Merge tag 'v5.13-rc6' into char-misc-next

We need the fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 76102efbf079..8583ed3ff344 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1185,7 +1185,15 @@ __gfn_to_memslot(struct kvm_memslots *slots, gfn_t gfn)
 static inline unsigned long
 __gfn_to_hva_memslot(const struct kvm_memory_slot *slot, gfn_t gfn)
 {
-	return slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE;
+	/*
+	 * The index was checked originally in search_memslots.  To avoid
+	 * that a malicious guest builds a Spectre gadget out of e.g. page
+	 * table walks, do not let the processor speculate loads outside
+	 * the guest's registered memslots.
+	 */
+	unsigned long offset = gfn - slot->base_gfn;
+	offset = array_index_nospec(offset, slot->npages);
+	return slot->userspace_addr + offset * PAGE_SIZE;
 }
 
 static inline int memslot_id(struct kvm *kvm, gfn_t gfn)