When userspace uses hugetlbfs for the VM memory, user_mem_abort() tries to use the same block size to map the faulting IPA in stage 2. If stage 2 cannot use the same size mapping because the block size doesn't fit in the memslot or the memslot is not properly aligned, user_mem_abort() will fall back to a page mapping, regardless of the block size. We can do better for PUD backed hugetlbfs by checking if a PMD block mapping is possible before deciding to use a page.
vma_pagesize is an unsigned long, use 1UL instead of 1ULL when assigning its value. Signed-off-by: Alexandru Elisei <[email protected]> --- arch/arm64/kvm/mmu.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 25e7dc52c086..f590f7355cda 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1871,15 +1871,24 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, else vma_shift = PAGE_SHIFT; - vma_pagesize = 1ULL << vma_shift; if (logging_active || - (vma->vm_flags & VM_PFNMAP) || - !fault_supports_stage2_huge_mapping(memslot, hva, vma_pagesize)) { + (vma->vm_flags & VM_PFNMAP)) { force_pte = true; - vma_pagesize = PAGE_SIZE; vma_shift = PAGE_SHIFT; } + if (vma_shift == PUD_SHIFT && + !fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE)) + vma_shift = PMD_SHIFT; + + if (vma_shift == PMD_SHIFT && + !fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) { + force_pte = true; + vma_shift = PAGE_SHIFT; + } + + vma_pagesize = 1UL << vma_shift; + /* * The stage2 has a minimum of 2 level table (For arm64 see * kvm_arm_setup_stage2()). Hence, we are guaranteed that we can @@ -1889,7 +1898,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, */ if (vma_pagesize == PMD_SIZE || (vma_pagesize == PUD_SIZE && kvm_stage2_has_pmd(kvm))) - gfn = (fault_ipa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT; + gfn = (fault_ipa & ~(vma_pagesize - 1)) >> PAGE_SHIFT; mmap_read_unlock(current->mm); /* We need minimum second+third level pages */ -- 2.28.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
