From: Paolo Bonzini <pbonzini@redhat.com>
To: Alexander Graf <graf@amazon.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Aaron Lewis <aaronlewis@google.com>, Peter Xu <peterx@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: Re: [PATCH] KVM: VMX: Forbid userspace MSR filters for x2APIC
Date: Tue, 20 Oct 2020 12:34:46 +0200 [thread overview]
Message-ID: <6edd5e08-92c2-40ff-57be-37b92d1ca2bc@redhat.com> (raw)
In-Reply-To: <bce2aee1-bfac-0640-066b-068fa5f12cf8@amazon.de>
On 20/10/20 11:48, Alexander Graf wrote:
>
> count: 1,
> default_allow: false,
> ranges: [
> {
> flags: KVM_MSR_FILTER_READ,
> nmsrs: 1,
> base: MSR_EFER,
> bitmap: { 1 },
> },
> ],
> }
>
> That filter would set all x2apic registers to "deny", but would not be
> caught by the code above. Conversely, a range that explicitly allows
> x2apic ranges with default_allow=0 would be rejected by this patch.
Yes, but the idea is that x2apic registers are always allowed, even
overriding default_allow, and therefore it makes no sense to have them
in a range. The patch is only making things fail early for userspace,
the policy is defined by Sean's patch.
Paolo
next prev parent reply other threads:[~2020-10-20 10:34 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
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 [this message]
2020-10-20 10:52 ` Alexander Graf
2020-10-20 11:49 ` Paolo Bonzini
2020-10-21 21:36 Paolo Bonzini
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