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A big Linux release over the weekend added the "Retpoline" Spectre mitigation to the Linux kernel, but BleepingComputer reports that Windows got the same treatment. Google shared the Retpoline software mitigation technique last year, shortly after they publicly revealed Spectre and Meltdown, which Microsoft says "works by replacing all indirect call or jumps in kernel-mode binaries with an indirect branch sequence that has safe speculation behavior." Microsoft claims the update that brings the mitigations is enabled by default in Windows Insider Fast Builds, but if you want to verify the Spectre protection status yourself, they posted a fairly straightforward Powershell tutorial. In a nutshell, just download the SpeculationControl module from a link in the guide, unzip it, open a powershell console via the start menu, and copy the commands into the console. Note that I couldn't get the script working without changing "Import-Module.SpeculationControl.psd1" to "Import-Module SpeculationControl.psd1".
Retpoline has significantly improved the performance of the Spectre variant 2 mitigations on Windows. When all relevant kernel-mode binaries are compiled with retpoline, we've measured ~25% speedup in Office app launch times and up to 1.5-2x improved throughput in the Diskspd (storage) and NTttcp (networking) benchmarks on Broadwell CPUs in our lab. It is enabled by default in the latest Windows Client Insider Fast builds (for builds 18272 and higher on machines exposing compatible speculation control capabilities) and is targeted to ship with 19H1.
EDIT: I tried to automate the Spectre checking tool with a BAT file, but it in short, it has to be done manually :/
Retpoline has significantly improved the performance of the Spectre variant 2 mitigations on Windows. When all relevant kernel-mode binaries are compiled with retpoline, we've measured ~25% speedup in Office app launch times and up to 1.5-2x improved throughput in the Diskspd (storage) and NTttcp (networking) benchmarks on Broadwell CPUs in our lab. It is enabled by default in the latest Windows Client Insider Fast builds (for builds 18272 and higher on machines exposing compatible speculation control capabilities) and is targeted to ship with 19H1.
EDIT: I tried to automate the Spectre checking tool with a BAT file, but it in short, it has to be done manually :/
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