summaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
authorMarc Zyngier <maz@kernel.org>2021-01-21 12:08:15 +0000
committerMarc Zyngier <maz@kernel.org>2021-01-21 14:17:36 +0000
commit139bc8a6146d92822c866cf2fd410159c56b3648 (patch)
tree47749e54b37ecdf138090403959ecd93c73a8ae6 /Documentation
parent9529aaa056edc76b3a41df616c71117ebe11e049 (diff)
KVM: Forbid the use of tagged userspace addresses for memslots
The use of a tagged address could be pretty confusing for the whole memslot infrastructure as well as the MMU notifiers. Forbid it altogether, as it never quite worked the first place. Cc: stable@vger.kernel.org Reported-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/virt/kvm/api.rst3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 4e5316ed10e9..c347b7083abf 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -1269,6 +1269,9 @@ field userspace_addr, which must point at user addressable memory for
the entire memory slot size. Any object may back this memory, including
anonymous memory, ordinary files, and hugetlbfs.
+On architectures that support a form of address tagging, userspace_addr must
+be an untagged address.
+
It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr
be identical. This allows large pages in the guest to be backed by large
pages in the host.