Commit graph

112 commits

Author SHA1 Message Date
Avi Kivity
6ec8a856e4 KVM: Avoid calling smp_call_function_single() with interrupts disabled
When taking a cpu down, we need to hardware_disable() it.
Unfortunately, the CPU_DYING notifier is called with interrupts
disabled, which means we can't use smp_call_function_single().

Fortunately, the CPU_DYING notifier is always called on the dying cpu,
so we don't need to use the function at all and can simply call
hardware_disable() directly.

Tested-by: Paolo Ornati <ornati@fastwebnet.it>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-19 10:13:49 -07:00
Avi Kivity
4c981b43d7 KVM: Fix removal of nx capability from guest cpuid
Testing the wrong bit caused kvm not to disable nx on the guest when it is
disabled on the host (an mmu optimization relies on the nx bits being the
same in the guest and host).

This allows Windows to boot when nx is disabled on te host (e.g. when
host pae is disabled).

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-25 14:31:13 +03:00
Avi Kivity
7cfa4b0a43 Revert "KVM: Avoid useless memory write when possible"
This reverts commit a3c870bdce.  While it
does save useless updates, it (probably) defeats the fork detector, causing
a massive performance loss.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-25 14:30:56 +03:00
Rusty Russell
5e58cfe41c KVM: Fix unlikely kvm_create vs decache_vcpus_on_cpu race
We add the kvm to the vm_list before initializing the vcpu mutexes,
which can be mutex_trylock()'ed by decache_vcpus_on_cpu().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-25 14:29:34 +03:00
Avi Kivity
b0fcd903e6 KVM: Correctly handle writes crossing a page boundary
Writes that are contiguous in virtual memory may not be contiguous in
physical memory; so split writes that straddle a page boundary.

Thanks to Aurelien for reporting the bug, patient testing, and a fix
to this very patch.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-25 14:29:17 +03:00
Avi Kivity
35f3f28613 KVM: x86 emulator: implement rdmsr and wrmsr
Allow real-mode emulation of rdmsr and wrmsr.  This allows smp Windows to
boot, presumably for its sipi trampoline.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-20 20:16:29 +03:00
Avi Kivity
90cb0529dd KVM: Fix memory slot management functions for guest smp
The memory slot management functions were oriented against vcpu 0, where
they should be kvm-wide.  This causes hangs starting X on guest smp.

Fix by making the functions (and resultant tail in the mmu) non-vcpu-specific.
Unfortunately this reduces the efficiency of the mmu object cache a bit.  We
may have to revisit this later.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-20 20:16:29 +03:00
Avi Kivity
cec9ad279b KVM: Use CPU_DYING for disabling virtualization
Only at the CPU_DYING stage can we be sure that no user process will
be scheduled onto the cpu and oops when trying to use virtualization
extensions.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:51 +03:00
Avi Kivity
4267c41a45 KVM: Tune hotplug/suspend IPIs
The hotplug IPIs can be called from the cpu on which we are currently
running on, so use on_cpu().  Similarly, drop on_each_cpu() for the
suspend/resume callbacks, as we're in atomic context here and only one
cpu is up anyway.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:51 +03:00
Avi Kivity
1b6c016818 KVM: Keep track of which cpus have virtualization enabled
By keeping track of which cpus have virtualization enabled, we
prevent double-enable or double-disable during hotplug, which is a
very fatal oops.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:51 +03:00
Avi Kivity
e495606dd0 KVM: Clean up #includes
Remove unnecessary ones, and rearange the remaining in the standard order.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:49 +03:00
Avi Kivity
d6d2816849 KVM: Remove kvmfs in favor of the anonymous inodes source
kvm uses a pseudo filesystem, kvmfs, to generate inodes, a job that the
new anonymous inodes source does much better.

Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:49 +03:00
Luca Tettamanti
a3c870bdce KVM: Avoid useless memory write when possible
When writing to normal memory and the memory area is unchanged the write
can be safely skipped, avoiding the costly kvm_mmu_pte_write.

Signed-Off-By: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Eddie Dong
74906345ff KVM: Add support for in-kernel pio handlers
Useful for the PIC and PIT.

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Gregory Haskins
2eeb2e94eb KVM: Adds support for in-kernel mmio handlers
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:47 +03:00
Avi Kivity
d9e368d612 KVM: Flush remote tlbs when reducing shadow pte permissions
When a vcpu causes a shadow tlb entry to have reduced permissions, it
must also clear the tlb on remote vcpus.  We do that by:

- setting a bit on the vcpu that requests a tlb flush before the next entry
- if the vcpu is currently executing, we send an ipi to make sure it
  exits before we continue

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
39c3b86e5c KVM: Keep an upper bound of initialized vcpus
That way, we don't need to loop for KVM_MAX_VCPUS for a single vcpu
vm.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
d3bef15f84 KVM: Move duplicate halt handling code into kvm_main.c
Will soon have a thid user.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
120e9a453b KVM: Fix adding an smp virtual machine to the vm list
If we add the vm once per vcpu, we corrupt the list if the guest has
multiple vcpus.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Avi Kivity
7b53aa5650 KVM: Fix vcpu freeing for guest smp
A vcpu can pin up to four mmu shadow pages, which means the freeing
loop will never terminate.  Fix by first unpinning shadow pages on
all vcpus, then freeing shadow pages.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Nguyen Anh Quynh
313899477f KVM: Remove unnecessary initialization and checks in mark_page_dirty()
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Avi Kivity
d3d25b048b KVM: MMU: Use slab caches for shadow pages and their headers
Use slab caches instead of a simple custom list.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:43 +03:00
Eddie Dong
2cc51560ae KVM: VMX: Avoid saving and restoring msr_efer on lightweight vmexit
MSR_EFER.LME/LMA bits are automatically save/restored by VMX
hardware, KVM only needs to save NX/SCE bits at time of heavy
weight VM Exit. But clearing NX bits in host envirnment may
cause system hang if the host page table is using EXB bits,
thus we leave NX bits as it is. If Host NX=1 and guest NX=0, we
can do guest page table EXB bits check before inserting a shadow
pte (though no guest is expecting to see this kind of gp fault).
If host NX=0, we present guest no Execute-Disable feature to guest,
thus no host NX=0, guest NX=1 combination.

This patch reduces raw vmexit time by ~27%.

Me: fix compile warnings on i386.

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:42 +03:00
Matthew Gregan
2dc7094b56 KVM: Implement IA32_EBL_CR_POWERON msr
Attempting to boot the default 'bsd' kernel of OpenBSD 4.1 i386 in a guest
fails early in the kernel init inside p3_get_bus_clock while trying to read
the IA32_EBL_CR_POWERON MSR.  KVM logs an 'unhandled MSR' message and the
guest kernel faults.

This patch is sufficient to allow OpenBSD to boot, after which it seems to
run fine.  I'm not sure if this is the correct solution for dealing with
this particular MSR, but it works for me.

Signed-off-by: Matthew Gregan <kinetik@flim.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:40 +03:00
Avi Kivity
09072daf37 KVM: Unify kvm_mmu_pre_write() and kvm_mmu_post_write()
Instead of calling two functions and repeating expensive checks, call one
function and provide it with before/after information.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:38 +03:00
Avi Kivity
e6adf28365 KVM: Avoid saving and restoring some host CPU state on lightweight vmexit
Many msrs and the like will only be used by the host if we schedule() or
return to userspace.  Therefore, we avoid saving them if we handle the
exit within the kernel, and if a reschedule is not requested.

Based on a patch from Eddie Dong <eddie.dong@intel.com> with a couple of
fixes by me.

Signed-off-by: Yaozu(Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:38 +03:00
Avi Kivity
7702fd1f6f KVM: Prevent guest fpu state from leaking into the host
The lazy fpu changes did not take into account that some vmexit handlers
can sleep.  Move loading the guest state into the inner loop so that it
can be reloaded if necessary, and move loading the host state into
vmx_vcpu_put() so it can be performed whenever we relinquish the vcpu.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-06-15 12:30:59 +03:00
Alexey Dobriyan
e8edc6e03a Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.

This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
   getting them indirectly

Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
   they don't need sched.h
b) sched.h stops being dependency for significant number of files:
   on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
   after patch it's only 3744 (-8.3%).

Cross-compile tested on

	all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
	alpha alpha-up
	arm
	i386 i386-up i386-defconfig i386-allnoconfig
	ia64 ia64-up
	m68k
	mips
	parisc parisc-up
	powerpc powerpc-up
	s390 s390-up
	sparc sparc-up
	sparc64 sparc64-up
	um-x86_64
	x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig

as well as my two usual configs.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21 09:18:19 -07:00
Rafael J. Wysocki
8bb7844286 Add suspend-related notifications for CPU hotplug
Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress.  This
patch introduces such notifications and causes them to be used during
suspend and resume transitions.  It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).

[oleg@tv-sign.ru: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:56 -07:00
Avi Kivity
02c8320972 KVM: Don't require explicit indication of completion of mmio or pio
It is illegal not to return from a pio or mmio request without completing
it, as mmio or pio is an atomic operation.  Therefore, we can simplify
the userspace interface by avoiding the completion indication.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:32 +03:00
Avi Kivity
e7df56e4a0 KVM: Remove extraneous guest entry on mmio read
When emulating an mmio read, we actually emulate twice: once to determine
the physical address of the mmio, and, after we've exited to userspace to
get the mmio value, we emulate again to place the value in the result
register and update any flags.

But we don't really need to enter the guest again for that, only to take
an immediate vmexit.  So, if we detect that we're doing an mmio read,
emulate a single instruction before entering the guest again.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:32 +03:00
Anthony Liguori
25c4c2762e KVM: VMX: Properly shadow the CR0 register in the vcpu struct
Set all of the host mask bits for CR0 so that we can maintain a proper
shadow of CR0.  This exposes CR0.TS, paving the way for lazy fpu handling.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:31 +03:00
Avi Kivity
4c690a1e86 KVM: Allow passing 64-bit values to the emulated read/write API
This simplifies the API somewhat (by eliminating the special-case
cmpxchg8b on i386).

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:31 +03:00
Avi Kivity
1165f5fec1 KVM: Per-vcpu statistics
Make the exit statistics per-vcpu instead of global.  This gives a 3.5%
boost when running one virtual machine per core on my two socket dual core
(4 cores total) machine.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:30 +03:00
Yaozu Dong
3fca036530 KVM: VMX: Avoid unnecessary vcpu_load()/vcpu_put() cycles
By checking if a reschedule is needed, we avoid dropping the vcpu.

[With changes by me, based on Anthony Liguori's observations]

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:30 +03:00
Avi Kivity
c9047f5333 KVM: Handle guest page faults when emulating mmio
Usually, guest page faults are detected by the kvm page fault handler,
which detects if they are shadow faults, mmio faults, pagetable faults,
or normal guest page faults.

However, in ceratin circumstances, we can detect a page fault much later.
One of these events is the following combination:

- A two memory operand instruction (e.g. movsb) is executed.
- The first operand is in mmio space (which is the fault reported to kvm)
- The second operand is in an ummaped address (e.g. a guest page fault)

The Windows 2000 installer does such an access, an promptly hangs.  Fix
by adding the missing page fault injection on that path.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:29 +03:00
Avi Kivity
b5a33a7572 KVM: Use slab caches to allocate mmu data structures
Better leak detection, statistics, memory use, speed -- goodness all
around.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:29 +03:00
Avi Kivity
d917a6b92d KVM: Initialize cr0 to indicate an fpu is present
Solaris panics if it sees a cpu with no fpu, and it seems to rely on this
bit.  Closes sourceforge bug 1698920.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:29 +03:00
Avi Kivity
b8836737d9 KVM: Add fpu get/set operations
These are really helpful when migrating an floating point app to another
machine.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:28 +03:00
Avi Kivity
e8207547d2 KVM: Add physical memory aliasing feature
With this, we can specify that accesses to one physical memory range will
be remapped to another.  This is useful for the vga window at 0xa0000 which
is used as a movable window into the (much larger) framebuffer.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:28 +03:00
Avi Kivity
954bbbc236 KVM: Simply gfn_to_page()
Mapping a guest page to a host page is a common operation.  Currently,
one has first to find the memory slot where the page belongs (gfn_to_memslot),
then locate the page itself (gfn_to_page()).

This is clumsy, and also won't work well with memory aliases.  So simplify
gfn_to_page() not to require memory slot translation first, and instead do it
internally.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:28 +03:00
Sergey Kiselev
0e5bf0d0e4 KVM: Handle writes to MCG_STATUS msr
Some older (~2.6.7) kernels write MCG_STATUS register during kernel
boot (mce_clear_all() function, called from mce_init()). It's not
currently handled by kvm and will cause it to inject a GPF.
Following patch adds a "nop" handler for this.

Signed-off-by: Sergey Kiselev <sergey.kiselev@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:26 +03:00
Avi Kivity
024aa1c02f KVM: Modify guest segments after potentially switching modes
The SET_SREGS ioctl modifies both cr0.pe (real mode/protected mode) and
guest segment registers.  Since segment handling is modified by the mode on
Intel procesors, update the segment registers after the mode switch has taken
place.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:26 +03:00
Avi Kivity
f6528b03f1 KVM: Remove set_cr0_no_modeswitch() arch op
set_cr0_no_modeswitch() was a hack to avoid corrupting segment registers.
As we now cache the protected mode values on entry to real mode, this
isn't an issue anymore, and it interferes with reboot (which usually _is_
a modeswitch).

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:25 +03:00
Avi Kivity
039576c03c KVM: Avoid guest virtual addresses in string pio userspace interface
The current string pio interface communicates using guest virtual addresses,
relying on userspace to translate addresses and to check permissions.  This
interface cannot fully support guest smp, as the check needs to take into
account two pages at one in case an unaligned string transfer straddles a
page boundary.

Change the interface not to communicate guest addresses at all; instead use
a buffer page (mmaped by userspace) and do transfers there.  The kernel
manages the virtual to physical translation and can perform the checks
atomically by taking the appropriate locks.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:25 +03:00
Avi Kivity
f0fe510864 KVM: Future-proof argument-less ioctls
Some ioctls ignore their arguments.  By requiring them to be zero now,
we allow a nonzero value to have some special meaning in the future.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:25 +03:00
Avi Kivity
07c45a366d KVM: Allow kernel to select size of mmap() buffer
This allows us to store offsets in the kernel/user kvm_run area, and be
sure that userspace has them mapped.  As offsets can be outside the
kvm_run struct, userspace has no way of knowing how much to mmap.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:24 +03:00
Avi Kivity
1961d276c8 KVM: Add guest mode signal mask
Allow a special signal mask to be used while executing in guest mode.  This
allows signals to be used to interrupt a vcpu without requiring signal
delivery to a userspace handler, which is quite expensive.  Userspace still
receives -EINTR and can get the signal via sigwait().

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:24 +03:00
Avi Kivity
8eb7d334bd KVM: Fold kvm_run::exit_type into kvm_run::exit_reason
Currently, userspace is told about the nature of the last exit from the
guest using two fields, exit_type and exit_reason, where exit_type has
just two enumerations (and no need for more).  So fold exit_type into
exit_reason, reducing the complexity of determining what really happened.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:24 +03:00
Avi Kivity
b4e63f560b KVM: Allow userspace to process hypercalls which have no kernel handler
This is useful for paravirtualized graphics devices, for example.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03 10:52:24 +03:00