From: Peter Xu <peterx@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Alexander Graf <graf@amazon.com>,
Aaron Lewis <aaronlewis@google.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: Re: [PATCH] KVM: VMX: Forbid userspace MSR filters for x2APIC
Date: Mon, 19 Oct 2020 13:35:47 -0400 [thread overview]
Message-ID: <20201019173547.GB3203@xz-x1> (raw)
In-Reply-To: <20201019170519.1855564-1-pbonzini@redhat.com>
On Mon, Oct 19, 2020 at 01:05:19PM -0400, Paolo Bonzini wrote:
> Allowing userspace to intercept reads to x2APIC MSRs when APICV is
> fully enabled for the guest simply can't work. But more in general,
> if the LAPIC is in-kernel, allowing accessed by userspace would be very
> confusing. If userspace wants to intercept x2APIC MSRs, then it should
> first disable in-kernel APIC.
>
> We could in principle allow userspace to intercept reads and writes to TPR,
> and writes to EOI and SELF_IPI, but while that could be made it work, it
> would still be silly.
>
> Cc: Alexander Graf <graf@amazon.com>
> Cc: Aaron Lewis <aaronlewis@google.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
next prev parent reply other threads:[~2020-10-19 17:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-19 17:05 [PATCH] KVM: VMX: Forbid userspace MSR filters for x2APIC Paolo Bonzini
2020-10-19 17:35 ` Peter Xu [this message]
2020-10-19 17:45 ` Graf (AWS), Alexander
2020-10-20 9:27 ` Paolo Bonzini
2020-10-20 9:48 ` Alexander Graf
2020-10-20 10:34 ` Paolo Bonzini
2020-10-20 10:52 ` Alexander Graf
2020-10-20 11:49 ` Paolo Bonzini
-- strict thread matches above, loose matches on Subject: below --
2020-10-21 21:36 Paolo Bonzini
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