[PATCH v2 09/15] KVM: s390: move some gmap shadowing functions away from mm/gmap.c

Claudio Imbrenda
2025-01-16T11:34:09Z

Move some gmap shadowing functions from mm/gmap.c to kvm/kvm-s390.c and
the newly created kvm/gmap-vsie.c

This is a step toward removing gmap from mm.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
arch/s390/include/asm/gmap.h | 9 +-
arch/s390/kvm/Makefile | 2 +-
arch/s390/kvm/gmap-vsie.c | 142 +++++++++++++++++++++
arch/s390/kvm/gmap.h | 20 +++
arch/s390/kvm/kvm-s390.c | 62 +++++++++-
arch/s390/kvm/kvm-s390.h | 2 +
arch/s390/kvm/vsie.c | 2 +
arch/s390/mm/gmap.c | 232 ++++-------------------------------
8 files changed, 254 insertions(+), 217 deletions(-)
create mode 100644 arch/s390/kvm/gmap-vsie.c

diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h
index 3652d8523e1f..2432c47d36db 100644
--- a/arch/s390/include/asm/gmap.h
+++ b/arch/s390/include/asm/gmap.h
@@ -106,6 +106,8 @@ struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit);
void gmap_remove(struct gmap *gmap);
struct gmap *gmap_get(struct gmap *gmap);
void gmap_put(struct gmap *gmap);
+void gmap_free(struct gmap *gmap);
+struct gmap *gmap_alloc(unsigned long limit);

int gmap_map_segment(struct gmap *gmap, unsigned long from,
unsigned long to, unsigned long len);
@@ -118,9 +120,7 @@ void gmap_unlink(struct mm_struct *, unsigned long *table, unsigned long vmaddr)

int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val);

-struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
- int edat_level);
-int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level);
+void gmap_unshadow(struct gmap *sg);
int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
int fake);
int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
@@ -136,8 +136,7 @@ int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte);
void gmap_register_pte_notifier(struct gmap_notifier *);
void gmap_unregister_pte_notifier(struct gmap_notifier *);

-int gmap_mprotect_notify(struct gmap *, unsigned long start,
- unsigned long len, int prot);
+int gmap_protect_one(struct gmap *gmap, unsigned long gaddr, int prot, unsigned long bits);

void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long dirty_bitmap[4],
unsigned long gaddr, unsigned long vmaddr);
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index d972dea657fd..f0ffe874adc2 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -8,7 +8,7 @@ include $(srctree)/virt/kvm/Makefile.kvm
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.o
+kvm-y += diag.o gaccess.o guestdbg.o vsie.o pv.o gmap.o gmap-vsie.o

kvm-$(CONFIG_VFIO_PCI_ZDEV_KVM) += pci.o
obj-$(CONFIG_KVM) += kvm.o
diff --git a/arch/s390/kvm/gmap-vsie.c b/arch/s390/kvm/gmap-vsie.c
new file mode 100644
index 000000000000..90427f114995
--- /dev/null
+++ b/arch/s390/kvm/gmap-vsie.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Guest memory management for KVM/s390 nested VMs.
+ *
+ * Copyright IBM Corp. 2008, 2020, 2024
+ *
+ * Author(s): Claudio Imbrenda <imbrenda@linux.ibm.com>
+ * Martin Schwidefsky <schwidefsky@de.ibm.com>
+ * David Hildenbrand <david@redhat.com>
+ * Janosch Frank <frankja@linux.vnet.ibm.com>
+ */
+
+#include <linux/compiler.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/pgtable.h>
+#include <linux/pagemap.h>
+#include <linux/mman.h>
+
+#include <asm/lowcore.h>
+#include <asm/gmap.h>
+#include <asm/uv.h>
+
+#include "kvm-s390.h"
+#include "gmap.h"
+
+/**
+ * gmap_find_shadow - find a specific asce in the list of shadow tables
+ * @parent: pointer to the parent gmap
+ * @asce: ASCE for which the shadow table is created
+ * @edat_level: edat level to be used for the shadow translation
+ *
+ * Returns the pointer to a gmap if a shadow table with the given asce is
+ * already available, ERR_PTR(-EAGAIN) if another one is just being created,
+ * otherwise NULL
+ */
+static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
+ int edat_level)
+{
+ struct gmap *sg;
+
+ list_for_each_entry(sg, &parent->children, list) {
+ if (sg->orig_asce != asce || sg->edat_level != edat_level ||
+ sg->removed)
+ continue;
+ if (!sg->initialized)
+ return ERR_PTR(-EAGAIN);
+ refcount_inc(&sg->ref_count);
+ return sg;
+ }
+ return NULL;
+}
+
+/**
+ * gmap_shadow - create/find a shadow guest address space
+ * @parent: pointer to the parent gmap
+ * @asce: ASCE for which the shadow table is created
+ * @edat_level: edat level to be used for the shadow translation
+ *
+ * The pages of the top level page table referred by the asce parameter
+ * will be set to read-only and marked in the PGSTEs of the kvm process.
+ * The shadow table will be removed automatically on any change to the
+ * PTE mapping for the source table.
+ *
+ * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
+ * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
+ * parent gmap table could not be protected.
+ */
+struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
+ int edat_level)
+{
+ struct gmap *sg, *new;
+ unsigned long limit;
+ int rc;
+
+ if (KVM_BUG_ON(parent->mm->context.allow_gmap_hpage_1m, (struct kvm *)parent->private) ||
+ KVM_BUG_ON(gmap_is_shadow(parent), (struct kvm *)parent->private))
+ return ERR_PTR(-EFAULT);
+ spin_lock(&parent->shadow_lock);
+ sg = gmap_find_shadow(parent, asce, edat_level);
+ spin_unlock(&parent->shadow_lock);
+ if (sg)
+ return sg;
+ /* Create a new shadow gmap */
+ limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
+ if (asce & _ASCE_REAL_SPACE)
+ limit = -1UL;
+ new = gmap_alloc(limit);
+ if (!new)
+ return ERR_PTR(-ENOMEM);
+ new->mm = parent->mm;
+ new->parent = gmap_get(parent);
+ new->private = parent->private;
+ new->orig_asce = asce;
+ new->edat_level = edat_level;
+ new->initialized = false;
+ spin_lock(&parent->shadow_lock);
+ /* Recheck if another CPU created the same shadow */
+ sg = gmap_find_shadow(parent, asce, edat_level);
+ if (sg) {
+ spin_unlock(&parent->shadow_lock);
+ gmap_free(new);
+ return sg;
+ }
+ if (asce & _ASCE_REAL_SPACE) {
+ /* only allow one real-space gmap shadow */
+ list_for_each_entry(sg, &parent->children, list) {
+ if (sg->orig_asce & _ASCE_REAL_SPACE) {
+ spin_lock(&sg->guest_table_lock);
+ gmap_unshadow(sg);
+ spin_unlock(&sg->guest_table_lock);
+ list_del(&sg->list);
+ gmap_put(sg);
+ break;
+ }
+ }
+ }
+ refcount_set(&new->ref_count, 2);
+ list_add(&new->list, &parent->children);
+ if (asce & _ASCE_REAL_SPACE) {
+ /* nothing to protect, return right away */
+ new->initialized = true;
+ spin_unlock(&parent->shadow_lock);
+ return new;
+ }
+ spin_unlock(&parent->shadow_lock);
+ /* protect after insertion, so it will get properly invalidated */
+ mmap_read_lock(parent->mm);
+ rc = __kvm_s390_mprotect_many(parent, asce & _ASCE_ORIGIN,
+ ((asce & _ASCE_TABLE_LENGTH) + 1),
+ PROT_READ, GMAP_NOTIFY_SHADOW);
+ mmap_read_unlock(parent->mm);
+ spin_lock(&parent->shadow_lock);
+ new->initialized = true;
+ if (rc) {
+ list_del(&new->list);
+ gmap_free(new);
+ new = ERR_PTR(rc);
+ }
+ spin_unlock(&parent->shadow_lock);
+ return new;
+}
diff --git a/arch/s390/kvm/gmap.h b/arch/s390/kvm/gmap.h
index f2b52ce29be3..978f541059f0 100644
--- a/arch/s390/kvm/gmap.h
+++ b/arch/s390/kvm/gmap.h
@@ -13,5 +13,25 @@
int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb);
int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr);
int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr);
+struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, int edat_level);
+
+/**
+ * gmap_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
+ *
+ * Returns 1 if the gmap shadow is still valid and matches the given
+ * properties, the caller can continue using it. Returns 0 otherwise, the
+ * caller has to request a new shadow gmap in this case.
+ *
+ */
+static inline int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
+{
+ if (sg->removed)
+ return 0;
+ return sg->orig_asce == asce && sg->edat_level == edat_level;
+}

#endif
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 7608cffb805f..769d66cedbb7 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4509,6 +4509,63 @@ static bool ibs_enabled(struct kvm_vcpu *vcpu)
return kvm_s390_test_cpuflags(vcpu, CPUSTAT_IBS);
}

+static int __kvm_s390_fixup_fault_sync(struct gmap *gmap, gpa_t gaddr, unsigned int flags)
+{
+ struct kvm *kvm = gmap->private;
+ gfn_t gfn = gpa_to_gfn(gaddr);
+ bool unlocked;
+ hva_t vmaddr;
+ gpa_t tmp;
+ int rc;
+
+ if (kvm_is_ucontrol(kvm)) {
+ tmp = __gmap_translate(gmap, gaddr);
+ gfn = gpa_to_gfn(tmp);
+ }
+
+ vmaddr = gfn_to_hva(kvm, gfn);
+ rc = fixup_user_fault(gmap->mm, vmaddr, FAULT_FLAG_WRITE, &unlocked);
+ if (!rc)
+ rc = __gmap_link(gmap, gaddr, vmaddr);
+ return rc;
+}
+
+int __kvm_s390_mprotect_many(struct gmap *gmap, gpa_t gpa, u8 npages, unsigned int prot,
+ unsigned long bits)
+{
+ unsigned int fault_flag = (prot & PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
+ gpa_t end = gpa + npages * PAGE_SIZE;
+ int rc;
+
+ for (; gpa < end; gpa = ALIGN(gpa + 1, rc ? HPAGE_SIZE : PAGE_SIZE)) {
+ rc = gmap_protect_one(gmap, gpa, prot, bits);
+ if (rc == -EAGAIN) {
+ __kvm_s390_fixup_fault_sync(gmap, gpa, fault_flag);
+ rc = gmap_protect_one(gmap, gpa, prot, bits);
+ }
+ if (rc < 0)
+ return rc;
+ }
+
+ return 0;
+}
+
+static int kvm_s390_mprotect_notify_prefix(struct kvm_vcpu *vcpu)
+{
+ gpa_t gaddr = kvm_s390_get_prefix(vcpu);
+ int idx, rc;
+
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
+ mmap_read_lock(vcpu->arch.gmap->mm);
+
+ rc = __kvm_s390_mprotect_many(vcpu->arch.gmap, gaddr, 2, PROT_WRITE, GMAP_NOTIFY_MPROT);
+
+ mmap_read_unlock(vcpu->arch.gmap->mm);
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+ return rc;
+}
+
static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
{
retry:
@@ -4524,9 +4581,8 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
*/
if (kvm_check_request(KVM_REQ_REFRESH_GUEST_PREFIX, vcpu)) {
int rc;
- rc = gmap_mprotect_notify(vcpu->arch.gmap,
- kvm_s390_get_prefix(vcpu),
- PAGE_SIZE * 2, PROT_WRITE);
+
+ rc = kvm_s390_mprotect_notify_prefix(vcpu);
if (rc) {
kvm_make_request(KVM_REQ_REFRESH_GUEST_PREFIX, vcpu);
return rc;
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 61e8544924b3..8d3bbb2dd8d2 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -420,6 +420,8 @@ void kvm_s390_set_cpu_timer(struct kvm_vcpu *vcpu, __u64 cputm);
__u64 kvm_s390_get_cpu_timer(struct kvm_vcpu *vcpu);
int kvm_s390_cpus_from_pv(struct kvm *kvm, u16 *rc, u16 *rrc);
int __kvm_s390_handle_dat_fault(struct kvm_vcpu *vcpu, gfn_t gfn, gpa_t gaddr, unsigned int flags);
+int __kvm_s390_mprotect_many(struct gmap *gmap, gpa_t gpa, u8 npages, unsigned int prot,
+ unsigned long bits);

static inline int kvm_s390_handle_dat_fault(struct kvm_vcpu *vcpu, gpa_t gaddr, unsigned int flags)
{
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index a687695d8f68..4fef3b38bd70 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -13,6 +13,7 @@
#include <linux/bitmap.h>
#include <linux/sched/signal.h>
#include <linux/io.h>
+#include <linux/mman.h>

#include <asm/gmap.h>
#include <asm/mmu_context.h>
@@ -22,6 +23,7 @@
#include <asm/facility.h>
#include "kvm-s390.h"
#include "gaccess.h"
+#include "gmap.h"

struct vsie_page {
struct kvm_s390_sie_block scb_s; /* 0x0000 */
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index ae6ccf034378..12d681b657b4 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -43,7 +43,7 @@ static struct page *gmap_alloc_crst(void)
*
* Returns a guest address space structure.
*/
-static struct gmap *gmap_alloc(unsigned long limit)
+struct gmap *gmap_alloc(unsigned long limit)
{
struct gmap *gmap;
struct page *page;
@@ -97,6 +97,7 @@ static struct gmap *gmap_alloc(unsigned long limit)
out:
return NULL;
}
+EXPORT_SYMBOL_GPL(gmap_alloc);

/**
* gmap_create - create a guest address space
@@ -191,7 +192,7 @@ static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
*
* No locks required. There are no references to this gmap anymore.
*/
-static void gmap_free(struct gmap *gmap)
+void gmap_free(struct gmap *gmap)
{
struct page *page, *next;

@@ -218,6 +219,7 @@ static void gmap_free(struct gmap *gmap)

kfree(gmap);
}
+EXPORT_SYMBOL_GPL(gmap_free);

/**
* gmap_get - increase reference counter for guest address space
@@ -958,86 +960,36 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
* @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
* @bits: pgste notification bits to set
*
- * Returns 0 if successfully protected, -ENOMEM if out of memory and
- * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
+ * Returns 0 if successfully protected, -ENOMEM if out of memory,
+ * -EFAULT if gaddr is invalid (or mapping for shadows is missing),
+ * -EAGAIN if the guest mapping is missing and should be fixed by the
+ * caller.
*
* Called with sg->mm->mmap_lock in read.
*/
-static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
- unsigned long len, int prot, unsigned long bits)
+int gmap_protect_one(struct gmap *gmap, unsigned long gaddr, int prot, unsigned long bits)
{
- unsigned long vmaddr, dist;
pmd_t *pmdp;
- int rc;
+ int rc = 0;

BUG_ON(gmap_is_shadow(gmap));
- while (len) {
- rc = -EAGAIN;
- pmdp = gmap_pmd_op_walk(gmap, gaddr);
- if (pmdp) {
- if (!pmd_leaf(*pmdp)) {
- rc = gmap_protect_pte(gmap, gaddr, pmdp, prot,
- bits);
- if (!rc) {
- len -= PAGE_SIZE;
- gaddr += PAGE_SIZE;
- }
- } else {
- rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot,
- bits);
- if (!rc) {
- dist = HPAGE_SIZE - (gaddr & ~HPAGE_MASK);
- len = len < dist ? 0 : len - dist;
- gaddr = (gaddr & HPAGE_MASK) + HPAGE_SIZE;
- }
- }
- gmap_pmd_op_end(gmap, pmdp);
- }
- if (rc) {
- if (rc == -EINVAL)
- return rc;

- /* -EAGAIN, fixup of userspace mm and gmap */
- vmaddr = __gmap_translate(gmap, gaddr);
- if (IS_ERR_VALUE(vmaddr))
- return vmaddr;
- rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot);
- if (rc)
- return rc;
- }
- }
- return 0;
-}
+ pmdp = gmap_pmd_op_walk(gmap, gaddr);
+ if (!pmdp)
+ return -EAGAIN;

-/**
- * gmap_mprotect_notify - change access rights for a range of ptes and
- * call the notifier if any pte changes again
- * @gmap: pointer to guest mapping meta data structure
- * @gaddr: virtual address in the guest address space
- * @len: size of area
- * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
- *
- * Returns 0 if for each page in the given range a gmap mapping exists,
- * the new access rights could be set and the notifier could be armed.
- * If the gmap mapping is missing for one or more pages -EFAULT is
- * returned. If no memory could be allocated -ENOMEM is returned.
- * This function establishes missing page table entries.
- */
-int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
- unsigned long len, int prot)
-{
- int rc;
+ if (!pmd_leaf(*pmdp)) {
+ rc = gmap_protect_pte(gmap, gaddr, pmdp, prot, bits);
+ } else {
+ rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot, bits);
+ if (!rc)
+ rc = 1;
+ }
+ gmap_pmd_op_end(gmap, pmdp);

- if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
- return -EINVAL;
- if (!MACHINE_HAS_ESOP && prot == PROT_READ)
- return -EINVAL;
- mmap_read_lock(gmap->mm);
- rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_NOTIFY_MPROT);
- mmap_read_unlock(gmap->mm);
return rc;
}
-EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
+EXPORT_SYMBOL_GPL(gmap_protect_one);

/**
* gmap_read_table - get an unsigned long value from a guest page table using
@@ -1488,7 +1440,7 @@ static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
*
* Called with sg->guest_table_lock
*/
-static void gmap_unshadow(struct gmap *sg)
+void gmap_unshadow(struct gmap *sg)
{
unsigned long *table;

@@ -1514,143 +1466,7 @@ static void gmap_unshadow(struct gmap *sg)
break;
}
}
-
-/**
- * gmap_find_shadow - find a specific asce in the list of shadow tables
- * @parent: pointer to the parent gmap
- * @asce: ASCE for which the shadow table is created
- * @edat_level: edat level to be used for the shadow translation
- *
- * Returns the pointer to a gmap if a shadow table with the given asce is
- * already available, ERR_PTR(-EAGAIN) if another one is just being created,
- * otherwise NULL
- */
-static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
- int edat_level)
-{
- struct gmap *sg;
-
- list_for_each_entry(sg, &parent->children, list) {
- if (sg->orig_asce != asce || sg->edat_level != edat_level ||
- sg->removed)
- continue;
- if (!sg->initialized)
- return ERR_PTR(-EAGAIN);
- refcount_inc(&sg->ref_count);
- return sg;
- }
- return NULL;
-}
-
-/**
- * gmap_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
- *
- * Returns 1 if the gmap shadow is still valid and matches the given
- * properties, the caller can continue using it. Returns 0 otherwise, the
- * caller has to request a new shadow gmap in this case.
- *
- */
-int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
-{
- if (sg->removed)
- return 0;
- return sg->orig_asce == asce && sg->edat_level == edat_level;
-}
-EXPORT_SYMBOL_GPL(gmap_shadow_valid);
-
-/**
- * gmap_shadow - create/find a shadow guest address space
- * @parent: pointer to the parent gmap
- * @asce: ASCE for which the shadow table is created
- * @edat_level: edat level to be used for the shadow translation
- *
- * The pages of the top level page table referred by the asce parameter
- * will be set to read-only and marked in the PGSTEs of the kvm process.
- * The shadow table will be removed automatically on any change to the
- * PTE mapping for the source table.
- *
- * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
- * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
- * parent gmap table could not be protected.
- */
-struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
- int edat_level)
-{
- struct gmap *sg, *new;
- unsigned long limit;
- int rc;
-
- BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
- BUG_ON(gmap_is_shadow(parent));
- spin_lock(&parent->shadow_lock);
- sg = gmap_find_shadow(parent, asce, edat_level);
- spin_unlock(&parent->shadow_lock);
- if (sg)
- return sg;
- /* Create a new shadow gmap */
- limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
- if (asce & _ASCE_REAL_SPACE)
- limit = -1UL;
- new = gmap_alloc(limit);
- if (!new)
- return ERR_PTR(-ENOMEM);
- new->mm = parent->mm;
- new->parent = gmap_get(parent);
- new->private = parent->private;
- new->orig_asce = asce;
- new->edat_level = edat_level;
- new->initialized = false;
- spin_lock(&parent->shadow_lock);
- /* Recheck if another CPU created the same shadow */
- sg = gmap_find_shadow(parent, asce, edat_level);
- if (sg) {
- spin_unlock(&parent->shadow_lock);
- gmap_free(new);
- return sg;
- }
- if (asce & _ASCE_REAL_SPACE) {
- /* only allow one real-space gmap shadow */
- list_for_each_entry(sg, &parent->children, list) {
- if (sg->orig_asce & _ASCE_REAL_SPACE) {
- spin_lock(&sg->guest_table_lock);
- gmap_unshadow(sg);
- spin_unlock(&sg->guest_table_lock);
- list_del(&sg->list);
- gmap_put(sg);
- break;
- }
- }
- }
- refcount_set(&new->ref_count, 2);
- list_add(&new->list, &parent->children);
- if (asce & _ASCE_REAL_SPACE) {
- /* nothing to protect, return right away */
- new->initialized = true;
- spin_unlock(&parent->shadow_lock);
- return new;
- }
- spin_unlock(&parent->shadow_lock);
- /* protect after insertion, so it will get properly invalidated */
- mmap_read_lock(parent->mm);
- rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
- ((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE,
- PROT_READ, GMAP_NOTIFY_SHADOW);
- mmap_read_unlock(parent->mm);
- spin_lock(&parent->shadow_lock);
- new->initialized = true;
- if (rc) {
- list_del(&new->list);
- gmap_free(new);
- new = ERR_PTR(rc);
- }
- spin_unlock(&parent->shadow_lock);
- return new;
-}
-EXPORT_SYMBOL_GPL(gmap_shadow);
+EXPORT_SYMBOL(gmap_unshadow);

/**
* gmap_shadow_r2t - create an empty shadow region 2 table
--
2.47.1