#include <linux/percpu.h>
#include <asm/tlbflush.h>
#include <asm/uaccess.h>
+#include <asm/bootparam.h>
#include "lg.h"
/*M:008 We hold reference to pages, which prevents them from being swapped.
*
* If we fixed up the fault (ie. we mapped the address), this routine returns
* true. Otherwise, it was a real fault and we need to tell the Guest. */
-int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
+bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
{
pgd_t gpgd;
pgd_t *spgd;
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
/* Toplevel not present? We can't map it in. */
if (!(pgd_flags(gpgd) & _PAGE_PRESENT))
- return 0;
+ return false;
/* Now look at the matching shadow entry. */
spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr);
* simple for this corner case. */
if (!ptepage) {
kill_guest(cpu, "out of memory allocating pte page");
- return 0;
+ return false;
}
/* We check that the Guest pgd is OK. */
check_gpgd(cpu, gpgd);
/* If this page isn't in the Guest page tables, we can't page it in. */
if (!(pte_flags(gpte) & _PAGE_PRESENT))
- return 0;
+ return false;
/* Check they're not trying to write to a page the Guest wants
* read-only (bit 2 of errcode == write). */
if ((errcode & 2) && !(pte_flags(gpte) & _PAGE_RW))
- return 0;
+ return false;
/* User access to a kernel-only page? (bit 3 == user access) */
if ((errcode & 4) && !(pte_flags(gpte) & _PAGE_USER))
- return 0;
+ return false;
/* Check that the Guest PTE flags are OK, and the page number is below
* the pfn_limit (ie. not mapping the Launcher binary). */
* manipulated, the result returned and the code complete. A small
* delay and a trace of alliteration are the only indications the Guest
* has that a page fault occurred at all. */
- return 1;
+ return true;
}
/*H:360
*
* This is a quick version which answers the question: is this virtual address
* mapped by the shadow page tables, and is it writable? */
-static int page_writable(struct lg_cpu *cpu, unsigned long vaddr)
+static bool page_writable(struct lg_cpu *cpu, unsigned long vaddr)
{
pgd_t *spgd;
unsigned long flags;
/* Look at the current top level entry: is it present? */
spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr);
if (!(pgd_flags(*spgd) & _PAGE_PRESENT))
- return 0;
+ return false;
/* Check the flags on the pte entry itself: it must be present and
* writable. */
/* First step: get the top-level Guest page table entry. */
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
/* Toplevel not present? We can't map it in. */
- if (!(pgd_flags(gpgd) & _PAGE_PRESENT))
+ if (!(pgd_flags(gpgd) & _PAGE_PRESENT)) {
kill_guest(cpu, "Bad address %#lx", vaddr);
+ return -1UL;
+ }
gpte = lgread(cpu, gpte_addr(gpgd, vaddr), pte_t);
if (!(pte_flags(gpte) & _PAGE_PRESENT))
release_pgd(lg, lg->pgdirs[pgdir].pgdir + idx);
}
+/* Once we know how much memory we have we can construct simple identity
+ * (which set virtual == physical) and linear mappings
+ * which will get the Guest far enough into the boot to create its own.
+ *
+ * We lay them out of the way, just below the initrd (which is why we need to
+ * know its size here). */
+static unsigned long setup_pagetables(struct lguest *lg,
+ unsigned long mem,
+ unsigned long initrd_size)
+{
+ pgd_t __user *pgdir;
+ pte_t __user *linear;
+ unsigned int mapped_pages, i, linear_pages, phys_linear;
+ unsigned long mem_base = (unsigned long)lg->mem_base;
+
+ /* We have mapped_pages frames to map, so we need
+ * linear_pages page tables to map them. */
+ mapped_pages = mem / PAGE_SIZE;
+ linear_pages = (mapped_pages + PTRS_PER_PTE - 1) / PTRS_PER_PTE;
+
+ /* We put the toplevel page directory page at the top of memory. */
+ pgdir = (pgd_t *)(mem + mem_base - initrd_size - PAGE_SIZE);
+
+ /* Now we use the next linear_pages pages as pte pages */
+ linear = (void *)pgdir - linear_pages * PAGE_SIZE;
+
+ /* Linear mapping is easy: put every page's address into the
+ * mapping in order. */
+ for (i = 0; i < mapped_pages; i++) {
+ pte_t pte;
+ pte = pfn_pte(i, __pgprot(_PAGE_PRESENT|_PAGE_RW|_PAGE_USER));
+ if (copy_to_user(&linear[i], &pte, sizeof(pte)) != 0)
+ return -EFAULT;
+ }
+
+ /* The top level points to the linear page table pages above.
+ * We setup the identity and linear mappings here. */
+ phys_linear = (unsigned long)linear - mem_base;
+ for (i = 0; i < mapped_pages; i += PTRS_PER_PTE) {
+ pgd_t pgd;
+ pgd = __pgd((phys_linear + i * sizeof(pte_t)) |
+ (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER));
+
+ if (copy_to_user(&pgdir[i / PTRS_PER_PTE], &pgd, sizeof(pgd))
+ || copy_to_user(&pgdir[pgd_index(PAGE_OFFSET)
+ + i / PTRS_PER_PTE],
+ &pgd, sizeof(pgd)))
+ return -EFAULT;
+ }
+
+ /* We return the top level (guest-physical) address: remember where
+ * this is. */
+ return (unsigned long)pgdir - mem_base;
+}
+
/*H:500 (vii) Setting up the page tables initially.
*
* When a Guest is first created, the Launcher tells us where the toplevel of
* its first page table is. We set some things up here: */
-int init_guest_pagetable(struct lguest *lg, unsigned long pgtable)
+int init_guest_pagetable(struct lguest *lg)
{
+ u64 mem;
+ u32 initrd_size;
+ struct boot_params __user *boot = (struct boot_params *)lg->mem_base;
+
+ /* Get the Guest memory size and the ramdisk size from the boot header
+ * located at lg->mem_base (Guest address 0). */
+ if (copy_from_user(&mem, &boot->e820_map[0].size, sizeof(mem))
+ || get_user(initrd_size, &boot->hdr.ramdisk_size))
+ return -EFAULT;
+
/* We start on the first shadow page table, and give it a blank PGD
* page. */
- lg->pgdirs[0].gpgdir = pgtable;
+ lg->pgdirs[0].gpgdir = setup_pagetables(lg, mem, initrd_size);
+ if (IS_ERR_VALUE(lg->pgdirs[0].gpgdir))
+ return lg->pgdirs[0].gpgdir;
lg->pgdirs[0].pgdir = (pgd_t *)get_zeroed_page(GFP_KERNEL);
if (!lg->pgdirs[0].pgdir)
return -ENOMEM;
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff