diff options
author | Peter Gonda <pgonda@google.com> | 2021-01-27 19:15:24 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-02-10 11:29:18 +0300 |
commit | 4f627ecde7329e476a077bb0590db8f27bb8f912 (patch) | |
tree | 48cc1a2b08c4562609b4239a6b6e02518c7a3ec6 /arch | |
parent | a03a8693b1a26a3ea435fd4b9607de00c573c60b (diff) | |
download | linux-4f627ecde7329e476a077bb0590db8f27bb8f912.tar.xz |
Fix unsynchronized access to sev members through svm_register_enc_region
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/kvm/svm/sev.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 5c9630c3f6ba..e3e04988fdab 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -320,6 +320,8 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr, unsigned long first, last; int ret; + lockdep_assert_held(&kvm->lock); + if (ulen == 0 || uaddr + ulen < uaddr) return ERR_PTR(-EINVAL); @@ -1001,12 +1003,20 @@ 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 (IS_ERR(region->pages)) { ret = PTR_ERR(region->pages); + mutex_unlock(&kvm->lock); goto e_free; } + region->uaddr = range->addr; + region->size = range->size; + + 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 @@ -1015,13 +1025,6 @@ 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: |