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Currently, the set_lazy_mode pv_op is overloaded with 5 functions:
1. enter lazy cpu mode
2. leave lazy cpu mode
3. enter lazy mmu mode
4. leave lazy mmu mode
5. flush pending batched operations
This complicates each paravirt backend, since it needs to deal with
all the possible state transitions, handling flushing, etc. In
particular, flushing is quite distinct from the other 4 functions, and
seems to just cause complication.
This patch removes the set_lazy_mode operation, and adds "enter" and
"leave" lazy mode operations on mmu_ops and cpu_ops. All the logic
associated with enter and leaving lazy states is now in common code
(basically BUG_ONs to make sure that no mode is current when entering
a lazy mode, and make sure that the mode is current when leaving).
Also, flush is handled in a common way, by simply leaving and
re-entering the lazy mode.
The result is that the Xen, lguest and VMI lazy mode implementations
are much simpler.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Zach Amsden <zach@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Anthony Liguory <aliguori@us.ibm.com>
Cc: "Glauber de Oliveira Costa" <glommer@gmail.com>
Cc: Jun Nakajima <jun.nakajima@intel.com>
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This patch refactors the paravirt_ops structure into groups of
functionally related ops:
pv_info - random info, rather than function entrypoints
pv_init_ops - functions used at boot time (some for module_init too)
pv_misc_ops - lazy mode, which didn't fit well anywhere else
pv_time_ops - time-related functions
pv_cpu_ops - various privileged instruction ops
pv_irq_ops - operations for managing interrupt state
pv_apic_ops - APIC operations
pv_mmu_ops - operations for managing pagetables
There are several motivations for this:
1. Some of these ops will be general to all x86, and some will be
i386/x86-64 specific. This makes it easier to share common stuff
while allowing separate implementations where needed.
2. At the moment we must export all of paravirt_ops, but modules only
need selected parts of it. This allows us to export on a case by case
basis (and also choose which export license we want to apply).
3. Functional groupings make things a bit more readable.
Struct paravirt_ops is now only used as a template to generate
patch-site identifiers, and to extract function pointers for inserting
into jmp/calls when patching. It is only instantiated when needed.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Cc: Zach Amsden <zach@vmware.com>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Anthony Liguory <aliguori@us.ibm.com>
Cc: "Glauber de Oliveira Costa" <glommer@gmail.com>
Cc: Jun Nakajima <jun.nakajima@intel.com>
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The assembly templates for lguest guest patching are in the .init.text
section. This means that modules get patched with "cc cc cc cc" or similar
junk.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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One of the very first things lguest_init() does is a memcpy. On
Athlon/Duron/K7 or CyrixIII/VIA-C3 or Geode GX/LX, this tries to use
MMX.
memcpy -> _mmx_memcpy -> kernel_fpu_begin -> clts -> paravirt_ops.clts
But we haven't set paravirt_ops.clts yet, so we do the native version
and crash. The simplest solution is to use __memcpy.
Thanks to Michael Rasenberger for the bug report.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If the stack pointer is 0xc057a000, then the first stack page is at
0xc0579000 (the stack pointer is decremented before use). Not
calculating this correctly caused guests with CONFIG_DEBUG_PAGEALLOC=y
to be killed with a "bad stack page" message: the initial kernel stack
was just proceeding the .smp_locks section which
CONFIG_DEBUG_PAGEALLOC marks read-only when freeing.
Thanks to Frederik Deweerdt for the bug report!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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It uses get_futex_key().
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit 19d36ccdc34f5ed444f8a6af0cbfdb6790eb1177 "x86: Fix alternatives
and kprobes to remap write-protected kernel text" uses code which is
being patched for patching.
In particular, paravirt_ops does patching in two stages: first it
calls paravirt_ops.patch, then it fills any remaining instructions
with nop_out(). nop_out calls text_poke() which calls
lookup_address() which calls pgd_val() (aka paravirt_ops.pgd_val):
that call site is one of the places we patch.
If we always do patching as one single call to text_poke(), we only
need make sure we're not patching the memcpy in text_poke itself.
This means the prototype to paravirt_ops.patch needs to change, to
marshal the new code into a buffer rather than patching in place as it
does now. It also means all patching goes through text_poke(), which
is known to be safe (apply_alternatives is also changed to make a
single patch).
AK: fix compilation on x86-64 (bad rusty!)
AK: fix boot on x86-64 (sigh)
AK: merged with other patches
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Files using bits from paravirt.h should explicitly include it rather than
relying on it being pulled in by something else.
Signed-off-by: Jes Sorensen <jes@sgi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If a Guest makes hypercall which sets a GDT entry to not present, we
currently set any segment registers using that GDT entry to 0.
Unfortunately, this is not sufficient: there are other ways of
altering GDT entries which will cause a fault.
The correct solution to do what Linux does: let them set any GDT value
they want and handle the #GP when popping causes a fault. This has
the added benefit of making our Switcher slightly more robust in the
case of any other bugs which cause it to fault.
We kill the Guest if it causes a fault in the Switcher: it's the
Guest's responsibility to make sure it's not using segments when it
changes them.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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lguest uses a host-supplied wallclock-based clocksource when the TSC
is not reliable. As this is already in nanoseconds, I naively used a
multiplier of 1 and a shift of 0.
But update_wall_time() in its infinite wisdom decides to adjust the
clock a little (where does it think it's getting a more accurate time
from?)
It will happily tweak the multiplier... to 0, then -1.
So the "fix" is to use a shift of 22 like everyone else, and a
multiplier of 1 << 22.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Lguest drivers need to default to "Y" otherwise they're never selected
for new builds. (We don't bother prompting, because they're less than
4k combined, and implied by selecting lguest support).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Gabriel C reports lguest doesn't compile with CONFIG_BLOCK=n. Fix this
by introducing a config var for the block device, which depends on
LGUEST && BLOCK. Do the same for the net driver, rather then depending
gratuitously on CONFIG_NET.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Gabriel C <nix.or.die@googlemail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A non-periodic clock_event_device and the "jiffies" clock don't mix well:
tick_handle_periodic() can go into an infinite loop.
Currently lguest guests use the jiffies clock when the TSC is
unusable. Instead, make the Host write the current time into the lguest
page on every interrupt. This doesn't cost much but is more precise
and at least as accurate as the jiffies clock. It also gets rid of
the GET_WALLCLOCK hypercall.
Also, delay setting sched_clock until our clock is set up, otherwise
the early printk timestamps can go backwards (not harmful, just ugly).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jason Yeh sent his crashing .config: bzImages made with
CONFIG_RELOCATABLE=y put the relocs where the BSS is expected, and we
crash with unusual results such as:
lguest: unhandled trap 14 at 0xc0122ae1 (0xa9)
Relying on BSS being zero was merely laziness on my part, and
unfortunately, lguest doesn't go through the normal startup path (which
does this in asm).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Documentation: The FIXMEs
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Documentation: The Switcher
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Documentation: The Host
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Documentation: The Launcher
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Documentation: The Drivers
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Documentation: The Guest
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The netfilter code had very good documentation: the Netfilter Hacking HOWTO.
Noone ever read it.
So this time I'm trying something different, using a bit of Knuthiness.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We need to make sure, that the clockevent devices are resumed, before
the tick is resumed. The current resume logic does not guarantee this.
Add CLOCK_EVT_MODE_RESUME and call the set mode functions of the clock
event devices before resuming the tick / oneshot functionality.
Fixup the existing users.
Thanks to Nigel Cunningham for tracking down a long standing thinko,
which affected the jinxed VAIO.
[akpm@linux-foundation.org: xen build fix]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Guests currently use the default scheduler clock: this means they
always use jiffies even if TSC is actually available. It doesn't make
any noticeable difference here, but it's a better thing to do.
Also remove commented-out asm/sched-clock.h from -mm tree.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The sense of the IF bit is backwards in the host interrupt handling.
This means we always save "IF=1" on the stack when injecting an
interrupt. It turns out this is almost always correct (unless the
guest is taking a page fault in an interrupt due to an unpopulated
vmalloc mapping), so went unnoticed.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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It's void __user *, not void * __user...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is the Kconfig and Makefile to allow lguest to actually be
compiled.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is the code for the "lg.ko" module, which allows lguest guests to
be launched.
[akpm@linux-foundation.org: update for futex-new-private-futexes]
[akpm@linux-foundation.org: build fix]
[jmorris@namei.org: lguest: use hrtimers]
[akpm@linux-foundation.org: x86_64 build fix]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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lguest is a simple hypervisor for Linux on Linux. Unlike kvm it doesn't need
VT/SVM hardware. Unlike Xen it's simply "modprobe and go". Unlike both, it's
5000 lines and self-contained.
Performance is ok, but not great (-30% on kernel compile). But given its
hackability, I expect this to improve, along with the paravirt_ops code which
it supplies a complete example for. There's also a 64-bit version being
worked on and other craziness.
But most of all, lguest is awesome fun! Too much of the kernel is a big ball
of hair. lguest is simple enough to dive into and hack, plus has some warts
which scream "fork me!".
This patch:
This is the code and headers required to make an i386 kernel an lguest guest.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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