From: Anthony Liguori <anthony@codemonkey.ws>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Avi Kivity <avi@redhat.com>, kvm-devel <kvm@vger.kernel.org>
Subject: Re: [PATCH] KVM: x86: Disallow hypercalls for guest callers in rings > 0
Date: Mon, 03 Aug 2009 09:04:53 -0500 [thread overview]
Message-ID: <4A76EE85.1090404@codemonkey.ws> (raw)
In-Reply-To: <4A76EA7B.4080509@siemens.com>
Jan Kiszka wrote:
> So far unprivileged guest callers running in ring 3 can issue, e.g., MMU
> hypercalls. Normally, such callers cannot provide any hand-crafted MMU
> command structure as it has to be passed by its physical address, but
> they can still crash the guest kernel by passing random addresses.
>
> To close the hole, this patch considers hypercalls valid only if issued
> from guest ring 0. This may still be relaxed on a per-hypercall base in
> the future once required.
>
Actually, VT mandates that vmcalls can only be done from CPL=0.
SVM allows hypercalls from CPL>0 unfortunately.
Regards,
Anthony Liguori
next prev parent reply other threads:[~2009-08-03 14:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-03 13:47 [PATCH] KVM: x86: Disallow hypercalls for guest callers in rings > 0 Jan Kiszka
2009-08-03 14:04 ` Anthony Liguori [this message]
2009-08-03 14:24 ` Avi Kivity
2009-08-03 15:04 ` Anthony Liguori
2009-08-03 16:01 ` Avi Kivity
2009-08-03 14:27 ` Avi Kivity
2009-08-03 16:43 ` [PATCH v2] " Jan Kiszka
2009-08-04 12:00 ` Avi Kivity
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