KVM: s390: gmap: Make storage keys optional

Guard guest storage key handling behind `KVM_S390_MANAGES_S390_GUEST`.
This enables other KVM implementations to use gmap without implementing
storage key infrastructure. Define KVM_S390_MANAGES_S390_GUEST to 1 for
KVM hosts managing s390 guests (in kvm_host_s390.h). A KVM
implementation not implementing those features must define
KVM_S390_MANAGES_S390_GUEST to 0 in its kvm_host_<guest_arch>.h.

No functional changes besides the new guard.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

5 files changed, 17 insertions, 0 deletions

diff --git a/arch/s390/include/asm/kvm_host_s390.h b/arch/s390/include/asm/kvm_host_s390.h
index 22e8d7c4a755..cd692f8fb764 100644
--- a/arch/s390/include/asm/kvm_host_s390.h
+++ b/arch/s390/include/asm/kvm_host_s390.h
@@ -32,6 +32,8 @@
 
 #define KVM_INTERNAL_MEM_SLOTS 1
 
+#define KVM_S390_MANAGES_S390_GUEST 1
+
 /*
  * These seem to be used for allocating ->chip in the routing table, which we
  * don't use. 1 is as small as we can get to reduce the needed memory. If we
diff --git a/arch/s390/kvm/gmap/dat.c b/arch/s390/kvm/gmap/dat.c
index f2ea013cb33e..d0790b3c96f4 100644
--- a/arch/s390/kvm/gmap/dat.c
+++ b/arch/s390/kvm/gmap/dat.c
@@ -613,6 +613,7 @@ long _dat_walk_gfn_range(gfn_t start, gfn_t end, union asce asce,
 	return dat_crste_walk_range(start, min(end, asce_end(asce)), table, &walk);
 }
 
+#if KVM_S390_MANAGES_S390_GUEST
 int dat_get_storage_key(union asce asce, gfn_t gfn, union skey *skey)
 {
 	union crste *crstep;
@@ -843,6 +844,7 @@ long dat_reset_skeys(union asce asce, gfn_t start)
 
 	return _dat_walk_gfn_range(start, asce_end(asce), asce, &ops, DAT_WALK_IGN_HOLES, NULL);
 }
+#endif /* KVM_S390_MANAGES_S390_GUEST */
 
 struct slot_priv {
 	unsigned long token;
diff --git a/arch/s390/kvm/gmap/dat.h b/arch/s390/kvm/gmap/dat.h
index 87108f51228e..2cc072168810 100644
--- a/arch/s390/kvm/gmap/dat.h
+++ b/arch/s390/kvm/gmap/dat.h
@@ -9,6 +9,7 @@
 #ifndef ARCH_KVM_GMAP_DAT_H
 #define ARCH_KVM_GMAP_DAT_H
 
+#include <linux/kvm_host.h>
 #include <linux/radix-tree.h>
 #include <linux/refcount.h>
 #include <linux/io.h>
@@ -532,6 +533,8 @@ int dat_entry_walk(struct kvm_s390_mmu_cache *mc, gfn_t gfn, union asce asce, in
 void dat_free_level(struct crst_table *table, bool owns_ptes);
 struct crst_table *dat_alloc_crst_sleepable(unsigned long init);
 int dat_set_asce_limit(struct kvm_s390_mmu_cache *mc, union asce *asce, int newtype);
+
+#if KVM_S390_MANAGES_S390_GUEST
 int dat_get_storage_key(union asce asce, gfn_t gfn, union skey *skey);
 int dat_set_storage_key(struct kvm_s390_mmu_cache *mc, union asce asce, gfn_t gfn,
 			union skey skey, bool nq);
@@ -539,6 +542,7 @@ int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gf
 			     union skey skey, union skey *oldkey, bool nq, bool mr, bool mc);
 int dat_reset_reference_bit(union asce asce, gfn_t gfn, union skey *skey);
 long dat_reset_skeys(union asce asce, gfn_t start);
+#endif /* KVM_S390_MANAGES_S390_GUEST */
 
 unsigned long dat_get_ptval(struct page_table *table, struct ptval_param param);
 void dat_set_ptval(struct page_table *table, struct ptval_param param, unsigned long val);
diff --git a/arch/s390/kvm/gmap/gmap.c b/arch/s390/kvm/gmap/gmap.c
index 9ae55a1d6f09..0c5e20f033b6 100644
--- a/arch/s390/kvm/gmap/gmap.c
+++ b/arch/s390/kvm/gmap/gmap.c
@@ -945,6 +945,8 @@ void gmap_split_huge_pages(struct gmap *gmap)
 	} while (start);
 }
 
+#if KVM_S390_MANAGES_S390_GUEST
+
 static int _gmap_enable_skeys(struct gmap *gmap)
 {
 	gfn_t start = 0;
@@ -977,6 +979,7 @@ int gmap_enable_skeys(struct gmap *gmap)
 	mmap_write_unlock(gmap->kvm->mm);
 	return rc;
 }
+#endif /* KVM_S390_MANAGES_S390_GUEST */
 
 static long _destroy_pages_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct dat_walk *walk)
 {
diff --git a/arch/s390/kvm/gmap/gmap.h b/arch/s390/kvm/gmap/gmap.h
index c54c35e47d6d..328a81c72c7a 100644
--- a/arch/s390/kvm/gmap/gmap.h
+++ b/arch/s390/kvm/gmap/gmap.h
@@ -10,6 +10,8 @@
 #ifndef ARCH_KVM_GMAP_GMAP_H
 #define ARCH_KVM_GMAP_GMAP_H
 
+#include <linux/kvm_host.h>
+
 #include "dat.h"
 
 /**
@@ -98,7 +100,11 @@ int gmap_set_limit(struct gmap *gmap, gfn_t limit);
 int gmap_ucas_translate(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, gpa_t *gaddr);
 int gmap_ucas_map(struct gmap *gmap, gfn_t p_gfn, gfn_t c_gfn, unsigned long count);
 void gmap_ucas_unmap(struct gmap *gmap, gfn_t c_gfn, unsigned long count);
+
+#if KVM_S390_MANAGES_S390_GUEST
 int gmap_enable_skeys(struct gmap *gmap);
+#endif /* KVM_S390_MANAGES_S390_GUEST */
+
 int gmap_pv_destroy_range(struct gmap *gmap, gfn_t start, gfn_t end, bool interruptible);
 int gmap_insert_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gfn,
 		     gfn_t r_gfn, int level);