On Mon, Dec 10, 2018 at 06:08:43PM -0200, Eduardo Habkost wrote: > On Mon, Dec 10, 2018 at 08:42:58PM +0100, Borislav Petkov wrote: > > On Mon, Dec 10, 2018 at 05:06:00PM -0200, Eduardo Habkost wrote: > > > I mean documenting it. We already have code that will print > > > warnings if a feature isn't available. > > > > > > See my previous attempt to document the minimum kernel version > > > at <https://www.mail-archive.com/qemu-devel@xxxxxxxxxx/msg486559.html>. > > > > Something like this? > > > > I still have no clue how to add RDTSCP on pc-*-4.0 and newer. > > qemu.git master have no PC_COMPAT_3_1 and pc-*-4.0 machine-types > yet. I've sent another reply with additional pointers. > > > > > Thx. > > > > --- > > diff --git a/qemu-doc.texi b/qemu-doc.texi > > index f7ad1dfe4b69..913b2ef68d54 100644 > > --- a/qemu-doc.texi > > +++ b/qemu-doc.texi > > @@ -37,6 +37,7 @@ > > * QEMU System emulator for non PC targets:: > > * QEMU Guest Agent:: > > * QEMU User space emulator:: > > +* System requirements:: > > * Implementation notes:: > > * Deprecated features:: > > * Supported build platforms:: > > @@ -2813,6 +2814,13 @@ Act as if the host page size was 'pagesize' bytes > > Run the emulation in single step mode. > > @end table > > > > +@node System requirements > > +@chapter System requirements > > + > > +@section KVM kernel module > > + > > +On x86_64 hosts, the default set of CPU features enabled by the KVM accelerator > > +require the host to be running Linux v4.5 or newer. > > > > Sounds good, but it would be nice to document what exactly makes > Linux 4.5+ necessary. e.g.: > > | On x86_64 hosts, it is recommended to run Linux 4.5 or newer on > | the host when using the KVM accelerator. > | > | The Opteron_G2, OpteronG3, Opteron_G4, and Opteron_G5 CPU > | models require KVM support for RDTSCP, which was added on > | Linux 4.5. > > I'm CCing some people who may help review English grammar and > style. Note that QEMU has a declared supported platform list which is used to set the minimum software versions required. https://qemu.weilnetz.de/doc/qemu-doc.html#Linux-OS Based on that policy, the Linux distros we aim to support have the following kernel versions: - Debian Jessie: 4.5 - Debian Stretch: 4.5 - RHEL-7: 3.10 - Ubuntu LTS (Xenial): 4.5 - OpenSUSE Leap 15: 4.12.14 So we can't require Linux 4.5 as a minimum version at this time. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
