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-rw-r--r--Documentation/admin-guide/hw-vuln/tsx_async_abort.rst33
1 files changed, 13 insertions, 20 deletions
diff --git a/Documentation/admin-guide/hw-vuln/tsx_async_abort.rst b/Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
index 014167ef8dd1..444f84e22a91 100644
--- a/Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
+++ b/Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
@@ -98,7 +98,19 @@ The possible values in this file are:
* - 'Vulnerable'
- The CPU is affected by this vulnerability and the microcode and kernel mitigation are not applied.
* - 'Vulnerable: Clear CPU buffers attempted, no microcode'
- - The system tries to clear the buffers but the microcode might not support the operation.
+ - The processor is vulnerable but microcode is not updated. The
+ mitigation is enabled on a best effort basis.
+
+ If the processor is vulnerable but the availability of the microcode
+ based mitigation mechanism is not advertised via CPUID, the kernel
+ selects a best effort mitigation mode. This mode invokes the mitigation
+ instructions without a guarantee that they clear the CPU buffers.
+
+ This is done to address virtualization scenarios where the host has the
+ microcode update applied, but the hypervisor is not yet updated to
+ expose the CPUID to the guest. If the host has updated microcode the
+ protection takes effect; otherwise a few CPU cycles are wasted
+ pointlessly.
* - 'Mitigation: Clear CPU buffers'
- The microcode has been updated to clear the buffers. TSX is still enabled.
* - 'Mitigation: TSX disabled'
@@ -106,25 +118,6 @@ The possible values in this file are:
* - 'Not affected'
- The CPU is not affected by this issue.
-.. _ucode_needed:
-
-Best effort mitigation mode
-^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-If the processor is vulnerable, but the availability of the microcode-based
-mitigation mechanism is not advertised via CPUID the kernel selects a best
-effort mitigation mode. This mode invokes the mitigation instructions
-without a guarantee that they clear the CPU buffers.
-
-This is done to address virtualization scenarios where the host has the
-microcode update applied, but the hypervisor is not yet updated to expose the
-CPUID to the guest. If the host has updated microcode the protection takes
-effect; otherwise a few CPU cycles are wasted pointlessly.
-
-The state in the tsx_async_abort sysfs file reflects this situation
-accordingly.
-
-
Mitigation mechanism
--------------------