Re: [STABLE 4.9.y PATCH 0/9] Backport of KVM Speculation Control support

From: Paolo Bonzini
Date: Thu Feb 08 2018 - 12:42:14 EST


On 08/02/2018 18:14, Greg KH wrote:
> On Thu, Feb 08, 2018 at 03:49:59AM +0100, Greg KH wrote:
>> On Tue, Feb 06, 2018 at 09:05:46PM +0000, Woodhouse, David wrote:
>>>
>>>
>>> On Tue, 2018-02-06 at 19:01 +0100, Paolo Bonzini wrote:
>>>> On 06/02/2018 18:29, David Woodhouse wrote:
>>>>> I've put together a linux-4.9.y branch atÂ
>>>>> http://git.infradead.org/retpoline-stable.git/shortlog/refs/heads/linux-4.9.y
>>>>> Â
>>>>> Most of it is fairly straightforward, apart from the IBPB on contextÂ
>>>>> switch for which Tim has already posted a candidate. I wanted some more
>>>>> review on my backports of the KVM bits though, including some extra
>>>>> historical patches I pulled in.
>>>>
>>>> Looks good! Thanks for the work,
>>>>
>>>> Paolo
>>>
>>> Thanks. In that case, Greg, the full set is lined up in
>>> http://git.infradead.org/retpoline-stable.git/shortlog/refs/heads/linux-4.9.y
>>> or git://git.infradead.org/retpoline-stable linux-4.9.y
>>
>> Many thanks for all of this work. I've now queued up all of these.
>
> There's a problem with the backport of 6342c50ad12e ("KVM: nVMX:
> vmx_complete_nested_posted_interrupt() can't fail") as there is still a
> check in the function that can fail:
>
> vapic_page = kmap(vmx->nested.virtual_apic_page);
> if (!vapic_page) {
> WARN_ON(1);
> return -ENOMEM;
> }
>
> Do we need something else before this patch in order to fix this? I
> guess kmap really can't fail, should I just drop the whole (!vapic_page)
> check?

Yes, that would be commit 42cf014d38d8822cce63703a467e00f65d000952.
Should David or I respin?

Thanks,

Paolo