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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Improve make_page_readonly and make_page_writable:
# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 8b384e7413827c381924cc741c818a5f33ed2ca2
# Parent 69ea493e415a2e583e91097bfd0d8d5146f6cc2a
Improve make_page_readonly and make_page_writable:
1. Use update_va_mapping where possible (much faster)
2. If that fails, fall back to explicit pte update rather
than using writable pagetables (very slow for singleton
updates)
Also many x86/64 cleanups and fix to handle vmalloc space
correctly.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
diff -r 69ea493e415a -r 8b384e741382
linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c
--- a/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c Fri Nov 18 16:41:03 2005
+++ b/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c Fri Nov 18 16:42:45 2005
@@ -386,19 +386,26 @@
void make_lowmem_page_readonly(void *va)
{
pte_t *pte = virt_to_ptep(va);
- set_pte(pte, pte_wrprotect(*pte));
+ int rc = HYPERVISOR_update_va_mapping(
+ (unsigned long)va, pte_wrprotect(*pte), 0);
+ BUG_ON(rc);
}
void make_lowmem_page_writable(void *va)
{
pte_t *pte = virt_to_ptep(va);
- set_pte(pte, pte_mkwrite(*pte));
+ int rc = HYPERVISOR_update_va_mapping(
+ (unsigned long)va, pte_mkwrite(*pte), 0);
+ BUG_ON(rc);
}
void make_page_readonly(void *va)
{
pte_t *pte = virt_to_ptep(va);
- set_pte(pte, pte_wrprotect(*pte));
+ int rc = HYPERVISOR_update_va_mapping(
+ (unsigned long)va, pte_wrprotect(*pte), 0);
+ if (rc) /* fallback? */
+ xen_l1_entry_update(pte, pte_wrprotect(*pte));
if ((unsigned long)va >= (unsigned long)high_memory) {
unsigned long pfn = pte_pfn(*pte);
#ifdef CONFIG_HIGHMEM
@@ -412,7 +419,10 @@
void make_page_writable(void *va)
{
pte_t *pte = virt_to_ptep(va);
- set_pte(pte, pte_mkwrite(*pte));
+ int rc = HYPERVISOR_update_va_mapping(
+ (unsigned long)va, pte_mkwrite(*pte), 0);
+ if (rc) /* fallback? */
+ xen_l1_entry_update(pte, pte_mkwrite(*pte));
if ((unsigned long)va >= (unsigned long)high_memory) {
unsigned long pfn = pte_pfn(*pte);
#ifdef CONFIG_HIGHMEM
diff -r 69ea493e415a -r 8b384e741382
linux-2.6-xen-sparse/arch/xen/x86_64/mm/init.c
--- a/linux-2.6-xen-sparse/arch/xen/x86_64/mm/init.c Fri Nov 18 16:41:03 2005
+++ b/linux-2.6-xen-sparse/arch/xen/x86_64/mm/init.c Fri Nov 18 16:42:45 2005
@@ -55,11 +55,9 @@
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
extern unsigned long start_pfn;
-static int init_mapping_done;
-
/*
* Use this until direct mapping is established, i.e. before __va() is
- * avaialble in init_memory_mapping().
+ * available in init_memory_mapping().
*/
#define addr_to_page(addr, page) \
@@ -68,91 +66,65 @@
(((mfn_to_pfn((addr) >> PAGE_SHIFT)) << PAGE_SHIFT) + \
__START_KERNEL_map)))
-static void __make_page_readonly(unsigned long va)
-{
- unsigned long addr;
+static void early_make_page_readonly(void *va)
+{
+ unsigned long addr, _va = (unsigned long)va;
pte_t pte, *ptep;
unsigned long *page = (unsigned long *) init_level4_pgt;
- addr = (unsigned long) page[pgd_index(va)];
+ addr = (unsigned long) page[pgd_index(_va)];
addr_to_page(addr, page);
- addr = page[pud_index(va)];
+ addr = page[pud_index(_va)];
addr_to_page(addr, page);
- addr = page[pmd_index(va)];
+ addr = page[pmd_index(_va)];
addr_to_page(addr, page);
- ptep = (pte_t *) &page[pte_index(va)];
- pte.pte = (ptep->pte & ~_PAGE_RW);
- xen_l1_entry_update(ptep, pte);
- __flush_tlb_one(addr);
-}
-
-static void __make_page_writable(unsigned long va)
-{
- unsigned long addr;
- pte_t pte, *ptep;
- unsigned long *page = (unsigned long *) init_level4_pgt;
-
- addr = (unsigned long) page[pgd_index(va)];
- addr_to_page(addr, page);
-
- addr = page[pud_index(va)];
- addr_to_page(addr, page);
-
- addr = page[pmd_index(va)];
- addr_to_page(addr, page);
-
- ptep = (pte_t *) &page[pte_index(va)];
- pte.pte = (ptep->pte | _PAGE_RW);
- xen_l1_entry_update(ptep, pte);
- __flush_tlb_one(addr);
-}
-
-
-/*
- * Assume the translation is already established.
- */
+ ptep = (pte_t *) &page[pte_index(_va)];
+
+ pte.pte = ptep->pte & ~_PAGE_RW;
+ if (HYPERVISOR_update_va_mapping(_va, pte, 0))
+ BUG();
+}
+
void make_page_readonly(void *va)
{
- pgd_t* pgd; pud_t *pud; pmd_t* pmd; pte_t pte, *ptep;
+ pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t pte, *ptep;
unsigned long addr = (unsigned long) va;
- if (!init_mapping_done) {
- __make_page_readonly(addr);
- return;
- }
-
pgd = pgd_offset_k(addr);
pud = pud_offset(pgd, addr);
pmd = pmd_offset(pud, addr);
ptep = pte_offset_kernel(pmd, addr);
- pte.pte = (ptep->pte & ~_PAGE_RW);
- xen_l1_entry_update(ptep, pte);
- __flush_tlb_one(addr);
+
+ pte.pte = ptep->pte & ~_PAGE_RW;
+ if (HYPERVISOR_update_va_mapping(addr, pte, 0))
+ xen_l1_entry_update(ptep, pte); /* fallback */
+
+ if ((addr >= VMALLOC_START) && (addr < VMALLOC_END))
+ make_page_readonly(__va(pte_pfn(pte) << PAGE_SHIFT));
}
void make_page_writable(void *va)
{
- pgd_t* pgd; pud_t *pud; pmd_t* pmd; pte_t pte, *ptep;
+ pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t pte, *ptep;
unsigned long addr = (unsigned long) va;
-
- if (!init_mapping_done) {
- __make_page_writable(addr);
- return;
- }
pgd = pgd_offset_k(addr);
pud = pud_offset(pgd, addr);
pmd = pmd_offset(pud, addr);
ptep = pte_offset_kernel(pmd, addr);
- pte.pte = (ptep->pte | _PAGE_RW);
- xen_l1_entry_update(ptep, pte);
- __flush_tlb_one(addr);
-}
-
-void make_pages_readonly(void* va, unsigned nr)
+
+ pte.pte = ptep->pte | _PAGE_RW;
+ if (HYPERVISOR_update_va_mapping(addr, pte, 0))
+ xen_l1_entry_update(ptep, pte); /* fallback */
+
+ if ((addr >= VMALLOC_START) && (addr < VMALLOC_END))
+ make_page_writable(__va(pte_pfn(pte) << PAGE_SHIFT));
+}
+
+void make_pages_readonly(void *va, unsigned nr)
{
while (nr-- != 0) {
make_page_readonly(va);
@@ -160,7 +132,7 @@
}
}
-void make_pages_writable(void* va, unsigned nr)
+void make_pages_writable(void *va, unsigned nr)
{
while (nr-- != 0) {
make_page_writable(va);
@@ -457,7 +429,7 @@
}
pmd = alloc_static_page(&pmd_phys);
- make_page_readonly(pmd);
+ early_make_page_readonly(pmd);
xen_pmd_pin(pmd_phys);
set_pud(pud, __pud(pmd_phys | _KERNPG_TABLE));
@@ -487,7 +459,7 @@
__set_pte(pte, __pte(paddr | _KERNPG_TABLE));
}
pte = pte_save;
- make_page_readonly(pte);
+ early_make_page_readonly(pte);
xen_pte_pin(pte_phys);
set_pmd(pmd, __pmd(pte_phys | _KERNPG_TABLE));
}
@@ -536,11 +508,11 @@
_KERNPG_TABLE | _PAGE_USER);
memcpy((void *)level2_kernel_pgt, page, PAGE_SIZE);
- make_page_readonly(init_level4_pgt);
- make_page_readonly(init_level4_user_pgt);
- make_page_readonly(level3_kernel_pgt);
- make_page_readonly(level3_user_pgt);
- make_page_readonly(level2_kernel_pgt);
+ early_make_page_readonly(init_level4_pgt);
+ early_make_page_readonly(init_level4_user_pgt);
+ early_make_page_readonly(level3_kernel_pgt);
+ early_make_page_readonly(level3_user_pgt);
+ early_make_page_readonly(level2_kernel_pgt);
xen_pgd_pin(__pa_symbol(init_level4_pgt));
xen_pgd_pin(__pa_symbol(init_level4_user_pgt));
@@ -578,7 +550,7 @@
pmd = (pmd_t *)&page[pmd_index(va)];
if (pmd_none(*pmd)) {
pte_page = alloc_static_page(&phys);
- make_page_readonly(pte_page);
+ early_make_page_readonly(pte_page);
xen_pte_pin(phys);
set_pmd(pmd, __pmd(phys | _KERNPG_TABLE | _PAGE_USER));
} else {
@@ -625,7 +597,7 @@
for (; start < end; start = next) {
unsigned long pud_phys;
pud_t *pud = alloc_static_page(&pud_phys);
- make_page_readonly(pud);
+ early_make_page_readonly(pud);
xen_pud_pin(pud_phys);
next = start + PGDIR_SIZE;
if (next > end)
@@ -640,7 +612,6 @@
BUG_ON(start_pfn != (table_start + (tables_space >> PAGE_SHIFT)));
__flush_tlb_all();
- init_mapping_done = 1;
}
extern struct x8664_pda cpu_pda[NR_CPUS];
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