linux/arch/arm/xen/p2m.c
Jan Beulich bce21a2b48 Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}
It's not helpful if every driver has to cook its own. Generalize
xenbus'es INVALID_GRANT_HANDLE and pcifront's INVALID_GRANT_REF (which
shouldn't have expanded to zero to begin with). Use the constants in
p2m.c and gntdev.c right away, and update field types where necessary so
they would match with the constants' types (albeit without touching
struct ioctl_gntdev_grant_ref's ref field, as that's part of the public
interface of the kernel and would require introducing a dependency on
Xen's grant_table.h public header).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/db7c38a5-0d75-d5d1-19de-e5fe9f0b9c48@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2021-03-10 16:39:29 -06:00

209 lines
4.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/memblock.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <linux/spinlock.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/grant_table.h>
#include <xen/page.h>
#include <xen/swiotlb-xen.h>
#include <asm/cacheflush.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_phys;
};
static rwlock_t p2m_lock;
struct rb_root phys_to_mach = RB_ROOT;
EXPORT_SYMBOL_GPL(phys_to_mach);
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->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) {
unsigned long mfn = entry->mfn + (pfn - entry->pfn);
read_unlock_irqrestore(&p2m_lock, irqflags);
return mfn;
}
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);
int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count)
{
int i;
for (i = 0; i < count; i++) {
struct gnttab_unmap_grant_ref unmap;
int rc;
if (map_ops[i].status)
continue;
if (likely(set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT)))
continue;
/*
* Signal an error for this slot. This in turn requires
* immediate unmapping.
*/
map_ops[i].status = GNTST_general_error;
unmap.host_addr = map_ops[i].host_addr,
unmap.handle = map_ops[i].handle;
map_ops[i].handle = INVALID_GRANT_HANDLE;
if (map_ops[i].flags & GNTMAP_device_map)
unmap.dev_bus_addr = map_ops[i].dev_bus_addr;
else
unmap.dev_bus_addr = 0;
/*
* Pre-populate the status field, to be recognizable in
* the log message below.
*/
unmap.status = 1;
rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
&unmap, 1);
if (rc || unmap.status != GNTST_okay)
pr_err_once("gnttab unmap failed: rc=%d st=%d\n",
rc, unmap.status);
}
return 0;
}
int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_unmap_grant_ref *kunmap_ops,
struct page **pages, unsigned int count)
{
int i;
for (i = 0; i < count; i++) {
set_phys_to_machine(unmap_ops[i].host_addr >> XEN_PAGE_SHIFT,
INVALID_P2M_ENTRY);
}
return 0;
}
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_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(*p2m_entry), GFP_NOWAIT);
if (!p2m_entry)
return false;
p2m_entry->pfn = pfn;
p2m_entry->nr_pages = nr_pages;
p2m_entry->mfn = mfn;
write_lock_irqsave(&p2m_lock, irqflags);
rc = xen_add_phys_to_mach_entry(p2m_entry);
if (rc < 0) {
write_unlock_irqrestore(&p2m_lock, irqflags);
kfree(p2m_entry);
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);