On 12/03/2019 11:31, Anshuman Khandual wrote:
On 03/12/2019 04:07 PM, Suzuki K Poulose wrote:Hi Anshuman, On 12/03/2019 02:19, Anshuman Khandual wrote:ARM64 standard pgtable functions are going to use pgtable_page_[ctor|dtor] or pgtable_pmd_page_[ctor|dtor] constructs. At present KVM guest stage-2 PUD|PMD|PTE level page tabe pages are allocated with __get_free_page() via mmu_memory_cache_alloc() but released with standard pud|pmd_free() or pte_free_kernel(). These will fail once they start calling into pgtable_ [pmd]_page_dtor() for pages which never originally went through respective constructor functions. Hence convert all stage-2 page table page release functions to call buddy directly while freeing pages. Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> --- arch/arm/include/asm/stage2_pgtable.h | 4 ++-- arch/arm64/include/asm/stage2_pgtable.h | 4 ++-- virt/kvm/arm/mmu.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm/include/asm/stage2_pgtable.h b/arch/arm/include/asm/stage2_pgtable.h index de2089501b8b..417a3be00718 100644 --- a/arch/arm/include/asm/stage2_pgtable.h +++ b/arch/arm/include/asm/stage2_pgtable.h @@ -32,14 +32,14 @@ #define stage2_pgd_present(kvm, pgd) pgd_present(pgd) #define stage2_pgd_populate(kvm, pgd, pud) pgd_populate(NULL, pgd, pud) #define stage2_pud_offset(kvm, pgd, address) pud_offset(pgd, address) -#define stage2_pud_free(kvm, pud) pud_free(NULL, pud) +#define stage2_pud_free(kvm, pud) free_page((unsigned long)pud)That must be a NOP, as we don't have pud on arm32 (we have 3 level table). The pud_* helpers here all fallback to the generic no-pud helpers.Which is the following here for pud_free() #define pud_free(mm, x) do { } while (0) On arm64 its protected by kvm_stage2_has_pud() helper before calling into pud_free(). In this case even though applicable pud_free() is NOP, it is still misleading. If we are sure about page table level will always remain three it can directly have a NOP (do/while) in there.
Yes, it is fixed for arm32 and you could have it as do {} while (0), which is
what I meant by NOP. On arm64, we had varied number of levels depending on the
PAGE_SIZE and now due to the dynamic IPA, hence the check.
Cheers
Suzuki
