Thank you Thomas. Wording issues understood and will post a new patch with updated subject.
Re goals: purpose is to expose feature bit with side effect of "ept_ad" in /proc/cpuinfo and is not necessarily related to VMX code. We are upstreaming some internal patches that we think would be generally useful and I will be careful from now on to remove any wording that is not publicly relevant. On Mon, Jul 30, 2018 at 3:12 PM Thomas Gleixner <t...@linutronix.de> wrote: > > 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
