| Message ID | 20191022003537.13013-2-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: Dynamically size memslot arrays | expand |
On Mon, Oct 21, 2019 at 05:35:23PM -0700, Sean Christopherson wrote: > Reinstall the old memslots if preparing the new memory region fails > after invalidating a to-be-{re}moved memslot. > > Remove the superfluous 'old_memslots' variable so that it's somewhat > clear that the error handling path needs to free the unused memslots, > not simply the 'old' memslots. > > Fixes: bc6678a33d9b9 ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update") > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > --- > virt/kvm/kvm_main.c | 23 ++++++++++++----------- > 1 file changed, 12 insertions(+), 11 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 67ef3f2e19e8..9afd706dc038 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -924,7 +924,7 @@ int __kvm_set_memory_region(struct kvm *kvm, > unsigned long npages; > struct kvm_memory_slot *slot; > struct kvm_memory_slot old, new; > - struct kvm_memslots *slots = NULL, *old_memslots; > + struct kvm_memslots *slots; > int as_id, id; > enum kvm_mr_change change; > > @@ -1032,7 +1032,13 @@ int __kvm_set_memory_region(struct kvm *kvm, > slot = id_to_memslot(slots, id); > slot->flags |= KVM_MEMSLOT_INVALID; > > - old_memslots = install_new_memslots(kvm, as_id, slots); > + /* > + * We can re-use the old memslots, the only difference from the > + * newly installed memslots is the invalid flag, which will get > + * dropped by update_memslots anyway. We'll also revert to the > + * old memslots if preparing the new memory region fails. > + */ > + slots = install_new_memslots(kvm, as_id, slots); > > /* From this point no new shadow pages pointing to a deleted, > * or moved, memslot will be created. > @@ -1042,13 +1048,6 @@ int __kvm_set_memory_region(struct kvm *kvm, > * - kvm_is_visible_gfn (mmu_check_roots) > */ > kvm_arch_flush_shadow_memslot(kvm, slot); > - > - /* > - * We can re-use the old_memslots from above, the only difference > - * from the currently installed memslots is the invalid flag. This > - * will get overwritten by update_memslots anyway. > - */ > - slots = old_memslots; > } > > r = kvm_arch_prepare_memory_region(kvm, &new, mem, change); > @@ -1062,15 +1061,17 @@ int __kvm_set_memory_region(struct kvm *kvm, > } > > update_memslots(slots, &new, change); > - old_memslots = install_new_memslots(kvm, as_id, slots); > + slots = install_new_memslots(kvm, as_id, slots); > > kvm_arch_commit_memory_region(kvm, mem, &old, &new, change); > > kvm_free_memslot(kvm, &old, &new); > - kvfree(old_memslots); > + kvfree(slots); > return 0; > > out_slots: > + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) > + slots = install_new_memslots(kvm, as_id, slots); > kvfree(slots); > out_free: > kvm_free_memslot(kvm, &new, &old); > -- > 2.22.0 Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 67ef3f2e19e8..9afd706dc038 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -924,7 +924,7 @@ int __kvm_set_memory_region(struct kvm *kvm, unsigned long npages; struct kvm_memory_slot *slot; struct kvm_memory_slot old, new; - struct kvm_memslots *slots = NULL, *old_memslots; + struct kvm_memslots *slots; int as_id, id; enum kvm_mr_change change; @@ -1032,7 +1032,13 @@ int __kvm_set_memory_region(struct kvm *kvm, slot = id_to_memslot(slots, id); slot->flags |= KVM_MEMSLOT_INVALID; - old_memslots = install_new_memslots(kvm, as_id, slots); + /* + * We can re-use the old memslots, the only difference from the + * newly installed memslots is the invalid flag, which will get + * dropped by update_memslots anyway. We'll also revert to the + * old memslots if preparing the new memory region fails. + */ + slots = install_new_memslots(kvm, as_id, slots); /* From this point no new shadow pages pointing to a deleted, * or moved, memslot will be created. @@ -1042,13 +1048,6 @@ int __kvm_set_memory_region(struct kvm *kvm, * - kvm_is_visible_gfn (mmu_check_roots) */ kvm_arch_flush_shadow_memslot(kvm, slot); - - /* - * We can re-use the old_memslots from above, the only difference - * from the currently installed memslots is the invalid flag. This - * will get overwritten by update_memslots anyway. - */ - slots = old_memslots; } r = kvm_arch_prepare_memory_region(kvm, &new, mem, change); @@ -1062,15 +1061,17 @@ int __kvm_set_memory_region(struct kvm *kvm, } update_memslots(slots, &new, change); - old_memslots = install_new_memslots(kvm, as_id, slots); + slots = install_new_memslots(kvm, as_id, slots); kvm_arch_commit_memory_region(kvm, mem, &old, &new, change); kvm_free_memslot(kvm, &old, &new); - kvfree(old_memslots); + kvfree(slots); return 0; out_slots: + if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) + slots = install_new_memslots(kvm, as_id, slots); kvfree(slots); out_free: kvm_free_memslot(kvm, &new, &old);
Reinstall the old memslots if preparing the new memory region fails after invalidating a to-be-{re}moved memslot. Remove the superfluous 'old_memslots' variable so that it's somewhat clear that the error handling path needs to free the unused memslots, not simply the 'old' memslots. Fixes: bc6678a33d9b9 ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- virt/kvm/kvm_main.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)