On 01/07/2018 03:35 PM, Ben Hutchings wrote:

I sent this out for review on the stable list after quite minimal testing, but have done more since then. On bare metal (Sandy Bridge, with pcid but not invpcid) it crashes at boot. In fact it reboots without any panic message, suggesting a triple fault, as soon as I apply the patch that turns on CR4.PCIDE, i.e. without KPTI itself.

My first guess would be something around this stuff:

commit c7ad5ad297e644601747d6dbee978bf85e14f7bc Author: Andy Lutomirski luto@kernel.org Date: Sun Sep 10 17:48:27 2017 -0700

x86/mm/64: Initialize CR4.PCIDE early

But, if you also want to toss a set of binaries up somewhere that I can test I can give them a quick run in the simulator or with a hardware debugger attached. It's been very useful in getting these things debugged, especially when normal debugging techniques fail.