1809开启retpoline

johnnyxz

源地址 Mitigating Spectre variant 2 with Retpoline on Windows

Updated March 5, 2019:   While the phased rollout is in progress, customers who would like to manually enable Retpoline on their machines can do so with the following registry configuration updates:



On Client SKUs:

    reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v FeatureSettingsOverride /t REG_DWORD /d 0x400
    reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v FeatureSettingsOverrideMask /t REG_DWORD /d 0x400
    Reboot

On Server SKUs:

    reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v FeatureSettingsOverride /t REG_DWORD /d 0x400
    reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management" /v FeatureSettingsOverrideMask /t REG_DWORD /d 0x401
    Reboot

Get-SpeculationControl PowerShell cmdlet can be used to verify Retpoline status. Here’s an example output showing Retpoline and import optimization enabled:

Speculation control settings for CVE-2017-5715 [branch target injection]
 
Hardware support for branch target injection mitigation is present: True  
Windows OS support for branch target injection mitigation is present: True
Windows OS support for branch target injection mitigation is enabled: True
…
BTIKernelRetpolineEnabled           : True
BTIKernelImportOptimizationEnabled  : True
...

Since Retpoline is a performance optimization for Spectre Variant 2, it requires that hardware and OS support for branch target injection to be present and enabled. Skylake and later generations of Intel processors are not compatible with Retpoline, so only Import Optimization will be enabled on these processors.

自由的云

感谢分享了。

ljk_huan

好快的速度啊

rubycon

18845 的键值与你这个不相同

lcydx

感谢分享了。

HFL045219

机   翻  截图

gaoyangbiao

没找到注册表路径 能不能写个完整的

jacklyl

Get-SpeculationControl : 无法将“Get-SpeculationControl”项识别为 cmdlet、函数、脚本文件或可运行程序的名称。请检查名称
的拼写，如果包括路径，请确保路径正确，然后再试一次。
所在位置 行:1 字符: 1
+ Get-SpeculationControl PowerShell cmdlet
+ ~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (Get-SpeculationControl:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

为什么修改注册表重启后Get-SpeculationControl PowerShell cmdlet显示以上内容？
17763.348

yalelynn

这意思是，1809默认关闭了retpoline？之前不是有人发帖说打了二月补丁就生效么？

惜_别

这玩意是什么，是那个减少CPU性能的老的还是新的那个性能影响减少到1的补丁

rubycon

gaoyangbiao 发表于 2019-3-6 11:52
没找到注册表路径 能不能写个完整的

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

jianbin11

感谢分享了。学习了

johnnyxz

jacklyl 发表于 2019-3-6 12:07
Get-SpeculationControl : 无法将“Get-SpeculationControl”项识别为 cmdlet、函数、脚本文件或可运行程序 ...

Install-Module -Name SpeculationControl
$SaveExecutionPolicy = Get-ExecutionPolicy
Set-ExecutionPolicy RemoteSigned -Scope Currentuser
Import-Module SpeculationControl
Get-SpeculationControlSettings
Set-ExecutionPolicy $SaveExecutionPolicy -Scope Currentuser

是这几条，依次运行

johnnyxz

yalelynn 发表于 2019-3-6 12:55
这意思是，1809默认关闭了retpoline？之前不是有人发帖说打了二月补丁就生效么？

1809二月补丁加入支持但是默认关闭，19H1默认开启

johnnyxz

简单来说就是HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management
下新建--DWORD-FeatureSettingsOverride及FeatureSettingsOverrideMask，值为400

johnnyxz

rubycon 发表于 2019-3-6 07:17
18845 的键值与你这个不相同

默认开启了？

johnnyxz

惜_别 发表于 2019-3-6 13:26
这玩意是什么，是那个减少CPU性能的老的还是新的那个性能影响减少到1的补丁

减少性能影响

wyhwrb

学习了，蟹蟹

rubycon

johnnyxz 发表于 2019-3-6 14:10
Install-Module -Name SpeculationControl
$SaveExecutionPolicy = Get-ExecutionPolicy
Set-Execution ...

多谢，学习了。

rubycon

johnnyxz 发表于 2019-3-6 14:13
默认开启了？

看新闻说，不支持 6 - 9 代 CPU，没有开启 retpoline