2007-07-18 03:37:04 +02:00
|
|
|
/*
|
|
|
|
* 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
|
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|
|
* fashion. In other words, the guest modifies the same pagetable
|
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|
|
* that the CPU actually uses, which eliminates the overhead of having
|
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|
|
* a separate shadow pagetable.
|
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|
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*
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|
* In order to allow this, it falls on the guest domain to map its
|
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|
|
* notion of a "physical" pfn - which is just a domain-local linear
|
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|
|
* address - into a real "machine address" which the CPU's MMU can
|
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|
|
* use.
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|
*
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|
* A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
|
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|
|
* inserted directly into the pagetable. When creating a new
|
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|
|
* pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely,
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* when reading the content back with __(pgd|pmd|pte)_val, it converts
|
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|
|
* the mfn back into a pfn.
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|
|
*
|
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|
|
* The other constraint is that all pages which make up a pagetable
|
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|
|
* must be mapped read-only in the guest. This prevents uncontrolled
|
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|
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* guest updates to the pagetable. Xen strictly enforces this, and
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|
|
* will disallow any pagetable update which will end up mapping a
|
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|
|
* pagetable page RW, and will disallow using any writable page as a
|
|
|
|
* pagetable.
|
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|
|
*
|
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|
|
* Naively, when loading %cr3 with the base of a new pagetable, Xen
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|
|
* would need to validate the whole pagetable before going on.
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|
|
* Naturally, this is quite slow. The solution is to "pin" a
|
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|
|
* pagetable, which enforces all the constraints on the pagetable even
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|
|
* when it is not actively in use. This menas that Xen can be assured
|
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|
|
* that it is still valid when you do load it into %cr3, and doesn't
|
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|
|
* need to revalidate it.
|
|
|
|
*
|
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|
|
* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
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|
|
*/
|
2007-07-18 03:37:06 +02:00
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|
#include <linux/sched.h>
|
2007-07-18 03:37:05 +02:00
|
|
|
#include <linux/highmem.h>
|
2007-07-18 03:37:04 +02:00
|
|
|
#include <linux/bug.h>
|
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|
|
#include <linux/sched.h>
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|
|
#include <asm/pgtable.h>
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|
|
#include <asm/tlbflush.h>
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|
|
#include <asm/mmu_context.h>
|
2007-07-18 03:37:05 +02:00
|
|
|
#include <asm/paravirt.h>
|
2007-07-18 03:37:04 +02:00
|
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|
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|
|
|
#include <asm/xen/hypercall.h>
|
2007-07-18 03:37:05 +02:00
|
|
|
#include <asm/xen/hypervisor.h>
|
2007-07-18 03:37:04 +02:00
|
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|
|
#include <xen/page.h>
|
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|
|
#include <xen/interface/xen.h>
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|
|
2007-07-18 03:37:05 +02:00
|
|
|
#include "multicalls.h"
|
2007-07-18 03:37:04 +02:00
|
|
|
#include "mmu.h"
|
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|
|
|
|
|
|
xmaddr_t arbitrary_virt_to_machine(unsigned long address)
|
|
|
|
{
|
|
|
|
pte_t *pte = lookup_address(address);
|
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|
|
unsigned offset = address & PAGE_MASK;
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|
|
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|
|
BUG_ON(pte == NULL);
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|
|
return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset);
|
|
|
|
}
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|
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|
|
void make_lowmem_page_readonly(void *vaddr)
|
|
|
|
{
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|
|
pte_t *pte, ptev;
|
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|
|
unsigned long address = (unsigned long)vaddr;
|
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|
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|
|
|
|
pte = lookup_address(address);
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|
|
BUG_ON(pte == NULL);
|
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|
|
|
|
|
|
ptev = pte_wrprotect(*pte);
|
|
|
|
|
|
|
|
if (HYPERVISOR_update_va_mapping(address, ptev, 0))
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
|
|
|
|
void make_lowmem_page_readwrite(void *vaddr)
|
|
|
|
{
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|
|
|
pte_t *pte, ptev;
|
|
|
|
unsigned long address = (unsigned long)vaddr;
|
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|
|
|
|
|
|
pte = lookup_address(address);
|
|
|
|
BUG_ON(pte == NULL);
|
|
|
|
|
|
|
|
ptev = pte_mkwrite(*pte);
|
|
|
|
|
|
|
|
if (HYPERVISOR_update_va_mapping(address, ptev, 0))
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
void xen_set_pmd(pmd_t *ptr, pmd_t val)
|
|
|
|
{
|
2007-07-18 03:37:06 +02:00
|
|
|
struct multicall_space mcs;
|
|
|
|
struct mmu_update *u;
|
2007-07-18 03:37:04 +02:00
|
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|
|
2007-07-18 03:37:06 +02:00
|
|
|
preempt_disable();
|
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|
|
|
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|
|
mcs = xen_mc_entry(sizeof(*u));
|
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|
|
u = mcs.args;
|
|
|
|
u->ptr = virt_to_machine(ptr).maddr;
|
|
|
|
u->val = pmd_val_ma(val);
|
|
|
|
MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
|
|
|
|
|
|
|
|
xen_mc_issue(PARAVIRT_LAZY_MMU);
|
|
|
|
|
|
|
|
preempt_enable();
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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)
|
|
|
|
{
|
|
|
|
pgd_t *pgd;
|
|
|
|
pud_t *pud;
|
|
|
|
pmd_t *pmd;
|
|
|
|
pte_t *pte;
|
|
|
|
|
|
|
|
pgd = swapper_pg_dir + pgd_index(vaddr);
|
|
|
|
if (pgd_none(*pgd)) {
|
|
|
|
BUG();
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
pud = pud_offset(pgd, vaddr);
|
|
|
|
if (pud_none(*pud)) {
|
|
|
|
BUG();
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
pmd = pmd_offset(pud, vaddr);
|
|
|
|
if (pmd_none(*pmd)) {
|
|
|
|
BUG();
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
pte = pte_offset_kernel(pmd, vaddr);
|
|
|
|
/* <mfn,flags> stored as-is, to permit clearing entries */
|
|
|
|
xen_set_pte(pte, mfn_pte(mfn, flags));
|
|
|
|
|
|
|
|
/*
|
|
|
|
* It's enough to flush this one mapping.
|
|
|
|
* (PGE mappings get flushed as well)
|
|
|
|
*/
|
|
|
|
__flush_tlb_one(vaddr);
|
|
|
|
}
|
|
|
|
|
|
|
|
void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
|
|
|
|
pte_t *ptep, pte_t pteval)
|
|
|
|
{
|
2007-07-18 03:37:06 +02:00
|
|
|
if (mm == current->mm || mm == &init_mm) {
|
|
|
|
if (xen_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
|
|
|
|
struct multicall_space mcs;
|
|
|
|
mcs = xen_mc_entry(0);
|
|
|
|
|
|
|
|
MULTI_update_va_mapping(mcs.mc, addr, pteval, 0);
|
|
|
|
xen_mc_issue(PARAVIRT_LAZY_MMU);
|
|
|
|
return;
|
|
|
|
} else
|
|
|
|
if (HYPERVISOR_update_va_mapping(addr, pteval, 0) == 0)
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
xen_set_pte(ptep, pteval);
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_X86_PAE
|
2007-07-18 03:37:05 +02:00
|
|
|
void xen_set_pud(pud_t *ptr, pud_t val)
|
|
|
|
{
|
2007-07-18 03:37:06 +02:00
|
|
|
struct multicall_space mcs;
|
|
|
|
struct mmu_update *u;
|
2007-07-18 03:37:05 +02:00
|
|
|
|
2007-07-18 03:37:06 +02:00
|
|
|
preempt_disable();
|
|
|
|
|
|
|
|
mcs = xen_mc_entry(sizeof(*u));
|
|
|
|
u = mcs.args;
|
|
|
|
u->ptr = virt_to_machine(ptr).maddr;
|
|
|
|
u->val = pud_val_ma(val);
|
|
|
|
MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
|
|
|
|
|
|
|
|
xen_mc_issue(PARAVIRT_LAZY_MMU);
|
|
|
|
|
|
|
|
preempt_enable();
|
2007-07-18 03:37:05 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
void xen_set_pte(pte_t *ptep, pte_t pte)
|
|
|
|
{
|
|
|
|
ptep->pte_high = pte.pte_high;
|
|
|
|
smp_wmb();
|
|
|
|
ptep->pte_low = pte.pte_low;
|
|
|
|
}
|
|
|
|
|
2007-07-18 03:37:04 +02:00
|
|
|
void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
|
|
|
|
{
|
|
|
|
set_64bit((u64 *)ptep, pte_val_ma(pte));
|
|
|
|
}
|
|
|
|
|
|
|
|
void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
|
|
|
|
{
|
|
|
|
ptep->pte_low = 0;
|
|
|
|
smp_wmb(); /* make sure low gets written first */
|
|
|
|
ptep->pte_high = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
void xen_pmd_clear(pmd_t *pmdp)
|
|
|
|
{
|
|
|
|
xen_set_pmd(pmdp, __pmd(0));
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned long long xen_pte_val(pte_t pte)
|
|
|
|
{
|
|
|
|
unsigned long long ret = 0;
|
|
|
|
|
|
|
|
if (pte.pte_low) {
|
|
|
|
ret = ((unsigned long long)pte.pte_high << 32) | pte.pte_low;
|
|
|
|
ret = machine_to_phys(XMADDR(ret)).paddr | 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned long long xen_pmd_val(pmd_t pmd)
|
|
|
|
{
|
|
|
|
unsigned long long ret = pmd.pmd;
|
|
|
|
if (ret)
|
|
|
|
ret = machine_to_phys(XMADDR(ret)).paddr | 1;
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned long long xen_pgd_val(pgd_t pgd)
|
|
|
|
{
|
|
|
|
unsigned long long ret = pgd.pgd;
|
|
|
|
if (ret)
|
|
|
|
ret = machine_to_phys(XMADDR(ret)).paddr | 1;
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
pte_t xen_make_pte(unsigned long long pte)
|
|
|
|
{
|
|
|
|
if (pte & 1)
|
|
|
|
pte = phys_to_machine(XPADDR(pte)).maddr;
|
|
|
|
|
|
|
|
return (pte_t){ pte, pte >> 32 };
|
|
|
|
}
|
|
|
|
|
|
|
|
pmd_t xen_make_pmd(unsigned long long pmd)
|
|
|
|
{
|
|
|
|
if (pmd & 1)
|
|
|
|
pmd = phys_to_machine(XPADDR(pmd)).maddr;
|
|
|
|
|
|
|
|
return (pmd_t){ pmd };
|
|
|
|
}
|
|
|
|
|
|
|
|
pgd_t xen_make_pgd(unsigned long long pgd)
|
|
|
|
{
|
|
|
|
if (pgd & _PAGE_PRESENT)
|
|
|
|
pgd = phys_to_machine(XPADDR(pgd)).maddr;
|
|
|
|
|
|
|
|
return (pgd_t){ pgd };
|
|
|
|
}
|
|
|
|
#else /* !PAE */
|
2007-07-18 03:37:05 +02:00
|
|
|
void xen_set_pte(pte_t *ptep, pte_t pte)
|
|
|
|
{
|
|
|
|
*ptep = pte;
|
|
|
|
}
|
|
|
|
|
2007-07-18 03:37:04 +02:00
|
|
|
unsigned long xen_pte_val(pte_t pte)
|
|
|
|
{
|
|
|
|
unsigned long ret = pte.pte_low;
|
|
|
|
|
|
|
|
if (ret & _PAGE_PRESENT)
|
|
|
|
ret = machine_to_phys(XMADDR(ret)).paddr;
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned long xen_pgd_val(pgd_t pgd)
|
|
|
|
{
|
|
|
|
unsigned long ret = pgd.pgd;
|
|
|
|
if (ret)
|
|
|
|
ret = machine_to_phys(XMADDR(ret)).paddr | 1;
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
pte_t xen_make_pte(unsigned long pte)
|
|
|
|
{
|
|
|
|
if (pte & _PAGE_PRESENT)
|
|
|
|
pte = phys_to_machine(XPADDR(pte)).maddr;
|
|
|
|
|
|
|
|
return (pte_t){ pte };
|
|
|
|
}
|
|
|
|
|
|
|
|
pgd_t xen_make_pgd(unsigned long pgd)
|
|
|
|
{
|
|
|
|
if (pgd & _PAGE_PRESENT)
|
|
|
|
pgd = phys_to_machine(XPADDR(pgd)).maddr;
|
|
|
|
|
|
|
|
return (pgd_t){ pgd };
|
|
|
|
}
|
|
|
|
#endif /* CONFIG_X86_PAE */
|
|
|
|
|
|
|
|
|
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
/*
|
|
|
|
(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 pte_limit. In the normal case
|
|
|
|
this will be TASK_SIZE, but at boot we need to pin up to
|
|
|
|
FIXADDR_TOP. But the important bit is that we don't pin beyond
|
|
|
|
there, because then we start getting into Xen's ptes.
|
|
|
|
*/
|
|
|
|
static int pgd_walk(pgd_t *pgd_base, int (*func)(struct page *, unsigned),
|
|
|
|
unsigned long limit)
|
2007-07-18 03:37:04 +02:00
|
|
|
{
|
|
|
|
pgd_t *pgd = pgd_base;
|
2007-07-18 03:37:05 +02:00
|
|
|
int flush = 0;
|
|
|
|
unsigned long addr = 0;
|
|
|
|
unsigned long pgd_next;
|
|
|
|
|
|
|
|
BUG_ON(limit > FIXADDR_TOP);
|
2007-07-18 03:37:04 +02:00
|
|
|
|
|
|
|
if (xen_feature(XENFEAT_auto_translated_physmap))
|
2007-07-18 03:37:05 +02:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
for (; addr != FIXADDR_TOP; pgd++, addr = pgd_next) {
|
|
|
|
pud_t *pud;
|
|
|
|
unsigned long pud_limit, pud_next;
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
pgd_next = pud_limit = pgd_addr_end(addr, FIXADDR_TOP);
|
|
|
|
|
|
|
|
if (!pgd_val(*pgd))
|
2007-07-18 03:37:04 +02:00
|
|
|
continue;
|
2007-07-18 03:37:05 +02:00
|
|
|
|
2007-07-18 03:37:04 +02:00
|
|
|
pud = pud_offset(pgd, 0);
|
|
|
|
|
|
|
|
if (PTRS_PER_PUD > 1) /* not folded */
|
2007-07-18 03:37:05 +02:00
|
|
|
flush |= (*func)(virt_to_page(pud), 0);
|
|
|
|
|
|
|
|
for (; addr != pud_limit; pud++, addr = pud_next) {
|
|
|
|
pmd_t *pmd;
|
|
|
|
unsigned long pmd_limit;
|
|
|
|
|
|
|
|
pud_next = pud_addr_end(addr, pud_limit);
|
|
|
|
|
|
|
|
if (pud_next < limit)
|
|
|
|
pmd_limit = pud_next;
|
|
|
|
else
|
|
|
|
pmd_limit = limit;
|
2007-07-18 03:37:04 +02:00
|
|
|
|
|
|
|
if (pud_none(*pud))
|
|
|
|
continue;
|
2007-07-18 03:37:05 +02:00
|
|
|
|
2007-07-18 03:37:04 +02:00
|
|
|
pmd = pmd_offset(pud, 0);
|
|
|
|
|
|
|
|
if (PTRS_PER_PMD > 1) /* not folded */
|
2007-07-18 03:37:05 +02:00
|
|
|
flush |= (*func)(virt_to_page(pmd), 0);
|
|
|
|
|
|
|
|
for (; addr != pmd_limit; pmd++) {
|
|
|
|
addr += (PAGE_SIZE * PTRS_PER_PTE);
|
|
|
|
if ((pmd_limit-1) < (addr-1)) {
|
|
|
|
addr = pmd_limit;
|
|
|
|
break;
|
|
|
|
}
|
2007-07-18 03:37:04 +02:00
|
|
|
|
|
|
|
if (pmd_none(*pmd))
|
|
|
|
continue;
|
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
flush |= (*func)(pmd_page(*pmd), 0);
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
flush |= (*func)(virt_to_page(pgd_base), UVMF_TLB_FLUSH);
|
|
|
|
|
|
|
|
return flush;
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
static int pin_page(struct page *page, unsigned flags)
|
|
|
|
{
|
|
|
|
unsigned pgfl = test_and_set_bit(PG_pinned, &page->flags);
|
|
|
|
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);
|
|
|
|
|
|
|
|
flush = 0;
|
|
|
|
|
|
|
|
MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
|
|
|
|
pfn_pte(pfn, PAGE_KERNEL_RO),
|
|
|
|
flags);
|
|
|
|
}
|
|
|
|
|
|
|
|
return flush;
|
|
|
|
}
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
/* 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. */
|
2007-07-18 03:37:04 +02:00
|
|
|
void xen_pgd_pin(pgd_t *pgd)
|
|
|
|
{
|
2007-07-18 03:37:05 +02:00
|
|
|
struct multicall_space mcs;
|
|
|
|
struct mmuext_op *op;
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
xen_mc_batch();
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:06 +02:00
|
|
|
if (pgd_walk(pgd, pin_page, TASK_SIZE)) {
|
|
|
|
/* re-enable interrupts for kmap_flush_unused */
|
|
|
|
xen_mc_issue(0);
|
2007-07-18 03:37:05 +02:00
|
|
|
kmap_flush_unused();
|
2007-07-18 03:37:06 +02:00
|
|
|
xen_mc_batch();
|
|
|
|
}
|
2007-07-18 03:37:05 +02:00
|
|
|
|
|
|
|
mcs = __xen_mc_entry(sizeof(*op));
|
|
|
|
op = mcs.args;
|
|
|
|
|
|
|
|
#ifdef CONFIG_X86_PAE
|
|
|
|
op->cmd = MMUEXT_PIN_L3_TABLE;
|
2007-07-18 03:37:04 +02:00
|
|
|
#else
|
2007-07-18 03:37:05 +02:00
|
|
|
op->cmd = MMUEXT_PIN_L2_TABLE;
|
2007-07-18 03:37:04 +02:00
|
|
|
#endif
|
2007-07-18 03:37:05 +02:00
|
|
|
op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
|
|
|
|
MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
|
|
|
|
|
|
|
|
xen_mc_issue(0);
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
/* 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 __init int mark_pinned(struct page *page, unsigned flags)
|
2007-07-18 03:37:04 +02:00
|
|
|
{
|
2007-07-18 03:37:05 +02:00
|
|
|
SetPagePinned(page);
|
|
|
|
return 0;
|
|
|
|
}
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
void __init xen_mark_init_mm_pinned(void)
|
|
|
|
{
|
|
|
|
pgd_walk(init_mm.pgd, mark_pinned, FIXADDR_TOP);
|
|
|
|
}
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
static int unpin_page(struct page *page, unsigned flags)
|
|
|
|
{
|
|
|
|
unsigned pgfl = test_and_clear_bit(PG_pinned, &page->flags);
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
if (pgfl && !PageHighMem(page)) {
|
|
|
|
void *pt = lowmem_page_address(page);
|
|
|
|
unsigned long pfn = page_to_pfn(page);
|
|
|
|
struct multicall_space mcs = __xen_mc_entry(0);
|
|
|
|
|
|
|
|
MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
|
|
|
|
pfn_pte(pfn, PAGE_KERNEL),
|
|
|
|
flags);
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0; /* never need to flush on unpin */
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
2007-07-18 03:37:05 +02:00
|
|
|
/* Release a pagetables pages back as normal RW */
|
|
|
|
static void xen_pgd_unpin(pgd_t *pgd)
|
|
|
|
{
|
|
|
|
struct mmuext_op *op;
|
|
|
|
struct multicall_space mcs;
|
|
|
|
|
|
|
|
xen_mc_batch();
|
|
|
|
|
|
|
|
mcs = __xen_mc_entry(sizeof(*op));
|
|
|
|
|
|
|
|
op = mcs.args;
|
|
|
|
op->cmd = MMUEXT_UNPIN_TABLE;
|
|
|
|
op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
|
|
|
|
|
|
|
|
MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
|
|
|
|
|
|
|
|
pgd_walk(pgd, unpin_page, TASK_SIZE);
|
|
|
|
|
|
|
|
xen_mc_issue(0);
|
|
|
|
}
|
2007-07-18 03:37:04 +02:00
|
|
|
|
|
|
|
void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
|
|
|
|
{
|
2007-07-18 03:37:05 +02:00
|
|
|
spin_lock(&next->page_table_lock);
|
2007-07-18 03:37:04 +02:00
|
|
|
xen_pgd_pin(next->pgd);
|
2007-07-18 03:37:05 +02:00
|
|
|
spin_unlock(&next->page_table_lock);
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
|
|
|
|
{
|
2007-07-18 03:37:05 +02:00
|
|
|
spin_lock(&mm->page_table_lock);
|
2007-07-18 03:37:04 +02:00
|
|
|
xen_pgd_pin(mm->pgd);
|
2007-07-18 03:37:05 +02:00
|
|
|
spin_unlock(&mm->page_table_lock);
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2007-07-18 03:37:06 +02:00
|
|
|
#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;
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:06 +02:00
|
|
|
if (__get_cpu_var(cpu_tlbstate).active_mm == mm)
|
|
|
|
leave_mm(smp_processor_id());
|
|
|
|
}
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:06 +02:00
|
|
|
static void drop_mm_ref(struct mm_struct *mm)
|
|
|
|
{
|
|
|
|
if (current->active_mm == mm) {
|
|
|
|
if (current->mm == mm)
|
|
|
|
load_cr3(swapper_pg_dir);
|
|
|
|
else
|
|
|
|
leave_mm(smp_processor_id());
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|
|
|
|
|
2007-07-18 03:37:06 +02:00
|
|
|
if (!cpus_empty(mm->cpu_vm_mask))
|
|
|
|
xen_smp_call_function_mask(mm->cpu_vm_mask, drop_other_mm_ref,
|
|
|
|
mm, 1);
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
static void 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.
|
|
|
|
*/
|
|
|
|
void xen_exit_mmap(struct mm_struct *mm)
|
|
|
|
{
|
|
|
|
get_cpu(); /* make sure we don't move around */
|
|
|
|
drop_mm_ref(mm);
|
|
|
|
put_cpu();
|
2007-07-18 03:37:04 +02:00
|
|
|
|
2007-07-18 03:37:06 +02:00
|
|
|
spin_lock(&mm->page_table_lock);
|
2007-07-18 03:37:04 +02:00
|
|
|
xen_pgd_unpin(mm->pgd);
|
2007-07-18 03:37:06 +02:00
|
|
|
spin_unlock(&mm->page_table_lock);
|
2007-07-18 03:37:04 +02:00
|
|
|
}
|