Re: [RFC PATCH 1/3] KVM: s390: Move out initialization code.

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Feb 21, 2013 at 02:12:58PM +0100, Cornelia Huck wrote:
> kvm-s390's module initialization code needs to live in a separate
> module (kvm-s390.ko) if we want to include eventfd (which has its
> own module init func).
> 
> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

I don't get this explanation.
What's the problem this solves?
Could you clarify please?

> ---
>  arch/s390/kvm/Makefile   |  4 +++-
>  arch/s390/kvm/init.c     | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
>  arch/s390/kvm/kvm-s390.c | 38 ++++-------------------------------
>  3 files changed, 59 insertions(+), 35 deletions(-)
>  create mode 100644 arch/s390/kvm/init.c
> 
> diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
> index 3975722..2441ffd 100644
> --- a/arch/s390/kvm/Makefile
> +++ b/arch/s390/kvm/Makefile
> @@ -11,4 +11,6 @@ common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o)
>  ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
>  
>  kvm-objs := $(common-objs) kvm-s390.o intercept.o interrupt.o priv.o sigp.o diag.o
> -obj-$(CONFIG_KVM) += kvm.o
> +kvm_s390-objs := init.o
> +
> +obj-$(CONFIG_KVM) += kvm.o kvm_s390.o
> diff --git a/arch/s390/kvm/init.c b/arch/s390/kvm/init.c
> new file mode 100644
> index 0000000..dc4028a
> --- /dev/null
> +++ b/arch/s390/kvm/init.c
> @@ -0,0 +1,52 @@
> +/*
> + * kvm on s390 module initialization
> + *
> + * Copyright IBM Corp. 2013
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License (version 2 only)
> + * as published by the Free Software Foundation.
> + *
> + *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
> + */
> +
> +#include <linux/kvm.h>
> +#include <linux/kvm_host.h>
> +#include <linux/module.h>
> +#include "kvm-s390.h"
> +
> +extern unsigned long long *facilities;
> +
> +static int __init kvm_s390_init(void)
> +{
> +	int ret;
> +	ret = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * guests can ask for up to 255+1 double words, we need a full page
> +	 * to hold the maximum amount of facilities. On the other hand, we
> +	 * only set facilities that are known to work in KVM.
> +	 */
> +	facilities = (unsigned long long *) get_zeroed_page(GFP_KERNEL|GFP_DMA);
> +	if (!facilities) {
> +		kvm_exit();
> +		return -ENOMEM;
> +	}
> +	memcpy(facilities, S390_lowcore.stfle_fac_list, 16);
> +	facilities[0] &= 0xff00fff3f47c0000ULL;
> +	facilities[1] &= 0x001c000000000000ULL;
> +	return 0;
> +}
> +
> +static void __exit kvm_s390_exit(void)
> +{
> +	free_page((unsigned long) facilities);
> +	kvm_exit();
> +}
> +
> +module_init(kvm_s390_init);
> +module_exit(kvm_s390_exit);
> +
> +MODULE_LICENSE("GPL");

GPL v2?

> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index f822d36..58a5f03 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -36,6 +36,9 @@
>  #include "trace.h"
>  #include "trace-s390.h"
>  
> +unsigned long long *facilities;
> +EXPORT_SYMBOL_GPL(facilities);
> +
>  #define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
>  
>  struct kvm_stats_debugfs_item debugfs_entries[] = {
> @@ -83,8 +86,6 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
>  	{ NULL }
>  };
>  
> -static unsigned long long *facilities;
> -
>  /* Section: not file related */
>  int kvm_arch_hardware_enable(void *garbage)
>  {
> @@ -823,6 +824,7 @@ int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr)
>  		return -EFAULT;
>  	return 0;
>  }
> +EXPORT_SYMBOL_GPL(kvm_s390_vcpu_store_status);
>  
>  static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
>  				     struct kvm_enable_cap *cap)
> @@ -1026,35 +1028,3 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
>  				   struct kvm_memory_slot *slot)
>  {
>  }
> -
> -static int __init kvm_s390_init(void)
> -{
> -	int ret;
> -	ret = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
> -	if (ret)
> -		return ret;
> -
> -	/*
> -	 * guests can ask for up to 255+1 double words, we need a full page
> -	 * to hold the maximum amount of facilities. On the other hand, we
> -	 * only set facilities that are known to work in KVM.
> -	 */
> -	facilities = (unsigned long long *) get_zeroed_page(GFP_KERNEL|GFP_DMA);
> -	if (!facilities) {
> -		kvm_exit();
> -		return -ENOMEM;
> -	}
> -	memcpy(facilities, S390_lowcore.stfle_fac_list, 16);
> -	facilities[0] &= 0xff00fff3f47c0000ULL;
> -	facilities[1] &= 0x001c000000000000ULL;
> -	return 0;
> -}
> -
> -static void __exit kvm_s390_exit(void)
> -{
> -	free_page((unsigned long) facilities);
> -	kvm_exit();
> -}
> -
> -module_init(kvm_s390_init);
> -module_exit(kvm_s390_exit);
> -- 
> 1.7.12.4
> 
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