Commit 13c72c06 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

x86/mm: Introduce lookup_address_in_mm() 



Add a helper, lookup_address_in_mm(), to traverse the page tables of a
given mm struct.  KVM will use the helper to retrieve the host mapping
level, e.g. 4k vs. 2mb vs. 1gb, of a compound (or DAX-backed) page
without having to resort to implementation specific metadata.  E.g. KVM
currently uses different logic for HugeTLB vs. THP, and would add a
third variant for DAX-backed files.

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 42cde48b

arch/x86/include/asm/pgtable_types.h

+4 −0
Original line number Diff line number Diff line
@@ -561,6 +561,10 @@ static inline void update_page_count(int level, unsigned long pages) { } 
extern pte_t *lookup_address(unsigned long address, unsigned int *level);

extern pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,

				    unsigned int *level);



struct mm_struct;

extern pte_t *lookup_address_in_mm(struct mm_struct *mm, unsigned long address,

				   unsigned int *level);

extern pmd_t *lookup_pmd_address(unsigned long address);

extern phys_addr_t slow_virt_to_phys(void *__address);

extern int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn,

arch/x86/mm/pageattr.c

+11 −0
Original line number Diff line number Diff line
@@ -618,6 +618,17 @@ pte_t *lookup_address(unsigned long address, unsigned int *level) 
}

EXPORT_SYMBOL_GPL(lookup_address);



/*

 * Lookup the page table entry for a virtual address in a given mm. Return a

 * pointer to the entry and the level of the mapping.

 */

pte_t *lookup_address_in_mm(struct mm_struct *mm, unsigned long address,

			    unsigned int *level)

{

	return lookup_address_in_pgd(pgd_offset(mm, address), address, level);

}

EXPORT_SYMBOL_GPL(lookup_address_in_mm);



static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address,

				  unsigned int *level)

{

CRA Git | Maintained and supported by SUSTech CRA and CCSE