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Merge branch 'stable/e820-3.2' of git://git.kernel.org/pub/scm/linux/…
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…kernel/git/konrad/xen

* 'stable/e820-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: release all pages within 1-1 p2m mappings
  xen: allow extra memory to be in multiple regions
  xen: allow balloon driver to use more than one memory region
  xen/balloon: simplify test for the end of usable RAM
  xen/balloon: account for pages released during memory setup
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Linus Torvalds committed Oct 25, 2011
2 parents 315eb8a + f3f436e commit 5eef150
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Showing 3 changed files with 165 additions and 181 deletions.
284 changes: 123 additions & 161 deletions arch/x86/xen/setup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,10 @@ extern void xen_syscall_target(void);
extern void xen_syscall32_target(void);

/* Amount of extra memory space we add to the e820 ranges */
phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;

/* Number of pages released from the initial allocation. */
unsigned long xen_released_pages;

/*
* The maximum amount of extra memory compared to the base size. The
Expand All @@ -51,48 +54,47 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
*/
#define EXTRA_MEM_RATIO (10)

static void __init xen_add_extra_mem(unsigned long pages)
static void __init xen_add_extra_mem(u64 start, u64 size)
{
unsigned long pfn;
int i;

u64 size = (u64)pages * PAGE_SIZE;
u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;

if (!pages)
return;

e820_add_region(extra_start, size, E820_RAM);
sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
/* Add new region. */
if (xen_extra_mem[i].size == 0) {
xen_extra_mem[i].start = start;
xen_extra_mem[i].size = size;
break;
}
/* Append to existing region. */
if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
xen_extra_mem[i].size += size;
break;
}
}
if (i == XEN_EXTRA_MEM_MAX_REGIONS)
printk(KERN_WARNING "Warning: not enough extra memory regions\n");

xen_extra_mem_size += size;
memblock_x86_reserve_range(start, start + size, "XEN EXTRA");

xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
xen_max_p2m_pfn = PFN_DOWN(start + size);

for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)
for (pfn = PFN_DOWN(start); pfn <= xen_max_p2m_pfn; pfn++)
__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
}

static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
phys_addr_t end_addr)
static unsigned long __init xen_release_chunk(unsigned long start,
unsigned long end)
{
struct xen_memory_reservation reservation = {
.address_bits = 0,
.extent_order = 0,
.domid = DOMID_SELF
};
unsigned long start, end;
unsigned long len = 0;
unsigned long pfn;
int ret;

start = PFN_UP(start_addr);
end = PFN_DOWN(end_addr);

if (end <= start)
return 0;

for(pfn = start; pfn < end; pfn++) {
unsigned long mfn = pfn_to_mfn(pfn);

Expand All @@ -117,72 +119,52 @@ static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
return len;
}

static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
const struct e820map *e820)
static unsigned long __init xen_set_identity_and_release(
const struct e820entry *list, size_t map_size, unsigned long nr_pages)
{
phys_addr_t max_addr = PFN_PHYS(max_pfn);
phys_addr_t last_end = ISA_END_ADDRESS;
phys_addr_t start = 0;
unsigned long released = 0;
int i;

/* Free any unused memory above the low 1Mbyte. */
for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
phys_addr_t end = e820->map[i].addr;
end = min(max_addr, end);

if (last_end < end)
released += xen_release_chunk(last_end, end);
last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
}

if (last_end < max_addr)
released += xen_release_chunk(last_end, max_addr);

printk(KERN_INFO "released %lu pages of unused memory\n", released);
return released;
}

static unsigned long __init xen_set_identity(const struct e820entry *list,
ssize_t map_size)
{
phys_addr_t last = xen_initial_domain() ? 0 : ISA_END_ADDRESS;
phys_addr_t start_pci = last;
const struct e820entry *entry;
unsigned long identity = 0;
const struct e820entry *entry;
int i;

/*
* Combine non-RAM regions and gaps until a RAM region (or the
* end of the map) is reached, then set the 1:1 map and
* release the pages (if available) in those non-RAM regions.
*
* The combined non-RAM regions are rounded to a whole number
* of pages so any partial pages are accessible via the 1:1
* mapping. This is needed for some BIOSes that put (for
* example) the DMI tables in a reserved region that begins on
* a non-page boundary.
*/
for (i = 0, entry = list; i < map_size; i++, entry++) {
phys_addr_t start = entry->addr;
phys_addr_t end = start + entry->size;
phys_addr_t end = entry->addr + entry->size;

if (start < last)
start = last;
if (entry->type == E820_RAM || i == map_size - 1) {
unsigned long start_pfn = PFN_DOWN(start);
unsigned long end_pfn = PFN_UP(end);

if (end <= start)
continue;
if (entry->type == E820_RAM)
end_pfn = PFN_UP(entry->addr);

/* Skip over the 1MB region. */
if (last > end)
continue;
if (start_pfn < end_pfn) {
if (start_pfn < nr_pages)
released += xen_release_chunk(
start_pfn, min(end_pfn, nr_pages));

if ((entry->type == E820_RAM) || (entry->type == E820_UNUSABLE)) {
if (start > start_pci)
identity += set_phys_range_identity(
PFN_UP(start_pci), PFN_DOWN(start));

/* Without saving 'last' we would gooble RAM too
* at the end of the loop. */
last = end;
start_pci = end;
continue;
start_pfn, end_pfn);
}
start = end;
}
start_pci = min(start, start_pci);
last = end;
}
if (last > start_pci)
identity += set_phys_range_identity(
PFN_UP(start_pci), PFN_DOWN(last));
return identity;

printk(KERN_INFO "Released %lu pages of unused memory\n", released);
printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);

return released;
}

static unsigned long __init xen_get_max_pages(void)
Expand All @@ -197,21 +179,32 @@ static unsigned long __init xen_get_max_pages(void)
return min(max_pages, MAX_DOMAIN_PAGES);
}

static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
{
u64 end = start + size;

/* Align RAM regions to page boundaries. */
if (type == E820_RAM) {
start = PAGE_ALIGN(start);
end &= ~((u64)PAGE_SIZE - 1);
}

e820_add_region(start, end - start, type);
}

/**
* machine_specific_memory_setup - Hook for machine specific memory setup.
**/
char * __init xen_memory_setup(void)
{
static struct e820entry map[E820MAX] __initdata;
static struct e820entry map_raw[E820MAX] __initdata;

unsigned long max_pfn = xen_start_info->nr_pages;
unsigned long long mem_end;
int rc;
struct xen_memory_map memmap;
unsigned long max_pages;
unsigned long extra_pages = 0;
unsigned long extra_limit;
unsigned long identity_pages = 0;
int i;
int op;

Expand All @@ -237,58 +230,65 @@ char * __init xen_memory_setup(void)
}
BUG_ON(rc);

memcpy(map_raw, map, sizeof(map));
e820.nr_map = 0;
xen_extra_mem_start = mem_end;
for (i = 0; i < memmap.nr_entries; i++) {
unsigned long long end;

/* Guard against non-page aligned E820 entries. */
if (map[i].type == E820_RAM)
map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;

end = map[i].addr + map[i].size;
if (map[i].type == E820_RAM && end > mem_end) {
/* RAM off the end - may be partially included */
u64 delta = min(map[i].size, end - mem_end);

map[i].size -= delta;
end -= delta;

extra_pages += PFN_DOWN(delta);
/*
* Set RAM below 4GB that is not for us to be unusable.
* This prevents "System RAM" address space from being
* used as potential resource for I/O address (happens
* when 'allocate_resource' is called).
*/
if (delta &&
(xen_initial_domain() && end < 0x100000000ULL))
e820_add_region(end, delta, E820_UNUSABLE);
/* Make sure the Xen-supplied memory map is well-ordered. */
sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);

max_pages = xen_get_max_pages();
if (max_pages > max_pfn)
extra_pages += max_pages - max_pfn;

/*
* Set P2M for all non-RAM pages and E820 gaps to be identity
* type PFNs. Any RAM pages that would be made inaccesible by
* this are first released.
*/
xen_released_pages = xen_set_identity_and_release(
map, memmap.nr_entries, max_pfn);
extra_pages += xen_released_pages;

/*
* Clamp the amount of extra memory to a EXTRA_MEM_RATIO
* factor the base size. On non-highmem systems, the base
* size is the full initial memory allocation; on highmem it
* is limited to the max size of lowmem, so that it doesn't
* get completely filled.
*
* In principle there could be a problem in lowmem systems if
* the initial memory is also very large with respect to
* lowmem, but we won't try to deal with that here.
*/
extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
extra_pages);

i = 0;
while (i < memmap.nr_entries) {
u64 addr = map[i].addr;
u64 size = map[i].size;
u32 type = map[i].type;

if (type == E820_RAM) {
if (addr < mem_end) {
size = min(size, mem_end - addr);
} else if (extra_pages) {
size = min(size, (u64)extra_pages * PAGE_SIZE);
extra_pages -= size / PAGE_SIZE;
xen_add_extra_mem(addr, size);
} else
type = E820_UNUSABLE;
}

if (map[i].size > 0 && end > xen_extra_mem_start)
xen_extra_mem_start = end;
xen_align_and_add_e820_region(addr, size, type);

/* Add region if any remains */
if (map[i].size > 0)
e820_add_region(map[i].addr, map[i].size, map[i].type);
map[i].addr += size;
map[i].size -= size;
if (map[i].size == 0)
i++;
}
/* Align the balloon area so that max_low_pfn does not get set
* to be at the _end_ of the PCI gap at the far end (fee01000).
* Note that xen_extra_mem_start gets set in the loop above to be
* past the last E820 region. */
if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32)))
xen_extra_mem_start = (1ULL<<32);

/*
* In domU, the ISA region is normal, usable memory, but we
* reserve ISA memory anyway because too many things poke
* about in there.
*
* In Dom0, the host E820 information can leave gaps in the
* ISA range, which would cause us to release those pages. To
* avoid this, we unconditionally reserve them here.
*/
e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
E820_RESERVED);
Expand All @@ -305,44 +305,6 @@ char * __init xen_memory_setup(void)

sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

extra_limit = xen_get_max_pages();
if (max_pfn + extra_pages > extra_limit) {
if (extra_limit > max_pfn)
extra_pages = extra_limit - max_pfn;
else
extra_pages = 0;
}

extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);

/*
* Clamp the amount of extra memory to a EXTRA_MEM_RATIO
* factor the base size. On non-highmem systems, the base
* size is the full initial memory allocation; on highmem it
* is limited to the max size of lowmem, so that it doesn't
* get completely filled.
*
* In principle there could be a problem in lowmem systems if
* the initial memory is also very large with respect to
* lowmem, but we won't try to deal with that here.
*/
extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
max_pfn + extra_pages);

if (extra_limit >= max_pfn)
extra_pages = extra_limit - max_pfn;
else
extra_pages = 0;

xen_add_extra_mem(extra_pages);

/*
* Set P2M for all non-RAM pages and E820 gaps to be identity
* type PFNs. We supply it with the non-sanitized version
* of the E820.
*/
identity_pages = xen_set_identity(map_raw, memmap.nr_entries);
printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages);
return "Xen";
}

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