Re: Paravirtualization on VMware's Platform [VMI].
From: Alok Kataria
Date: Mon Sep 28 2009 - 23:00:44 EST
On Mon, 2009-09-28 at 19:25 -0700, H. Peter Anvin wrote:
> On 09/28/2009 05:45 PM, Alok Kataria wrote:
> > + bool "VMI Guest support [will be deprecated soon]"
> > + default n
>
> This is incorrect use of the word "deprecated"... it's *already*
> deprecated (a word which pretty much means the opposite of "recommended".)
>
> As far as "default n" is concerned... this is usually not necessary; "n"
> is the default unless anything else is specified.
How about this ? Thanks.
--
Mark VMI for removal in feature-removal-schedule.txt.
From: Alok N Kataria <akataria@xxxxxxxxxx>
Add text in feature-removal.txt and also modify Kconfig to disable
vmi by default.
---
Documentation/feature-removal-schedule.txt | 30 ++++++++++++++++++++++++++++
arch/x86/Kconfig | 12 ++++++++---
2 files changed, 39 insertions(+), 3 deletions(-)
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 89a47b5..d24c1af 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -451,3 +451,33 @@ 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@xxxxxxxxxx>
+
+----------------------------
+
+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@xxxxxxxxxx>
+
+----------------------------
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f777aaf..44c1660 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -496,14 +496,20 @@ if PARAVIRT_GUEST
source "arch/x86/xen/Kconfig"
config VMI
- bool "VMI Guest support"
- select PARAVIRT
- depends on X86_32
+ bool "VMI Guest support [deprecated]"
+ 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"
--
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