x86/xen: split off mmu_pv.c

Basically, mmu.c is renamed to mmu_pv.c and some code moved out to common
mmu.c.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

3 files changed, 2721 insertions, 2714 deletions

diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 6a95a8ba3801..8da1ca92e604 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -8,12 +8,12 @@ endif
 # Make sure early boot has no stackprotector
 nostackp := $(call cc-option, -fno-stack-protector)
 CFLAGS_enlighten_pv.o		:= $(nostackp)
-CFLAGS_mmu.o			:= $(nostackp)
+CFLAGS_mmu_pv.o		:= $(nostackp)
 
 obj-y		:= enlighten.o setup.o multicalls.o mmu.o irq.o \
 			time.o xen-asm.o xen-asm_$(BITS).o \
 			grant-table.o suspend.o platform-pci-unplug.o \
-			p2m.o apic.o pmu.o enlighten_pv.o
+			p2m.o apic.o pmu.o enlighten_pv.o mmu_pv.o
 
 obj-$(CONFIG_XEN_PVHVM)		+= enlighten_hvm.o mmu_hvm.o
 obj-$(CONFIG_XEN_PVH)			+= enlighten_pvh.o
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index a376f5e2e947..5e375a5e815f 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1,84 +1,10 @@
-/*
- * Xen mmu operations
- *
- * This file contains the various mmu fetch and update operations.
- * The most important job they must perform is the mapping between the
- * domain's pfn and the overall machine mfns.
- *
- * Xen allows guests to directly update the pagetable, in a controlled
- * fashion.  In other words, the guest modifies the same pagetable
- * that the CPU actually uses, which eliminates the overhead of having
- * a separate shadow pagetable.
- *
- * In order to allow this, it falls on the guest domain to map its
- * notion of a "physical" pfn - which is just a domain-local linear
- * address - into a real "machine address" which the CPU's MMU can
- * use.
- *
- * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
- * inserted directly into the pagetable.  When creating a new
- * pte/pmd/pgd, it converts the passed pfn into an mfn.  Conversely,
- * when reading the content back with __(pgd|pmd|pte)_val, it converts
- * the mfn back into a pfn.
- *
- * The other constraint is that all pages which make up a pagetable
- * must be mapped read-only in the guest.  This prevents uncontrolled
- * guest updates to the pagetable.  Xen strictly enforces this, and
- * will disallow any pagetable update which will end up mapping a
- * pagetable page RW, and will disallow using any writable page as a
- * pagetable.
- *
- * Naively, when loading %cr3 with the base of a new pagetable, Xen
- * would need to validate the whole pagetable before going on.
- * Naturally, this is quite slow.  The solution is to "pin" a
- * pagetable, which enforces all the constraints on the pagetable even
- * when it is not actively in use.  This menas that Xen can be assured
- * that it is still valid when you do load it into %cr3, and doesn't
- * need to revalidate it.
- *
- * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
- */
-#include <linux/sched/mm.h>
-#include <linux/highmem.h>
-#include <linux/debugfs.h>
-#include <linux/bug.h>
-#include <linux/vmalloc.h>
-#include <linux/export.h>
-#include <linux/init.h>
-#include <linux/gfp.h>
-#include <linux/memblock.h>
-#include <linux/seq_file.h>
-#include <linux/crash_dump.h>
-
-#include <trace/events/xen.h>
-
-#include <asm/pgtable.h>
-#include <asm/tlbflush.h>
-#include <asm/fixmap.h>
-#include <asm/mmu_context.h>
-#include <asm/setup.h>
-#include <asm/paravirt.h>
-#include <asm/e820/api.h>
-#include <asm/linkage.h>
-#include <asm/page.h>
-#include <asm/init.h>
-#include <asm/pat.h>
-#include <asm/smp.h>
-
+#include <linux/pfn.h>
+#include <asm/xen/page.h>
 #include <asm/xen/hypercall.h>
-#include <asm/xen/hypervisor.h>
-
-#include <xen/xen.h>
-#include <xen/page.h>
-#include <xen/interface/xen.h>
-#include <xen/interface/hvm/hvm_op.h>
-#include <xen/interface/version.h>
 #include <xen/interface/memory.h>
-#include <xen/hvc-console.h>
 
 #include "multicalls.h"
 #include "mmu.h"
-#include "debugfs.h"
 
 /*
  * Protects atomic reservation decrease/increase against concurrent increases.
@@ -86,45 +12,6 @@
  */
 DEFINE_SPINLOCK(xen_reservation_lock);
 
-#ifdef CONFIG_X86_32
-/*
- * Identity map, in addition to plain kernel map.  This needs to be
- * large enough to allocate page table pages to allocate the rest.
- * Each page can map 2MB.
- */
-#define LEVEL1_IDENT_ENTRIES	(PTRS_PER_PTE * 4)
-static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
-#endif
-#ifdef CONFIG_X86_64
-/* l3 pud for userspace vsyscall mapping */
-static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
-#endif /* CONFIG_X86_64 */
-
-/*
- * Note about cr3 (pagetable base) values:
- *
- * xen_cr3 contains the current logical cr3 value; it contains the
- * last set cr3.  This may not be the current effective cr3, because
- * its update may be being lazily deferred.  However, a vcpu looking
- * at its own cr3 can use this value knowing that it everything will
- * be self-consistent.
- *
- * xen_current_cr3 contains the actual vcpu cr3; it is set once the
- * hypercall to set the vcpu cr3 is complete (so it may be a little
- * out of date, but it will never be set early).  If one vcpu is
- * looking at another vcpu's cr3 value, it should use this variable.
- */
-DEFINE_PER_CPU(unsigned long, xen_cr3);	 /* cr3 stored as physaddr */
-DEFINE_PER_CPU(unsigned long, xen_current_cr3);	 /* actual vcpu cr3 */
-
-static phys_addr_t xen_pt_base, xen_pt_size __initdata;
-
-/*
- * Just beyond the highest usermode address.  STACK_TOP_MAX has a
- * redzone above it, so round it up to a PGD boundary.
- */
-#define USER_LIMIT	((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
-
 unsigned long arbitrary_virt_to_mfn(void *vaddr)
 {
 	xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
@@ -155,1218 +42,6 @@ xmaddr_t arbitrary_virt_to_machine(void *vaddr)
 }
 EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
 
-void make_lowmem_page_readonly(void *vaddr)
-{
-	pte_t *pte, ptev;
-	unsigned long address = (unsigned long)vaddr;
-	unsigned int level;
-
-	pte = lookup_address(address, &level);
-	if (pte == NULL)
-		return;		/* vaddr missing */
-
-	ptev = pte_wrprotect(*pte);
-
-	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
-		BUG();
-}
-
-void make_lowmem_page_readwrite(void *vaddr)
-{
-	pte_t *pte, ptev;
-	unsigned long address = (unsigned long)vaddr;
-	unsigned int level;
-
-	pte = lookup_address(address, &level);
-	if (pte == NULL)
-		return;		/* vaddr missing */
-
-	ptev = pte_mkwrite(*pte);
-
-	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
-		BUG();
-}
-
-
-static bool xen_page_pinned(void *ptr)
-{
-	struct page *page = virt_to_page(ptr);
-
-	return PagePinned(page);
-}
-
-void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
-{
-	struct multicall_space mcs;
-	struct mmu_update *u;
-
-	trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
-
-	mcs = xen_mc_entry(sizeof(*u));
-	u = mcs.args;
-
-	/* ptep might be kmapped when using 32-bit HIGHPTE */
-	u->ptr = virt_to_machine(ptep).maddr;
-	u->val = pte_val_ma(pteval);
-
-	MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
-
-	xen_mc_issue(PARAVIRT_LAZY_MMU);
-}
-EXPORT_SYMBOL_GPL(xen_set_domain_pte);
-
-static void xen_extend_mmu_update(const struct mmu_update *update)
-{
-	struct multicall_space mcs;
-	struct mmu_update *u;
-
-	mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
-
-	if (mcs.mc != NULL) {
-		mcs.mc->args[1]++;
-	} else {
-		mcs = __xen_mc_entry(sizeof(*u));
-		MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
-	}
-
-	u = mcs.args;
-	*u = *update;
-}
-
-static void xen_extend_mmuext_op(const struct mmuext_op *op)
-{
-	struct multicall_space mcs;
-	struct mmuext_op *u;
-
-	mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
-
-	if (mcs.mc != NULL) {
-		mcs.mc->args[1]++;
-	} else {
-		mcs = __xen_mc_entry(sizeof(*u));
-		MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
-	}
-
-	u = mcs.args;
-	*u = *op;
-}
-
-static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
-{
-	struct mmu_update u;
-
-	preempt_disable();
-
-	xen_mc_batch();
-
-	/* ptr may be ioremapped for 64-bit pagetable setup */
-	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
-	u.val = pmd_val_ma(val);
-	xen_extend_mmu_update(&u);
-
-	xen_mc_issue(PARAVIRT_LAZY_MMU);
-
-	preempt_enable();
-}
-
-static void xen_set_pmd(pmd_t *ptr, pmd_t val)
-{
-	trace_xen_mmu_set_pmd(ptr, val);
-
-	/* If page is not pinned, we can just update the entry
-	   directly */
-	if (!xen_page_pinned(ptr)) {
-		*ptr = val;
-		return;
-	}
-
-	xen_set_pmd_hyper(ptr, val);
-}
-
-/*
- * Associate a virtual page frame with a given physical page frame
- * and protection flags for that frame.
- */
-void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
-{
-	set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
-}
-
-static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
-{
-	struct mmu_update u;
-
-	if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
-		return false;
-
-	xen_mc_batch();
-
-	u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
-	u.val = pte_val_ma(pteval);
-	xen_extend_mmu_update(&u);
-
-	xen_mc_issue(PARAVIRT_LAZY_MMU);
-
-	return true;
-}
-
-static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
-{
-	if (!xen_batched_set_pte(ptep, pteval)) {
-		/*
-		 * Could call native_set_pte() here and trap and
-		 * emulate the PTE write but with 32-bit guests this
-		 * needs two traps (one for each of the two 32-bit
-		 * words in the PTE) so do one hypercall directly
-		 * instead.
-		 */
-		struct mmu_update u;
-
-		u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
-		u.val = pte_val_ma(pteval);
-		HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
-	}
-}
-
-static void xen_set_pte(pte_t *ptep, pte_t pteval)
-{
-	trace_xen_mmu_set_pte(ptep, pteval);
-	__xen_set_pte(ptep, pteval);
-}
-
-static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
-		    pte_t *ptep, pte_t pteval)
-{
-	trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
-	__xen_set_pte(ptep, pteval);
-}
-
-pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
-				 unsigned long addr, pte_t *ptep)
-{
-	/* Just return the pte as-is.  We preserve the bits on commit */
-	trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
-	return *ptep;
-}
-
-void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
-				 pte_t *ptep, pte_t pte)
-{
-	struct mmu_update u;
-
-	trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
-	xen_mc_batch();
-
-	u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
-	u.val = pte_val_ma(pte);
-	xen_extend_mmu_update(&u);
-
-	xen_mc_issue(PARAVIRT_LAZY_MMU);
-}
-
-/* Assume pteval_t is equivalent to all the other *val_t types. */
-static pteval_t pte_mfn_to_pfn(pteval_t val)
-{
-	if (val & _PAGE_PRESENT) {
-		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
-		unsigned long pfn = mfn_to_pfn(mfn);
-
-		pteval_t flags = val & PTE_FLAGS_MASK;
-		if (unlikely(pfn == ~0))
-			val = flags & ~_PAGE_PRESENT;
-		else
-			val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
-	}
-
-	return val;
-}
-
-static pteval_t pte_pfn_to_mfn(pteval_t val)
-{
-	if (val & _PAGE_PRESENT) {
-		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
-		pteval_t flags = val & PTE_FLAGS_MASK;
-		unsigned long mfn;
-
-		if (!xen_feature(XENFEAT_auto_translated_physmap))
-			mfn = __pfn_to_mfn(pfn);
-		else
-			mfn = pfn;
-		/*
-		 * If there's no mfn for the pfn, then just create an
-		 * empty non-present pte.  Unfortunately this loses
-		 * information about the original pfn, so
-		 * pte_mfn_to_pfn is asymmetric.
-		 */
-		if (unlikely(mfn == INVALID_P2M_ENTRY)) {
-			mfn = 0;
-			flags = 0;
-		} else
-			mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
-		val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
-	}
-
-	return val;
-}
-
-__visible pteval_t xen_pte_val(pte_t pte)
-{
-	pteval_t pteval = pte.pte;
-
-	return pte_mfn_to_pfn(pteval);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
-
-__visible pgdval_t xen_pgd_val(pgd_t pgd)
-{
-	return pte_mfn_to_pfn(pgd.pgd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
-
-__visible pte_t xen_make_pte(pteval_t pte)
-{
-	pte = pte_pfn_to_mfn(pte);
-
-	return native_make_pte(pte);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
-
-__visible pgd_t xen_make_pgd(pgdval_t pgd)
-{
-	pgd = pte_pfn_to_mfn(pgd);
-	return native_make_pgd(pgd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
-
-__visible pmdval_t xen_pmd_val(pmd_t pmd)
-{
-	return pte_mfn_to_pfn(pmd.pmd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
-
-static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
-{
-	struct mmu_update u;
-
-	preempt_disable();
-
-	xen_mc_batch();
-
-	/* ptr may be ioremapped for 64-bit pagetable setup */
-	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
-	u.val = pud_val_ma(val);
-	xen_extend_mmu_update(&u);
-
-	xen_mc_issue(PARAVIRT_LAZY_MMU);
-
-	preempt_enable();
-}
-
-static void xen_set_pud(pud_t *ptr, pud_t val)
-{
-	trace_xen_mmu_set_pud(ptr, val);
-
-	/* If page is not pinned, we can just update the entry
-	   directly */
-	if (!xen_page_pinned(ptr)) {
-		*ptr = val;
-		return;
-	}
-
-	xen_set_pud_hyper(ptr, val);
-}
-
-#ifdef CONFIG_X86_PAE
-static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
-{
-	trace_xen_mmu_set_pte_atomic(ptep, pte);
-	set_64bit((u64 *)ptep, native_pte_val(pte));
-}
-
-static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
-{
-	trace_xen_mmu_pte_clear(mm, addr, ptep);
-	if (!xen_batched_set_pte(ptep, native_make_pte(0)))
-		native_pte_clear(mm, addr, ptep);
-}
-
-static void xen_pmd_clear(pmd_t *pmdp)
-{
-	trace_xen_mmu_pmd_clear(pmdp);
-	set_pmd(pmdp, __pmd(0));
-}
-#endif	/* CONFIG_X86_PAE */
-
-__visible pmd_t xen_make_pmd(pmdval_t pmd)
-{
-	pmd = pte_pfn_to_mfn(pmd);
-	return native_make_pmd(pmd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
-
-#if CONFIG_PGTABLE_LEVELS == 4
-__visible pudval_t xen_pud_val(pud_t pud)
-{
-	return pte_mfn_to_pfn(pud.pud);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
-
-__visible pud_t xen_make_pud(pudval_t pud)
-{
-	pud = pte_pfn_to_mfn(pud);
-
-	return native_make_pud(pud);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
-
-static pgd_t *xen_get_user_pgd(pgd_t *pgd)
-{
-	pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
-	unsigned offset = pgd - pgd_page;
-	pgd_t *user_ptr = NULL;
-
-	if (offset < pgd_index(USER_LIMIT)) {
-		struct page *page = virt_to_page(pgd_page);
-		user_ptr = (pgd_t *)page->private;
-		if (user_ptr)
-			user_ptr += offset;
-	}
-
-	return user_ptr;
-}
-
-static void __xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
-{
-	struct mmu_update u;
-
-	u.ptr = virt_to_machine(ptr).maddr;
-	u.val = p4d_val_ma(val);
-	xen_extend_mmu_update(&u);
-}
-
-/*
- * Raw hypercall-based set_p4d, intended for in early boot before
- * there's a page structure.  This implies:
- *  1. The only existing pagetable is the kernel's
- *  2. It is always pinned
- *  3. It has no user pagetable attached to it
- */
-static void __init xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
-{
-	preempt_disable();
-
-	xen_mc_batch();
-
-	__xen_set_p4d_hyper(ptr, val);
-
-	xen_mc_issue(PARAVIRT_LAZY_MMU);
-
-	preempt_enable();
-}
-
-static void xen_set_p4d(p4d_t *ptr, p4d_t val)
-{
-	pgd_t *user_ptr = xen_get_user_pgd((pgd_t *)ptr);
-	pgd_t pgd_val;
-
-	trace_xen_mmu_set_p4d(ptr, (p4d_t *)user_ptr, val);
-
-	/* If page is not pinned, we can just update the entry
-	   directly */
-	if (!xen_page_pinned(ptr)) {
-		*ptr = val;
-		if (user_ptr) {
-			WARN_ON(xen_page_pinned(user_ptr));
-			pgd_val.pgd = p4d_val_ma(val);
-			*user_ptr = pgd_val;
-		}
-		return;
-	}
-
-	/* If it's pinned, then we can at least batch the kernel and
-	   user updates together. */
-	xen_mc_batch();
-
-	__xen_set_p4d_hyper(ptr, val);
-	if (user_ptr)
-		__xen_set_p4d_hyper((p4d_t *)user_ptr, val);
-
-	xen_mc_issue(PARAVIRT_LAZY_MMU);
-}
-#endif	/* CONFIG_PGTABLE_LEVELS == 4 */
-
-static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
-		int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
-		bool last, unsigned long limit)
-{
-	int i, nr, flush = 0;
-
-	nr = last ? pmd_index(limit) + 1 : PTRS_PER_PMD;
-	for (i = 0; i < nr; i++) {
-		if (!pmd_none(pmd[i]))
-			flush |= (*func)(mm, pmd_page(pmd[i]), PT_PTE);
-	}
-	return flush;
-}
-
-static int xen_pud_walk(struct mm_struct *mm, pud_t *pud,
-		int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
-		bool last, unsigned long limit)
-{
-	int i, nr, flush = 0;
-
-	nr = last ? pud_index(limit) + 1 : PTRS_PER_PUD;
-	for (i = 0; i < nr; i++) {
-		pmd_t *pmd;
-
-		if (pud_none(pud[i]))
-			continue;
-
-		pmd = pmd_offset(&pud[i], 0);
-		if (PTRS_PER_PMD > 1)
-			flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
-		flush |= xen_pmd_walk(mm, pmd, func,
-				last && i == nr - 1, limit);
-	}
-	return flush;
-}
-
-static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
-		int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
-		bool last, unsigned long limit)
-{
-	int i, nr, flush = 0;
-
-	nr = last ? p4d_index(limit) + 1 : PTRS_PER_P4D;
-	for (i = 0; i < nr; i++) {
-		pud_t *pud;
-
-		if (p4d_none(p4d[i]))
-			continue;
-
-		pud = pud_offset(&p4d[i], 0);
-		if (PTRS_PER_PUD > 1)
-			flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
-		flush |= xen_pud_walk(mm, pud, func,
-				last && i == nr - 1, limit);
-	}
-	return flush;
-}
-
-/*
- * (Yet another) pagetable walker.  This one is intended for pinning a
- * pagetable.  This means that it walks a pagetable and calls the
- * callback function on each page it finds making up the page table,
- * at every level.  It walks the entire pagetable, but it only bothers
- * pinning pte pages which are below limit.  In the normal case this
- * will be STACK_TOP_MAX, but at boot we need to pin up to
- * FIXADDR_TOP.
- *
- * For 32-bit the important bit is that we don't pin beyond there,
- * because then we start getting into Xen's ptes.
- *
- * For 64-bit, we must skip the Xen hole in the middle of the address
- * space, just after the big x86-64 virtual hole.
- */
-static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
-			  int (*func)(struct mm_struct *mm, struct page *,
-				      enum pt_level),
-			  unsigned long limit)
-{
-	int i, nr, flush = 0;
-	unsigned hole_low, hole_high;
-
-	/* The limit is the last byte to be touched */
-	limit--;
-	BUG_ON(limit >= FIXADDR_TOP);
-
-	if (xen_feature(XENFEAT_auto_translated_physmap))
-		return 0;
-
-	/*
-	 * 64-bit has a great big hole in the middle of the address
-	 * space, which contains the Xen mappings.  On 32-bit these
-	 * will end up making a zero-sized hole and so is a no-op.
-	 */
-	hole_low = pgd_index(USER_LIMIT);
-	hole_high = pgd_index(PAGE_OFFSET);
-
-	nr = pgd_index(limit) + 1;
-	for (i = 0; i < nr; i++) {
-		p4d_t *p4d;
-
-		if (i >= hole_low && i < hole_high)
-			continue;
-
-		if (pgd_none(pgd[i]))
-			continue;
-
-		p4d = p4d_offset(&pgd[i], 0);
-		if (PTRS_PER_P4D > 1)
-			flush |= (*func)(mm, virt_to_page(p4d), PT_P4D);
-		flush |= xen_p4d_walk(mm, p4d, func, i == nr - 1, limit);
-	}
-
-	/* Do the top level last, so that the callbacks can use it as
-	   a cue to do final things like tlb flushes. */
-	flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
-
-	return flush;
-}
-
-static int xen_pgd_walk(struct mm_struct *mm,
-			int (*func)(struct mm_struct *mm, struct page *,
-				    enum pt_level),
-			unsigned long limit)
-{
-	return __xen_pgd_walk(mm, mm->pgd, func, limit);
-}
-
-/* If we're using split pte locks, then take the page's lock and
-   return a pointer to it.  Otherwise return NULL. */
-static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
-{
-	spinlock_t *ptl = NULL;
-
-#if USE_SPLIT_PTE_PTLOCKS
-	ptl = ptlock_ptr(page);
-	spin_lock_nest_lock(ptl, &mm->page_table_lock);
-#endif
-
-	return ptl;
-}
-
-static void xen_pte_unlock(void *v)
-{
-	spinlock_t *ptl = v;
-	spin_unlock(ptl);
-}
-
-static void xen_do_pin(unsigned level, unsigned long pfn)
-{
-	struct mmuext_op op;
-
-	op.cmd = level;
-	op.arg1.mfn = pfn_to_mfn(pfn);
-
-	xen_extend_mmuext_op(&op);
-}
-
-static int xen_pin_page(struct mm_struct *mm, struct page *page,
-			enum pt_level level)
-{
-	unsigned pgfl = TestSetPagePinned(page);
-	int flush;
-
-	if (pgfl)
-		flush = 0;		/* already pinned */
-	else if (PageHighMem(page))
-		/* kmaps need flushing if we found an unpinned
-		   highpage */
-		flush = 1;
-	else {
-		void *pt = lowmem_page_address(page);
-		unsigned long pfn = page_to_pfn(page);
-		struct multicall_space mcs = __xen_mc_entry(0);
-		spinlock_t *ptl;
-
-		flush = 0;
-
-		/*
-		 * We need to hold the pagetable lock between the time
-		 * we make the pagetable RO and when we actually pin
-		 * it.  If we don't, then other users may come in and
-		 * attempt to update the pagetable by writing it,
-		 * which will fail because the memory is RO but not
-		 * pinned, so Xen won't do the trap'n'emulate.
-		 *
-		 * If we're using split pte locks, we can't hold the
-		 * entire pagetable's worth of locks during the
-		 * traverse, because we may wrap the preempt count (8
-		 * bits).  The solution is to mark RO and pin each PTE
-		 * page while holding the lock.  This means the number
-		 * of locks we end up holding is never more than a
-		 * batch size (~32 entries, at present).
-		 *
-		 * If we're not using split pte locks, we needn't pin
-		 * the PTE pages independently, because we're
-		 * protected by the overall pagetable lock.
-		 */
-		ptl = NULL;
-		if (level == PT_PTE)
-			ptl = xen_pte_lock(page, mm);
-
-		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
-					pfn_pte(pfn, PAGE_KERNEL_RO),
-					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
-
-		if (ptl) {
-			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
-
-			/* Queue a deferred unlock for when this batch
-			   is completed. */
-			xen_mc_callback(xen_pte_unlock, ptl);
-		}
-	}
-
-	return flush;
-}
-
-/* This is called just after a mm has been created, but it has not
-   been used yet.  We need to make sure that its pagetable is all
-   read-only, and can be pinned. */
-static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
-{
-	trace_xen_mmu_pgd_pin(mm, pgd);
-
-	xen_mc_batch();
-
-	if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
-		/* re-enable interrupts for flushing */
-		xen_mc_issue(0);
-
-		kmap_flush_unused();
-
-		xen_mc_batch();
-	}
-
-#ifdef CONFIG_X86_64
-	{
-		pgd_t *user_pgd = xen_get_user_pgd(pgd);
-
-		xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
-
-		if (user_pgd) {
-			xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
-			xen_do_pin(MMUEXT_PIN_L4_TABLE,
-				   PFN_DOWN(__pa(user_pgd)));
-		}
-	}
-#else /* CONFIG_X86_32 */
-#ifdef CONFIG_X86_PAE
-	/* Need to make sure unshared kernel PMD is pinnable */
-	xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
-		     PT_PMD);
-#endif
-	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
-#endif /* CONFIG_X86_64 */
-	xen_mc_issue(0);
-}
-
-static void xen_pgd_pin(struct mm_struct *mm)
-{
-	__xen_pgd_pin(mm, mm->pgd);
-}
-
-/*
- * On save, we need to pin all pagetables to make sure they get their
- * mfns turned into pfns.  Search the list for any unpinned pgds and pin
- * them (unpinned pgds are not currently in use, probably because the
- * process is under construction or destruction).
- *
- * Expected to be called in stop_machine() ("equivalent to taking
- * every spinlock in the system"), so the locking doesn't really
- * matter all that much.
- */
-void xen_mm_pin_all(void)
-{
-	struct page *page;
-
-	spin_lock(&pgd_lock);
-
-	list_for_each_entry(page, &pgd_list, lru) {
-		if (!PagePinned(page)) {
-			__xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
-			SetPageSavePinned(page);
-		}
-	}
-
-	spin_unlock(&pgd_lock);
-}
-
-/*
- * The init_mm pagetable is really pinned as soon as its created, but
- * that's before we have page structures to store the bits.  So do all
- * the book-keeping now.
- */
-static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
-				  enum pt_level level)
-{
-	SetPagePinned(page);
-	return 0;
-}
-
-static void __init xen_mark_init_mm_pinned(void)
-{
-	xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
-}
-
-static int xen_unpin_page(struct mm_struct *mm, struct page *page,
-			  enum pt_level level)
-{
-	unsigned pgfl = TestClearPagePinned(page);
-
-	if (pgfl && !PageHighMem(page)) {
-		void *pt = lowmem_page_address(page);
-		unsigned long pfn = page_to_pfn(page);
-		spinlock_t *ptl = NULL;
-		struct multicall_space mcs;
-
-		/*
-		 * Do the converse to pin_page.  If we're using split
-		 * pte locks, we must be holding the lock for while
-		 * the pte page is unpinned but still RO to prevent
-		 * concurrent updates from seeing it in this
-		 * partially-pinned state.
-		 */
-		if (level == PT_PTE) {
-			ptl = xen_pte_lock(page, mm);
-
-			if (ptl)
-				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
-		}
-
-		mcs = __xen_mc_entry(0);
-
-		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
-					pfn_pte(pfn, PAGE_KERNEL),
-					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
-
-		if (ptl) {
-			/* unlock when batch completed */
-			xen_mc_callback(xen_pte_unlock, ptl);
-		}
-	}
-
-	return 0;		/* never need to flush on unpin */
-}
-
-/* Release a pagetables pages back as normal RW */
-static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
-{
-	trace_xen_mmu_pgd_unpin(mm, pgd);
-
-	xen_mc_batch();
-
-	xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
-
-#ifdef CONFIG_X86_64
-	{
-		pgd_t *user_pgd = xen_get_user_pgd(pgd);
-
-		if (user_pgd) {
-			xen_do_pin(MMUEXT_UNPIN_TABLE,
-				   PFN_DOWN(__pa(user_pgd)));
-			xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
-		}
-	}
-#endif
-
-#ifdef CONFIG_X86_PAE
-	/* Need to make sure unshared kernel PMD is unpinned */
-	xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
-		       PT_PMD);
-#endif
-
-	__xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
-
-	xen_mc_issue(0);
-}
-
-static void xen_pgd_unpin(struct mm_struct *mm)
-{
-	__xen_pgd_unpin(mm, mm->pgd);
-}
-
-/*
- * On resume, undo any pinning done at save, so that the rest of the
- * kernel doesn't see any unexpected pinned pagetables.
- */
-void xen_mm_unpin_all(void)
-{
-	struct page *page;
-
-	spin_lock(&pgd_lock);
-
-	list_for_each_entry(page, &pgd_list, lru) {
-		if (PageSavePinned(page)) {
-			BUG_ON(!PagePinned(page));
-			__xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
-			ClearPageSavePinned(page);
-		}
-	}
-
-	spin_unlock(&pgd_lock);
-}
-
-static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
-{
-	spin_lock(&next->page_table_lock);
-	xen_pgd_pin(next);
-	spin_unlock(&next->page_table_lock);
-}
-
-static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
-{
-	spin_lock(&mm->page_table_lock);
-	xen_pgd_pin(mm);
-	spin_unlock(&mm->page_table_lock);
-}
-
-
-#ifdef CONFIG_SMP
-/* Another cpu may still have their %cr3 pointing at the pagetable, so
-   we need to repoint it somewhere else before we can unpin it. */
-static void drop_other_mm_ref(void *info)
-{
-	struct mm_struct *mm = info;
-	struct mm_struct *active_mm;
-
-	active_mm = this_cpu_read(cpu_tlbstate.active_mm);
-
-	if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
-		leave_mm(smp_processor_id());
-
-	/* If this cpu still has a stale cr3 reference, then make sure
-	   it has been flushed. */
-	if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
-		load_cr3(swapper_pg_dir);
-}
-
-static void xen_drop_mm_ref(struct mm_struct *mm)
-{
-	cpumask_var_t mask;
-	unsigned cpu;
-
-	if (current->active_mm == mm) {
-		if (current->mm == mm)
-			load_cr3(swapper_pg_dir);
-		else
-			leave_mm(smp_processor_id());
-	}
-
-	/* Get the "official" set of cpus referring to our pagetable. */
-	if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
-		for_each_online_cpu(cpu) {
-			if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
-			    && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
-				continue;
-			smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
-		}
-		return;
-	}
-	cpumask_copy(mask, mm_cpumask(mm));
-
-	/* It's possible that a vcpu may have a stale reference to our
-	   cr3, because its in lazy mode, and it hasn't yet flushed
-	   its set of pending hypercalls yet.  In this case, we can
-	   look at its actual current cr3 value, and force it to flush
-	   if needed. */
-	for_each_online_cpu(cpu) {
-		if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
-			cpumask_set_cpu(cpu, mask);
-	}
-
-	if (!cpumask_empty(mask))
-		smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
-	free_cpumask_var(mask);
-}
-#else
-static void xen_drop_mm_ref(struct mm_struct *mm)
-{
-	if (current->active_mm == mm)
-		load_cr3(swapper_pg_dir);
-}
-#endif
-
-/*
- * While a process runs, Xen pins its pagetables, which means that the
- * hypervisor forces it to be read-only, and it controls all updates
- * to it.  This means that all pagetable updates have to go via the
- * hypervisor, which is moderately expensive.
- *
- * Since we're pulling the pagetable down, we switch to use init_mm,
- * unpin old process pagetable and mark it all read-write, which
- * allows further operations on it to be simple memory accesses.
- *
- * The only subtle point is that another CPU may be still using the
- * pagetable because of lazy tlb flushing.  This means we need need to
- * switch all CPUs off this pagetable before we can unpin it.
- */
-static void xen_exit_mmap(struct mm_struct *mm)
-{
-	get_cpu();		/* make sure we don't move around */
-	xen_drop_mm_ref(mm);
-	put_cpu();
-
-	spin_lock(&mm->page_table_lock);
-
-	/* pgd may not be pinned in the error exit path of execve */
-	if (xen_page_pinned(mm->pgd))
-		xen_pgd_unpin(mm);
-
-	spin_unlock(&mm->page_table_lock);
-}
-
-static void xen_post_allocator_init(void);
-
-static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
-{
-	struct mmuext_op op;
-
-	op.cmd = cmd;
-	op.arg1.mfn = pfn_to_mfn(pfn);
-	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
-		BUG();
-}
-
-#ifdef CONFIG_X86_64
-static void __init xen_cleanhighmap(unsigned long vaddr,
-				    unsigned long vaddr_end)
-{
-	unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
-	pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
-
-	/* NOTE: The loop is more greedy than the cleanup_highmap variant.
-	 * We include the PMD passed in on _both_ boundaries. */
-	for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
-			pmd++, vaddr += PMD_SIZE) {
-		if (pmd_none(*pmd))
-			continue;
-		if (vaddr < (unsigned long) _text || vaddr > kernel_end)
-			set_pmd(pmd, __pmd(0));
-	}
-	/* In case we did something silly, we should crash in this function
-	 * instead of somewhere later and be confusing. */
-	xen_mc_flush();
-}
-
-/*
- * Make a page range writeable and free it.
- */
-static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
-{
-	void *vaddr = __va(paddr);
-	void *vaddr_end = vaddr + size;
-
-	for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
-		make_lowmem_page_readwrite(vaddr);
-
-	memblock_free(paddr, size);
-}
-
-static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
-{
-	unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
-
-	i