Skip to contentSkip to conversation

KVM: Plan obsolescence of kernel allocated slots, paravirt mmu

PATCH/RFC Avi Kivity 2 participants 3 messages Jan 26, 2010 – Feb 11, 2010

Subsystems (2)
lore
Share & tools
lore

Avi Kivity

author
#0 lore raw

These features are unused by modern userspace and can go away. Paravirt mmu needs to stay a little longer for live migration.

---
 Documentation/feature-removal-schedule.txt |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)
Documentation/feature-removal-schedule.txt +23 -0
index 870d190..88ca110 100644
@@ -493,3 +493,26 @@ Why:	These two features use non-standard interfaces. There are the
 Who:	Corentin Chary <[email protected]>
 
 ----------------------------
+What:	KVM memory aliases support
+When:	July 2010
+Why:	Memory aliasing support is used for speeding up guest vga access
+	through the vga windows.
+
+	Modern userspace no longer uses this feature, so it's just bitrotted
+	code and can be removed with no impact.
+Who:	Avi Kivity <[email protected]>
+----------------------------
+What:	KVM kernel-allocated memory slots
+When:	July 2010
+Why:	Since 2.6.25, kvm supports user-allocated memory slots, which are
+	much more flexible than kernel-allocated slots.  All current userspace
+	supports the newer interface and this code can be removed with no
+	impact.
+Who:	Avi Kivity <[email protected]>
+----------------------------
+What:	KVM paravirt mmu host support
+When:	January 2011
+Why:	The paravirt mmu host support is slower than non-paravirt mmu, both
+	on newer and older hardware.  It is already not exposed to the guest,
+	and kept only for live migration purposes.
+Who:	Avi Kivity <[email protected]>
Signature · 1 line
1.6.5.3
#1 lore raw
Quoted 21 lines · Avi Kivity

These features are unused by modern userspace and can go away. Paravirt mmu needs to stay a little longer for live migration.

---
 Documentation/feature-removal-schedule.txt |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)
Documentation/feature-removal-schedule.txt +5 -0
index 870d190..88ca110 100644
@@ -493,3 +493,26 @@ Why:	These two features use non-standard interfaces. There are the
 Who:	Corentin Chary <[email protected]>
 
 ----------------------------
+What:	KVM memory aliases support
+When:	July 2010
+Why:	Memory aliasing support is used for speeding up guest vga access
+	through the vga windows.
+

Documentation/feature-removal-schedule.txt Why: These two features use non-standard interfaces. There are the · line 510

Quoted 10 lines
Documentation/feature-removal-schedule.txt +10 -0
+	Modern userspace no longer uses this feature, so it's just bitrotted
+	code and can be removed with no impact.
+Who:	Avi Kivity <[email protected]>
+----------------------------
+What:	KVM kernel-allocated memory slots
+When:	July 2010
+Why:	Since 2.6.25, kvm supports user-allocated memory slots, which are
+	much more flexible than kernel-allocated slots.  All current userspace
+	supports the newer interface and this code can be removed with no
+	impact.

Just a note: can block userspace usage but can't really remove code since there are in-kernel users (special purpose vmx pages).

Otherwise looks good to me.

Quoted 15 lines
Documentation/feature-removal-schedule.txt +8 -0
+Who:	Avi Kivity <[email protected]>
+----------------------------
+What:	KVM paravirt mmu host support
+When:	January 2011
+Why:	The paravirt mmu host support is slower than non-paravirt mmu, both
+	on newer and older hardware.  It is already not exposed to the guest,
+	and kept only for live migration purposes.
+Who:	Avi Kivity <[email protected]>
Signature · 6 lines
1.6.5.3

--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
author
#2 lore raw
Quoted 12 lines · Marcelo Tosatti
Quoted 12 lines

----------------------------

Documentation/feature-removal-schedule.txt +10 -0
+What:	KVM memory aliases support
+When:	July 2010
+Why:	Memory aliasing support is used for speeding up guest vga access
+	through the vga windows.
+
+	Modern userspace no longer uses this feature, so it's just bitrotted
+	code and can be removed with no impact.
+Who:	Avi Kivity<[email protected]>
+----------------------------
+What:	KVM kernel-allocated memory slots
Quoted 10 lines

Documentation/feature-removal-schedule.txt Why: These two features use non-standard interfaces. There are the · line 510

Quoted 6 lines
Documentation/feature-removal-schedule.txt +5 -0
+When:	July 2010
+Why:	Since 2.6.25, kvm supports user-allocated memory slots, which are
+	much more flexible than kernel-allocated slots.  All current userspace
+	supports the newer interface and this code can be removed with no
+	impact.

Just a note: can block userspace usage but can't really remove code since there are in-kernel users (special purpose vmx pages).

Hm, we can add a new ioctl to ask userspace for a gpa range, but require it to allocate the memory.

Quoted 2 lines

Otherwise looks good to me.

Okay - applying.

Signature · 1 line
error compiling committee.c: too many arguments to function