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OpenCloudOS-Kernel/arch/x86/xen/mmu_pv.c

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/*
* 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>
#ifdef CONFIG_KEXEC_CORE
#include <linux/kexec.h>
#endif
#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 <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"
#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)
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;
mfn = __pfn_to_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);
/*
* 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);
}
static void drop_mm_ref_this_cpu(void *info)
{
struct mm_struct *mm = info;
if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm)
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))
xen_mc_flush();
}
#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 xen_drop_mm_ref(struct mm_struct *mm)
{
cpumask_var_t mask;
unsigned cpu;
drop_mm_ref_this_cpu(mm);
/* 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_mm_ref_this_cpu, 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);
}
smp_call_function_many(mask, drop_mm_ref_this_cpu, mm, 1);
free_cpumask_var(mask);
}
#else
static void xen_drop_mm_ref(struct mm_struct *mm)
{
drop_mm_ref_this_cpu(mm);
}
#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;
if (unpin)
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
ClearPagePinned(virt_to_page(__va(pa)));
xen_free_ro_pages(pa, PAGE_SIZE);
}
static void __init xen_cleanmfnmap_pmd(pmd_t *pmd, bool unpin)
{
unsigned long pa;
pte_t *pte_tbl;
int i;
if (pmd_large(*pmd)) {
pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
xen_free_ro_pages(pa, PMD_SIZE);
return;
}
pte_tbl = pte_offset_kernel(pmd, 0);
for (i = 0; i < PTRS_PER_PTE; i++) {
if (pte_none(pte_tbl[i]))
continue;
pa = pte_pfn(pte_tbl[i]) << PAGE_SHIFT;
xen_free_ro_pages(pa, PAGE_SIZE);
}
set_pmd(pmd, __pmd(0));
xen_cleanmfnmap_free_pgtbl(pte_tbl, unpin);
}
static void __init xen_cleanmfnmap_pud(pud_t *pud, bool unpin)
{
unsigned long pa;
pmd_t *pmd_tbl;
int i;
if (pud_large(*pud)) {
pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
xen_free_ro_pages(pa, PUD_SIZE);
return;
}
pmd_tbl = pmd_offset(pud, 0);
for (i = 0; i < PTRS_PER_PMD; i++) {
if (pmd_none(pmd_tbl[i]))
continue;
xen_cleanmfnmap_pmd(pmd_tbl + i, unpin);
}
set_pud(pud, __pud(0));
xen_cleanmfnmap_free_pgtbl(pmd_tbl, unpin);
}
static void __init xen_cleanmfnmap_p4d(p4d_t *p4d, bool unpin)
{
unsigned long pa;
pud_t *pud_tbl;
int i;
if (p4d_large(*p4d)) {
pa = p4d_val(*p4d) & PHYSICAL_PAGE_MASK;
xen_free_ro_pages(pa, P4D_SIZE);
return;
}
pud_tbl = pud_offset(p4d, 0);
for (i = 0; i < PTRS_PER_PUD; i++) {
if (pud_none(pud_tbl[i]))
continue;
xen_cleanmfnmap_pud(pud_tbl + i, unpin);
}
set_p4d(p4d, __p4d(0));
xen_cleanmfnmap_free_pgtbl(pud_tbl, unpin);
}
/*
* Since it is well isolated we can (and since it is perhaps large we should)
* also free the page tables mapping the initial P->M table.
*/
static void __init xen_cleanmfnmap(unsigned long vaddr)
{
pgd_t *pgd;
p4d_t *p4d;
unsigned int i;
bool unpin;
unpin = (vaddr == 2 * PGDIR_SIZE);
vaddr &= PMD_MASK;
pgd = pgd_offset_k(vaddr);
p4d = p4d_offset(pgd, 0);
for (i = 0; i < PTRS_PER_P4D; i++) {
if (p4d_none(p4d[i]))
continue;
xen_cleanmfnmap_p4d(p4d + i, unpin);
}
if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
set_pgd(pgd, __pgd(0));
xen_cleanmfnmap_free_pgtbl(p4d, unpin);
}
}
static void __init xen_pagetable_p2m_free(void)
{
unsigned long size;
unsigned long addr;
size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
/* No memory or already called. */
if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list)
return;
/* using __ka address and sticking INVALID_P2M_ENTRY! */
memset((void *)xen_start_info->mfn_list, 0xff, size);
addr = xen_start_info->mfn_list;
/*
* We could be in __ka space.
* We roundup to the PMD, which means that if anybody at this stage is
* using the __ka address of xen_start_info or
* xen_start_info->shared_info they are in going to crash. Fortunatly
* we have already revectored in xen_setup_kernel_pagetable and in
* xen_setup_shared_info.
*/
size = roundup(size, PMD_SIZE);
if (addr >= __START_KERNEL_map) {
xen_cleanhighmap(addr, addr + size);
size = PAGE_ALIGN(xen_start_info->nr_pages *
sizeof(unsigned long));
memblock_free(__pa(addr), size);
} else {
xen_cleanmfnmap(addr);
}
}
static void __init xen_pagetable_cleanhighmap(void)
{
unsigned long size;
unsigned long addr;
/* At this stage, cleanup_highmap has already cleaned __ka space
* from _brk_limit way up to the max_pfn_mapped (which is the end of
* the ramdisk). We continue on, erasing PMD entries that point to page
* tables - do note that they are accessible at this stage via __va.
* For good measure we also round up to the PMD - which means that if
* anybody is using __ka address to the initial boot-stack - and try
* to use it - they are going to crash. The xen_start_info has been
* taken care of already in xen_setup_kernel_pagetable. */
addr = xen_start_info->pt_base;
size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);
xen_cleanhighmap(addr, addr + size);
xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
#ifdef DEBUG
/* This is superfluous and is not necessary, but you know what
* lets do it. The MODULES_VADDR -> MODULES_END should be clear of
* anything at this stage. */
xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
#endif
}
#endif
static void __init xen_pagetable_p2m_setup(void)
{
xen_vmalloc_p2m_tree();
#ifdef CONFIG_X86_64
xen_pagetable_p2m_free();
xen_pagetable_cleanhighmap();
#endif
/* And revector! Bye bye old array */
xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
}
static void __init xen_pagetable_init(void)
{
paging_init();
xen_post_allocator_init();
xen_pagetable_p2m_setup();
/* Allocate and initialize top and mid mfn levels for p2m structure */
xen_build_mfn_list_list();
/* Remap memory freed due to conflicts with E820 map */
xen_remap_memory();
xen_setup_shared_info();
}
static void xen_write_cr2(unsigned long cr2)
{
this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
}
static unsigned long xen_read_cr2(void)
{
return this_cpu_read(xen_vcpu)->arch.cr2;
}
unsigned long xen_read_cr2_direct(void)
{
return this_cpu_read(xen_vcpu_info.arch.cr2);
}
static void xen_flush_tlb(void)
{
struct mmuext_op *op;
struct multicall_space mcs;
trace_xen_mmu_flush_tlb(0);
preempt_disable();
mcs = xen_mc_entry(sizeof(*op));
op = mcs.args;
op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
xen_mc_issue(PARAVIRT_LAZY_MMU);
preempt_enable();
}
static void xen_flush_tlb_single(unsigned long addr)
{
struct mmuext_op *op;
struct multicall_space mcs;
trace_xen_mmu_flush_tlb_single(addr);
preempt_disable();
mcs = xen_mc_entry(sizeof(*op));
op = mcs.args;
op->cmd = MMUEXT_INVLPG_LOCAL;
op->arg1.linear_addr = addr & PAGE_MASK;
MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
xen_mc_issue(PARAVIRT_LAZY_MMU);
preempt_enable();
}
static void xen_flush_tlb_others(const struct cpumask *cpus,
const struct flush_tlb_info *info)
{
struct {
struct mmuext_op op;
#ifdef CONFIG_SMP
DECLARE_BITMAP(mask, num_processors);
#else
DECLARE_BITMAP(mask, NR_CPUS);
#endif
} *args;
struct multicall_space mcs;
trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end);
if (cpumask_empty(cpus))
return; /* nothing to do */
mcs = xen_mc_entry(sizeof(*args));
args = mcs.args;
args->op.arg2.vcpumask = to_cpumask(args->mask);
/* Remove us, and any offline CPUS. */
cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
if (info->end != TLB_FLUSH_ALL &&
(info->end - info->start) <= PAGE_SIZE) {
args->op.cmd = MMUEXT_INVLPG_MULTI;
args->op.arg1.linear_addr = info->start;
}
MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
xen_mc_issue(PARAVIRT_LAZY_MMU);
}
static unsigned long xen_read_cr3(void)
{
return this_cpu_read(xen_cr3);
}
static void set_current_cr3(void *v)
{
this_cpu_write(xen_current_cr3, (unsigned long)v);
}
static void __xen_write_cr3(bool kernel, unsigned long cr3)
{
struct mmuext_op op;
unsigned long mfn;
trace_xen_mmu_write_cr3(kernel, cr3);
if (cr3)
mfn = pfn_to_mfn(PFN_DOWN(cr3));
else
mfn = 0;
WARN_ON(mfn == 0 && kernel);
op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
op.arg1.mfn = mfn;
xen_extend_mmuext_op(&op);
if (kernel) {
this_cpu_write(xen_cr3, cr3);
/* Update xen_current_cr3 once the batch has actually
been submitted. */
xen_mc_callback(set_current_cr3, (void *)cr3);
}
}
static void xen_write_cr3(unsigned long cr3)
{
BUG_ON(preemptible());
xen_mc_batch(); /* disables interrupts */
/* Update while interrupts are disabled, so its atomic with
respect to ipis */
this_cpu_write(xen_cr3, cr3);
__xen_write_cr3(true, cr3);
#ifdef CONFIG_X86_64
{
pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
if (user_pgd)
__xen_write_cr3(false, __pa(user_pgd));
else
__xen_write_cr3(false, 0);
}
#endif
xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
}
#ifdef CONFIG_X86_64
/*
* At the start of the day - when Xen launches a guest, it has already
* built pagetables for the guest. We diligently look over them
* in xen_setup_kernel_pagetable and graft as appropriate them in the
* init_top_pgt and its friends. Then when we are happy we load
* the new init_top_pgt - and continue on.
*
* The generic code starts (start_kernel) and 'init_mem_mapping' sets
* up the rest of the pagetables. When it has completed it loads the cr3.
* N.B. that baremetal would start at 'start_kernel' (and the early
* #PF handler would create bootstrap pagetables) - so we are running
* with the same assumptions as what to do when write_cr3 is executed
* at this point.
*
* Since there are no user-page tables at all, we have two variants
* of xen_write_cr3 - the early bootup (this one), and the late one
* (xen_write_cr3). The reason we have to do that is that in 64-bit
* the Linux kernel and user-space are both in ring 3 while the
* hypervisor is in ring 0.
*/
static void __init xen_write_cr3_init(unsigned long cr3)
{
BUG_ON(preemptible());
xen_mc_batch(); /* disables interrupts */
/* Update while interrupts are disabled, so its atomic with
respect to ipis */
this_cpu_write(xen_cr3, cr3);
__xen_write_cr3(true, cr3);
xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
}
#endif
static int xen_pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd = mm->pgd;
int ret = 0;
BUG_ON(PagePinned(virt_to_page(pgd)));
#ifdef CONFIG_X86_64
{
struct page *page = virt_to_page(pgd);
pgd_t *user_pgd;
BUG_ON(page->private != 0);
ret = -ENOMEM;
user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
page->private = (unsigned long)user_pgd;
if (user_pgd != NULL) {
#ifdef CONFIG_X86_VSYSCALL_EMULATION
user_pgd[pgd_index(VSYSCALL_ADDR)] =
__pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
#endif
ret = 0;
}
BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
}
#endif
return ret;
}
static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
#ifdef CONFIG_X86_64
pgd_t *user_pgd = xen_get_user_pgd(pgd);
if (user_pgd)
free_page((unsigned long)user_pgd);
#endif
}
/*
* Init-time set_pte while constructing initial pagetables, which
* doesn't allow RO page table pages to be remapped RW.
*
* If there is no MFN for this PFN then this page is initially
* ballooned out so clear the PTE (as in decrease_reservation() in
* drivers/xen/balloon.c).
*
* Many of these PTE updates are done on unpinned and writable pages
* and doing a hypercall for these is unnecessary and expensive. At
* this point it is not possible to tell if a page is pinned or not,
* so always write the PTE directly and rely on Xen trapping and
* emulating any updates as necessary.
*/
__visible pte_t xen_make_pte_init(pteval_t pte)
{
#ifdef CONFIG_X86_64
unsigned long pfn;
/*
* Pages belonging to the initial p2m list mapped outside the default
* address range must be mapped read-only. This region contains the
* page tables for mapping the p2m list, too, and page tables MUST be
* mapped read-only.
*/
pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT;
if (xen_start_info->mfn_list < __START_KERNEL_map &&
pfn >= xen_start_info->first_p2m_pfn &&
pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
pte &= ~_PAGE_RW;
#endif
pte = pte_pfn_to_mfn(pte);
return native_make_pte(pte);
}
PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);
static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
{
#ifdef CONFIG_X86_32
/* If there's an existing pte, then don't allow _PAGE_RW to be set */
if (pte_mfn(pte) != INVALID_P2M_ENTRY
&& pte_val_ma(*ptep) & _PAGE_PRESENT)
pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
pte_val_ma(pte));
#endif
native_set_pte(ptep, pte);
}
/* Early in boot, while setting up the initial pagetable, assume
everything is pinned. */
static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
{
#ifdef CONFIG_FLATMEM
BUG_ON(mem_map); /* should only be used early */
#endif
make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
}
/* Used for pmd and pud */
static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
{
#ifdef CONFIG_FLATMEM
BUG_ON(mem_map); /* should only be used early */
#endif
make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
}
/* Early release_pte assumes that all pts are pinned, since there's
only init_mm and anything attached to that is pinned. */
static void __init xen_release_pte_init(unsigned long pfn)
{
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
}
static void __init xen_release_pmd_init(unsigned long pfn)
{
make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
}
static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
{
struct multicall_space mcs;
struct mmuext_op *op;
mcs = __xen_mc_entry(sizeof(*op));
op = mcs.args;
op->cmd = cmd;
op->arg1.mfn = pfn_to_mfn(pfn);
MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
}
static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
{
struct multicall_space mcs;
unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
mcs = __xen_mc_entry(0);
MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
pfn_pte(pfn, prot), 0);
}
/* This needs to make sure the new pte page is pinned iff its being
attached to a pinned pagetable. */
static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
unsigned level)
{
bool pinned = PagePinned(virt_to_page(mm->pgd));
trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
if (pinned) {
struct page *page = pfn_to_page(pfn);
SetPagePinned(page);
if (!PageHighMem(page)) {
xen_mc_batch();
__set_pfn_prot(pfn, PAGE_KERNEL_RO);
if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
__pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
xen_mc_issue(PARAVIRT_LAZY_MMU);
} else {
/* make sure there are no stray mappings of
this page */
kmap_flush_unused();
}
}
}
static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
{
xen_alloc_ptpage(mm, pfn, PT_PTE);
}
static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
{
xen_alloc_ptpage(mm, pfn, PT_PMD);
}
/* This should never happen until we're OK to use struct page */
static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
{
struct page *page = pfn_to_page(pfn);
bool pinned = PagePinned(page);
trace_xen_mmu_release_ptpage(pfn, level, pinned);
if (pinned) {
if (!PageHighMem(page)) {
xen_mc_batch();
if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
__pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
__set_pfn_prot(pfn, PAGE_KERNEL);
xen_mc_issue(PARAVIRT_LAZY_MMU);
}
ClearPagePinned(page);
}
}
static void xen_release_pte(unsigned long pfn)
{
xen_release_ptpage(pfn, PT_PTE);
}
static void xen_release_pmd(unsigned long pfn)
{
xen_release_ptpage(pfn, PT_PMD);
}
#if CONFIG_PGTABLE_LEVELS >= 4
static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
{
xen_alloc_ptpage(mm, pfn, PT_PUD);
}
static void xen_release_pud(unsigned long pfn)
{
xen_release_ptpage(pfn, PT_PUD);
}
#endif
void __init xen_reserve_top(void)
{
#ifdef CONFIG_X86_32
unsigned long top = HYPERVISOR_VIRT_START;
struct xen_platform_parameters pp;
if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
top = pp.virt_start;
reserve_top_address(-top);
#endif /* CONFIG_X86_32 */
}
/*
* Like __va(), but returns address in the kernel mapping (which is
* all we have until the physical memory mapping has been set up.
*/
static void * __init __ka(phys_addr_t paddr)
{
#ifdef CONFIG_X86_64
return (void *)(paddr + __START_KERNEL_map);
#else
return __va(paddr);
#endif
}
/* Convert a machine address to physical address */
static unsigned long __init m2p(phys_addr_t maddr)
{
phys_addr_t paddr;
maddr &= PTE_PFN_MASK;
paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
return paddr;
}
/* Convert a machine address to kernel virtual */
static void * __init m2v(phys_addr_t maddr)
{
return __ka(m2p(maddr));
}
/* Set the page permissions on an identity-mapped pages */
static void __init set_page_prot_flags(void *addr, pgprot_t prot,
unsigned long flags)
{
unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
pte_t pte = pfn_pte(pfn, prot);
if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
BUG();
}
static void __init set_page_prot(void *addr, pgprot_t prot)
{
return set_page_prot_flags(addr, prot, UVMF_NONE);
}
#ifdef CONFIG_X86_32
static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
{
unsigned pmdidx, pteidx;
unsigned ident_pte;
unsigned long pfn;
level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
PAGE_SIZE);
ident_pte = 0;
pfn = 0;
for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
pte_t *pte_page;
/* Reuse or allocate a page of ptes */
if (pmd_present(pmd[pmdidx]))
pte_page = m2v(pmd[pmdidx].pmd);
else {
/* Check for free pte pages */
if (ident_pte == LEVEL1_IDENT_ENTRIES)
break;
pte_page = &level1_ident_pgt[ident_pte];
ident_pte += PTRS_PER_PTE;
pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
}
/* Install mappings */
for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
pte_t pte;
if (pfn > max_pfn_mapped)
max_pfn_mapped = pfn;
if (!pte_none(pte_page[pteidx]))
continue;
pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
pte_page[pteidx] = pte;
}
}
for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
set_page_prot(pmd, PAGE_KERNEL_RO);
}
#endif
void __init xen_setup_machphys_mapping(void)
{
struct xen_machphys_mapping mapping;
if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
machine_to_phys_mapping = (unsigned long *)mapping.v_start;
machine_to_phys_nr = mapping.max_mfn + 1;
} else {
machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
}
#ifdef CONFIG_X86_32
WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
< machine_to_phys_mapping);
#endif
}
#ifdef CONFIG_X86_64
static void __init convert_pfn_mfn(void *v)
{
pte_t *pte = v;
int i;
/* All levels are converted the same way, so just treat them
as ptes. */
for (i = 0; i < PTRS_PER_PTE; i++)
pte[i] = xen_make_pte(pte[i].pte);
}
static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
unsigned long addr)
{
if (*pt_base == PFN_DOWN(__pa(addr))) {
set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
clear_page((void *)addr);
(*pt_base)++;
}
if (*pt_end == PFN_DOWN(__pa(addr))) {
set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
clear_page((void *)addr);
(*pt_end)--;
}
}
/*
* Set up the initial kernel pagetable.
*
* We can construct this by grafting the Xen provided pagetable into
* head_64.S's preconstructed pagetables. We copy the Xen L2's into
* level2_ident_pgt, and level2_kernel_pgt. This means that only the
* kernel has a physical mapping to start with - but that's enough to
* get __va working. We need to fill in the rest of the physical
* mapping once some sort of allocator has been set up.
*/
void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pud_t *l3;
pmd_t *l2;
unsigned long addr[3];
unsigned long pt_base, pt_end;
unsigned i;
/* max_pfn_mapped is the last pfn mapped in the initial memory
* mappings. Considering that on Xen after the kernel mappings we
* have the mappings of some pages that don't exist in pfn space, we
* set max_pfn_mapped to the last real pfn mapped. */
if (xen_start_info->mfn_list < __START_KERNEL_map)
max_pfn_mapped = xen_start_info->first_p2m_pfn;
else
max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
pt_end = pt_base + xen_start_info->nr_pt_frames;
/* Zap identity mapping */
init_top_pgt[0] = __pgd(0);
/* Pre-constructed entries are in pfn, so convert to mfn */
/* L4[272] -> level3_ident_pgt */
/* L4[511] -> level3_kernel_pgt */
convert_pfn_mfn(init_top_pgt);
/* L3_i[0] -> level2_ident_pgt */
convert_pfn_mfn(level3_ident_pgt);
/* L3_k[510] -> level2_kernel_pgt */
/* L3_k[511] -> level2_fixmap_pgt */
convert_pfn_mfn(level3_kernel_pgt);
/* L3_k[511][506] -> level1_fixmap_pgt */
convert_pfn_mfn(level2_fixmap_pgt);
/* We get [511][511] and have Xen's version of level2_kernel_pgt */
l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
addr[0] = (unsigned long)pgd;
addr[1] = (unsigned long)l3;
addr[2] = (unsigned long)l2;
/* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
* Both L4[272][0] and L4[511][510] have entries that point to the same
* L2 (PMD) tables. Meaning that if you modify it in __va space
* it will be also modified in the __ka space! (But if you just
* modify the PMD table to point to other PTE's or none, then you
* are OK - which is what cleanup_highmap does) */
copy_page(level2_ident_pgt, l2);
/* Graft it onto L4[511][510] */
copy_page(level2_kernel_pgt, l2);
/* Copy the initial P->M table mappings if necessary. */
i = pgd_index(xen_start_info->mfn_list);
if (i && i < pgd_index(__START_KERNEL_map))
init_top_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
/* Make pagetable pieces RO */
set_page_prot(init_top_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
set_page_prot(level1_fixmap_pgt, PAGE_KERNEL_RO);
/* Pin down new L4 */
pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
PFN_DOWN(__pa_symbol(init_top_pgt)));
/* Unpin Xen-provided one */
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
/*
* At this stage there can be no user pgd, and no page structure to
* attach it to, so make sure we just set kernel pgd.
*/
xen_mc_batch();
__xen_write_cr3(true, __pa(init_top_pgt));
xen_mc_issue(PARAVIRT_LAZY_CPU);
/* We can't that easily rip out L3 and L2, as the Xen pagetables are
* set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
* the initial domain. For guests using the toolstack, they are in:
* [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
* rip out the [L4] (pgd), but for guests we shave off three pages.
*/
for (i = 0; i < ARRAY_SIZE(addr); i++)
check_pt_base(&pt_base, &pt_end, addr[i]);
/* Our (by three pages) smaller Xen pagetable that we are using */
xen_pt_base = PFN_PHYS(pt_base);
xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
memblock_reserve(xen_pt_base, xen_pt_size);
/* Revector the xen_start_info */
xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
}
/*
* Read a value from a physical address.
*/
static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
{
unsigned long *vaddr;
unsigned long val;
vaddr = early_memremap_ro(addr, sizeof(val));
val = *vaddr;
early_memunmap(vaddr, sizeof(val));
return val;
}
/*
* Translate a virtual address to a physical one without relying on mapped
* page tables. Don't rely on big pages being aligned in (guest) physical
* space!
*/
static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
{
phys_addr_t pa;
pgd_t pgd;
pud_t pud;
pmd_t pmd;
pte_t pte;
pa = read_cr3_pa();
pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
sizeof(pgd)));
if (!pgd_present(pgd))
return 0;
pa = pgd_val(pgd) & PTE_PFN_MASK;
pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
sizeof(pud)));
if (!pud_present(pud))
return 0;
pa = pud_val(pud) & PTE_PFN_MASK;
if (pud_large(pud))
return pa + (vaddr & ~PUD_MASK);
pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
sizeof(pmd)));
if (!pmd_present(pmd))
return 0;
pa = pmd_val(pmd) & PTE_PFN_MASK;
if (pmd_large(pmd))
return pa + (vaddr & ~PMD_MASK);
pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
sizeof(pte)));
if (!pte_present(pte))
return 0;
pa = pte_pfn(pte) << PAGE_SHIFT;
return pa | (vaddr & ~PAGE_MASK);
}
/*
* Find a new area for the hypervisor supplied p2m list and relocate the p2m to
* this area.
*/
void __init xen_relocate_p2m(void)
{
phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys, p4d_phys;
unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
int n_pte, n_pt, n_pmd, n_pud, n_p4d, idx_pte, idx_pt, idx_pmd, idx_pud, idx_p4d;
pte_t *pt;
pmd_t *pmd;
pud_t *pud;
p4d_t *p4d = NULL;
pgd_t *pgd;
unsigned long *new_p2m;
int save_pud;
size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
n_pud = roundup(size, P4D_SIZE) >> P4D_SHIFT;
if (PTRS_PER_P4D > 1)
n_p4d = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT;
else
n_p4d = 0;
n_frames = n_pte + n_pt + n_pmd + n_pud + n_p4d;
new_area = xen_find_free_area(PFN_PHYS(n_frames));
if (!new_area) {
xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
BUG();
}
/*
* Setup the page tables for addressing the new p2m list.
* We have asked the hypervisor to map the p2m list at the user address
* PUD_SIZE. It may have done so, or it may have used a kernel space
* address depending on the Xen version.
* To avoid any possible virtual address collision, just use
* 2 * PUD_SIZE for the new area.
*/
p4d_phys = new_area;
pud_phys = p4d_phys + PFN_PHYS(n_p4d);
pmd_phys = pud_phys + PFN_PHYS(n_pud);
pt_phys = pmd_phys + PFN_PHYS(n_pmd);
p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
pgd = __va(read_cr3_pa());
new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
idx_p4d = 0;
save_pud = n_pud;
do {
if (n_p4d > 0) {
p4d = early_memremap(p4d_phys, PAGE_SIZE);
clear_page(p4d);
n_pud = min(save_pud, PTRS_PER_P4D);
}
for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
pud = early_memremap(pud_phys, PAGE_SIZE);
clear_page(pud);
for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
idx_pmd++) {
pmd = early_memremap(pmd_phys, PAGE_SIZE);
clear_page(pmd);
for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
idx_pt++) {
pt = early_memremap(pt_phys, PAGE_SIZE);
clear_page(pt);
for (idx_pte = 0;
idx_pte < min(n_pte, PTRS_PER_PTE);
idx_pte++) {
set_pte(pt + idx_pte,
pfn_pte(p2m_pfn, PAGE_KERNEL));
p2m_pfn++;
}
n_pte -= PTRS_PER_PTE;
early_memunmap(pt, PAGE_SIZE);
make_lowmem_page_readonly(__va(pt_phys));
pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
PFN_DOWN(pt_phys));
set_pmd(pmd + idx_pt,
__pmd(_PAGE_TABLE | pt_phys));
pt_phys += PAGE_SIZE;
}
n_pt -= PTRS_PER_PMD;
early_memunmap(pmd, PAGE_SIZE);
make_lowmem_page_readonly(__va(pmd_phys));
pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
PFN_DOWN(pmd_phys));
set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
pmd_phys += PAGE_SIZE;
}
n_pmd -= PTRS_PER_PUD;
early_memunmap(pud, PAGE_SIZE);
make_lowmem_page_readonly(__va(pud_phys));
pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
if (n_p4d > 0)
set_p4d(p4d + idx_pud, __p4d(_PAGE_TABLE | pud_phys));
else
set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
pud_phys += PAGE_SIZE;
}
if (n_p4d > 0) {
save_pud -= PTRS_PER_P4D;
early_memunmap(p4d, PAGE_SIZE);
make_lowmem_page_readonly(__va(p4d_phys));
pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(p4d_phys));
set_pgd(pgd + 2 + idx_p4d, __pgd(_PAGE_TABLE | p4d_phys));
p4d_phys += PAGE_SIZE;
}
} while (++idx_p4d < n_p4d);
/* Now copy the old p2m info to the new area. */
memcpy(new_p2m, xen_p2m_addr, size);
xen_p2m_addr = new_p2m;
/* Release the old p2m list and set new list info. */
p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
BUG_ON(!p2m_pfn);
p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
if (xen_start_info->mfn_list < __START_KERNEL_map) {
pfn = xen_start_info->first_p2m_pfn;
pfn_end = xen_start_info->first_p2m_pfn +
xen_start_info->nr_p2m_frames;
set_pgd(pgd + 1, __pgd(0));
} else {
pfn = p2m_pfn;
pfn_end = p2m_pfn_end;
}
memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
while (pfn < pfn_end) {
if (pfn == p2m_pfn) {
pfn = p2m_pfn_end;
continue;
}
make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
pfn++;
}
xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
xen_start_info->first_p2m_pfn = PFN_DOWN(new_area);
xen_start_info->nr_p2m_frames = n_frames;
}
#else /* !CONFIG_X86_64 */
static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
static void __init xen_write_cr3_init(unsigned long cr3)
{
unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
BUG_ON(read_cr3_pa() != __pa(initial_page_table));
BUG_ON(cr3 != __pa(swapper_pg_dir));
/*
* We are switching to swapper_pg_dir for the first time (from
* initial_page_table) and therefore need to mark that page
* read-only and then pin it.
*
* Xen disallows sharing of kernel PMDs for PAE
* guests. Therefore we must copy the kernel PMD from
* initial_page_table into a new kernel PMD to be used in
* swapper_pg_dir.
*/
swapper_kernel_pmd =
extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
copy_page(swapper_kernel_pmd, initial_kernel_pmd);
swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
__pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
xen_write_cr3(cr3);
pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
PFN_DOWN(__pa(initial_page_table)));
set_page_prot(initial_page_table, PAGE_KERNEL);
set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
pv_mmu_ops.write_cr3 = &xen_write_cr3;
}
/*
* For 32 bit domains xen_start_info->pt_base is the pgd address which might be
* not the first page table in the page table pool.
* Iterate through the initial page tables to find the real page table base.
*/
static phys_addr_t xen_find_pt_base(pmd_t *pmd)
{
phys_addr_t pt_base, paddr;
unsigned pmdidx;
pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
paddr = m2p(pmd[pmdidx].pmd);
pt_base = min(pt_base, paddr);
}
return pt_base;
}
void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pmd_t *kernel_pmd;
kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
xen_pt_base = xen_find_pt_base(kernel_pmd);
xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
initial_kernel_pmd =
extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
copy_page(initial_kernel_pmd, kernel_pmd);
xen_map_identity_early(initial_kernel_pmd, max_pfn);
copy_page(initial_page_table, pgd);
initial_page_table[KERNEL_PGD_BOUNDARY] =
__pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
set_page_prot(initial_page_table, PAGE_KERNEL_RO);
set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
PFN_DOWN(__pa(initial_page_table)));
xen_write_cr3(__pa(initial_page_table));
memblock_reserve(xen_pt_base, xen_pt_size);
}
#endif /* CONFIG_X86_64 */
void __init xen_reserve_special_pages(void)
{
phys_addr_t paddr;
memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
if (xen_start_info->store_mfn) {
paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
memblock_reserve(paddr, PAGE_SIZE);
}
if (!xen_initial_domain()) {
paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
memblock_reserve(paddr, PAGE_SIZE);
}
}
void __init xen_pt_check_e820(void)
{
if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
BUG();
}
}
static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
{
pte_t pte;
phys >>= PAGE_SHIFT;
switch (idx) {
case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
case FIX_RO_IDT:
#ifdef CONFIG_X86_32
case FIX_WP_TEST:
# ifdef CONFIG_HIGHMEM
case FIX_KMAP_BEGIN ... FIX_KMAP_END:
# endif
#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
case VSYSCALL_PAGE:
#endif
case FIX_TEXT_POKE0:
case FIX_TEXT_POKE1:
case FIX_GDT_REMAP_BEGIN ... FIX_GDT_REMAP_END:
/* All local page mappings */
pte = pfn_pte(phys, prot);
break;
#ifdef CONFIG_X86_LOCAL_APIC
case FIX_APIC_BASE: /* maps dummy local APIC */
pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
break;
#endif
#ifdef CONFIG_X86_IO_APIC
case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
/*
* We just don't map the IO APIC - all access is via
* hypercalls. Keep the address in the pte for reference.
*/
pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
break;
#endif
case FIX_PARAVIRT_BOOTMAP:
/* This is an MFN, but it isn't an IO mapping from the
IO domain */
pte = mfn_pte(phys, prot);
break;
default:
/* By default, set_fixmap is used for hardware mappings */
pte = mfn_pte(phys, prot);
break;
}
__native_set_fixmap(idx, pte);
#ifdef CONFIG_X86_VSYSCALL_EMULATION
/* Replicate changes to map the vsyscall page into the user
pagetable vsyscall mapping. */
if (idx == VSYSCALL_PAGE) {
unsigned long vaddr = __fix_to_virt(idx);
set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
}
#endif
}
static void __init xen_post_allocator_init(void)
{
pv_mmu_ops.set_pte = xen_set_pte;
pv_mmu_ops.set_pmd = xen_set_pmd;
pv_mmu_ops.set_pud = xen_set_pud;
#if CONFIG_PGTABLE_LEVELS >= 4
pv_mmu_ops.set_p4d = xen_set_p4d;
#endif
/* This will work as long as patching hasn't happened yet
(which it hasn't) */
pv_mmu_ops.alloc_pte = xen_alloc_pte;
pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
pv_mmu_ops.release_pte = xen_release_pte;
pv_mmu_ops.release_pmd = xen_release_pmd;
#if CONFIG_PGTABLE_LEVELS >= 4
pv_mmu_ops.alloc_pud = xen_alloc_pud;
pv_mmu_ops.release_pud = xen_release_pud;
#endif
pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte);
#ifdef CONFIG_X86_64
pv_mmu_ops.write_cr3 = &xen_write_cr3;
SetPagePinned(virt_to_page(level3_user_vsyscall));
#endif
xen_mark_init_mm_pinned();
}
static void xen_leave_lazy_mmu(void)
{
preempt_disable();
xen_mc_flush();
paravirt_leave_lazy_mmu();
preempt_enable();
}
static const struct pv_mmu_ops xen_mmu_ops __initconst = {
.read_cr2 = xen_read_cr2,
.write_cr2 = xen_write_cr2,
.read_cr3 = xen_read_cr3,
.write_cr3 = xen_write_cr3_init,
.flush_tlb_user = xen_flush_tlb,
.flush_tlb_kernel = xen_flush_tlb,
.flush_tlb_single = xen_flush_tlb_single,
.flush_tlb_others = xen_flush_tlb_others,
.pte_update = paravirt_nop,
.pgd_alloc = xen_pgd_alloc,
.pgd_free = xen_pgd_free,
.alloc_pte = xen_alloc_pte_init,
.release_pte = xen_release_pte_init,
.alloc_pmd = xen_alloc_pmd_init,
.release_pmd = xen_release_pmd_init,
.set_pte = xen_set_pte_init,
.set_pte_at = xen_set_pte_at,
.set_pmd = xen_set_pmd_hyper,
.ptep_modify_prot_start = __ptep_modify_prot_start,
.ptep_modify_prot_commit = __ptep_modify_prot_commit,
.pte_val = PV_CALLEE_SAVE(xen_pte_val),
.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
.make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
#ifdef CONFIG_X86_PAE
.set_pte_atomic = xen_set_pte_atomic,
.pte_clear = xen_pte_clear,
.pmd_clear = xen_pmd_clear,
#endif /* CONFIG_X86_PAE */
.set_pud = xen_set_pud_hyper,
.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
#if CONFIG_PGTABLE_LEVELS >= 4
.pud_val = PV_CALLEE_SAVE(xen_pud_val),
.make_pud = PV_CALLEE_SAVE(xen_make_pud),
.set_p4d = xen_set_p4d_hyper,
.alloc_pud = xen_alloc_pmd_init,
.release_pud = xen_release_pmd_init,
#endif /* CONFIG_PGTABLE_LEVELS == 4 */
.activate_mm = xen_activate_mm,
.dup_mmap = xen_dup_mmap,
.exit_mmap = xen_exit_mmap,
.lazy_mode = {
.enter = paravirt_enter_lazy_mmu,
.leave = xen_leave_lazy_mmu,
.flush = paravirt_flush_lazy_mmu,
},
.set_fixmap = xen_set_fixmap,
};
void __init xen_init_mmu_ops(void)
{
x86_init.paging.pagetable_init = xen_pagetable_init;
pv_mmu_ops = xen_mmu_ops;
memset(dummy_mapping, 0xff, PAGE_SIZE);
}
/* Protected by xen_reservation_lock. */
#define MAX_CONTIG_ORDER 9 /* 2MB */
static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
#define VOID_PTE (mfn_pte(0, __pgprot(0)))
static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
unsigned long *in_frames,
unsigned long *out_frames)
{
int i;
struct multicall_space mcs;
xen_mc_batch();
for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
mcs = __xen_mc_entry(0);
if (in_frames)
in_frames[i] = virt_to_mfn(vaddr);
MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
if (out_frames)
out_frames[i] = virt_to_pfn(vaddr);
}
xen_mc_issue(0);
}
/*
* Update the pfn-to-mfn mappings for a virtual address range, either to
* point to an array of mfns, or contiguously from a single starting
* mfn.
*/
static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
unsigned long *mfns,
unsigned long first_mfn)
{
unsigned i, limit;
unsigned long mfn;
xen_mc_batch();
limit = 1u << order;
for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
struct multicall_space mcs;
unsigned flags;
mcs = __xen_mc_entry(0);
if (mfns)
mfn = mfns[i];
else
mfn = first_mfn + i;
if (i < (limit - 1))
flags = 0;
else {
if (order == 0)
flags = UVMF_INVLPG | UVMF_ALL;
else
flags = UVMF_TLB_FLUSH | UVMF_ALL;
}
MULTI_update_va_mapping(mcs.mc, vaddr,
mfn_pte(mfn, PAGE_KERNEL), flags);
set_phys_to_machine(virt_to_pfn(vaddr), mfn);
}
xen_mc_issue(0);
}
/*
* Perform the hypercall to exchange a region of our pfns to point to
* memory with the required contiguous alignment. Takes the pfns as
* input, and populates mfns as output.
*
* Returns a success code indicating whether the hypervisor was able to
* satisfy the request or not.
*/
static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
unsigned long *pfns_in,
unsigned long extents_out,
unsigned int order_out,
unsigned long *mfns_out,
unsigned int address_bits)
{
long rc;
int success;
struct xen_memory_exchange exchange = {
.in = {
.nr_extents = extents_in,
.extent_order = order_in,
.extent_start = pfns_in,
.domid = DOMID_SELF
},
.out = {
.nr_extents = extents_out,
.extent_order = order_out,
.extent_start = mfns_out,
.address_bits = address_bits,
.domid = DOMID_SELF
}
};
BUG_ON(extents_in << order_in != extents_out << order_out);
rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
success = (exchange.nr_exchanged == extents_in);
BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
BUG_ON(success && (rc != 0));
return success;
}
int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
unsigned int address_bits,
dma_addr_t *dma_handle)
{
unsigned long *in_frames = discontig_frames, out_frame;
unsigned long flags;
int success;
unsigned long vstart = (unsigned long)phys_to_virt(pstart);
/*
* Currently an auto-translated guest will not perform I/O, nor will
* it require PAE page directories below 4GB. Therefore any calls to
* this function are redundant and can be ignored.
*/
if (unlikely(order > MAX_CONTIG_ORDER))
return -ENOMEM;
memset((void *) vstart, 0, PAGE_SIZE << order);
spin_lock_irqsave(&xen_reservation_lock, flags);
/* 1. Zap current PTEs, remembering MFNs. */
xen_zap_pfn_range(vstart, order, in_frames, NULL);
/* 2. Get a new contiguous memory extent. */
out_frame = virt_to_pfn(vstart);
success = xen_exchange_memory(1UL << order, 0, in_frames,
1, order, &out_frame,
address_bits);
/* 3. Map the new extent in place of old pages. */
if (success)
xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
else
xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
spin_unlock_irqrestore(&xen_reservation_lock, flags);
*dma_handle = virt_to_machine(vstart).maddr;
return success ? 0 : -ENOMEM;
}
EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
{
unsigned long *out_frames = discontig_frames, in_frame;
unsigned long flags;
int success;
unsigned long vstart;
if (unlikely(order > MAX_CONTIG_ORDER))
return;
vstart = (unsigned long)phys_to_virt(pstart);
memset((void *) vstart, 0, PAGE_SIZE << order);
spin_lock_irqsave(&xen_reservation_lock, flags);
/* 1. Find start MFN of contiguous extent. */
in_frame = virt_to_mfn(vstart);
/* 2. Zap current PTEs. */
xen_zap_pfn_range(vstart, order, NULL, out_frames);
/* 3. Do the exchange for non-contiguous MFNs. */
success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
0, out_frames, 0);
/* 4. Map new pages in place of old pages. */
if (success)
xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
else
xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
spin_unlock_irqrestore(&xen_reservation_lock, flags);
}
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
#ifdef CONFIG_KEXEC_CORE
phys_addr_t paddr_vmcoreinfo_note(void)
{
if (xen_pv_domain())
return virt_to_machine(vmcoreinfo_note).maddr;
else
return __pa(vmcoreinfo_note);
}
#endif /* CONFIG_KEXEC_CORE */
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