From: Peter Gonda <pgonda@google.com> commit 19a23da53932bc8011220bd8c410cb76012de004 upstream. Grab kvm->lock before pinning memory when registering an encrypted region; sev_pin_memory() relies on kvm->lock being held to ensure correctness when checking and updating the number of pinned pages. Add a lockdep assertion to help prevent future regressions. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Sean Christopherson <seanjc@google.com> Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Fixes: 1e80fdc09d12 ("KVM: SVM: Pin guest memory when SEV is active") Signed-off-by: Peter Gonda <pgonda@google.com> V2 - Fix up patch description - Correct file paths svm.c -> sev.c - Add unlock of kvm->lock on sev_pin_memory error V1 - https://lore.kernel.org/kvm/20210126185431.1824530-1-pgonda@google.com/ Message-Id: <20210127161524.2832400-1-pgonda@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/x86/kvm/svm.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index f1e86051aa5f3..b34d11f22213f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1832,6 +1832,8 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr, struct page **pages; unsigned long first, last; + lockdep_assert_held(&kvm->lock); + if (ulen == 0 || uaddr + ulen < uaddr) return NULL; @@ -7084,12 +7086,21 @@ static int svm_register_enc_region(struct kvm *kvm, if (!region) return -ENOMEM; + mutex_lock(&kvm->lock); region->pages = sev_pin_memory(kvm, range->addr, range->size, ®ion->npages, 1); if (!region->pages) { ret = -ENOMEM; + mutex_unlock(&kvm->lock); goto e_free; } + region->uaddr = range->addr; + region->size = range->size; + + mutex_lock(&kvm->lock); + list_add_tail(®ion->list, &sev->regions_list); + mutex_unlock(&kvm->lock); + /* * The guest may change the memory encryption attribute from C=0 -> C=1 * or vice versa for this memory range. Lets make sure caches are @@ -7098,13 +7109,6 @@ static int svm_register_enc_region(struct kvm *kvm, */ sev_clflush_pages(region->pages, region->npages); - region->uaddr = range->addr; - region->size = range->size; - - mutex_lock(&kvm->lock); - list_add_tail(®ion->list, &sev->regions_list); - mutex_unlock(&kvm->lock); - return ret; e_free: -- 2.25.1