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Date: Mon, 28 Sep 2009 17:45:07 -0700 From: Alok Kataria <akataria@...are.com> To: Gerd Hoffmann <kraxel@...hat.com> Cc: Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>, "H. Peter Anvin" <hpa@...or.com>, the arch/x86 maintainers <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>, Jeremy Fitzhardinge <jeremy@...p.org>, Chris Wright <chrisw@...s-sol.org>, Rusty Russell <rusty@...tcorp.com.au>, "virtualization@...ts.osdl.org" <virtualization@...ts.osdl.org>, Greg KH <greg@...ah.com>, Linus Torvalds <torvalds@...ux-foundation.org>, Andrew Morton <akpm@...ux-foundation.org> Subject: Re: Paravirtualization on VMware's Platform [VMI]. On Wed, 2009-09-23 at 00:29 -0700, Gerd Hoffmann wrote: > On 09/22/09 21:30, Alok Kataria wrote: > > Hi Ingo, > > > > On Sun, 2009-09-20 at 00:42 -0700, Ingo Molnar wrote: > > > >> > >> The thing is, the overwhelming majority of vmware users dont benefit > >> from hardware features like nested page tables yet. So this needs to be > >> done _way_ more carefully, with a proper sunset period of a couple of > >> kernel cycles. > > > > I am fine with that too. Below is a patch which adds notes in > > feature-removal-schedule.txt, I have marked it for removal from 2.6.34. > > Please consider this patch for 2.6.32. > > Hmm. Given that you are talking about vmi not being supported any more > in *future* products, there is a huge installed base with vmi support > available, right? I don't think we should zap the code that quickly. Yep, hpa too raised the same issue, I spoke to him during LPC and we decided that 2.6.37 will be the right time frame for removal of this code. For now I have just added some text in the feature-removal file and disabled VMI by default in the Kconfig, the reason that needs to be done is because "Live Migration" of a VMI enabled VM to future products which don't support VMI will not work, so its important that newer distros keep this disabled, if they want seamless migration that is. > > > config VMI > > - bool "VMI Guest support" > > - select PARAVIRT > > - depends on X86_32 > > + bool "VMI Guest support [will be deprecated soon]" > > + default n > > + depends on X86_32&& PARAVIRT > > ---help--- > > VMI provides a paravirtualized interface to the VMware ESX server > > (it could be used by other hypervisors in theory too, but is not > > at the moment), by linking the kernel to a GPL-ed ROM module > > provided by the hypervisor. > > + VMware has started a phased retirement of this feature from there > > + products. Please see feature-removal-schedule.txt for details. > > How about adding version numbers here? i.e. latest versions with vmi > support are workstation x.y, ... > > So people can easily figure whenever it makes sense to turn this on for > their environment. Okay, have added that text too. Thanks for your comments. Ingo/hpa, please consider the patch below for tip. -- Mark VMI for deprecation in feature-removal-schedule.txt. From: Alok N Kataria <akataria@...are.com> Add text in feature-removal.txt and also modify Kconfig to disable vmi by default. --- Documentation/feature-removal-schedule.txt | 30 ++++++++++++++++++++++++++++ arch/x86/Kconfig | 13 +++++++++--- 2 files changed, 40 insertions(+), 3 deletions(-) diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index fa75220..0271f37 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -459,3 +459,33 @@ Why: OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR will also allow making ALSA OSS emulation independent of sound_core. The dependency will be broken then too. Who: Tejun Heo <tj@...nel.org> + +---------------------------- + +What: Support for VMware's guest paravirtuliazation technique [VMI] will be + dropped. +When: 2.6.37 or earlier. +Why: With the recent innovations in CPU hardware acceleration technologies + from Intel and AMD, VMware ran a few experiments to compare these + techniques to guest paravirtualization technique on VMware's platform. + These hardware assisted virtualization techniques have outperformed the + performance benefits provided by VMI in most of the workloads. VMware + expects that these hardware features will be ubiquitous in a couple of + years, as a result, VMware has started a phased retirement of this + feature from the hypervisor. We will be removing this feature from the + Kernel too. Right now we are targeting 2.6.37 but can retire earlier if + technical reasons ( read opportunity to remove major chunk of pvops) + arise. + + Please note that VMI has always been an optimization and non-VMI kernels + still work fine on VMware's platform. + Latest versions of VMware's product which support VMI are, + Workstation 7.0 and VSphere 4.0 on ESX side, future maintainence + releases for these products will continue supporting VMI. + + For more details about VMI retirement take a look at this, + http://blogs.vmware.com/guestosguide/2009/09/vmi-retirement.html + +Who: Alok N Kataria <akataria@...are.com> + +---------------------------- diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index e214f45..84fd47c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -485,14 +485,21 @@ if PARAVIRT_GUEST source "arch/x86/xen/Kconfig" config VMI - bool "VMI Guest support" - select PARAVIRT - depends on X86_32 + bool "VMI Guest support [will be deprecated soon]" + default n + depends on X86_32 && PARAVIRT ---help--- VMI provides a paravirtualized interface to the VMware ESX server (it could be used by other hypervisors in theory too, but is not at the moment), by linking the kernel to a GPL-ed ROM module provided by the hypervisor. + As of September 2009, VMware has started a phased retirement of this + feature from VMware's products. Please see + feature-removal-schedule.txt for details. + If you are planning to enable this option, please note that you + cannot live migrate a VMI enabled VM to a future VMware product, + which doesn't support VMI. So if you expect your kernel to seamlessly + migrate to newer VMware products, keep this disabled. config KVM_CLOCK bool "KVM paravirtualized clock" -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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