From: Kevin Wolf <kwolf@redhat.com>
To: Joerg Roedel <joerg.roedel@amd.com>
Cc: kvm@vger.kernel.org, gleb@redhat.com,
yoshikawa.takuya@oss.ntt.co.jp, avi@redhat.com,
mtosatti@redhat.com
Subject: Re: [PATCH 1/3] KVM: x86 emulator: Fix task switch privilege checks
Date: Tue, 24 Jan 2012 15:15:13 +0100 [thread overview]
Message-ID: <4F1EBCF1.9050808@redhat.com> (raw)
In-Reply-To: <20120124140316.GD19255@amd.com>
Am 24.01.2012 15:03, schrieb Joerg Roedel:
> On Mon, Jan 23, 2012 at 05:10:46PM +0100, Kevin Wolf wrote:
>> This patch fixes the problem for VMX. For SVM, the logic used to
>> determine the source of the task switch is buggy, so we can't pass
>> useful information to the emulator there and just disable the check in
>> all cases.
>
> Actually, SVM isn't buggy :) For SVM you do not need to do any
> priviledge checks in software because the hardware already takes care of
> that.
> In other words, KVM only gets a task-switch intercept if the priviledges
> are all checked and correct.
Okay, that's good to hear. The current code is still buggy because as
Gleb noted it checks against the TSS DPL. We need to disable that check
for SVM then. Also all checks for TASK_SWITCH_GATE indicate that
something is wrong because it will never happen.
Are you going to rewrite task_switch_interception() on top of this series?
Kevin
next prev parent reply other threads:[~2012-01-24 14:11 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-23 16:10 [PATCH 0/3] Fix task switches into/out of VM86 Kevin Wolf
2012-01-23 16:10 ` [PATCH 1/3] KVM: x86 emulator: Fix task switch privilege checks Kevin Wolf
2012-01-24 9:52 ` Gleb Natapov
2012-01-24 10:09 ` Kevin Wolf
2012-01-24 10:17 ` Gleb Natapov
2012-01-24 10:38 ` Kevin Wolf
2012-01-24 10:52 ` Gleb Natapov
2012-01-24 11:23 ` Kevin Wolf
2012-01-24 11:25 ` Gleb Natapov
2012-01-24 14:03 ` Joerg Roedel
2012-01-24 14:15 ` Kevin Wolf [this message]
2012-01-24 14:16 ` Gleb Natapov
2012-01-24 14:24 ` Kevin Wolf
2012-01-24 16:23 ` Gleb Natapov
2012-01-25 16:00 ` Joerg Roedel
2012-01-25 18:29 ` Gleb Natapov
2012-01-27 12:58 ` Kevin Wolf
2012-01-27 13:34 ` Joerg Roedel
2012-01-27 13:55 ` Kevin Wolf
2012-01-27 14:17 ` Joerg Roedel
2012-01-27 15:02 ` Kevin Wolf
2012-01-27 15:45 ` Gleb Natapov
2012-01-23 16:10 ` [PATCH 2/3] KVM: x86 emulator: VM86 segments must have DPL 3 Kevin Wolf
2012-01-23 16:10 ` [PATCH 3/3] KVM: x86 emulator: Allow PM/VM86 switch during task switch Kevin Wolf
2012-01-24 10:57 ` Gleb Natapov
2012-01-24 11:31 ` Kevin Wolf
2012-01-24 11:37 ` Gleb Natapov
2012-01-24 11:44 ` Kevin Wolf
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