---

yaml
---
r: 123986
b: refs/heads/master
c: 58a2456
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: be3c5832d51174ef7f21cefd6ad612dabdcb62fd
+refs/heads/master: 58a24566449892dda409b9ad92c2e56c76c5670c

trunk/Documentation/lguest/lguest.c

@@ -481,51 +481,6 @@ static unsigned long load_initrd(const char *name, unsigned long mem)
 	/* We return the initrd size. */
 	return len;
 }
-
-/* Once we know how much memory we have we can construct simple linear page
- * tables which set virtual == physical 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(unsigned long mem,
-				      unsigned long initrd_size)
-{
-	unsigned long *pgdir, *linear;
-	unsigned int mapped_pages, i, linear_pages;
-	unsigned int ptes_per_page = getpagesize()/sizeof(void *);
-
-	mapped_pages = mem/getpagesize();
-
-	/* Each PTE page can map ptes_per_page pages: how many do we need? */
-	linear_pages = (mapped_pages + ptes_per_page-1)/ptes_per_page;
-
-	/* We put the toplevel page directory page at the top of memory. */
-	pgdir = from_guest_phys(mem) - initrd_size - getpagesize();
-
-	/* Now we use the next linear_pages pages as pte pages */
-	linear = (void *)pgdir - linear_pages*getpagesize();
-
-	/* Linear mapping is easy: put every page's address into the mapping in
-	 * order.  PAGE_PRESENT contains the flags Present, Writable and
-	 * Executable. */
-	for (i = 0; i < mapped_pages; i++)
-		linear[i] = ((i * getpagesize()) | PAGE_PRESENT);
-
-	/* The top level points to the linear page table pages above. */
-	for (i = 0; i < mapped_pages; i += ptes_per_page) {
-		pgdir[i/ptes_per_page]
-			= ((to_guest_phys(linear) + i*sizeof(void *))
-			   | PAGE_PRESENT);
-	}
-
-	verbose("Linear mapping of %u pages in %u pte pages at %#lx\n",
-		mapped_pages, linear_pages, to_guest_phys(linear));
-
-	/* We return the top level (guest-physical) address: the kernel needs
-	 * to know where it is. */
-	return to_guest_phys(pgdir);
-}
 /*:*/
 
 /* Simple routine to roll all the commandline arguments together with spaces
@@ -548,13 +503,13 @@ static void concat(char *dst, char *args[])
 
 /*L:185 This is where we actually tell the kernel to initialize the Guest.  We
  * saw the arguments it expects when we looked at initialize() in lguest_user.c:
- * the base of Guest "physical" memory, the top physical page to allow, the
- * top level pagetable and the entry point for the Guest. */
-static int tell_kernel(unsigned long pgdir, unsigned long start)
+ * the base of Guest "physical" memory, the top physical page to allow and the
+ * entry point for the Guest. */
+static int tell_kernel(unsigned long start)
 {
 	unsigned long args[] = { LHREQ_INITIALIZE,
 				 (unsigned long)guest_base,
-				 guest_limit / getpagesize(), pgdir, start };
+				 guest_limit / getpagesize(), start };
 	int fd;
 
 	verbose("Guest: %p - %p (%#lx)\n",
@@ -1941,7 +1896,7 @@ int main(int argc, char *argv[])
 {
 	/* Memory, top-level pagetable, code startpoint and size of the
 	 * (optional) initrd. */
-	unsigned long mem = 0, pgdir, start, initrd_size = 0;
+	unsigned long mem = 0, start, initrd_size = 0;
 	/* Two temporaries and the /dev/lguest file descriptor. */
 	int i, c, lguest_fd;
 	/* The boot information for the Guest. */
@@ -2040,9 +1995,6 @@ int main(int argc, char *argv[])
 		boot->hdr.type_of_loader = 0xFF;
 	}
 
-	/* Set up the initial linear pagetables, starting below the initrd. */
-	pgdir = setup_pagetables(mem, initrd_size);
-
 	/* The Linux boot header contains an "E820" memory map: ours is a
 	 * simple, single region. */
 	boot->e820_entries = 1;
@@ -2064,7 +2016,7 @@ int main(int argc, char *argv[])
 
 	/* We tell the kernel to initialize the Guest: this returns the open
 	 * /dev/lguest file descriptor. */
-	lguest_fd = tell_kernel(pgdir, start);
+	lguest_fd = tell_kernel(start);
 
 	/* We clone off a thread, which wakes the Launcher whenever one of the
 	 * input file descriptors needs attention.  We call this the Waker, and

trunk/arch/x86/lguest/i386_head.S

@@ -30,21 +30,6 @@ ENTRY(lguest_entry)
 	movl $lguest_data - __PAGE_OFFSET, %edx
 	int $LGUEST_TRAP_ENTRY
 
-	/* The Host put the toplevel pagetable in lguest_data.pgdir.  The movsl
-	 * instruction uses %esi implicitly as the source for the copy we're
-	 * about to do. */
-	movl lguest_data - __PAGE_OFFSET + LGUEST_DATA_pgdir, %esi
-
-	/* Copy first 32 entries of page directory to __PAGE_OFFSET entries.
-	 * This means the first 128M of kernel memory will be mapped at
-	 * PAGE_OFFSET where the kernel expects to run.  This will get it far
-	 * enough through boot to switch to its own pagetables. */
-	movl $32, %ecx
-	movl %esi, %edi
-	addl $((__PAGE_OFFSET >> 22) * 4), %edi
-	rep
-	movsl
-
 	/* Set up the initial stack so we can run C code. */
 	movl $(init_thread_union+THREAD_SIZE),%esp
 

trunk/drivers/lguest/lg.h

@@ -164,7 +164,7 @@ void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
 void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
 
 /* page_tables.c: */
-int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
+int init_guest_pagetable(struct lguest *lg);
 void free_guest_pagetable(struct lguest *lg);
 void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
 void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);

trunk/drivers/lguest/lguest_user.c

@@ -146,7 +146,7 @@ static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip)
 	return 0;
 }
 
-/*L:020 The initialization write supplies 4 pointer sized (32 or 64 bit)
+/*L:020 The initialization write supplies 3 pointer sized (32 or 64 bit)
  * values (in addition to the LHREQ_INITIALIZE value).  These are:
  *
  * base: The start of the Guest-physical memory inside the Launcher memory.
@@ -155,9 +155,6 @@ static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip)
  * allowed to access.  The Guest memory lives inside the Launcher, so it sets
  * this to ensure the Guest can only reach its own memory.
  *
- * pgdir: The (Guest-physical) address of the top of the initial Guest
- * pagetables (which are set up by the Launcher).
- *
  * start: The first instruction to execute ("eip" in x86-speak).
  */
 static int initialize(struct file *file, const unsigned long __user *input)
@@ -166,7 +163,7 @@ static int initialize(struct file *file, const unsigned long __user *input)
 	 * Guest. */
 	struct lguest *lg;
 	int err;
-	unsigned long args[4];
+	unsigned long args[3];
 
 	/* We grab the Big Lguest lock, which protects against multiple
 	 * simultaneous initializations. */
@@ -192,14 +189,14 @@ static int initialize(struct file *file, const unsigned long __user *input)
 	lg->mem_base = (void __user *)args[0];
 	lg->pfn_limit = args[1];
 
-	/* This is the first cpu (cpu 0) and it will start booting at args[3] */
-	err = lg_cpu_start(&lg->cpus[0], 0, args[3]);
+	/* This is the first cpu (cpu 0) and it will start booting at args[2] */
+	err = lg_cpu_start(&lg->cpus[0], 0, args[2]);
 	if (err)
 		goto release_guest;
 
 	/* Initialize the Guest's shadow page tables, using the toplevel
 	 * address the Launcher gave us.  This allocates memory, so can fail. */
-	err = init_guest_pagetable(lg, args[2]);
+	err = init_guest_pagetable(lg);
 	if (err)
 		goto free_regs;
 

trunk/drivers/lguest/page_tables.c

@@ -14,6 +14,7 @@
 #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.
@@ -581,15 +582,82 @@ void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 idx)
 		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;

trunk/include/linux/lguest_launcher.h

@@ -54,7 +54,7 @@ struct lguest_vqconfig {
 /* Write command first word is a request. */
 enum lguest_req
 {
-	LHREQ_INITIALIZE, /* + base, pfnlimit, pgdir, start */
+	LHREQ_INITIALIZE, /* + base, pfnlimit, start */
 	LHREQ_GETDMA, /* No longer used */
 	LHREQ_IRQ, /* + irq */
 	LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */