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Revert "x86/mm: Introduce lookup_address_in_mm()"

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Drop lookup_address_in_mm() now that KVM is providing it's own variant
of lookup_address_in_pgd() that is safe for use with user addresses, e.g.
guards against page tables being torn down.  A variant that provides a
non-init mm is inherently dangerous and flawed, as the only reason to use
an mm other than init_mm is to walk a userspace mapping, and
lookup_address_in_pgd() does not play nice with userspace mappings, e.g.
doesn't disable IRQs to block TLB shootdowns and doesn't use READ_ONCE()
to ensure an upper level entry isn't converted to a huge page between
checking the PAGE_SIZE bit and grabbing the address of the next level
down.

This reverts commit 13c72c060f.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <YmwIi3bXr/1yhYV/@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2022-04-29 07:57:53 -07:00 committed by Paolo Bonzini
parent 73331c5d84
commit 643d95aac5
2 changed files with 0 additions and 15 deletions
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4
arch/x86/include/asm/pgtable_types.h
View File

@ -559,10 +559,6 @@ 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,

11
arch/x86/mm/pat/set_memory.c
View File

@ -638,17 +638,6 @@ 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)
{