Messages in this thread | | | Date | Tue, 31 Jul 2018 00:12:09 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH] proc: added ept_ad flag to /proc/cpuinfo |
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On Mon, 30 Jul 2018, Peter Shier wrote:
> Subject: [PATCH] proc: added ept_ad flag to /proc/cpuinfo
The 'proc:' prefix is misleading here. x86/cpufeatures is the right choice. The /proc/cpuinfo display is a side effect.
Also please avoid 'added'. Changelogs should be written in imperative mood. Something like this:
x86/cpufeatures: Add EPT_AD feature bit
> The Intel Haswell architecture has an EPT feature whereby the access & > dirty bits in EPT entries are updated without taking a guest exit.
Why would this be Haswell specific?
Aside of that I don't see what this has to do with exits. From the SDM:
" * If bit 21 is read as 1, accessed and dirty flags for EPT are supported (see Section 28.2.4)"
And nothing in 28.2.4 says anything about exits. It's all about whether the feature is supported or not. If it is supported it can be enabled in EPTP.
> This patch adds the "ept_ad" flag to /proc/cpuinfo if this feature is > available.
See Documentation/process/submitting-patches.rst and search for 'This patch'.
The other question is why is this new feature bit not used in the VMX code? It needs to be checked to enable the AD bit in EPTP ....
Thanks,
tglx
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