AMD has published a document warning that Zen 3-based processors may be targeted by side-channel attacks. As per its description, this vulnerability is similar to Spectre, which plagued Intel processors three years ago.
AMD Zen 3 core architecture features a new technology that improves performance by predicting the “relationship between loads and stores without waiting for the address calculation to complete”. This technology is called Predictive Store Forwarding (PSF).
Most of the time, the prediction is calculated correctly, but occasionally it may not be as accurate as it should. When a bad PSF speculation occurs, Zen 3-based processors can be targeted by side-channel attacks similar to Intel processors affected by Spectre.
The company described two scenarios where a bad PSF speculation may happen: when a store/load pair with a dependency seizes and when a store/load pair with a dependency may alias in the predictor with another store/load pair without a dependency.
Despite this vulnerability, AMD recommends users keep PSF enabled. In case you wish to disable it, you can by following the instructions found on the last page of this PDF. AMD has also stated that it already proposed a Linux patch to enable/disable PSF. For now, the company has not shared its plans regarding Windows systems.
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KitGuru says: AMD may be recommending that users keep PSF enabled due to the performance benefits. Once deactivated, there should be a noticeable difference. Do you own a Zen 3-based processor? Will you disable PSF or just keep it as it is?