static void __make_page_writable(void *va)
{
pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t pte, *ptep;
unsigned long addr = (unsigned long) va;
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;
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_page_writable(void *va, unsigned int feature)
{
pte_t *pte;
int rc;
if (xen_feature(feature))
return;
pte = virt_to_ptep(va);
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
if (pfn < highstart_pfn)
#endif
make_lowmem_page_writable(
phys_to_virt(pfn << PAGE_SHIFT), feature);
}
}
void make_page_readonly(void *va, unsigned int feature)
{
pte_t *pte;
int rc;
if (xen_feature(feature))
return;
pte = virt_to_ptep(va);
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
if (pfn >= highstart_pfn)
kmap_flush_unused(); /* flush stale writable kmaps */
else
#endif
make_lowmem_page_readonly(
phys_to_virt(pfn << PAGE_SHIFT), feature);
}
}
void __init adjust_boot_vcpu_info(void)
{
unsigned long lpfn, rpfn, lmfn, rmfn;
pte_t *lpte, *rpte;
unsigned int level;
mmu_update_t mmu[2];
/*
* setup_vcpu_info() cannot be used more than once for a given (v)CPU,
* hence we must swap the underlying MFNs of the two pages holding old
* and new vcpu_info of the boot CPU.
*
* Do *not* use __get_cpu_var() or percpu_{write,...}() here, as the per-
* CPU segment didn't get reloaded yet. Using percpu_read(), as in
* arch_use_lazy_mmu_mode(), though undesirable, is safe except for the
* accesses to variables that were updated in setup_percpu_areas().
*/
lpte = lookup_address((unsigned long)&per_cpu_var(vcpu_info)
+ (__per_cpu_load - __per_cpu_start),
&level);
rpte = lookup_address((unsigned long)&per_cpu(vcpu_info, 0), &level);
BUG_ON(!lpte || !(pte_flags(*lpte) & _PAGE_PRESENT));
BUG_ON(!rpte || !(pte_flags(*rpte) & _PAGE_PRESENT));
lmfn = __pte_mfn(*lpte);
rmfn = __pte_mfn(*rpte);
if (lmfn == rmfn)
return;
lpfn = mfn_to_local_pfn(lmfn);
rpfn = mfn_to_local_pfn(rmfn);
printk(KERN_INFO
"Swapping MFNs for PFN %lx and %lx (MFN %lx and %lx)\n",
lpfn, rpfn, lmfn, rmfn);
xen_l1_entry_update(lpte, pfn_pte_ma(rmfn, pte_pgprot(*lpte)));
xen_l1_entry_update(rpte, pfn_pte_ma(lmfn, pte_pgprot(*rpte)));
#ifdef CONFIG_X86_64
if (HYPERVISOR_update_va_mapping((unsigned long)__va(lpfn<<PAGE_SHIFT),
pfn_pte_ma(rmfn, PAGE_KERNEL_RO), 0))
BUG();
#endif
if (HYPERVISOR_update_va_mapping((unsigned long)__va(rpfn<<PAGE_SHIFT),
pfn_pte_ma(lmfn, PAGE_KERNEL),
UVMF_TLB_FLUSH))
BUG();
set_phys_to_machine(lpfn, rmfn);
set_phys_to_machine(rpfn, lmfn);
mmu[0].ptr = ((uint64_t)lmfn << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE;
mmu[0].val = rpfn;
mmu[1].ptr = ((uint64_t)rmfn << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE;
mmu[1].val = lpfn;
if (HYPERVISOR_mmu_update(mmu, 2, NULL, DOMID_SELF))
BUG();
/*
* Copy over all contents of the page just replaced, except for the
* vcpu_info itself, as it may have got updated after having been
* copied from __per_cpu_load[].
*/
memcpy(__va(rpfn << PAGE_SHIFT),
__va(lpfn << PAGE_SHIFT),
(unsigned long)&per_cpu_var(vcpu_info) & (PAGE_SIZE - 1));
level = (unsigned long)(&per_cpu_var(vcpu_info) + 1) & (PAGE_SIZE - 1);
if (level)
memcpy(__va(rpfn << PAGE_SHIFT) + level,
__va(lpfn << PAGE_SHIFT) + level,
PAGE_SIZE - level);
}
