From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ingo Molnar <mingo@elte.hu>
Subject: Re: [patch] kvm: fix GFP_KERNEL allocation in atomic section in kvm_dev_ioctl_create_vcpu()
Date: Thu, 28 Dec 2006 13:55:44 +0100
Message-ID: <20061228125544.GA31207@elte.hu>
References: <45939755.7010603@qumranet.com> <20061228124224.GA28573@elte.hu> <4593BEE6.30206@qumranet.com>
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Cc: kvm-devel <kvm-devel@lists.sourceforge.net>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>,
	Linus Torvalds <torvalds@osdl.org>
Return-path: <linux-kernel-owner+glk-linux-kernel-3=40m.gmane.org-S1754841AbWL1M6p@vger.kernel.org>
To: Avi Kivity <avi@qumranet.com>
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* Avi Kivity <avi@qumranet.com> wrote:

> >fix a GFP_KERNEL allocation in atomic section bug: 
> >kvm_dev_ioctl_create_vcpu() called kvm_mmu_init(), which calls 
> >alloc_pages(), while holding the vcpu. The fix is to set up the MMU 
> >state earlier, it does not require a loaded CPU state.
> 
> Yes it does.  It calls nonpaging_init_context() which calls 
> vmx_set_cr3() which promptly trashes address space of the VM that 
> previously ran on that vcpu (or, if there were none, logs a vmwrite 
> error).

ok, i missed that. Nevertheless the problem of the nonatomic alloc 
remains. I guess a kvm_mmu_init() needs to be split into 
kvm_mmu_create() and kvm_mmu_setup()?

	Ingo