#include <asm/e820.h>
#include <asm/linkage.h>
#include <asm/page.h>
++#include <asm/init.h>
++ #include <asm/pat.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
*/
#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
- #define P2M_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
- #define TOP_ENTRIES (MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)
++ /*
++ * 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.
++ */
+
++ unsigned long xen_max_p2m_pfn __read_mostly;
- #define P2M_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
- #define TOP_ENTRIES (MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)
- /* Placeholder for holes in the address space */
- static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE] __page_aligned_data =
- { [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
++ #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 **))
- /* Placeholder for holes in the address space */
- static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE] __page_aligned_data =
- { [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
- /* Array of pointers to pages containing p2m entries */
- static unsigned long *p2m_top[TOP_ENTRIES] __page_aligned_data =
- { [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
++ #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
- /* Array of pointers to pages containing p2m entries */
- static unsigned long *p2m_top[TOP_ENTRIES] __page_aligned_data =
- { [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
- /* Arrays of p2m arrays expressed in mfns used for save/restore */
- static unsigned long p2m_top_mfn[TOP_ENTRIES] __page_aligned_bss;
++ /* 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);
- /* Arrays of p2m arrays expressed in mfns used for save/restore */
- static unsigned long p2m_top_mfn[TOP_ENTRIES] __page_aligned_bss;
- static unsigned long p2m_top_mfn_list[TOP_ENTRIES / P2M_ENTRIES_PER_PAGE]
- __page_aligned_bss;
++ 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);
+
- static unsigned long p2m_top_mfn_list[TOP_ENTRIES / P2M_ENTRIES_PER_PAGE]
- __page_aligned_bss;
++ 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)
{
static inline unsigned p2m_index(unsigned long pfn)
{
-- return pfn % P2M_ENTRIES_PER_PAGE;
++ return pfn % P2M_PER_PAGE;
+ }
+
- /* Build the parallel p2m_top_mfn structures */
++ 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);
+ }
+
- /* Build the parallel p2m_top_mfn structures */
++ 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 pfn, idx;
++ unsigned long pfn;
-- for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_ENTRIES_PER_PAGE) {
-- unsigned topidx = p2m_top_index(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[topidx] = virt_to_mfn(p2m_top[topidx]);
++ 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 (idx = 0; idx < ARRAY_SIZE(p2m_top_mfn_list); idx++) {
-- unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
-- p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
++ 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]);
}
}
{
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 pfn;
++ unsigned long pfn;
++
++ xen_max_p2m_pfn = max_pfn;
+
- for (pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
++ p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
++ p2m_init(p2m_missing);
+
- for (pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
++ 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);
-- p2m_top[topidx] = &mfn_list[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;
++ }
-- xen_build_mfn_list_list();
++ p2m_top[topidx][mididx] = &mfn_list[pfn];
++ }
}
unsigned long get_phys_to_machine(unsigned long pfn)
}
EXPORT_SYMBOL_GPL(get_phys_to_machine);
-- /* install a new p2m_top page */
-- bool install_p2mtop_page(unsigned long pfn, unsigned long *p)
++ static void *alloc_p2m_page(void)
{
-- unsigned topidx = p2m_top_index(pfn);
-- unsigned long **pfnp, *mfnp;
-- unsigned i;
++ return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
++ }
-- pfnp = &p2m_top[topidx];
-- mfnp = &p2m_top_mfn[topidx];
++ static void free_p2m_page(void *p)
++ {
++ free_page((unsigned long)p);
++ }
-- for (i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
-- p[i] = INVALID_P2M_ENTRY;
++ /*
++ * 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;
-- if (cmpxchg(pfnp, p2m_missing, p) == p2m_missing) {
-- *mfnp = virt_to_mfn(p);
-- return true;
++ 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);
}
-- return false;
-- }
++ top_mfn_p = &p2m_top_mfn[topidx];
++ mid_mfn = p2m_top_mfn_p[topidx];
-- static void alloc_p2m(unsigned long pfn)
-- {
-- unsigned long *p;
++ 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;
+
- p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);
- BUG_ON(p == NULL);
++ mid_mfn = alloc_p2m_page();
++ if (!mid_mfn)
++ return false;
+
- if (!install_p2mtop_page(pfn, p))
- free_page((unsigned long)p);
++ 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;
+
- p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);
- BUG_ON(p == NULL);
++ p2m_init(p2m);
++
++ if (cmpxchg(&mid[mididx], p2m_missing, p2m) != p2m_missing)
++ free_p2m_page(p2m);
++ else
++ mid_mfn[mididx] = virt_to_mfn(p2m);
++ }
+
- if (!install_p2mtop_page(pfn, p))
- free_page((unsigned long)p);
++ return true;
}
/* Try to install p2m mapping; fail if intermediate bits missing */
projects / cascardo / linux.git / commitdiff