the bare metal x2apic (if enabled) to the guest. >> Oops. >> >> Remove the erroneous '!apic_x2apic_mode()' check to fix that. >> >> This fixes CVE-2023-5090 >> >> Fixes: 4d1d7942e36a ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode") >> Cc: stable@vger.kernel.org >> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> >> --- > > Reviewed-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
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