Re: [GIT PULL] Last straggler for 4.20-rc8 or final

From: Paolo Bonzini <pbonzini@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>,
	torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
	rkrcmar@redhat.com, kvm@vger.kernel.org
Subject: Re: [GIT PULL] Last straggler for 4.20-rc8 or final
Date: Sun, 23 Dec 2018 09:45:17 +0100	[thread overview]
Message-ID: <58dd99ea-f13f-d211-2d4d-cefad81655df@redhat.com> (raw)
In-Reply-To: <20181222205916.GA64950@gmail.com>

On 22/12/18 21:59, Ingo Molnar wrote:
> 
> * Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
>> On 21/12/18 23:40, Borislav Petkov wrote:
>>> + mingo.
>>>
>>> On Fri, Dec 21, 2018 at 02:09:02PM +0100, Paolo Bonzini wrote:
>>>> Linus,
>>>>
>>>> The following changes since commit 7566ec393f4161572ba6f11ad5171fd5d59b0fbd:
>>>>
>>>>   Linux 4.20-rc7 (2018-12-16 15:46:55 -0800)
>>>>
>>>> are available in the git repository at:
>>>>
>>>>   https://git.kernel.org/pub/scm/virt/kvm/kvm.git tags/for-linus
>>>>
>>>> for you to fetch changes up to 3cf85f9f6bd7b172122865432b4c6f0ec844e22a:
>>>>
>>>>   KVM: x86: nSVM: fix switch to guest mmu (2018-12-19 22:19:22 +0100)
>>>>
>>>> A simple patch for a pretty bad bug.  I haven't yet sent my 4.21 pull
>>>> request because currently I'm waiting for a patch to be removed from
>>>> tip (MPX removal breaks KVM live migration and was committed without
>>>> Cc or Ack from me) and until that happens I cannot finalize my
>>>> conflict resolution instructions.
>>>
>>> Lemme make sure I understand it correctly: you'd like us to not send
>>>
>>> https://git.kernel.org/tip/eb012ef3b4e331ae479dd7cd9378041d9b7f851c
>>>
>>> up now and delay it for 4.22, right?
>>
>> Right, and also I will have to provide you with a topic branch to base
>> that patch on.
> 
> Ok - x86/mpx delayed for v4.22 at least.
> 
> Can we turn off CONFIG_X86_INTEL_MPX configurability in the Kconfig, via 
> a patch like below?
> 
> Thanks,
> 
> 	Ingo
> 
>  arch/x86/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 8689e794a43c..20fd5695f265 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1870,6 +1870,7 @@ config X86_INTEL_MPX
>  	def_bool n
>  	# Note: only available in 64-bit mode due to VMA flags shortage
>  	depends on CPU_SUP_INTEL && X86_64
> +	depends on DEPRECATED
>  	select ARCH_USES_HIGH_VMA_FLAGS
>  	---help---
>  	  MPX provides hardware features that can be used in
> 

I think so, you can even delete all X86_INTEL_MPX code already.  All
that KVM still needs is that BNDCSR and BNDREGS remain in XCR0, I don't
see anything that affects that depending on X86_INTEL_MPX.

Thanks,

Paolo