mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-12 05:24:12 +08:00
cf04d120d9
In case the mfn_list does not have enough entries to fill a p2m page we do not want the entries from max_pfn up to the boundary to be filled with unknown values. Hence set them to INVALID_P2M_ENTRY. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
523 lines
13 KiB
C
523 lines
13 KiB
C
/*
|
|
* Xen leaves the responsibility for maintaining p2m mappings to the
|
|
* guests themselves, but it must also access and update the p2m array
|
|
* during suspend/resume when all the pages are reallocated.
|
|
*
|
|
* The p2m table is logically a flat array, but we implement it as a
|
|
* three-level tree to allow the address space to be sparse.
|
|
*
|
|
* Xen
|
|
* |
|
|
* p2m_top p2m_top_mfn
|
|
* / \ / \
|
|
* p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn
|
|
* / \ / \ / /
|
|
* p2m p2m p2m p2m p2m p2m p2m ...
|
|
*
|
|
* The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
|
|
*
|
|
* The p2m_top and p2m_top_mfn levels are limited to 1 page, so the
|
|
* maximum representable pseudo-physical address space is:
|
|
* P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
|
|
*
|
|
* P2M_PER_PAGE depends on the architecture, as a mfn is always
|
|
* unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
|
|
* 512 and 1024 entries respectively.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/list.h>
|
|
#include <linux/hash.h>
|
|
#include <linux/sched.h>
|
|
|
|
#include <asm/cache.h>
|
|
#include <asm/setup.h>
|
|
|
|
#include <asm/xen/page.h>
|
|
#include <asm/xen/hypercall.h>
|
|
#include <asm/xen/hypervisor.h>
|
|
|
|
#include "xen-ops.h"
|
|
|
|
static void __init m2p_override_init(void);
|
|
|
|
unsigned long xen_max_p2m_pfn __read_mostly;
|
|
|
|
#define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
|
|
#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
|
|
#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
|
|
|
|
#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
|
|
|
|
/* Placeholders for holes in the address space */
|
|
static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);
|
|
static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);
|
|
static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE);
|
|
|
|
static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
|
|
static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);
|
|
static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);
|
|
|
|
RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
|
|
RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
|
|
|
|
static inline unsigned p2m_top_index(unsigned long pfn)
|
|
{
|
|
BUG_ON(pfn >= MAX_P2M_PFN);
|
|
return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
|
|
}
|
|
|
|
static inline unsigned p2m_mid_index(unsigned long pfn)
|
|
{
|
|
return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
|
|
}
|
|
|
|
static inline unsigned p2m_index(unsigned long pfn)
|
|
{
|
|
return pfn % P2M_PER_PAGE;
|
|
}
|
|
|
|
static void p2m_top_init(unsigned long ***top)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < P2M_TOP_PER_PAGE; i++)
|
|
top[i] = p2m_mid_missing;
|
|
}
|
|
|
|
static void p2m_top_mfn_init(unsigned long *top)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < P2M_TOP_PER_PAGE; i++)
|
|
top[i] = virt_to_mfn(p2m_mid_missing_mfn);
|
|
}
|
|
|
|
static void p2m_top_mfn_p_init(unsigned long **top)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < P2M_TOP_PER_PAGE; i++)
|
|
top[i] = p2m_mid_missing_mfn;
|
|
}
|
|
|
|
static void p2m_mid_init(unsigned long **mid)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < P2M_MID_PER_PAGE; i++)
|
|
mid[i] = p2m_missing;
|
|
}
|
|
|
|
static void p2m_mid_mfn_init(unsigned long *mid)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < P2M_MID_PER_PAGE; i++)
|
|
mid[i] = virt_to_mfn(p2m_missing);
|
|
}
|
|
|
|
static void p2m_init(unsigned long *p2m)
|
|
{
|
|
unsigned i;
|
|
|
|
for (i = 0; i < P2M_MID_PER_PAGE; i++)
|
|
p2m[i] = INVALID_P2M_ENTRY;
|
|
}
|
|
|
|
/*
|
|
* Build the parallel p2m_top_mfn and p2m_mid_mfn structures
|
|
*
|
|
* This is called both at boot time, and after resuming from suspend:
|
|
* - At boot time we're called very early, and must use extend_brk()
|
|
* to allocate memory.
|
|
*
|
|
* - After resume we're called from within stop_machine, but the mfn
|
|
* tree should alreay be completely allocated.
|
|
*/
|
|
void xen_build_mfn_list_list(void)
|
|
{
|
|
unsigned long pfn;
|
|
|
|
/* Pre-initialize p2m_top_mfn to be completely missing */
|
|
if (p2m_top_mfn == NULL) {
|
|
p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_mid_mfn_init(p2m_mid_missing_mfn);
|
|
|
|
p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_top_mfn_p_init(p2m_top_mfn_p);
|
|
|
|
p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_top_mfn_init(p2m_top_mfn);
|
|
} else {
|
|
/* Reinitialise, mfn's all change after migration */
|
|
p2m_mid_mfn_init(p2m_mid_missing_mfn);
|
|
}
|
|
|
|
for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
|
|
unsigned topidx = p2m_top_index(pfn);
|
|
unsigned mididx = p2m_mid_index(pfn);
|
|
unsigned long **mid;
|
|
unsigned long *mid_mfn_p;
|
|
|
|
mid = p2m_top[topidx];
|
|
mid_mfn_p = p2m_top_mfn_p[topidx];
|
|
|
|
/* Don't bother allocating any mfn mid levels if
|
|
* they're just missing, just update the stored mfn,
|
|
* since all could have changed over a migrate.
|
|
*/
|
|
if (mid == p2m_mid_missing) {
|
|
BUG_ON(mididx);
|
|
BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
|
|
p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
|
|
pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
|
|
continue;
|
|
}
|
|
|
|
if (mid_mfn_p == p2m_mid_missing_mfn) {
|
|
/*
|
|
* XXX boot-time only! We should never find
|
|
* missing parts of the mfn tree after
|
|
* runtime. extend_brk() will BUG if we call
|
|
* it too late.
|
|
*/
|
|
mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_mid_mfn_init(mid_mfn_p);
|
|
|
|
p2m_top_mfn_p[topidx] = mid_mfn_p;
|
|
}
|
|
|
|
p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
|
|
mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]);
|
|
}
|
|
}
|
|
|
|
void xen_setup_mfn_list_list(void)
|
|
{
|
|
BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
|
|
|
|
HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
|
|
virt_to_mfn(p2m_top_mfn);
|
|
HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
|
|
}
|
|
|
|
/* Set up p2m_top to point to the domain-builder provided p2m pages */
|
|
void __init xen_build_dynamic_phys_to_machine(void)
|
|
{
|
|
unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
|
|
unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
|
|
unsigned long pfn;
|
|
|
|
xen_max_p2m_pfn = max_pfn;
|
|
|
|
p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_init(p2m_missing);
|
|
|
|
p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_mid_init(p2m_mid_missing);
|
|
|
|
p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_top_init(p2m_top);
|
|
|
|
/*
|
|
* The domain builder gives us a pre-constructed p2m array in
|
|
* mfn_list for all the pages initially given to us, so we just
|
|
* need to graft that into our tree structure.
|
|
*/
|
|
for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) {
|
|
unsigned topidx = p2m_top_index(pfn);
|
|
unsigned mididx = p2m_mid_index(pfn);
|
|
|
|
if (p2m_top[topidx] == p2m_mid_missing) {
|
|
unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
|
|
p2m_mid_init(mid);
|
|
|
|
p2m_top[topidx] = mid;
|
|
}
|
|
|
|
/*
|
|
* As long as the mfn_list has enough entries to completely
|
|
* fill a p2m page, pointing into the array is ok. But if
|
|
* not the entries beyond the last pfn will be undefined.
|
|
*/
|
|
if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) {
|
|
unsigned long p2midx;
|
|
|
|
p2midx = max_pfn % P2M_PER_PAGE;
|
|
for ( ; p2midx < P2M_PER_PAGE; p2midx++)
|
|
mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY;
|
|
}
|
|
p2m_top[topidx][mididx] = &mfn_list[pfn];
|
|
}
|
|
|
|
m2p_override_init();
|
|
}
|
|
|
|
unsigned long get_phys_to_machine(unsigned long pfn)
|
|
{
|
|
unsigned topidx, mididx, idx;
|
|
|
|
if (unlikely(pfn >= MAX_P2M_PFN))
|
|
return INVALID_P2M_ENTRY;
|
|
|
|
topidx = p2m_top_index(pfn);
|
|
mididx = p2m_mid_index(pfn);
|
|
idx = p2m_index(pfn);
|
|
|
|
return p2m_top[topidx][mididx][idx];
|
|
}
|
|
EXPORT_SYMBOL_GPL(get_phys_to_machine);
|
|
|
|
static void *alloc_p2m_page(void)
|
|
{
|
|
return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
|
|
}
|
|
|
|
static void free_p2m_page(void *p)
|
|
{
|
|
free_page((unsigned long)p);
|
|
}
|
|
|
|
/*
|
|
* Fully allocate the p2m structure for a given pfn. We need to check
|
|
* that both the top and mid levels are allocated, and make sure the
|
|
* parallel mfn tree is kept in sync. We may race with other cpus, so
|
|
* the new pages are installed with cmpxchg; if we lose the race then
|
|
* simply free the page we allocated and use the one that's there.
|
|
*/
|
|
static bool alloc_p2m(unsigned long pfn)
|
|
{
|
|
unsigned topidx, mididx;
|
|
unsigned long ***top_p, **mid;
|
|
unsigned long *top_mfn_p, *mid_mfn;
|
|
|
|
topidx = p2m_top_index(pfn);
|
|
mididx = p2m_mid_index(pfn);
|
|
|
|
top_p = &p2m_top[topidx];
|
|
mid = *top_p;
|
|
|
|
if (mid == p2m_mid_missing) {
|
|
/* Mid level is missing, allocate a new one */
|
|
mid = alloc_p2m_page();
|
|
if (!mid)
|
|
return false;
|
|
|
|
p2m_mid_init(mid);
|
|
|
|
if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing)
|
|
free_p2m_page(mid);
|
|
}
|
|
|
|
top_mfn_p = &p2m_top_mfn[topidx];
|
|
mid_mfn = p2m_top_mfn_p[topidx];
|
|
|
|
BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
|
|
|
|
if (mid_mfn == p2m_mid_missing_mfn) {
|
|
/* Separately check the mid mfn level */
|
|
unsigned long missing_mfn;
|
|
unsigned long mid_mfn_mfn;
|
|
|
|
mid_mfn = alloc_p2m_page();
|
|
if (!mid_mfn)
|
|
return false;
|
|
|
|
p2m_mid_mfn_init(mid_mfn);
|
|
|
|
missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
|
|
mid_mfn_mfn = virt_to_mfn(mid_mfn);
|
|
if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn)
|
|
free_p2m_page(mid_mfn);
|
|
else
|
|
p2m_top_mfn_p[topidx] = mid_mfn;
|
|
}
|
|
|
|
if (p2m_top[topidx][mididx] == p2m_missing) {
|
|
/* p2m leaf page is missing */
|
|
unsigned long *p2m;
|
|
|
|
p2m = alloc_p2m_page();
|
|
if (!p2m)
|
|
return false;
|
|
|
|
p2m_init(p2m);
|
|
|
|
if (cmpxchg(&mid[mididx], p2m_missing, p2m) != p2m_missing)
|
|
free_p2m_page(p2m);
|
|
else
|
|
mid_mfn[mididx] = virt_to_mfn(p2m);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Try to install p2m mapping; fail if intermediate bits missing */
|
|
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
|
|
{
|
|
unsigned topidx, mididx, idx;
|
|
|
|
if (unlikely(pfn >= MAX_P2M_PFN)) {
|
|
BUG_ON(mfn != INVALID_P2M_ENTRY);
|
|
return true;
|
|
}
|
|
|
|
topidx = p2m_top_index(pfn);
|
|
mididx = p2m_mid_index(pfn);
|
|
idx = p2m_index(pfn);
|
|
|
|
if (p2m_top[topidx][mididx] == p2m_missing)
|
|
return mfn == INVALID_P2M_ENTRY;
|
|
|
|
p2m_top[topidx][mididx][idx] = mfn;
|
|
|
|
return true;
|
|
}
|
|
|
|
bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
|
|
{
|
|
if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
|
|
BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
|
|
return true;
|
|
}
|
|
|
|
if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
|
|
if (!alloc_p2m(pfn))
|
|
return false;
|
|
|
|
if (!__set_phys_to_machine(pfn, mfn))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
#define M2P_OVERRIDE_HASH_SHIFT 10
|
|
#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
|
|
|
|
static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH);
|
|
static DEFINE_SPINLOCK(m2p_override_lock);
|
|
|
|
static void __init m2p_override_init(void)
|
|
{
|
|
unsigned i;
|
|
|
|
m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH,
|
|
sizeof(unsigned long));
|
|
|
|
for (i = 0; i < M2P_OVERRIDE_HASH; i++)
|
|
INIT_LIST_HEAD(&m2p_overrides[i]);
|
|
}
|
|
|
|
static unsigned long mfn_hash(unsigned long mfn)
|
|
{
|
|
return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT);
|
|
}
|
|
|
|
/* Add an MFN override for a particular page */
|
|
int m2p_add_override(unsigned long mfn, struct page *page)
|
|
{
|
|
unsigned long flags;
|
|
unsigned long pfn;
|
|
unsigned long address;
|
|
unsigned level;
|
|
pte_t *ptep = NULL;
|
|
|
|
pfn = page_to_pfn(page);
|
|
if (!PageHighMem(page)) {
|
|
address = (unsigned long)__va(pfn << PAGE_SHIFT);
|
|
ptep = lookup_address(address, &level);
|
|
|
|
if (WARN(ptep == NULL || level != PG_LEVEL_4K,
|
|
"m2p_add_override: pfn %lx not mapped", pfn))
|
|
return -EINVAL;
|
|
}
|
|
|
|
page->private = mfn;
|
|
page->index = pfn_to_mfn(pfn);
|
|
|
|
__set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));
|
|
if (!PageHighMem(page))
|
|
/* Just zap old mapping for now */
|
|
pte_clear(&init_mm, address, ptep);
|
|
|
|
spin_lock_irqsave(&m2p_override_lock, flags);
|
|
list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]);
|
|
spin_unlock_irqrestore(&m2p_override_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int m2p_remove_override(struct page *page)
|
|
{
|
|
unsigned long flags;
|
|
unsigned long mfn;
|
|
unsigned long pfn;
|
|
unsigned long address;
|
|
unsigned level;
|
|
pte_t *ptep = NULL;
|
|
|
|
pfn = page_to_pfn(page);
|
|
mfn = get_phys_to_machine(pfn);
|
|
if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
|
|
return -EINVAL;
|
|
|
|
if (!PageHighMem(page)) {
|
|
address = (unsigned long)__va(pfn << PAGE_SHIFT);
|
|
ptep = lookup_address(address, &level);
|
|
|
|
if (WARN(ptep == NULL || level != PG_LEVEL_4K,
|
|
"m2p_remove_override: pfn %lx not mapped", pfn))
|
|
return -EINVAL;
|
|
}
|
|
|
|
spin_lock_irqsave(&m2p_override_lock, flags);
|
|
list_del(&page->lru);
|
|
spin_unlock_irqrestore(&m2p_override_lock, flags);
|
|
__set_phys_to_machine(pfn, page->index);
|
|
|
|
if (!PageHighMem(page))
|
|
set_pte_at(&init_mm, address, ptep,
|
|
pfn_pte(pfn, PAGE_KERNEL));
|
|
/* No tlb flush necessary because the caller already
|
|
* left the pte unmapped. */
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct page *m2p_find_override(unsigned long mfn)
|
|
{
|
|
unsigned long flags;
|
|
struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)];
|
|
struct page *p, *ret;
|
|
|
|
ret = NULL;
|
|
|
|
spin_lock_irqsave(&m2p_override_lock, flags);
|
|
|
|
list_for_each_entry(p, bucket, lru) {
|
|
if (p->private == mfn) {
|
|
ret = p;
|
|
break;
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&m2p_override_lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn)
|
|
{
|
|
struct page *p = m2p_find_override(mfn);
|
|
unsigned long ret = pfn;
|
|
|
|
if (p)
|
|
ret = page_to_pfn(p);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(m2p_find_override_pfn);
|