KVM: s390: New gmap code

New gmap (guest map) code. This new gmap code will only be used by KVM.

This will replace the existing gmap.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

arch/s390/kvm/Makefile

@@ -9,7 +9,7 @@ ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
 
 kvm-y += kvm-s390.o intercept.o interrupt.o priv.o sigp.o
 kvm-y += diag.o gaccess.o guestdbg.o vsie.o pv.o gmap-vsie.o
-kvm-y += dat.o
+kvm-y += dat.o gmap.o
 
 kvm-$(CONFIG_VFIO_PCI_ZDEV_KVM) += pci.o
 obj-$(CONFIG_KVM) += kvm.o

arch/s390/kvm/gmap.h

@@ -0,0 +1,244 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  KVM guest address space mapping code
+ *
+ *    Copyright IBM Corp. 2007, 2016, 2025
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *               Claudio Imbrenda <imbrenda@linux.ibm.com>
+ */
+
+#ifndef ARCH_KVM_S390_GMAP_H
+#define ARCH_KVM_S390_GMAP_H
+
+#include "dat.h"
+
+/**
+ * enum gmap_flags - Flags of a gmap.
+ *
+ * @GMAP_FLAG_SHADOW: The gmap is a vsie shadow gmap.
+ * @GMAP_FLAG_OWNS_PAGETABLES: The gmap owns all dat levels; normally 1, is 0
+ *                             only for ucontrol per-cpu gmaps, since they
+ *                             share the page tables with the main gmap.
+ * @GMAP_FLAG_IS_UCONTROL: The gmap is ucontrol (main gmap or per-cpu gmap).
+ * @GMAP_FLAG_ALLOW_HPAGE_1M: 1M hugepages are allowed for this gmap,
+ *                            independently of the page size used by userspace.
+ * @GMAP_FLAG_ALLOW_HPAGE_2G: 2G hugepages are allowed for this gmap,
+ *                            independently of the page size used by userspace.
+ * @GMAP_FLAG_PFAULT_ENABLED: Pfault is enabled for the gmap.
+ * @GMAP_FLAG_USES_SKEYS: If the guest uses storage keys.
+ * @GMAP_FLAG_USES_CMM: Whether the guest uses CMMA.
+ * @GMAP_FLAG_EXPORT_ON_UNMAP: Whether to export guest pages when unmapping.
+ */
+enum gmap_flags {
+	GMAP_FLAG_SHADOW = 0,
+	GMAP_FLAG_OWNS_PAGETABLES,
+	GMAP_FLAG_IS_UCONTROL,
+	GMAP_FLAG_ALLOW_HPAGE_1M,
+	GMAP_FLAG_ALLOW_HPAGE_2G,
+	GMAP_FLAG_PFAULT_ENABLED,
+	GMAP_FLAG_USES_SKEYS,
+	GMAP_FLAG_USES_CMM,
+	GMAP_FLAG_EXPORT_ON_UNMAP,
+};
+
+/**
+ * struct gmap_struct - Guest address space.
+ *
+ * @flags: GMAP_FLAG_* flags.
+ * @edat_level: The edat level of this shadow gmap.
+ * @kvm: The vm.
+ * @asce: The ASCE used by this gmap.
+ * @list: List head used in children gmaps for the children gmap list.
+ * @children_lock: Protects children and scb_users.
+ * @children: List of child gmaps of this gmap.
+ * @scb_users: List of vsie_scb that use this shadow gmap.
+ * @parent: Parent gmap of a child gmap.
+ * @guest_asce: Original ASCE of this shadow gmap.
+ * @host_to_rmap_lock: Protects host_to_rmap.
+ * @host_to_rmap: Radix tree mapping host addresses to guest addresses.
+ */
+struct gmap {
+	unsigned long flags;
+	unsigned char edat_level;
+	struct kvm *kvm;
+	union asce asce;
+	struct list_head list;
+	spinlock_t children_lock;	/* Protects: children, scb_users */
+	struct list_head children;
+	struct list_head scb_users;
+	struct gmap *parent;
+	union asce guest_asce;
+	spinlock_t host_to_rmap_lock;	/* Protects host_to_rmap */
+	struct radix_tree_root host_to_rmap;
+	refcount_t refcount;
+};
+
+struct gmap_cache {
+	struct list_head list;
+	struct gmap *gmap;
+};
+
+#define gmap_for_each_rmap_safe(pos, n, head) \
+	for (pos = (head); n = pos ? pos->next : NULL, pos; pos = n)
+
+int s390_replace_asce(struct gmap *gmap);
+bool _gmap_unmap_prefix(struct gmap *gmap, gfn_t gfn, gfn_t end, bool hint);
+bool gmap_age_gfn(struct gmap *gmap, gfn_t start, gfn_t end);
+bool gmap_unmap_gfn_range(struct gmap *gmap, struct kvm_memory_slot *slot, gfn_t start, gfn_t end);
+int gmap_try_fixup_minor(struct gmap *gmap, struct guest_fault *fault);
+struct gmap *gmap_new(struct kvm *kvm, gfn_t limit);
+struct gmap *gmap_new_child(struct gmap *parent, gfn_t limit);
+void gmap_remove_child(struct gmap *child);
+void gmap_dispose(struct gmap *gmap);
+int gmap_link(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, struct guest_fault *fault);
+void gmap_sync_dirty_log(struct gmap *gmap, gfn_t start, gfn_t end);
+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);
+int gmap_enable_skeys(struct gmap *gmap);
+int gmap_pv_destroy_range(struct gmap *gmap, gfn_t start, gfn_t end, bool interruptible);
+int gmap_insert_rmap(struct gmap *sg, gfn_t p_gfn, gfn_t r_gfn, int level);
+int gmap_protect_rmap(struct kvm_s390_mmu_cache *mc, struct gmap *sg, gfn_t p_gfn, gfn_t r_gfn,
+		      kvm_pfn_t pfn, int level, bool wr);
+void gmap_set_cmma_all_dirty(struct gmap *gmap);
+void _gmap_handle_vsie_unshadow_event(struct gmap *parent, gfn_t gfn);
+struct gmap *gmap_create_shadow(struct kvm_s390_mmu_cache *mc, struct gmap *gmap,
+				union asce asce, int edat_level);
+void gmap_split_huge_pages(struct gmap *gmap);
+
+static inline bool uses_skeys(struct gmap *gmap)
+{
+	return test_bit(GMAP_FLAG_USES_SKEYS, &gmap->flags);
+}
+
+static inline bool uses_cmm(struct gmap *gmap)
+{
+	return test_bit(GMAP_FLAG_USES_CMM, &gmap->flags);
+}
+
+static inline bool pfault_enabled(struct gmap *gmap)
+{
+	return test_bit(GMAP_FLAG_PFAULT_ENABLED, &gmap->flags);
+}
+
+static inline bool is_ucontrol(struct gmap *gmap)
+{
+	return test_bit(GMAP_FLAG_IS_UCONTROL, &gmap->flags);
+}
+
+static inline bool is_shadow(struct gmap *gmap)
+{
+	return test_bit(GMAP_FLAG_SHADOW, &gmap->flags);
+}
+
+static inline bool owns_page_tables(struct gmap *gmap)
+{
+	return test_bit(GMAP_FLAG_OWNS_PAGETABLES, &gmap->flags);
+}
+
+static inline struct gmap *gmap_put(struct gmap *gmap)
+{
+	if (refcount_dec_and_test(&gmap->refcount))
+		gmap_dispose(gmap);
+	return NULL;
+}
+
+static inline void gmap_get(struct gmap *gmap)
+{
+	WARN_ON_ONCE(unlikely(!refcount_inc_not_zero(&gmap->refcount)));
+}
+
+static inline void gmap_handle_vsie_unshadow_event(struct gmap *parent, gfn_t gfn)
+{
+	scoped_guard(spinlock, &parent->children_lock)
+		_gmap_handle_vsie_unshadow_event(parent, gfn);
+}
+
+static inline bool gmap_mkold_prefix(struct gmap *gmap, gfn_t gfn, gfn_t end)
+{
+	return _gmap_unmap_prefix(gmap, gfn, end, true);
+}
+
+static inline bool gmap_unmap_prefix(struct gmap *gmap, gfn_t gfn, gfn_t end)
+{
+	return _gmap_unmap_prefix(gmap, gfn, end, false);
+}
+
+static inline union pgste _gmap_ptep_xchg(struct gmap *gmap, union pte *ptep, union pte newpte,
+					  union pgste pgste, gfn_t gfn, bool needs_lock)
+{
+	lockdep_assert_held(&gmap->kvm->mmu_lock);
+	if (!needs_lock)
+		lockdep_assert_held(&gmap->children_lock);
+	else
+		lockdep_assert_not_held(&gmap->children_lock);
+
+	if (pgste.prefix_notif && (newpte.h.p || newpte.h.i)) {
+		pgste.prefix_notif = 0;
+		gmap_unmap_prefix(gmap, gfn, gfn + 1);
+	}
+	if (pgste.vsie_notif && (ptep->h.p != newpte.h.p || newpte.h.i)) {
+		pgste.vsie_notif = 0;
+		if (needs_lock)
+			gmap_handle_vsie_unshadow_event(gmap, gfn);
+		else
+			_gmap_handle_vsie_unshadow_event(gmap, gfn);
+	}
+	return __dat_ptep_xchg(ptep, pgste, newpte, gfn, gmap->asce, uses_skeys(gmap));
+}
+
+static inline union pgste gmap_ptep_xchg(struct gmap *gmap, union pte *ptep, union pte newpte,
+					 union pgste pgste, gfn_t gfn)
+{
+	return _gmap_ptep_xchg(gmap, ptep, newpte, pgste, gfn, true);
+}
+
+static inline void _gmap_crstep_xchg(struct gmap *gmap, union crste *crstep, union crste ne,
+				     gfn_t gfn, bool needs_lock)
+{
+	unsigned long align = 8 + (is_pmd(*crstep) ? 0 : 11);
+
+	lockdep_assert_held(&gmap->kvm->mmu_lock);
+	if (!needs_lock)
+		lockdep_assert_held(&gmap->children_lock);
+
+	gfn = ALIGN_DOWN(gfn, align);
+	if (crste_prefix(*crstep) && (ne.h.p || ne.h.i || !crste_prefix(ne))) {
+		ne.s.fc1.prefix_notif = 0;
+		gmap_unmap_prefix(gmap, gfn, gfn + align);
+	}
+	if (crste_leaf(*crstep) && crstep->s.fc1.vsie_notif &&
+	    (ne.h.p || ne.h.i || !ne.s.fc1.vsie_notif)) {
+		ne.s.fc1.vsie_notif = 0;
+		if (needs_lock)
+			gmap_handle_vsie_unshadow_event(gmap, gfn);
+		else
+			_gmap_handle_vsie_unshadow_event(gmap, gfn);
+	}
+	dat_crstep_xchg(crstep, ne, gfn, gmap->asce);
+}
+
+static inline void gmap_crstep_xchg(struct gmap *gmap, union crste *crstep, union crste ne,
+				    gfn_t gfn)
+{
+	return _gmap_crstep_xchg(gmap, crstep, ne, gfn, true);
+}
+
+/**
+ * gmap_is_shadow_valid() - check if a shadow guest address space matches the
+ *                          given properties and is still valid.
+ * @sg: Pointer to the shadow guest address space structure.
+ * @asce: ASCE for which the shadow table is requested.
+ * @edat_level: Edat level to be used for the shadow translation.
+ *
+ * Return: true if the gmap shadow is still valid and matches the given
+ * properties and the caller can continue using it; false otherwise, the
+ * caller has to request a new shadow gmap in this case.
+ */
+static inline bool gmap_is_shadow_valid(struct gmap *sg, union asce asce, int edat_level)
+{
+	return sg->guest_asce.val == asce.val && sg->edat_level == edat_level;
+}
+
+#endif /* ARCH_KVM_S390_GMAP_H */