pending-4.9/kvm-s390-fix-memory-slot-handling-for-kvm_set_user_m.patch

   1 From 928ef7ef0ea00fd23187f23ea566268060fe0526 Mon Sep 17 00:00:00 2001
   2 From: Christian Borntraeger <borntraeger@de.ibm.com>
   3 Date: Fri, 24 May 2019 16:06:23 +0200
   4 Subject: KVM: s390: fix memory slot handling for KVM_SET_USER_MEMORY_REGION
   5
   6 [ Upstream commit 19ec166c3f39fe1d3789888a74cc95544ac266d4 ]
   7
   8 kselftests exposed a problem in the s390 handling for memory slots.
   9 Right now we only do proper memory slot handling for creation of new
  10 memory slots. Neither MOVE, nor DELETION are handled properly. Let us
  11 implement those.
  12
  13 Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
  14 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
  15 Signed-off-by: Sasha Levin <sashal@kernel.org>
  16 ---
  17  arch/s390/kvm/kvm-s390.c | 35 +++++++++++++++++++++--------------
  18  1 file changed, 21 insertions(+), 14 deletions(-)
  19
  20 diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
  21 index 2032ab81b2d7..07f571900676 100644
  22 --- a/arch/s390/kvm/kvm-s390.c
  23 +++ b/arch/s390/kvm/kvm-s390.c
  24 @@ -3288,21 +3288,28 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
  25                                 const struct kvm_memory_slot *new,
  26                                 enum kvm_mr_change change)
  27  {
  28 -       int rc;
  29 -
  30 -       /* If the basics of the memslot do not change, we do not want
  31 -        * to update the gmap. Every update causes several unnecessary
  32 -        * segment translation exceptions. This is usually handled just
  33 -        * fine by the normal fault handler + gmap, but it will also
  34 -        * cause faults on the prefix page of running guest CPUs.
  35 -        */
  36 -       if (old->userspace_addr == mem->userspace_addr &&
  37 -           old->base_gfn * PAGE_SIZE == mem->guest_phys_addr &&
  38 -           old->npages * PAGE_SIZE == mem->memory_size)
  39 -               return;
  40 +       int rc = 0;
  41
  42 -       rc = gmap_map_segment(kvm->arch.gmap, mem->userspace_addr,
  43 -               mem->guest_phys_addr, mem->memory_size);
  44 +       switch (change) {
  45 +       case KVM_MR_DELETE:
  46 +               rc = gmap_unmap_segment(kvm->arch.gmap, old->base_gfn * PAGE_SIZE,
  47 +                                       old->npages * PAGE_SIZE);
  48 +               break;
  49 +       case KVM_MR_MOVE:
  50 +               rc = gmap_unmap_segment(kvm->arch.gmap, old->base_gfn * PAGE_SIZE,
  51 +                                       old->npages * PAGE_SIZE);
  52 +               if (rc)
  53 +                       break;
  54 +               /* FALLTHROUGH */
  55 +       case KVM_MR_CREATE:
  56 +               rc = gmap_map_segment(kvm->arch.gmap, mem->userspace_addr,
  57 +                                     mem->guest_phys_addr, mem->memory_size);
  58 +               break;
  59 +       case KVM_MR_FLAGS_ONLY:
  60 +               break;
  61 +       default:
  62 +               WARN(1, "Unknown KVM MR CHANGE: %d\n", change);
  63 +       }
  64         if (rc)
  65                 pr_warn("failed to commit memory region\n");
  66         return;
  67 --
  68 2.20.1
  69