像我们许多人一样，我昨天花了很多时间来更新整个系统，以缓解Meltdown和Spectre攻击。据我了解，有必要安装两个软件包并重新启动：
kernel-3.10.0-693.11.6.el7.x86_64
microcode_ctl-2.1-22.2.el7.x86_64
我有两个安装了这些软件包并重新引导的CentOS 7系统。
根据Red Hat，我可以通过检查这些sysctls并确保它们全部为1来检查缓解状态。但是，在这些系统上，它们并非全部为1：
# cat /sys/kernel/debug/x86/pti_enabled
1
# cat /sys/kernel/debug/x86/ibpb_enabled
0
# cat /sys/kernel/debug/x86/ibrs_enabled
0
而且我也不能将它们设置为1：
# echo 1 > /sys/kernel/debug/x86/ibpb_enabled
-bash: echo: write error: No such device
# echo 1 > /sys/kernel/debug/x86/ibrs_enabled
-bash: echo: write error: No such device
我确认英特尔微码似乎已在启动时加载：
# systemctl status microcode -l
● microcode.service - Load CPU microcode update
Loaded: loaded (/usr/lib/systemd/system/microcode.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Fri 2018-01-05 16:42:25 UTC; 9min ago
Process: 30383 ExecStart=/usr/bin/bash -c grep -l GenuineIntel /proc/cpuinfo | xargs grep -l -E "model[[:space:]]*: 79$" > /dev/null || echo 1 > /sys/devices/system/cpu/microcode/reload (code=exited, status=0/SUCCESS)
Main PID: 30383 (code=exited, status=0/SUCCESS)
Jan 05 16:42:25 makrura systemd[1]: Starting Load CPU microcode update...
Jan 05 16:42:25 makrura systemd[1]: Started Load CPU microcode update.
甚至dmesg似乎已经确认了这一点：
[ 3.245580] microcode: CPU0 sig=0x50662, pf=0x10, revision=0xf
[ 3.245627] microcode: CPU1 sig=0x50662, pf=0x10, revision=0xf
[ 3.245674] microcode: CPU2 sig=0x50662, pf=0x10, revision=0xf
[ 3.245722] microcode: CPU3 sig=0x50662, pf=0x10, revision=0xf
[ 3.245768] microcode: CPU4 sig=0x50662, pf=0x10, revision=0xf
[ 3.245816] microcode: CPU5 sig=0x50662, pf=0x10, revision=0xf
[ 3.245869] microcode: CPU6 sig=0x50662, pf=0x10, revision=0xf
[ 3.245880] microcode: CPU7 sig=0x50662, pf=0x10, revision=0xf
[ 3.245924] microcode: CPU8 sig=0x50662, pf=0x10, revision=0xf
[ 3.245972] microcode: CPU9 sig=0x50662, pf=0x10, revision=0xf
[ 3.245989] microcode: CPU10 sig=0x50662, pf=0x10, revision=0xf
[ 3.246036] microcode: CPU11 sig=0x50662, pf=0x10, revision=0xf
[ 3.246083] microcode: CPU12 sig=0x50662, pf=0x10, revision=0xf
[ 3.246131] microcode: CPU13 sig=0x50662, pf=0x10, revision=0xf
[ 3.246179] microcode: CPU14 sig=0x50662, pf=0x10, revision=0xf
[ 3.246194] microcode: CPU15 sig=0x50662, pf=0x10, revision=0xf
[ 3.246273] microcode: Microcode Update Driver: v2.01 <tigran@aivazian.fsnet.co.uk>, Peter Oruba
我有一个以前名为Broadwell的Intel CPU：
processor : 15
vendor_id : GenuineIntel
cpu family : 6
model : 86
model name : Intel(R) Xeon(R) CPU D-1540 @ 2.00GHz
stepping : 2
microcode : 0xf
cpu MHz : 2499.921
cache size : 12288 KB
physical id : 0
siblings : 16
core id : 7
cpu cores : 8
apicid : 15
initial apicid : 15
fpu : yes
fpu_exception : yes
cpuid level : 20
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb cat_l3 invpcid_single intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm rdt_a rdseed adx smap xsaveopt cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts
bogomips : 3999.90
clflush size : 64
cache_alignment : 64
address sizes : 46 bits physical, 48 bits virtual
power management:
该cpuid实用程序报告：
# cpuid -1
Disclaimer: cpuid may not support decoding of all cpuid registers.
CPU:
vendor_id = "GenuineIntel"
version information (1/eax):
processor type = primary processor (0)
family = Intel Pentium Pro/II/III/Celeron/Core/Core 2/Atom, AMD Athlon/Duron, Cyrix M2, VIA C3 (6)
model = 0x6 (6)
stepping id = 0x2 (2)
extended family = 0x0 (0)
extended model = 0x5 (5)
(simple synth) = Intel Xeon D-1500 (Broadwell-DE V1), 14nm
miscellaneous (1/ebx):
process local APIC physical ID = 0x9 (9)
cpu count = 0x10 (16)
CLFLUSH line size = 0x8 (8)
brand index = 0x0 (0)
brand id = 0x00 (0): unknown
feature information (1/edx):
x87 FPU on chip = true
virtual-8086 mode enhancement = true
debugging extensions = true
page size extensions = true
time stamp counter = true
RDMSR and WRMSR support = true
physical address extensions = true
machine check exception = true
CMPXCHG8B inst. = true
APIC on chip = true
SYSENTER and SYSEXIT = true
memory type range registers = true
PTE global bit = true
machine check architecture = true
conditional move/compare instruction = true
page attribute table = true
page size extension = true
processor serial number = false
CLFLUSH instruction = true
debug store = true
thermal monitor and clock ctrl = true
MMX Technology = true
FXSAVE/FXRSTOR = true
SSE extensions = true
SSE2 extensions = true
self snoop = true
hyper-threading / multi-core supported = true
therm. monitor = true
IA64 = false
pending break event = true
feature information (1/ecx):
PNI/SSE3: Prescott New Instructions = true
PCLMULDQ instruction = true
64-bit debug store = true
MONITOR/MWAIT = true
CPL-qualified debug store = true
VMX: virtual machine extensions = true
SMX: safer mode extensions = true
Enhanced Intel SpeedStep Technology = true
thermal monitor 2 = true
SSSE3 extensions = true
context ID: adaptive or shared L1 data = false
FMA instruction = true
CMPXCHG16B instruction = true
xTPR disable = true
perfmon and debug = true
process context identifiers = true
direct cache access = true
SSE4.1 extensions = true
SSE4.2 extensions = true
extended xAPIC support = true
MOVBE instruction = true
POPCNT instruction = true
time stamp counter deadline = true
AES instruction = true
XSAVE/XSTOR states = true
OS-enabled XSAVE/XSTOR = true
AVX: advanced vector extensions = true
F16C half-precision convert instruction = true
RDRAND instruction = true
hypervisor guest status = false
cache and TLB information (2):
0x63: data TLB: 1G pages, 4-way, 4 entries
0x03: data TLB: 4K pages, 4-way, 64 entries
0x76: instruction TLB: 2M/4M pages, fully, 8 entries
0xff: cache data is in CPUID 4
0xb5: instruction TLB: 4K, 8-way, 64 entries
0xf0: 64 byte prefetching
0xc3: L2 TLB: 4K/2M pages, 6-way, 1536 entries
processor serial number: 0005-0662-0000-0000-0000-0000
deterministic cache parameters (4):
--- cache 0 ---
cache type = data cache (1)
cache level = 0x1 (1)
self-initializing cache level = true
fully associative cache = false
extra threads sharing this cache = 0x1 (1)
extra processor cores on this die = 0x7 (7)
system coherency line size = 0x3f (63)
physical line partitions = 0x0 (0)
ways of associativity = 0x7 (7)
ways of associativity = 0x0 (0)
WBINVD/INVD behavior on lower caches = false
inclusive to lower caches = false
complex cache indexing = false
number of sets - 1 (s) = 63
--- cache 1 ---
cache type = instruction cache (2)
cache level = 0x1 (1)
self-initializing cache level = true
fully associative cache = false
extra threads sharing this cache = 0x1 (1)
extra processor cores on this die = 0x7 (7)
system coherency line size = 0x3f (63)
physical line partitions = 0x0 (0)
ways of associativity = 0x7 (7)
ways of associativity = 0x0 (0)
WBINVD/INVD behavior on lower caches = false
inclusive to lower caches = false
complex cache indexing = false
number of sets - 1 (s) = 63
--- cache 2 ---
cache type = unified cache (3)
cache level = 0x2 (2)
self-initializing cache level = true
fully associative cache = false
extra threads sharing this cache = 0x1 (1)
extra processor cores on this die = 0x7 (7)
system coherency line size = 0x3f (63)
physical line partitions = 0x0 (0)
ways of associativity = 0x7 (7)
ways of associativity = 0x0 (0)
WBINVD/INVD behavior on lower caches = false
inclusive to lower caches = false
complex cache indexing = false
number of sets - 1 (s) = 511
--- cache 3 ---
cache type = unified cache (3)
cache level = 0x3 (3)
self-initializing cache level = true
fully associative cache = false
extra threads sharing this cache = 0xf (15)
extra processor cores on this die = 0x7 (7)
system coherency line size = 0x3f (63)
physical line partitions = 0x0 (0)
ways of associativity = 0xb (11)
ways of associativity = 0x6 (6)
WBINVD/INVD behavior on lower caches = false
inclusive to lower caches = true
complex cache indexing = true
number of sets - 1 (s) = 16383
MONITOR/MWAIT (5):
smallest monitor-line size (bytes) = 0x40 (64)
largest monitor-line size (bytes) = 0x40 (64)
enum of Monitor-MWAIT exts supported = true
supports intrs as break-event for MWAIT = true
number of C0 sub C-states using MWAIT = 0x0 (0)
number of C1 sub C-states using MWAIT = 0x2 (2)
number of C2 sub C-states using MWAIT = 0x1 (1)
number of C3 sub C-states using MWAIT = 0x2 (2)
number of C4 sub C-states using MWAIT = 0x0 (0)
number of C5 sub C-states using MWAIT = 0x0 (0)
number of C6 sub C-states using MWAIT = 0x0 (0)
number of C7 sub C-states using MWAIT = 0x0 (0)
Thermal and Power Management Features (6):
digital thermometer = true
Intel Turbo Boost Technology = true
ARAT always running APIC timer = true
PLN power limit notification = true
ECMD extended clock modulation duty = true
PTM package thermal management = true
HWP base registers = false
HWP notification = false
HWP activity window = false
HWP energy performance preference = false
HWP package level request = false
HDC base registers = false
digital thermometer thresholds = 0x2 (2)
ACNT/MCNT supported performance measure = true
ACNT2 available = false
performance-energy bias capability = true
extended feature flags (7):
FSGSBASE instructions = true
IA32_TSC_ADJUST MSR supported = true
SGX: Software Guard Extensions supported = false
BMI instruction = true
HLE hardware lock elision = true
AVX2: advanced vector extensions 2 = true
FDP_EXCPTN_ONLY = false
SMEP supervisor mode exec protection = true
BMI2 instructions = true
enhanced REP MOVSB/STOSB = true
INVPCID instruction = true
RTM: restricted transactional memory = true
QM: quality of service monitoring = true
deprecated FPU CS/DS = true
intel memory protection extensions = false
PQE: platform quality of service enforce = true
AVX512F: AVX-512 foundation instructions = false
AVX512DQ: double & quadword instructions = false
RDSEED instruction = true
ADX instructions = true
SMAP: supervisor mode access prevention = true
AVX512IFMA: fused multiply add = false
CLFLUSHOPT instruction = false
CLWB instruction = false
Intel processor trace = true
AVX512PF: prefetch instructions = false
AVX512ER: exponent & reciprocal instrs = false
AVX512CD: conflict detection instrs = false
SHA instructions = false
AVX512BW: byte & word instructions = false
AVX512VL: vector length = false
PREFETCHWT1 = false
AVX512VBMI: vector byte manipulation = false
UMIP: user-mode instruction prevention = false
PKU protection keys for user-mode = false
OSPKE CR4.PKE and RDPKRU/WRPKRU = false
BNDLDX/BNDSTX MAWAU value in 64-bit mode = 0x0 (0)
RDPID: read processor D supported = false
SGX_LC: SGX launch config supported = false
AVX512_4VNNIW: neural network instrs = false
AVX512_4FMAPS: multiply acc single prec = false
Direct Cache Access Parameters (9):
PLATFORM_DCA_CAP MSR bits = 1
Architecture Performance Monitoring Features (0xa/eax):
version ID = 0x3 (3)
number of counters per logical processor = 0x4 (4)
bit width of counter = 0x30 (48)
length of EBX bit vector = 0x7 (7)
Architecture Performance Monitoring Features (0xa/ebx):
core cycle event not available = false
instruction retired event not available = false
reference cycles event not available = false
last-level cache ref event not available = false
last-level cache miss event not avail = false
branch inst retired event not available = false
branch mispred retired event not avail = false
Architecture Performance Monitoring Features (0xa/edx):
number of fixed counters = 0x3 (3)
bit width of fixed counters = 0x30 (48)
x2APIC features / processor topology (0xb):
--- level 0 (thread) ---
bits to shift APIC ID to get next = 0x1 (1)
logical processors at this level = 0x2 (2)
level number = 0x0 (0)
level type = thread (1)
extended APIC ID = 9
--- level 1 (core) ---
bits to shift APIC ID to get next = 0x4 (4)
logical processors at this level = 0x10 (16)
level number = 0x1 (1)
level type = core (2)
extended APIC ID = 9
XSAVE features (0xd/0):
XCR0 lower 32 bits valid bit field mask = 0x00000007
XCR0 upper 32 bits valid bit field mask = 0x00000000
XCR0 supported: x87 state = true
XCR0 supported: SSE state = true
XCR0 supported: AVX state = true
XCR0 supported: MPX BNDREGS = false
XCR0 supported: MPX BNDCSR = false
XCR0 supported: AVX-512 opmask = false
XCR0 supported: AVX-512 ZMM_Hi256 = false
XCR0 supported: AVX-512 Hi16_ZMM = false
IA32_XSS supported: PT state = false
XCR0 supported: PKRU state = false
bytes required by fields in XCR0 = 0x00000340 (832)
bytes required by XSAVE/XRSTOR area = 0x00000340 (832)
XSAVE features (0xd/1):
XSAVEOPT instruction = true
XSAVEC instruction = false
XGETBV instruction = false
XSAVES/XRSTORS instructions = false
SAVE area size in bytes = 0x00000000 (0)
IA32_XSS lower 32 bits valid bit field mask = 0x00000000
IA32_XSS upper 32 bits valid bit field mask = 0x00000000
AVX/YMM features (0xd/2):
AVX/YMM save state byte size = 0x00000100 (256)
AVX/YMM save state byte offset = 0x00000240 (576)
supported in IA32_XSS or XCR0 = XCR0 (user state)
64-byte alignment in compacted XSAVE = false
Quality of Service Monitoring Resource Type (0xf/0):
Maximum range of RMID = 63
supports L3 cache QoS monitoring = false
L3 Cache Quality of Service Monitoring (0xf/1):
Conversion factor from IA32_QM_CTR to bytes = 32768
Maximum range of RMID = 63
supports L3 occupancy monitoring = true
supports L3 total bandwidth monitoring = true
supports L3 local bandwidth monitoring = true
Resource Director Technology allocation (0x10/0):
L3 cache allocation technology supported = true
L2 cache allocation technology supported = false
L3 Cache Allocation Technology (0x10/1):
length of capacity bit mask - 1 = 0xb (11)
Bit-granular map of isolation/contention = 0x00000c00
infrequent updates of COS = true
code and data prioritization supported = false
highest COS number supported = 0xb (11)
0x00000011 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
SGX capability (0x12/0):
SGX1 supported = false
SGX2 supported = false
MISCSELECT.EXINFO supported: #PF & #GP = false
MaxEnclaveSize_Not64 (log2) = 0x0 (0)
MaxEnclaveSize_64 (log2) = 0x0 (0)
0x00000013 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000
Intel Processor Trace (0x14):
IA32_RTIT_CR3_MATCH is accessible = true
configurable PSB & cycle-accurate = false
IP & TraceStop filtering; PT preserve = false
MTC timing packet; suppress COFI-based = false
PTWRITE support = false
power event trace support = false
IA32_RTIT_CTL can enable tracing = true
ToPA can hold many output entries = false
single-range output scheme = false
output to trace transport = false
IP payloads have LIP values & CS = false
extended feature flags (0x80000001/edx):
SYSCALL and SYSRET instructions = true
execution disable = true
1-GB large page support = true
RDTSCP = true
64-bit extensions technology available = true
Intel feature flags (0x80000001/ecx):
LAHF/SAHF supported in 64-bit mode = true
LZCNT advanced bit manipulation = true
3DNow! PREFETCH/PREFETCHW instructions = true
brand = "Intel(R) Xeon(R) CPU D-1540 @ 2.00GHz"
L1 TLB/cache information: 2M/4M pages & L1 TLB (0x80000005/eax):
instruction # entries = 0x0 (0)
instruction associativity = 0x0 (0)
data # entries = 0x0 (0)
data associativity = 0x0 (0)
L1 TLB/cache information: 4K pages & L1 TLB (0x80000005/ebx):
instruction # entries = 0x0 (0)
instruction associativity = 0x0 (0)
data # entries = 0x0 (0)
data associativity = 0x0 (0)
L1 data cache information (0x80000005/ecx):
line size (bytes) = 0x0 (0)
lines per tag = 0x0 (0)
associativity = 0x0 (0)
size (KB) = 0x0 (0)
L1 instruction cache information (0x80000005/edx):
line size (bytes) = 0x0 (0)
lines per tag = 0x0 (0)
associativity = 0x0 (0)
size (KB) = 0x0 (0)
L2 TLB/cache information: 2M/4M pages & L2 TLB (0x80000006/eax):
instruction # entries = 0x0 (0)
instruction associativity = L2 off (0)
data # entries = 0x0 (0)
data associativity = L2 off (0)
L2 TLB/cache information: 4K pages & L2 TLB (0x80000006/ebx):
instruction # entries = 0x0 (0)
instruction associativity = L2 off (0)
data # entries = 0x0 (0)
data associativity = L2 off (0)
L2 unified cache information (0x80000006/ecx):
line size (bytes) = 0x40 (64)
lines per tag = 0x0 (0)
associativity = 8-way (6)
size (KB) = 0x100 (256)
L3 cache information (0x80000006/edx):
line size (bytes) = 0x0 (0)
lines per tag = 0x0 (0)
associativity = L2 off (0)
size (in 512KB units) = 0x0 (0)
Advanced Power Management Features (0x80000007/edx):
temperature sensing diode = false
frequency ID (FID) control = false
voltage ID (VID) control = false
thermal trip (TTP) = false
thermal monitor (TM) = false
software thermal control (STC) = false
100 MHz multiplier control = false
hardware P-State control = false
TscInvariant = true
Physical Address and Linear Address Size (0x80000008/eax):
maximum physical address bits = 0x2e (46)
maximum linear (virtual) address bits = 0x30 (48)
maximum guest physical address bits = 0x0 (0)
Logical CPU cores (0x80000008/ecx):
number of CPU cores - 1 = 0x0 (0)
ApicIdCoreIdSize = 0x0 (0)
(multi-processing synth): multi-core (c=8), hyper-threaded (t=2)
(multi-processing method): Intel leaf 0xb
(APIC widths synth): CORE_width=4 SMT_width=1
(APIC synth): PKG_ID=0 CORE_ID=4 SMT_ID=1
(synth) = Intel Xeon D-1500 (Broadwell-DE V1), 14nm
该系统是最新的：
# yum upgrade
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
* base: centos.mirror.colo-serv.net
* epel: mirror.steadfast.net
* extras: centos.mirror.colo-serv.net
* updates: centos.mirror.colo-serv.net
No packages marked for update
我觉得自己已经错过了一些重要的事情，但是现在我真的不知道可能会发生什么。这里发生了什么？如何使系统完全缓解？
我还在Fedora 27工作站，带有Core i7-3770 CPU的台式机和带有Core i7-7500U的笔记本电脑上看到了相同的行为。
4
我在RHEL7上看到了完全相同的行为。
—
自由报
系统上还有其他任何未决的更新吗？在我们的CentOS系统上，Linux固件补丁也是新的。（但显然也丢失了一些内容；在您所使用的补丁上也存在与禁用状态相同的问题）
—
Shane Madden
@ShaneMadden百胜报告
—
迈克尔·汉普顿
No packages marked for update。
然后我们在同一条船上，无赖。造成此问题的根本原因可能与我们尝试在Windows上激活修补程序时看到的情况相同，
—
Shane Madden
Windows OS support for branch target injection mitigation is disabled by absence of hardware support: True在完整补丁程序的系统上（在执行必要的注册表键启动激活补丁程序之后），我们看到的是-我认为这是因为Windows Update上尚未进行微码更新，但可能是两个操作系统都缺少相同的代码。
@ShaneMadden我假设我们将不得不去硬件供应商（在我们的例子中是Dell）来获取微代码/ BIOS更新。那不正确吗？微软会发行微代码更新吗？
—
Todd Wilcox
