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-rw-r--r--Documentation/x86/mds.rst5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/x86/mds.rst b/Documentation/x86/mds.rst
index 3d6f943f1afb..979945be257a 100644
--- a/Documentation/x86/mds.rst
+++ b/Documentation/x86/mds.rst
@@ -12,6 +12,7 @@ on internal buffers in Intel CPUs. The variants are:
- Microarchitectural Store Buffer Data Sampling (MSBDS) (CVE-2018-12126)
- Microarchitectural Fill Buffer Data Sampling (MFBDS) (CVE-2018-12130)
- Microarchitectural Load Port Data Sampling (MLPDS) (CVE-2018-12127)
+ - Microarchitectural Data Sampling Uncacheable Memory (MDSUM) (CVE-2019-11091)
MSBDS leaks Store Buffer Entries which can be speculatively forwarded to a
dependent load (store-to-load forwarding) as an optimization. The forward
@@ -38,6 +39,10 @@ faulting or assisting loads under certain conditions, which again can be
exploited eventually. Load ports are shared between Hyper-Threads so cross
thread leakage is possible.
+MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from
+memory that takes a fault or assist can leave data in a microarchitectural
+structure that may later be observed using one of the same methods used by
+MSBDS, MFBDS or MLPDS.
Exposure assumptions
--------------------