Re: [PATCH v2 01/15] KVM: s390: refactor crypto initialization

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 28 Feb 2018 16:23:29 -0500
Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:

> On 02/28/2018 12:37 PM, Cornelia Huck wrote:
> > On Tue, 27 Feb 2018 09:27:59 -0500
> > Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:

> >> diff --git a/arch/s390/kvm/kvm-ap.c b/arch/s390/kvm/kvm-ap.c
> >> new file mode 100644
> >> index 0000000..5305f4c
> >> --- /dev/null
> >> +++ b/arch/s390/kvm/kvm-ap.c
> >> @@ -0,0 +1,47 @@
> >> +/*
> >> + * Adjunct Processor (AP) configuration management for KVM guests
> >> + *
> >> + * Copyright IBM Corp. 2017
> >> + *
> >> + * Author(s): Tony Krowiak <akrowia@linux.vnet.ibm.com>
> >> + */
> >> +
> >> +#include <asm/kvm-ap.h>
> >> +#include <asm/ap.h>
> >> +
> >> +#include "kvm-s390.h"
> >> +
> >> +static int kvm_ap_apxa_installed(void)
> >> +{
> >> +	int ret;
> >> +	struct ap_config_info config;
> >> +
> >> +	ret = ap_query_configuration(&config);  
> > Doesn't that introduce a dependency on CONFIG_ZCRYPT?  
> It does, but AFAIK zcrypt is built into the kernel. Or is that not what 
> you are asking?

It is built into the kernel (and not into a module) if CONFIG_ZCRYPT is
set. When I compile a kernel with CONFIG_KVM set and CONFIG_ZCRYPT
unset, with this patch applied I get

arch/s390/kvm/kvm-ap.o: In function `kvm_ap_apxa_installed':
/home/cohuck/git/linux/arch/s390/kvm/kvm-ap.c:19: undefined reference to `ap_query_configuration'

So I'm afraid you cannot use ap_query_configuration() in base s390 kvm
code unless you move that function to a place where it is always built
(or at least always built if either CONFIG_KVM or CONFIG_ZCRYPT are
set).