Intel has released microcode update v20180108 with Meltdown/Spectre fixes for some CPU families. Of the 94 microcodes in the previous release (v20171117), 19 have been modified in this release; I verified this with a file comparison-by-contents program. I assume that the other 75 microcodes do not yet have Meltdown/Spectre fixes, but I don’t know that for sure.
Download: https://downloadcenter.intel.com/download/27431/Linux-Processor-Microcode-Data-File.
Edit: The file is now not available for download.
From the download’s release notes:
“20180108 Release
— Updates upon 20171117 release —
IVT C0 (06-3e-04:ed) 428->42a
SKL-U/Y D0 (06-4e-03:c0) ba->c2
BDW-U/Y E/F (06-3d-04:c0) 25->28
HSW-ULT Cx/Dx (06-45-01:72) 20->21
Crystalwell Cx (06-46-01:32) 17->18
BDW-H E/G (06-47-01:22) 17->1b
HSX-EX E0 (06-3f-04:80) 0f->10
SKL-H/S R0 (06-5e-03:36) ba->c2
HSW Cx/Dx (06-3c-03:32) 22->23
HSX C0 (06-3f-02:6f) 3a->3b
BDX-DE V0/V1 (06-56-02:10) 0f->14
BDX-DE V2 (06-56-03:10) 700000d->7000011
KBL-U/Y H0 (06-8e-09:c0) 62->80
KBL Y0 / CFL D0 (06-8e-0a:c0) 70->80
KBL-H/S B0 (06-9e-09:2a) 5e->80
CFL U0 (06-9e-0a:22) 70->80
CFL B0 (06-9e-0b:02) 72->80
SKX H0 (06-55-04:b7) 2000035->200003c
GLK B0 (06-7a-01:01) 1e->22″
From https://packages.qa.debian.org/i/intel-microcode/news/20180110T100610Z.html:
” + Updated Microcodes:
sig 0x000306c3, pf_mask 0x32, 2017-11-20, rev 0x0023, size 23552
sig 0x000306d4, pf_mask 0xc0, 2017-11-17, rev 0x0028, size 18432
sig 0x000306e4, pf_mask 0xed, 2017-12-01, rev 0x042a, size 15360
sig 0x000306f2, pf_mask 0x6f, 2017-11-17, rev 0x003b, size 33792
sig 0x000306f4, pf_mask 0x80, 2017-11-17, rev 0x0010, size 17408
sig 0x00040651, pf_mask 0x72, 2017-11-20, rev 0x0021, size 22528
sig 0x00040661, pf_mask 0x32, 2017-11-20, rev 0x0018, size 25600
sig 0x00040671, pf_mask 0x22, 2017-11-17, rev 0x001b, size 13312
sig 0x000406e3, pf_mask 0xc0, 2017-11-16, rev 0x00c2, size 99328
sig 0x00050654, pf_mask 0xb7, 2017-12-08, rev 0x200003c, size 27648
sig 0x00050662, pf_mask 0x10, 2017-12-16, rev 0x0014, size 31744
sig 0x00050663, pf_mask 0x10, 2017-12-16, rev 0x7000011, size 22528
sig 0x000506e3, pf_mask 0x36, 2017-11-16, rev 0x00c2, size 99328
sig 0x000706a1, pf_mask 0x01, 2017-12-26, rev 0x0022, size 73728
sig 0x000806e9, pf_mask 0xc0, 2018-01-04, rev 0x0080, size 98304
sig 0x000806ea, pf_mask 0xc0, 2018-01-04, rev 0x0080, size 98304
sig 0x000906e9, pf_mask 0x2a, 2018-01-04, rev 0x0080, size 98304
sig 0x000906ea, pf_mask 0x22, 2018-01-04, rev 0x0080, size 97280
sig 0x000906eb, pf_mask 0x02, 2018-01-04, rev 0x0080, size 98304
+ Implements IBRS/IBPB support and enhances LFENCE: mitigation against Spectre (CVE-2017-5715)
+ Very likely fixes several other errata on some of the processors”
I believe that you can check if your CPU has the Spectre/Meltdown fixes available in this release by getting its CPUID signature at http://www.cpu-world.com/cgi-bin/CPUID.pl (there is also a program at that page) and comparing with the last 5 letters/digits of the 19 sigs listed above.
These microcode updates can be applied at every startup of a Windows system by using the program at https://www.askwoody.com/forums/topic/meltdown-and-spectre-from-a-windows-users-point-of-view/#post-156348. Warning: I have no personal experience doing this. Use at your own discretion. Other options available might be BIOS/UEFI updates from your device manufacturer, and microcode updates shipped by Microsoft via Windows Update.
Another discussion thread: https://news.ycombinator.com/item?id=16111433.