It is becoming increasingly important to combine software and hardware aspects to take new software attacks into account. For example, hardware vulnerabilities such as Spectre or Meltdown can be exploited by purely software attacks. Such attacks can be executed remotely and do not require physical access to the targeted hardware platform. On the other hand, hardware features can be used to better detect and respond to traditional software attacks, such as memory corruption. Therefore, it is necessary to study the security of software/hardware interfaces, both in terms of attacks and defenses. The purpose of the SILM workshop is to share experiences, tools, and methodologies to handle security in software/hardware interfaces. On the one hand, we need to better assess the security guarantees provided by existing hardware architectures against software attacks, especially attacks against micro-architecture.