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| 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 /arch | |
| parent | a1708ce8a362c4999f1201237ae7b77c4d13af82 (diff) | |
| download | linux-604b38ac0369bd50fcbb33344aa5553c071009f7.tar.gz linux-604b38ac0369bd50fcbb33344aa5553c071009f7.tar.bz2 linux-604b38ac0369bd50fcbb33344aa5553c071009f7.zip | |
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 'arch')
| -rw-r--r-- | arch/x86/kvm/x86.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9870ce422920..c7b01efe0646 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3974,16 +3974,23 @@ int kvm_arch_set_memory_region(struct kvm *kvm, */ if (!user_alloc) { if (npages && !old.rmap) { + unsigned long userspace_addr; + down_write(¤t->mm->mmap_sem); - memslot->userspace_addr = do_mmap(NULL, 0, - npages * PAGE_SIZE, - PROT_READ | PROT_WRITE, - MAP_SHARED | MAP_ANONYMOUS, - 0); + userspace_addr = do_mmap(NULL, 0, + npages * PAGE_SIZE, + PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_ANONYMOUS, + 0); up_write(¤t->mm->mmap_sem); - if (IS_ERR((void *)memslot->userspace_addr)) - return PTR_ERR((void *)memslot->userspace_addr); + if (IS_ERR((void *)userspace_addr)) + return PTR_ERR((void *)userspace_addr); + + /* set userspace_addr atomically for kvm_hva_to_rmapp */ + spin_lock(&kvm->mmu_lock); + memslot->userspace_addr = userspace_addr; + spin_unlock(&kvm->mmu_lock); } else { if (!old.user_alloc && old.rmap) { int ret; |