target/linux/layerscape/patches-5.4/811-kvm-0003-arm-arm64-KVM-drop-qman-mmio-cacheable-mapping-hack.patch

   1 From d637252f72998261c9d77c0be57317c73ad77f83 Mon Sep 17 00:00:00 2001
   2 From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
   3 Date: Tue, 26 Jul 2016 16:38:18 +0300
   4 Subject: [PATCH] arm/arm64: KVM: drop qman mmio cacheable mapping hack
   5
   6 Instead of hardcoding checks for qman cacheable
   7 mmio region physical addresses extract mapping
   8 information from the user-space mapping.
   9 The involves several steps;
  10  - get access to a pte part of the user-space mapping
  11    by using get_locked_pte() / pte_unmap_unlock() apis
  12  - extract memtype (normal / device), shareability from
  13    the pte
  14  - convert to S2 translation bits in newly added
  15    function stage1_to_stage2_pgprot()
  16  - finish making the s2 translation with the obtained bits
  17
  18 Another explored option was using vm_area_struct::vm_page_prot
  19 which is set in vfio-mc mmap code to the correct page bits.
  20 However, experiments show that these bits are later altered
  21 in the generic mmap code (e.g. the shareability bit is always
  22 set on arm64).
  23 The only place where the original bits can still be found
  24 is the user-space mapping, using the method described above.
  25
  26 Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
  27 [Bharat - Fixed mem_type check issue]
  28 [changed "ifdef ARM64" to CONFIG_ARM64]
  29 Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
  30 [Ioana - added a sanity check for hugepages]
  31 Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
  32 [Fixed format issues]
  33 Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
  34 ---
  35  virt/kvm/arm/mmu.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
  36  1 file changed, 53 insertions(+), 2 deletions(-)
  37
  38 --- a/virt/kvm/arm/mmu.c
  39 +++ b/virt/kvm/arm/mmu.c
  40 @@ -1375,6 +1375,30 @@ out:
  41         return ret;
  42  }
  43
  44 +#ifdef CONFIG_ARM64
  45 +static pgprot_t stage1_to_stage2_pgprot(pgprot_t prot)
  46 +{
  47 +       switch (pgprot_val(prot) & PTE_ATTRINDX_MASK) {
  48 +       case PTE_ATTRINDX(MT_DEVICE_nGnRE):
  49 +       case PTE_ATTRINDX(MT_DEVICE_nGnRnE):
  50 +       case PTE_ATTRINDX(MT_DEVICE_GRE):
  51 +               return PAGE_S2_DEVICE;
  52 +       case PTE_ATTRINDX(MT_NORMAL_NC):
  53 +       case PTE_ATTRINDX(MT_NORMAL):
  54 +               return (pgprot_val(prot) & PTE_SHARED)
  55 +                       ? PAGE_S2
  56 +                       : PAGE_S2_NS;
  57 +       }
  58 +
  59 +       return PAGE_S2_DEVICE;
  60 +}
  61 +#else
  62 +static pgprot_t stage1_to_stage2_pgprot(pgprot_t prot)
  63 +{
  64 +       return PAGE_S2_DEVICE;
  65 +}
  66 +#endif
  67 +
  68  static bool transparent_hugepage_adjust(kvm_pfn_t *pfnp, phys_addr_t *ipap)
  69  {
  70         kvm_pfn_t pfn = *pfnp;
  71 @@ -1719,8 +1743,23 @@ static int user_mem_abort(struct kvm_vcp
  72          * 3 levels, i.e, PMD is not folded.
  73          */
  74         if (vma_pagesize == PMD_SIZE ||
  75 -           (vma_pagesize == PUD_SIZE && kvm_stage2_has_pmd(kvm)))
  76 +           (vma_pagesize == PUD_SIZE && kvm_stage2_has_pmd(kvm))) {
  77                 gfn = (fault_ipa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT;
  78 +       } else {
  79 +               if (!is_vm_hugetlb_page(vma)) {
  80 +                       pte_t *pte;
  81 +                       spinlock_t *ptl;
  82 +                       pgprot_t prot;
  83 +
  84 +                       pte = get_locked_pte(current->mm, memslot->userspace_addr, &ptl);
  85 +                       prot = stage1_to_stage2_pgprot(__pgprot(pte_val(*pte)));
  86 +                       pte_unmap_unlock(pte, ptl);
  87 +#ifdef CONFIG_ARM64
  88 +                       if (pgprot_val(prot) == pgprot_val(PAGE_S2_NS))
  89 +                               mem_type = PAGE_S2_NS;
  90 +#endif
  91 +               }
  92 +       }
  93         up_read(&current->mm->mmap_sem);
  94
  95         /* We need minimum second+third level pages */
  96 @@ -1749,6 +1788,11 @@ static int user_mem_abort(struct kvm_vcp
  97         if (is_error_noslot_pfn(pfn))
  98                 return -EFAULT;
  99
 100 +#ifdef CONFIG_ARM64
 101 +       if (pgprot_val(mem_type) == pgprot_val(PAGE_S2_NS)) {
 102 +               flags |= KVM_S2PTE_FLAG_IS_IOMAP;
 103 +       } else
 104 +#endif
 105         if (kvm_is_device_pfn(pfn)) {
 106                 mem_type = PAGE_S2_DEVICE;
 107                 flags |= KVM_S2PTE_FLAG_IS_IOMAP;
 108 @@ -2336,6 +2380,9 @@ int kvm_arch_prepare_memory_region(struc
 109                         gpa_t gpa = mem->guest_phys_addr +
 110                                     (vm_start - mem->userspace_addr);
 111                         phys_addr_t pa;
 112 +                       pgprot_t prot;
 113 +                       pte_t *pte;
 114 +                       spinlock_t *ptl;
 115
 116                         pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
 117                         pa += vm_start - vma->vm_start;
 118 @@ -2346,9 +2393,13 @@ int kvm_arch_prepare_memory_region(struc
 119                                 goto out;
 120                         }
 121
 122 +                       pte = get_locked_pte(current->mm, mem->userspace_addr, &ptl);
 123 +                       prot = stage1_to_stage2_pgprot(__pgprot(pte_val(*pte)));
 124 +                       pte_unmap_unlock(pte, ptl);
 125 +
 126                         ret = kvm_phys_addr_ioremap(kvm, gpa, pa,
 127                                                     vm_end - vm_start,
 128 -                                                   writable, PAGE_S2_DEVICE);
 129 +                                                   writable, prot);
 130                         if (ret)
 131                                 break;
 132                 }