Probabilistic tracker management for memory attack mitigation

A memory, comprising:

• a hardware buffer to track memory access requests that have been pseudo-randomly or randomly sampled from a stream of memory access requests issued to the memory;
• and
• logic to:
• (a) update the hardware buffer based on the memory access requests sampled from the stream including, for each of the memory access requests:
• determining whether the hardware buffer includes an existing entry tracking accesses for a portion of the memory associated with the memory access request;
• when the hardware buffer includes the existing entry for the portion of the memory associated with the memory access request, updating an access counter included in the existing entry;
• and
• when the hardware buffer does not include the existing entry for the portion of the memory associated with the memory access request:
• when the hardware buffer is occupied above a threshold or is full, evicting from the hardware buffer an existing entry tracking accesses for another portion of the memory, and
• inserting a new entry in the hardware buffer for the portion of the memory associated with the memory access request, and
• (b) perform one or more attack mitigation actions, using the updated hardware buffer.

A memory controller that interfaces a memory, comprising:

• a hardware buffer to track memory access requests that have been pseudo-randomly or randomly sampled from a stream of memory access requests issued to the memory;
• and
• logic that:
• (a) updates the hardware buffer based on the memory access requests sampled from the stream including, for each of the memory access requests:
• determining whether the hardware buffer includes an existing entry tracking accesses for a portion of the memory associated with the memory access request;
• when the hardware buffer includes the existing entry for the portion of the memory associated with the memory access request, updating an access counter included in the existing entry;
• and
• when the hardware buffer does not include the existing entry for the portion of the memory associated with the memory access request:
• when the hardware buffer is occupied above a threshold or is full, evicting from the hardware buffer an existing entry tracking accesses for another portion of the memory, and
• inserting a new entry in the hardware buffer for the portion of the memory associated with the memory access request, and
• (b) uses the updated hardware buffer to cause the memory to perform one or more attack mitigation actions.