Thank you, Sean. I will revise the patch accordingly and submit a new version as well as update the description of kvm-intel.nested to reflect that it is enabled by default. On Wed, May 3, 2023 at 1:12 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > On Tue, May 02, 2023, Yan-Jie Wang wrote: > > The descriptions of certain KVM related kernel parameters can be > > ambiguous and confusing. They state 'Disable ...,' which implies that > > setting them to 1 would disable the associated features or options, > > when in fact the opposite is true. > > > > This commit addresses this issue by revising the descriptions of these > > parameters to make their intended behavior clear. > > Less wrong perhaps, but IMO the actual behavior is still not captured, and from > a certain perspective the existing "Disable" verbiage better reflects how/when > most users would actually want to explicitly set a param. > > Rather than commit one way or the other, what about reworking the descriptions > using this as a template? E.g. state that the param controls something, state > the default and use that to communicate that 1==enabled, and then, when appropriate, > clarify that KVM disables (or in some cases ignores) params if hardware doesn't > support the related feature(s). > > kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables, > a.k.a. Two-Dimensional Page Tables. Default is 1 > (enabled). Disabled by KVM if hardware lacks support > for EPT. > > > > > Signed-off-by: Yan-Jie Wang <yanjiewtw@xxxxxxxxx> > > --- > > Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++-------- > > 1 file changed, 8 insertions(+), 8 deletions(-) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index 9e5bab29685f..cc5abb3d54b9 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2552,10 +2552,10 @@ > > on the ratio, such that a page is zapped after 1 hour on average. > > > > kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM. > > Eh, I don't see any reason to have this one say "allow" instead of "enable/disable". > > > - Default is 1 (enabled) > > + Default is 1 (allow) > > > > - kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU) > > - for all guests. > > + kvm-amd.npt= [KVM,AMD] Enable nested paging (virtualized MMU) > > + for all guests on capable AMD chips. > > Default is 1 (enabled) if in 64-bit or 32-bit PAE mode. > > > > kvm-arm.mode= > > @@ -2602,12 +2602,12 @@ > > Format: <integer> > > Default: 5 > > > > - kvm-intel.ept= [KVM,Intel] Disable extended page tables > > + kvm-intel.ept= [KVM,Intel] Enable extended page tables > > (virtualized MMU) support on capable Intel chips. > > Default is 1 (enabled) > > > > kvm-intel.emulate_invalid_guest_state= > > - [KVM,Intel] Disable emulation of invalid guest state. > > + [KVM,Intel] Enable emulation of invalid guest state. > > Ignored if kvm-intel.enable_unrestricted_guest=1, as > > guest state is never invalid for unrestricted guests. > > This param doesn't apply to nested guests (L2), as KVM > > @@ -2615,7 +2615,7 @@ > > Default is 1 (enabled) > > > > kvm-intel.flexpriority= > > - [KVM,Intel] Disable FlexPriority feature (TPR shadow). > > + [KVM,Intel] Enable FlexPriority feature (TPR shadow). > > Default is 1 (enabled) > > > > kvm-intel.nested= > > @@ -2623,7 +2623,7 @@ > > Default is 0 (disabled) > > Heh, kvm-intel.nested has been enabled by default for quite some time. Can you > fix that up too? > > > > > kvm-intel.unrestricted_guest= > > - [KVM,Intel] Disable unrestricted guest feature > > + [KVM,Intel] Enable unrestricted guest feature > > (virtualized real and unpaged mode) on capable > > Intel chips. Default is 1 (enabled) > > > > @@ -2639,7 +2639,7 @@ > > > > Default is cond (do L1 cache flush in specific instances) > > > > - kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification > > + kvm-intel.vpid= [KVM,Intel] Enable Virtual Processor Identification > > feature (tagged TLBs) on capable Intel chips. > > Default is 1 (enabled) > > > > > > base-commit: 865fdb08197e657c59e74a35fa32362b12397f58 > > -- > > 2.34.1 > >
