diff options
Diffstat (limited to 'virt/kvm')
| -rw-r--r-- | virt/kvm/guest_memfd.c | 45 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 7 |
2 files changed, 39 insertions, 13 deletions
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index fbca8c0972da6e..ffadc5ee8e0455 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -623,31 +623,50 @@ err: return r; } -void kvm_gmem_unbind(struct kvm_memory_slot *slot) +static void __kvm_gmem_unbind(struct kvm_memory_slot *slot, struct kvm_gmem *gmem) { unsigned long start = slot->gmem.pgoff; unsigned long end = start + slot->npages; - struct kvm_gmem *gmem; + + xa_store_range(&gmem->bindings, start, end - 1, NULL, GFP_KERNEL); + + /* + * synchronize_srcu(&kvm->srcu) ensured that kvm_gmem_get_pfn() + * cannot see this memslot. + */ + WRITE_ONCE(slot->gmem.file, NULL); +} + +void kvm_gmem_unbind(struct kvm_memory_slot *slot) +{ struct file *file; /* - * Nothing to do if the underlying file was already closed (or is being - * closed right now), kvm_gmem_release() invalidates all bindings. + * Nothing to do if the underlying file was _already_ closed, as + * kvm_gmem_release() invalidates and nullifies all bindings. */ - file = kvm_gmem_get_file(slot); - if (!file) + if (!slot->gmem.file) return; - gmem = file->private_data; - - filemap_invalidate_lock(file->f_mapping); - xa_store_range(&gmem->bindings, start, end - 1, NULL, GFP_KERNEL); + file = kvm_gmem_get_file(slot); /* - * synchronize_srcu(&kvm->srcu) ensured that kvm_gmem_get_pfn() - * cannot see this memslot. + * However, if the file is _being_ closed, then the bindings need to be + * removed as kvm_gmem_release() might not run until after the memslot + * is freed. Note, modifying the bindings is safe even though the file + * is dying as kvm_gmem_release() nullifies slot->gmem.file under + * slots_lock, and only puts its reference to KVM after destroying all + * bindings. I.e. reaching this point means kvm_gmem_release() hasn't + * yet destroyed the bindings or freed the gmem_file, and can't do so + * until the caller drops slots_lock. */ - WRITE_ONCE(slot->gmem.file, NULL); + if (!file) { + __kvm_gmem_unbind(slot, slot->gmem.file->private_data); + return; + } + + filemap_invalidate_lock(file->f_mapping); + __kvm_gmem_unbind(slot, file->private_data); filemap_invalidate_unlock(file->f_mapping); fput(file); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index b7a0ae2a7b205c..4255fcf9c6e581 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -49,6 +49,7 @@ #include <linux/lockdep.h> #include <linux/kthread.h> #include <linux/suspend.h> +#include <linux/rseq.h> #include <asm/processor.h> #include <asm/ioctl.h> @@ -4476,6 +4477,12 @@ static long kvm_vcpu_ioctl(struct file *filp, r = kvm_arch_vcpu_ioctl_run(vcpu); vcpu->wants_to_run = false; + /* + * FIXME: Remove this hack once all KVM architectures + * support the generic TIF bits, i.e. a dedicated TIF_RSEQ. + */ + rseq_virt_userspace_exit(); + trace_kvm_userspace_exit(vcpu->run->exit_reason, r); break; } |