minios: make allocation of page tables for ondemand mapping lazy
Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx>
diff -r 898ce9341e6b extras/mini-os/arch/x86/mm.c
--- a/extras/mini-os/arch/x86/mm.c Tue Jan 22 14:20:37 2008 +0000
+++ b/extras/mini-os/arch/x86/mm.c Tue Jan 22 17:34:29 2008 +0000
@@ -366,93 +366,106 @@
}
-static pgentry_t *demand_map_pgt;
-static void *demand_map_area_start;
-#define DEMAND_MAP_PAGES 1024
-
-void arch_init_demand_mapping_area(unsigned long max_pfn)
+static pgentry_t *get_pgt(unsigned long addr)
{
unsigned long mfn;
pgentry_t *tab;
- unsigned long start_addr;
+ unsigned offset;
+
+ tab = (pgentry_t *)start_info.pt_base;
+ mfn = virt_to_mfn(start_info.pt_base);
+
+#if defined(__x86_64__)
+ offset = l4_table_offset(addr);
+ if (!(tab[offset] & _PAGE_PRESENT))
+ return NULL;
+ mfn = pte_to_mfn(tab[offset]);
+ tab = mfn_to_virt(mfn);
+#endif
+#if defined(__x86_64__) || defined(CONFIG_X86_PAE)
+ offset = l3_table_offset(addr);
+ if (!(tab[offset] & _PAGE_PRESENT))
+ return NULL;
+ mfn = pte_to_mfn(tab[offset]);
+ tab = mfn_to_virt(mfn);
+#endif
+ offset = l2_table_offset(addr);
+ if (!(tab[offset] & _PAGE_PRESENT))
+ return NULL;
+ mfn = pte_to_mfn(tab[offset]);
+ tab = mfn_to_virt(mfn);
+ offset = l1_table_offset(addr);
+ return &tab[offset];
+}
+
+static pgentry_t *need_pgt(unsigned long addr)
+{
+ unsigned long mfn;
+ pgentry_t *tab;
unsigned long pt_pfn;
unsigned offset;
- /* Round up to four megs. + 1024 rather than + 1023 since we want
- to be sure we don't end up in the same place we started. */
- max_pfn = (max_pfn + L1_PAGETABLE_ENTRIES) & ~(L1_PAGETABLE_ENTRIES - 1);
- if (max_pfn == 0 ||
- (unsigned long)pfn_to_virt(max_pfn + L1_PAGETABLE_ENTRIES) >=
- HYPERVISOR_VIRT_START) {
- printk("Too much memory; no room for demand map hole.\n");
- do_exit();
- }
-
- demand_map_area_start = pfn_to_virt(max_pfn);
- printk("Demand map pfns start at %lx (%p).\n", max_pfn,
- demand_map_area_start);
- start_addr = (unsigned long)demand_map_area_start;
-
tab = (pgentry_t *)start_info.pt_base;
mfn = virt_to_mfn(start_info.pt_base);
- pt_pfn = virt_to_pfn(alloc_page());
#if defined(__x86_64__)
- offset = l4_table_offset(start_addr);
+ offset = l4_table_offset(addr);
if (!(tab[offset] & _PAGE_PRESENT)) {
+ pt_pfn = virt_to_pfn(alloc_page());
new_pt_frame(&pt_pfn, mfn, offset, L3_FRAME);
- pt_pfn = virt_to_pfn(alloc_page());
}
ASSERT(tab[offset] & _PAGE_PRESENT);
mfn = pte_to_mfn(tab[offset]);
- tab = to_virt(mfn_to_pfn(mfn) << PAGE_SHIFT);
+ tab = mfn_to_virt(mfn);
#endif
#if defined(__x86_64__) || defined(CONFIG_X86_PAE)
- offset = l3_table_offset(start_addr);
+ offset = l3_table_offset(addr);
if (!(tab[offset] & _PAGE_PRESENT)) {
+ pt_pfn = virt_to_pfn(alloc_page());
new_pt_frame(&pt_pfn, mfn, offset, L2_FRAME);
- pt_pfn = virt_to_pfn(alloc_page());
}
ASSERT(tab[offset] & _PAGE_PRESENT);
mfn = pte_to_mfn(tab[offset]);
- tab = to_virt(mfn_to_pfn(mfn) << PAGE_SHIFT);
+ tab = mfn_to_virt(mfn);
#endif
- offset = l2_table_offset(start_addr);
- if (tab[offset] & _PAGE_PRESENT) {
- printk("Demand map area already has a page table covering it?\n");
- BUG();
+ offset = l2_table_offset(addr);
+ if (!(tab[offset] & _PAGE_PRESENT)) {
+ pt_pfn = virt_to_pfn(alloc_page());
+ new_pt_frame(&pt_pfn, mfn, offset, L1_FRAME);
}
- demand_map_pgt = pfn_to_virt(pt_pfn);
- new_pt_frame(&pt_pfn, mfn, offset, L1_FRAME);
ASSERT(tab[offset] & _PAGE_PRESENT);
- printk("Initialised demand area.\n");
+ mfn = pte_to_mfn(tab[offset]);
+ tab = mfn_to_virt(mfn);
+
+ offset = l1_table_offset(addr);
+ return &tab[offset];
+}
+
+static unsigned long demand_map_area_start;
+#ifdef __x86_64__
+#define DEMAND_MAP_PAGES ((128ULL << 30) / PAGE_SIZE)
+#else
+#define DEMAND_MAP_PAGES ((2ULL << 30) / PAGE_SIZE)
+#endif
+
+void arch_init_demand_mapping_area(unsigned long cur_pfn)
+{
+ cur_pfn++;
+
+ demand_map_area_start = (unsigned long) pfn_to_virt(cur_pfn);
+ cur_pfn += DEMAND_MAP_PAGES;
+ printk("Demand map pfns at %lx-%lx.\n", demand_map_area_start,
pfn_to_virt(cur_pfn));
}
#define MAP_BATCH ((STACK_SIZE / 2) / sizeof(mmu_update_t))
-
-void *map_frames_ex(unsigned long *f, unsigned long n, unsigned long stride,
- unsigned long increment, unsigned long alignment, domid_t id,
- int may_fail, unsigned long prot)
+void do_map_frames(unsigned long addr,
+ unsigned long *f, unsigned long n, unsigned long stride,
+ unsigned long increment, domid_t id, int may_fail, unsigned long prot)
{
- unsigned long x;
- unsigned long y = 0;
+ pgentry_t *pgt = NULL;
+ unsigned long done = 0;
+ unsigned long i;
int rc;
- unsigned long done = 0;
-
- /* Find a run of n contiguous frames */
- for (x = 0; x <= DEMAND_MAP_PAGES - n; x = (x + y + 1 + alignment - 1) &
~(alignment - 1)) {
- for (y = 0; y < n; y++)
- if (demand_map_pgt[x+y] & _PAGE_PRESENT)
- break;
- if (y == n)
- break;
- }
- if (y != n) {
- printk("Failed to find %ld frames!\n", n);
- return NULL;
- }
-
- /* Found it at x. Map it in. */
while (done < n) {
unsigned long todo;
@@ -468,9 +481,11 @@
{
mmu_update_t mmu_updates[todo];
- for (y = 0; y < todo; y++) {
- mmu_updates[y].ptr = virt_to_mach(&demand_map_pgt[x + done +
y]);
- mmu_updates[y].val = ((f[(done + y) * stride] + (done + y) *
increment) << PAGE_SHIFT) | prot;
+ for (i = 0; i < todo; i++, addr += PAGE_SIZE, pgt++) {
+ if (!pgt || !(addr & L1_MASK))
+ pgt = need_pgt(addr);
+ mmu_updates[i].ptr = virt_to_mach(pgt);
+ mmu_updates[i].val = ((f[(done + i) * stride] + (done + i) *
increment) << PAGE_SHIFT) | prot;
}
rc = HYPERVISOR_mmu_update(mmu_updates, todo, NULL, id);
@@ -478,16 +493,48 @@
if (may_fail)
f[done * stride] |= 0xF0000000;
else {
- printk("Map %ld (%lx, ...) failed: %d.\n", todo, f[done *
stride], rc);
- return NULL;
+ printk("Map %ld (%lx, ...) at %p failed: %d.\n", todo,
f[done * stride] + done * increment, addr, rc);
+ do_exit();
}
}
}
done += todo;
}
- return (void *)(unsigned long)((unsigned long)demand_map_area_start +
- x * PAGE_SIZE);
+}
+
+void *map_frames_ex(unsigned long *f, unsigned long n, unsigned long stride,
+ unsigned long increment, unsigned long alignment, domid_t id,
+ int may_fail, unsigned long prot)
+{
+ unsigned long x;
+ unsigned long y = 0;
+
+ /* Find a properly aligned run of n contiguous frames */
+ for (x = 0; x <= DEMAND_MAP_PAGES - n; x = (x + y + 1 + alignment - 1) &
~(alignment - 1)) {
+ unsigned long addr = demand_map_area_start + x * PAGE_SIZE;
+ pgentry_t *pgt = get_pgt(addr);
+ for (y = 0; y < n; y++, addr += PAGE_SIZE) {
+ if (!(addr & L1_MASK))
+ pgt = get_pgt(addr);
+ if (pgt) {
+ if (*pgt & _PAGE_PRESENT)
+ break;
+ pgt++;
+ }
+ }
+ if (y == n)
+ break;
+ }
+ if (y != n) {
+ printk("Failed to find %ld frames!\n", n);
+ return NULL;
+ }
+
+ /* Found it at x. Map it in. */
+ do_map_frames(demand_map_area_start + x * PAGE_SIZE, f, n, stride,
increment, id, may_fail, prot);
+
+ return (void *)(unsigned long)(demand_map_area_start + x * PAGE_SIZE);
}
static void clear_bootstrap(void)
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