Hi, On 11/27/18 10:00 AM, Sergey Dyasli wrote:
Some x86 CPUs has errata regarding microcode updates. The most notorious is Broadwell's BDX90: "Loading Microcode ... May Result in a System Hang". (URL: https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e7-v4-spec-update.pdf)CPUs are supposed to be idle during initial microcode update. Idle-scrub changes this, making a CPU to go scrubbing (memset) right after it was brought up. This can get in a way of microcode update for other CPUs, which results in a system hang: [ 0.000000] CPU Vendor: Intel, Family 6 (0x6), Model 71 (0x47), Stepping 1 (raw 00040671) ... [ 2.598813] HVM: Hardware Assisted Paging (HAP) detected [ 2.600211] HVM: HAP page sizes: 4kB, 2MB, 1GB [ 0.000000] microcode: CPU2 updated from revision 0x11 to 0x1e, date = 2018-04-03 [ 0.000000] microcode: CPU4 updated from revision 0x11 to 0x1e, d€ [2J[1;1H[2J Prevent this situation by disabling idle scrubbing until SYS_STATE_smp_booted is reached.
I am not aware of any issue on Arm that requires delaying the idle scrubbing. It is actually probably better to avoid delaying it as it may take a long time to boot all CPUs on platform with a high number of cores (48 cores or upper).
Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
