linux-kernel - Re: [PATCH] KVM: x86: fix ordering of cr0 initialization code in vmx_cpu

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Message-ID: <20160422221810.GA10089@kroah.com>
Date:	Sat, 23 Apr 2016 07:18:10 +0900
From:	Greg KH <greg@...ah.com>
To:	Bruce Rogers <brogers@...e.com>
Cc:	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	namit@...technion.ac.il, stable@...r.kernel.org
Subject: Re: [PATCH] KVM: x86: fix ordering of cr0 initialization code in
 vmx_cpu_reset

On Fri, Apr 22, 2016 at 12:56:03PM -0600, Bruce Rogers wrote:
> Commit d28bc9dd25ce reversed the order of two lines which initialize cr0,
> allowing the current (old) cr0 value to mess up vcpu initialization.
> This was observed in the checks for cr0 X86_CR0_WP bit in the context of
> kvm_mmu_reset_context(). Besides, setting vcpu->arch.cr0 after vmx_set_cr0()
> is completely redundant. Change the order back to ensure proper vcpu
> initialization.
> 
> The combination of booting with ovmf firmware when guest vcpus > 1 and kvm's
> ept=N option being set results in a VM-entry failure. This patch fixes that.
> 
> Signed-off-by: Bruce Rogers <brogers@...e.com>
> ---
>  arch/x86/kvm/vmx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>