b534816b55
On an x86 system which doesn't support global mappings,
__supported_pte_mask has _PAGE_GLOBAL clear, to make sure it never
appears in the PTE. pfn_pte() and so on will enforce it with:
static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
{
return __pte((((phys_addr_t)page_nr << PAGE_SHIFT) |
pgprot_val(pgprot)) & __supported_pte_mask);
}
However, we overload _PAGE_GLOBAL with _PAGE_PROTNONE on non-present
ptes to distinguish them from swap entries. However, applying
__supported_pte_mask indiscriminately will clear the bit and corrupt the
pte.
I guess the best fix is to only apply __supported_pte_mask to present
ptes. This seems like the right solution to me, as it means we can
completely ignore the issue of overlaps between the present pte bits and
the non-present pte-as-swap entry use of the bits.
__supported_pte_mask contains the set of flags we support on the
current hardware. We also use bits in the pte for things like
logically present ptes with no permissions, and swap entries for
swapped out pages. We should only apply __supported_pte_mask to
present ptes, because otherwise we may destroy other information being
stored in the ptes.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
171 lines
4.7 KiB
C
171 lines
4.7 KiB
C
#ifndef _ASM_X86_XEN_PAGE_H
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#define _ASM_X86_XEN_PAGE_H
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/pfn.h>
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#include <asm/uaccess.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <xen/interface/xen.h>
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#include <xen/features.h>
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/* Xen machine address */
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typedef struct xmaddr {
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phys_addr_t maddr;
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} xmaddr_t;
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/* Xen pseudo-physical address */
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typedef struct xpaddr {
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phys_addr_t paddr;
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} xpaddr_t;
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#define XMADDR(x) ((xmaddr_t) { .maddr = (x) })
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#define XPADDR(x) ((xpaddr_t) { .paddr = (x) })
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/**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
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#define INVALID_P2M_ENTRY (~0UL)
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#define FOREIGN_FRAME_BIT (1UL<<31)
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#define FOREIGN_FRAME(m) ((m) | FOREIGN_FRAME_BIT)
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/* Maximum amount of memory we can handle in a domain in pages */
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#define MAX_DOMAIN_PAGES \
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((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))
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extern unsigned long get_phys_to_machine(unsigned long pfn);
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extern void set_phys_to_machine(unsigned long pfn, unsigned long mfn);
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static inline unsigned long pfn_to_mfn(unsigned long pfn)
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{
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return pfn;
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return get_phys_to_machine(pfn) & ~FOREIGN_FRAME_BIT;
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}
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static inline int phys_to_machine_mapping_valid(unsigned long pfn)
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{
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return 1;
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return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
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}
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static inline unsigned long mfn_to_pfn(unsigned long mfn)
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{
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unsigned long pfn;
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return mfn;
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#if 0
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if (unlikely((mfn >> machine_to_phys_order) != 0))
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return max_mapnr;
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#endif
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pfn = 0;
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/*
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* The array access can fail (e.g., device space beyond end of RAM).
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* In such cases it doesn't matter what we return (we return garbage),
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* but we must handle the fault without crashing!
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*/
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__get_user(pfn, &machine_to_phys_mapping[mfn]);
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return pfn;
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}
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static inline xmaddr_t phys_to_machine(xpaddr_t phys)
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{
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unsigned offset = phys.paddr & ~PAGE_MASK;
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return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
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}
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static inline xpaddr_t machine_to_phys(xmaddr_t machine)
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{
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unsigned offset = machine.maddr & ~PAGE_MASK;
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return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
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}
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/*
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* We detect special mappings in one of two ways:
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* 1. If the MFN is an I/O page then Xen will set the m2p entry
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* to be outside our maximum possible pseudophys range.
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* 2. If the MFN belongs to a different domain then we will certainly
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* not have MFN in our p2m table. Conversely, if the page is ours,
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* then we'll have p2m(m2p(MFN))==MFN.
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* If we detect a special mapping then it doesn't have a 'struct page'.
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* We force !pfn_valid() by returning an out-of-range pointer.
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*
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* NB. These checks require that, for any MFN that is not in our reservation,
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* there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
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* we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
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* Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
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*
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* NB2. When deliberately mapping foreign pages into the p2m table, you *must*
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* use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
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* require. In all the cases we care about, the FOREIGN_FRAME bit is
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* masked (e.g., pfn_to_mfn()) so behaviour there is correct.
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*/
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static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
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{
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extern unsigned long max_mapnr;
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unsigned long pfn = mfn_to_pfn(mfn);
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if ((pfn < max_mapnr)
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&& !xen_feature(XENFEAT_auto_translated_physmap)
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&& (get_phys_to_machine(pfn) != mfn))
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return max_mapnr; /* force !pfn_valid() */
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/* XXX fixme; not true with sparsemem */
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return pfn;
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}
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/* VIRT <-> MACHINE conversion */
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#define virt_to_machine(v) (phys_to_machine(XPADDR(__pa(v))))
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#define virt_to_mfn(v) (pfn_to_mfn(PFN_DOWN(__pa(v))))
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#define mfn_to_virt(m) (__va(mfn_to_pfn(m) << PAGE_SHIFT))
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static inline unsigned long pte_mfn(pte_t pte)
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{
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return (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
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}
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static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
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{
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pte_t pte;
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pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
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massage_pgprot(pgprot);
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return pte;
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}
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static inline pteval_t pte_val_ma(pte_t pte)
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{
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return pte.pte;
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}
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static inline pte_t __pte_ma(pteval_t x)
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{
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return (pte_t) { .pte = x };
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}
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#define pmd_val_ma(v) ((v).pmd)
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#ifdef __PAGETABLE_PUD_FOLDED
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#define pud_val_ma(v) ((v).pgd.pgd)
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#else
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#define pud_val_ma(v) ((v).pud)
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#endif
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#define __pmd_ma(x) ((pmd_t) { (x) } )
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#define pgd_val_ma(x) ((x).pgd)
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xmaddr_t arbitrary_virt_to_machine(void *address);
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void make_lowmem_page_readonly(void *vaddr);
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void make_lowmem_page_readwrite(void *vaddr);
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#endif /* _ASM_X86_XEN_PAGE_H */
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