From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson Date: Wed, 08 Jan 2020 20:24:39 +0000 Subject: [PATCH 05/14] x86/mm: Introduce lookup_address_in_mm() Message-Id: <20200108202448.9669-6-sean.j.christopherson@intel.com> List-Id: References: <20200108202448.9669-1-sean.j.christopherson@intel.com> In-Reply-To: <20200108202448.9669-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Paolo Bonzini Cc: Paul Mackerras , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Andrew Morton , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, syzbot+c9d1fb51ac9d0d10c39d@syzkaller.appspotmail.com, Andrea Arcangeli , Barret Rhoden , David Hildenbrand , Jason Zeng , Liran Alon , linux-nvdimm 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 Signed-off-by: Sean Christopherson --- arch/x86/include/asm/pgtable_types.h | 4 ++++ arch/x86/mm/pageattr.c | 11 +++++++++++ 2 files changed, 15 insertions(+) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index b5e49e6bac63..400ac8da75e8 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -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; +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, diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 0d09cc5aad61..8787fec876e4 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -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) { -- 2.24.1