On Thu, Sep 03, 2020 at 09:48:18PM +1000, Gavin Shan wrote: > On 9/3/20 9:13 PM, Gavin Shan wrote: > > On 9/3/20 5:34 PM, Gavin Shan wrote: > > > On 8/25/20 7:39 PM, Will Deacon wrote: > > > > Hello folks, > > > > > > > > This is version three of the KVM page-table rework that I previously posted > > > > here: > > > > > > > > v1: https://lore.kernel.org/r/20200730153406.25136-1-will@xxxxxxxxxx > > > > v2: https://lore.kernel.org/r/20200818132818.16065-1-will@xxxxxxxxxx > > > > > > > > Changes since v2 include: > > > > > > > > * Rebased onto -rc2, which includes the conflicting OOM blocking fixes > > > > * Dropped the patch trying to "fix" the memcache in kvm_phys_addr_ioremap() > > > > > > > > > > It's really nice work, making the code unified/simplified greatly. > > > However, it seems it doesn't work well with HugeTLBfs. Please refer > > > to the following test result and see if you have quick idea, or I > > > can debug it a bit :) Nice testing matrix, and thanks for reporting the problem! > > > Machine Host Guest Result > > > =============================================================== > > > ThunderX2 VA_BITS: 42 PAGE_SIZE: 4KB Passed > > > PAGE_SIZE: 64KB 64KB passed > > > THP: disabled > > > HugeTLB: disabled > > > --------------------------------------------------------------- > > > ThunderX2 VA_BITS: 42 PAGE_SIZE: 4KB Passed > > > PAGE_SIZE: 64KB 64KB passed > > > THP: enabled > > > HugeTLB: disabled > > > ---------------------------------------------------------------- > > > ThunderX2 VA_BITS: 42 PAGE_SIZE: 4KB Fail[1] > > > PAGE_SIZE: 64KB 64KB Fail[1] > > > THP: disabled > > > HugeTLB: enabled > > > --------------------------------------------------------------- > > > ThunderX2 VA_BITS: 39 PAGE_SIZE: 4KB Passed > > > PAGE_SIZE: 4KB 64KB Passed > > > THP: disabled > > > HugeTLB: disabled > > > --------------------------------------------------------------- > > > ThunderX2 VA_BITS: 39 PAGE_SIZE: 4KB Passed > > > PAGE_SIZE: 4KB 64KB Passed > > > THP: enabled > > > HugeTLB: disabled > > > -------------------------------------------------------------- > > > ThunderX2 VA_BITS: 39 PAGE_SIZE: 4KB Fail[2] > > > PAGE_SIZE: 4KB 64KB Fail[2] > > > THP: disabled > > > HugeTLB: enabled > > > > > > > I debugged the code and found the issue is caused by the following > > patch. > > > > [PATCH v3 06/21] KVM: arm64: Add support for stage-2 map()/unmap() in generic page-table (I think this is just a symptom of the page-table being out of whack) > Sorry that the guest could hang sometimes with above changes. I have no idea what > has been happening before I'm going to debug for more.. I'm pasting the used command > and output from guest. Can you try the diff below, please? I think we can end up sticking down a huge-page-sized mapping at an unaligned address, which causes us both to overmap and also to fail to use the huge granule for a block mapping. Cheers, Will --->8 diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index f28e03dcb897..3bff942e5f33 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -737,11 +737,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, bool exec_fault; bool device = false; unsigned long mmu_seq; - gfn_t gfn = fault_ipa >> PAGE_SHIFT; struct kvm *kvm = vcpu->kvm; struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; struct vm_area_struct *vma; short vma_shift; + gfn_t gfn; kvm_pfn_t pfn; bool logging_active = memslot_is_logging(memslot); unsigned long vma_pagesize; @@ -780,7 +780,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, } if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE) - gfn = (fault_ipa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT; + fault_ipa &= huge_page_mask(hstate_vma(vma)); + + gfn = fault_ipa >> PAGE_SHIFT; mmap_read_unlock(current->mm); if (fault_status != FSC_PERM) { _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
