@@ -59,8 +59,11 @@ void gmap_discard(struct gmap *, unsigned long from, unsigned long to);
void __gmap_zap(struct gmap *, unsigned long gaddr);
void gmap_unlink(struct mm_struct *, unsigned long *table, unsigned long vmaddr);
-void gmap_register_ipte_notifier(struct gmap_notifier *);
-void gmap_unregister_ipte_notifier(struct gmap_notifier *);
-int gmap_ipte_notify(struct gmap *, unsigned long start, unsigned long len);
+void gmap_register_pte_notifier(struct gmap_notifier *);
+void gmap_unregister_pte_notifier(struct gmap_notifier *);
+void gmap_pte_notify(struct mm_struct *, unsigned long addr, pte_t *);
+
+int gmap_mprotect_notify(struct gmap *, unsigned long start,
+ unsigned long len, int prot);
#endif /* _ASM_S390_GMAP_H */
@@ -886,6 +886,8 @@ void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t entry);
void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
void ptep_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
+int ptep_force_prot(struct mm_struct *mm, unsigned long gaddr,
+ pte_t *ptep, int prot);
void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
pte_t *ptep , int reset);
void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
@@ -21,6 +21,7 @@
#include <linux/init.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
+#include <linux/mman.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>
@@ -185,7 +186,7 @@ static struct notifier_block kvm_clock_notifier = {
int kvm_arch_hardware_setup(void)
{
gmap_notifier.notifier_call = kvm_gmap_notifier;
- gmap_register_ipte_notifier(&gmap_notifier);
+ gmap_register_pte_notifier(&gmap_notifier);
atomic_notifier_chain_register(&s390_epoch_delta_notifier,
&kvm_clock_notifier);
return 0;
@@ -193,7 +194,7 @@ int kvm_arch_hardware_setup(void)
void kvm_arch_hardware_unsetup(void)
{
- gmap_unregister_ipte_notifier(&gmap_notifier);
+ gmap_unregister_pte_notifier(&gmap_notifier);
atomic_notifier_chain_unregister(&s390_epoch_delta_notifier,
&kvm_clock_notifier);
}
@@ -2272,16 +2273,16 @@ retry:
return 0;
/*
* We use MMU_RELOAD just to re-arm the ipte notifier for the
- * guest prefix page. gmap_ipte_notify will wait on the ptl lock.
+ * guest prefix page. gmap_mprotect_notify will wait on the ptl lock.
* This ensures that the ipte instruction for this request has
* already finished. We might race against a second unmapper that
* wants to set the blocking bit. Lets just retry the request loop.
*/
if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu)) {
int rc;
- rc = gmap_ipte_notify(vcpu->arch.gmap,
- kvm_s390_get_prefix(vcpu),
- PAGE_SIZE * 2);
+ rc = gmap_mprotect_notify(vcpu->arch.gmap,
+ kvm_s390_get_prefix(vcpu),
+ PAGE_SIZE * 2, PROT_WRITE);
if (rc)
return rc;
goto retry;
@@ -553,29 +553,29 @@ static LIST_HEAD(gmap_notifier_list);
static DEFINE_SPINLOCK(gmap_notifier_lock);
/**
- * gmap_register_ipte_notifier - register a pte invalidation callback
+ * gmap_register_pte_notifier - register a pte invalidation callback
* @nb: pointer to the gmap notifier block
*/
-void gmap_register_ipte_notifier(struct gmap_notifier *nb)
+void gmap_register_pte_notifier(struct gmap_notifier *nb)
{
spin_lock(&gmap_notifier_lock);
list_add_rcu(&nb->list, &gmap_notifier_list);
spin_unlock(&gmap_notifier_lock);
}
-EXPORT_SYMBOL_GPL(gmap_register_ipte_notifier);
+EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
/**
- * gmap_unregister_ipte_notifier - remove a pte invalidation callback
+ * gmap_unregister_pte_notifier - remove a pte invalidation callback
* @nb: pointer to the gmap notifier block
*/
-void gmap_unregister_ipte_notifier(struct gmap_notifier *nb)
+void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
{
spin_lock(&gmap_notifier_lock);
list_del_rcu(&nb->list);
spin_unlock(&gmap_notifier_lock);
synchronize_rcu();
}
-EXPORT_SYMBOL_GPL(gmap_unregister_ipte_notifier);
+EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
/**
* gmap_call_notifier - call all registered invalidation callbacks
@@ -593,62 +593,150 @@ static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
}
/**
- * gmap_ipte_notify - mark a range of ptes for invalidation notification
+ * gmap_table_walk - walk the gmap page tables
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ *
+ * Returns a table pointer for the given guest address.
+ */
+static inline unsigned long *gmap_table_walk(struct gmap *gmap,
+ unsigned long gaddr)
+{
+ unsigned long *table;
+
+ table = gmap->table;
+ switch (gmap->asce & _ASCE_TYPE_MASK) {
+ case _ASCE_TYPE_REGION1:
+ table += (gaddr >> 53) & 0x7ff;
+ if (*table & _REGION_ENTRY_INVALID)
+ return NULL;
+ table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+ /* Fallthrough */
+ case _ASCE_TYPE_REGION2:
+ table += (gaddr >> 42) & 0x7ff;
+ if (*table & _REGION_ENTRY_INVALID)
+ return NULL;
+ table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+ /* Fallthrough */
+ case _ASCE_TYPE_REGION3:
+ table += (gaddr >> 31) & 0x7ff;
+ if (*table & _REGION_ENTRY_INVALID)
+ return NULL;
+ table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
+ /* Fallthrough */
+ case _ASCE_TYPE_SEGMENT:
+ table += (gaddr >> 20) & 0x7ff;
+ }
+ return table;
+}
+
+/**
+ * gmap_pte_op_walk - walk the gmap page table, get the page table lock
+ * and return the pte pointer
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @ptl: pointer to the spinlock pointer
+ *
+ * Returns a pointer to the locked pte for a guest address, or NULL
+ */
+static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
+ spinlock_t **ptl)
+{
+ unsigned long *table;
+
+ /* Walk the gmap page table, lock and get pte pointer */
+ table = gmap_table_walk(gmap, gaddr);
+ if (!table || *table & _SEGMENT_ENTRY_INVALID)
+ return NULL;
+ return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
+}
+
+/**
+ * gmap_pte_op_fixup - force a page in and connect the gmap page table
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @vmaddr: address in the host process address space
+ *
+ * Returns 0 if the caller can retry __gmap_translate (might fail again),
+ * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
+ * up or connecting the gmap page table.
+ */
+static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
+ unsigned long vmaddr)
+{
+ struct mm_struct *mm = gmap->mm;
+ bool unlocked = false;
+
+ if (fixup_user_fault(current, mm, vmaddr, FAULT_FLAG_WRITE, &unlocked))
+ return -EFAULT;
+ if (unlocked)
+ /* lost mmap_sem, caller has to retry __gmap_translate */
+ return 0;
+ /* Connect the page tables */
+ return __gmap_link(gmap, gaddr, vmaddr);
+}
+
+/**
+ * gmap_pte_op_end - release the page table lock
+ * @ptl: pointer to the spinlock pointer
+ */
+static void gmap_pte_op_end(spinlock_t *ptl)
+{
+ spin_unlock(ptl);
+}
+
+/**
+ * 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 and
- * the invalidation notification could be set. 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.
+ * 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_ipte_notify(struct gmap *gmap, unsigned long gaddr, unsigned long len)
+int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
+ unsigned long len, int prot)
{
- unsigned long addr;
+ unsigned long vmaddr;
spinlock_t *ptl;
pte_t *ptep;
- bool unlocked;
int rc = 0;
if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK))
return -EINVAL;
+ if (!MACHINE_HAS_ESOP && prot == PROT_READ)
+ return -EINVAL;
down_read(&gmap->mm->mmap_sem);
while (len) {
- unlocked = false;
- /* Convert gmap address and connect the page tables */
- addr = __gmap_translate(gmap, gaddr);
- if (IS_ERR_VALUE(addr)) {
- rc = addr;
- break;
+ rc = -EAGAIN;
+ ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
+ if (ptep) {
+ rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot);
+ gmap_pte_op_end(ptl);
}
- /* Get the page mapped */
- if (fixup_user_fault(current, gmap->mm, addr, FAULT_FLAG_WRITE,
- &unlocked)) {
- rc = -EFAULT;
- break;
- }
- /* While trying to map mmap_sem got unlocked. Let us retry */
- if (unlocked)
+ if (rc) {
+ vmaddr = __gmap_translate(gmap, gaddr);
+ if (IS_ERR_VALUE(vmaddr)) {
+ rc = vmaddr;
+ break;
+ }
+ rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr);
+ if (rc)
+ break;
continue;
- rc = __gmap_link(gmap, gaddr, addr);
- if (rc)
- break;
- /* Walk the process page table, lock and get pte pointer */
- ptep = get_locked_pte(gmap->mm, addr, &ptl);
- VM_BUG_ON(!ptep);
- /* Set notification bit in the pgste of the pte */
- if ((pte_val(*ptep) & (_PAGE_INVALID | _PAGE_PROTECT)) == 0) {
- ptep_set_notify(gmap->mm, addr, ptep);
- gaddr += PAGE_SIZE;
- len -= PAGE_SIZE;
}
- pte_unmap_unlock(ptep, ptl);
+ gaddr += PAGE_SIZE;
+ len -= PAGE_SIZE;
}
up_read(&gmap->mm->mmap_sem);
return rc;
}
-EXPORT_SYMBOL_GPL(gmap_ipte_notify);
+EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
/**
* ptep_notify - call all invalidation callbacks for a specific pte.
@@ -179,9 +179,9 @@ static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
return pgste;
}
-static inline pgste_t pgste_ipte_notify(struct mm_struct *mm,
- unsigned long addr,
- pte_t *ptep, pgste_t pgste)
+static inline pgste_t pgste_pte_notify(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep, pgste_t pgste)
{
#ifdef CONFIG_PGSTE
if (pgste_val(pgste) & PGSTE_IN_BIT) {
@@ -199,7 +199,7 @@ static inline pgste_t ptep_xchg_start(struct mm_struct *mm,
if (mm_has_pgste(mm)) {
pgste = pgste_get_lock(ptep);
- pgste = pgste_ipte_notify(mm, addr, ptep, pgste);
+ pgste = pgste_pte_notify(mm, addr, ptep, pgste);
}
return pgste;
}
@@ -414,6 +414,50 @@ void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
pgste_set_unlock(ptep, pgste);
}
+/**
+ * ptep_force_prot - change access rights of a locked pte
+ * @mm: pointer to the process mm_struct
+ * @addr: virtual address in the guest address space
+ * @ptep: pointer to the page table entry
+ * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
+ *
+ * Returns 0 if the access rights were changed and -EAGAIN if the current
+ * and requested access rights are incompatible.
+ */
+int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, int prot)
+{
+ pte_t entry;
+ pgste_t pgste;
+ int pte_i, pte_p;
+
+ pgste = pgste_get_lock(ptep);
+ entry = *ptep;
+ /* Check pte entry after all locks have been acquired */
+ pte_i = pte_val(entry) & _PAGE_INVALID;
+ pte_p = pte_val(entry) & _PAGE_PROTECT;
+ if ((pte_i && (prot != PROT_NONE)) ||
+ (pte_p && (prot & PROT_WRITE))) {
+ pgste_set_unlock(ptep, pgste);
+ return -EAGAIN;
+ }
+ /* Change access rights and set the pgste notification bit */
+ if (prot == PROT_NONE && !pte_i) {
+ ptep_flush_direct(mm, addr, ptep);
+ pgste = pgste_update_all(entry, pgste, mm);
+ pte_val(entry) |= _PAGE_INVALID;
+ }
+ if (prot == PROT_READ && !pte_p) {
+ ptep_flush_direct(mm, addr, ptep);
+ pte_val(entry) &= ~_PAGE_INVALID;
+ pte_val(entry) |= _PAGE_PROTECT;
+ }
+ pgste_val(pgste) |= PGSTE_IN_BIT;
+ pgste = pgste_set_pte(ptep, pgste, entry);
+ pgste_set_unlock(ptep, pgste);
+ return 0;
+}
+
static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
{
if (!non_swap_entry(entry))
@@ -483,7 +527,7 @@ bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
pgste_val(pgste) &= ~PGSTE_UC_BIT;
pte = *ptep;
if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
- pgste = pgste_ipte_notify(mm, addr, ptep, pgste);
+ pgste = pgste_pte_notify(mm, addr, ptep, pgste);
__ptep_ipte(addr, ptep);
if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
pte_val(pte) |= _PAGE_PROTECT;