On 10/02/2020 08:55, Jan Beulich wrote: > On 10.02.2020 00:06, Marek Marczykowski-Górecki wrote: >> Hi, >> >> Multiple Qubes users have reported issues with resuming from S3 on AMD >> systems (Ryzen 2500U, Ryzen Pro 3700U, maybe more). The error message >> is: >> >> (XEN) CPU0: cap[ 1] is 7ed8320b (expected f6d8320b) >> >> If I read it right, this is: >> - OSXSAVE: 0 -> 1 >> - HYPERVISOR: 1 -> 0 >> >> Commenting out the panic on a failed recheck_cpu_features() in power.c >> makes the system work after resume, reportedly stable. But that doesn't >> sounds like a good idea generally. >> >> Is this difference a Xen fault (some missing MSR / other register >> restore on resume)? Or BIOS vendor / AMD, that could be worked around in >> Xen? > The transition of the HYPERVISOR bit is definitely a Xen issue, > with Andrew having sent a patch already (iirc).
https://lore.kernel.org/xen-devel/20200127202121.2961-1-andrew.coop...@citrix.com/ Code is correct. Commit message needs rework, including in light of this discovery. (I may eventually split it into two patches.) > The OSXSAVE part is a little more surprising, Not to me. The checks only care if feature bits have gone missing, not if new ones have appeared. mmu_cr4_features includes OSXSAVE (from much later on boot than features get cached), so the s3 path observing the gain of OSXSAVE will have been happening ever since the checks were introduced (even on Intel.) ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
