p2m.c
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#include <linux/bootmem.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <linux/rwlock.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/swiotlb.h>
#include <xen/xen.h>
#include <xen/interface/memory.h>
#include <xen/swiotlb-xen.h>
#include <asm/cacheflush.h>
#include <asm/xen/page.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>
struct xen_p2m_entry {
unsigned long pfn;
unsigned long mfn;
unsigned long nr_pages;
struct rb_node rbnode_mach;
struct rb_node rbnode_phys;
};
static rwlock_t p2m_lock;
struct rb_root phys_to_mach = RB_ROOT;
EXPORT_SYMBOL_GPL(phys_to_mach);
static struct rb_root mach_to_phys = RB_ROOT;
static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
{
struct rb_node **link = &phys_to_mach.rb_node;
struct rb_node *parent = NULL;
struct xen_p2m_entry *entry;
int rc = 0;
while (*link) {
parent = *link;
entry = rb_entry(parent, struct xen_p2m_entry, rbnode_phys);
if (new->mfn == entry->mfn)
goto err_out;
if (new->pfn == entry->pfn)
goto err_out;
if (new->pfn < entry->pfn)
link = &(*link)->rb_left;
else
link = &(*link)->rb_right;
}
rb_link_node(&new->rbnode_phys, parent, link);
rb_insert_color(&new->rbnode_phys, &phys_to_mach);
goto out;
err_out:
rc = -EINVAL;
pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
__func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
out:
return rc;
}
unsigned long __pfn_to_mfn(unsigned long pfn)
{
struct rb_node *n = phys_to_mach.rb_node;
struct xen_p2m_entry *entry;
unsigned long irqflags;
read_lock_irqsave(&p2m_lock, irqflags);
while (n) {
entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
if (entry->pfn <= pfn &&
entry->pfn + entry->nr_pages > pfn) {
read_unlock_irqrestore(&p2m_lock, irqflags);
return entry->mfn + (pfn - entry->pfn);
}
if (pfn < entry->pfn)
n = n->rb_left;
else
n = n->rb_right;
}
read_unlock_irqrestore(&p2m_lock, irqflags);
return INVALID_P2M_ENTRY;
}
EXPORT_SYMBOL_GPL(__pfn_to_mfn);
static int xen_add_mach_to_phys_entry(struct xen_p2m_entry *new)
{
struct rb_node **link = &mach_to_phys.rb_node;
struct rb_node *parent = NULL;
struct xen_p2m_entry *entry;
int rc = 0;
while (*link) {
parent = *link;
entry = rb_entry(parent, struct xen_p2m_entry, rbnode_mach);
if (new->mfn == entry->mfn)
goto err_out;
if (new->pfn == entry->pfn)
goto err_out;
if (new->mfn < entry->mfn)
link = &(*link)->rb_left;
else
link = &(*link)->rb_right;
}
rb_link_node(&new->rbnode_mach, parent, link);
rb_insert_color(&new->rbnode_mach, &mach_to_phys);
goto out;
err_out:
rc = -EINVAL;
pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
__func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
out:
return rc;
}
unsigned long __mfn_to_pfn(unsigned long mfn)
{
struct rb_node *n = mach_to_phys.rb_node;
struct xen_p2m_entry *entry;
unsigned long irqflags;
read_lock_irqsave(&p2m_lock, irqflags);
while (n) {
entry = rb_entry(n, struct xen_p2m_entry, rbnode_mach);
if (entry->mfn <= mfn &&
entry->mfn + entry->nr_pages > mfn) {
read_unlock_irqrestore(&p2m_lock, irqflags);
return entry->pfn + (mfn - entry->mfn);
}
if (mfn < entry->mfn)
n = n->rb_left;
else
n = n->rb_right;
}
read_unlock_irqrestore(&p2m_lock, irqflags);
return INVALID_P2M_ENTRY;
}
EXPORT_SYMBOL_GPL(__mfn_to_pfn);
bool __set_phys_to_machine_multi(unsigned long pfn,
unsigned long mfn, unsigned long nr_pages)
{
int rc;
unsigned long irqflags;
struct xen_p2m_entry *p2m_entry;
struct rb_node *n = phys_to_mach.rb_node;
if (mfn == INVALID_P2M_ENTRY) {
write_lock_irqsave(&p2m_lock, irqflags);
while (n) {
p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
if (p2m_entry->pfn <= pfn &&
p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
rb_erase(&p2m_entry->rbnode_mach, &mach_to_phys);
rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
write_unlock_irqrestore(&p2m_lock, irqflags);
kfree(p2m_entry);
return true;
}
if (pfn < p2m_entry->pfn)
n = n->rb_left;
else
n = n->rb_right;
}
write_unlock_irqrestore(&p2m_lock, irqflags);
return true;
}
p2m_entry = kzalloc(sizeof(struct xen_p2m_entry), GFP_NOWAIT);
if (!p2m_entry) {
pr_warn("cannot allocate xen_p2m_entry\n");
return false;
}
p2m_entry->pfn = pfn;
p2m_entry->nr_pages = nr_pages;
p2m_entry->mfn = mfn;
write_lock_irqsave(&p2m_lock, irqflags);
if ((rc = xen_add_phys_to_mach_entry(p2m_entry) < 0) ||
(rc = xen_add_mach_to_phys_entry(p2m_entry) < 0)) {
write_unlock_irqrestore(&p2m_lock, irqflags);
return false;
}
write_unlock_irqrestore(&p2m_lock, irqflags);
return true;
}
EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
return __set_phys_to_machine_multi(pfn, mfn, 1);
}
EXPORT_SYMBOL_GPL(__set_phys_to_machine);
static int p2m_init(void)
{
rwlock_init(&p2m_lock);
return 0;
}
arch_initcall(p2m_init);