diff options
| author | Andrea Arcangeli <andrea@qumranet.com> | 2008-07-25 16:32:03 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-07-29 12:33:50 +0300 |
| commit | 604b38ac0369bd50fcbb33344aa5553c071009f7 (patch) | |
| tree | 149325ef8ddbeb607a19052bb807383a6aa7a549 /virt/kvm | |
| parent | a1708ce8a362c4999f1201237ae7b77c4d13af82 (diff) | |
KVM: Allow browsing memslots with mmu_lock
This allows reading memslots with only the mmu_lock hold for mmu
notifiers that runs in atomic context and with mmu_lock held.
Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'virt/kvm')
| -rw-r--r-- | virt/kvm/kvm_main.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a845890b680..3735212cd3f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -375,7 +375,15 @@ int __kvm_set_memory_region(struct kvm *kvm, memset(new.rmap, 0, npages * sizeof(*new.rmap)); new.user_alloc = user_alloc; - new.userspace_addr = mem->userspace_addr; + /* + * hva_to_rmmap() serialzies with the mmu_lock and to be + * safe it has to ignore memslots with !user_alloc && + * !userspace_addr. + */ + if (user_alloc) + new.userspace_addr = mem->userspace_addr; + else + new.userspace_addr = 0; } if (npages && !new.lpage_info) { int largepages = npages / KVM_PAGES_PER_HPAGE; @@ -408,17 +416,21 @@ int __kvm_set_memory_region(struct kvm *kvm, } #endif /* not defined CONFIG_S390 */ - if (mem->slot >= kvm->nmemslots) - kvm->nmemslots = mem->slot + 1; - if (!npages) kvm_arch_flush_shadow(kvm); + spin_lock(&kvm->mmu_lock); + if (mem->slot >= kvm->nmemslots) + kvm->nmemslots = mem->slot + 1; + *memslot = new; + spin_unlock(&kvm->mmu_lock); r = kvm_arch_set_memory_region(kvm, mem, old, user_alloc); if (r) { + spin_lock(&kvm->mmu_lock); *memslot = old; + spin_unlock(&kvm->mmu_lock); goto out_free; } |