Sorry, I am using Xen version 4.9.2, specifically 4.9.2-0ubuntu1. I am seeing the bug with *kernel* version 4.15.0, and specifically Ubuntu's tag Ubuntu-4.15.0-23.25. That appears to have the "x86/cpu: Re-apply forced caps every time CPU caps are re-read" patch, but not "x86/xen: Add call of speculative_store_bypass_ht_init() to PV paths".
I can try cherry-picking that commit. Are there other commits in particular that might need to be pulled into the Ubuntu kernel to get it to work? On Tue, Jul 31, 2018 at 4:58 AM, Juergen Gross <jgr...@suse.com> wrote: > On 31/07/18 03:14, Adam Novak wrote: >> Hello, >> >> I was advised to take this here, and to Boris Ostrovsky and Juergen >> Gross, by Thomas Gleixner. >> >> I am having some trouble with the new speculation control code that >> has been added to the Linux kernel, for AMD Zen CPUs. I am running an >> AMD Ryzen 7 1700, and I am running Linux as a Xen dom0 (which is part >> of the problem; the code seems to work fine running outside of Xen). >> >> I started having trouble on Ubuntu's commit >> 3f6a3b035f91a22c0d3bd27630bf61eac9c8cf6c, "x86/speculation: Handle HT >> correctly on AMD", which appears to be cherry-picked from >> 1f50ddb4f4189243c05926b842dc1a0332195f31. Since that commit, my system >> hangs during the boot process; it starts starting stuff up and trying >> to mount things and printing "[OK]" messages, but then fairly early in >> the boot process the kernel complains that it is "unable to handle >> kernel NULL pointer deference at 000...0008" >> >> On my Ubuntu bug: >> >> https://bugs.launchpad.net/bugs/1777338 >> >> I have a "Screenshot of the null pointer dereference message". It is >> running into trouble during a spin lock in the new >> speculative_store_bypass_update(). >> >> Has anyone else seen this behavior on these CPUs under Xen (I am using 4.9)? > > You want at least 4.9.112, especially due to the missing patches > "x86/xen: Add call of speculative_store_bypass_ht_init() to PV paths", > "x86/cpu: Re-apply forced caps every time CPU caps are re-read" > > Juergen
