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Diffstat (limited to 'include/linux/kvm_host.h')
-rw-r--r--include/linux/kvm_host.h10
1 files changed, 9 insertions, 1 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 76102efbf079..74995f0a2a3c 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 = array_index_nospec(gfn - slot->base_gfn,
+ slot->npages);
+ return slot->userspace_addr + offset * PAGE_SIZE;
}
static inline int memslot_id(struct kvm *kvm, gfn_t gfn)