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: NAvi Kivity <avi@qumranet.com>

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: NAvi Kivity <avi@qumranet.com>

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: NAvi Kivity <avi@qumranet.com>

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: NAvi Kivity <avi@qumranet.com>

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: NAvi Kivity <avi@qumranet.com>

This is useful for paravirtualized graphics devices, for example.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

We no longer emulate single instructions in userspace.  Instead, we service
mmio or pio requests.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

KVM used to handle cpuid by letting userspace decide what values to
return to the guest.  We now handle cpuid completely in the kernel.  We
still let userspace decide which values the guest will see by having
userspace set up the value table beforehand (this is necessary to allow
management software to set the cpu features to the least common denominator,
so that live migration can work).

The motivation for the change is that kvm kernel code can be impacted by
cpuid features, for example the x86 emulator.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Currently when passing the a PIO emulation request to userspace, we
rely on userspace updating %rax (on 'in' instructions) and %rsi/%rdi/%rcx
(on string instructions).  This (a) requires two extra ioctls for getting
and setting the registers and (b) is unfriendly to non-x86 archs, when
they get kvm ports.

So fix by doing the register fixups in the kernel and passing to userspace
only an abstract description of the PIO to be done.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Instead of passing a 'struct kvm_run' back and forth between the kernel and
userspace, allocate a page and allow the user to mmap() it.  This reduces
needless copying and makes the interface expandable by providing lots of
free space.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Use the minor number (232) allocated to kvm by lanana.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The hypercall code mixes up the ->cache_regs() and ->decache_regs()
callbacks, resulting in guest register corruption.
Signed-off-by: NDor Laor <dor.laor@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Otherwise, the core module thinks the arch module is loaded, and won't
let you reload it after you've fixed the bug.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Use the standard magic.h for kvmfs.

Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

A bogus 'return r' can cause an otherwise successful module load to fail.
This both denies users the use of kvm, and it also denies them the use of
their machine, as it leaves a filesystem registered with its callbacks
pointing into now-freed module memory.

Fix by returning a zero like a good module.

Thanks to Richard Lucassen <mailinglists@lucassen.org> (?) for reporting
the problem and for providing access to a machine which exhibited it.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Enabling dirty page logging is done using KVM_SET_MEMORY_REGION ioctl.
If the memory region already exists, we need to remove write accesses,
so writes will be caught, and dirty pages will be logged.
Signed-off-by: NUri Lublin <uril@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

To be called from kvm_vm_ioctl_set_memory_region()
Signed-off-by: NUri Lublin <uril@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Since dirty_bitmap is an unsigned long array, the alignment and size need
to take that into account.
Signed-off-by: NUri Lublin <uril@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

A few places where we modify guest memory fail to call mark_page_dirty(),
causing live migration to fail.  This adds the missing calls.
Signed-off-by: NUri Lublin <uril@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Allocate a distinct inode for every vcpu in a VM.  This has the following
benefits:

 - the filp cachelines are no longer bounced when f_count is incremented on
   every ioctl()
 - the API and internal code are distinctly clearer; for example, on the
   KVM_GET_REGS ioctl, there is no need to copy the vcpu number from
   userspace and then copy the registers back; the vcpu identity is derived
   from the fd used to make the call

Right now the performance benefits are completely theoretical since (a) we
don't support more than one vcpu per VM and (b) virtualization hardware
inefficiencies completely everwhelm any cacheline bouncing effects.  But
both of these will change, and we need to prepare the API today.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

In preparation of some hacking.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This reflects the changed scope, from device-wide to single vm (previously
every device open created a virtual machine).
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This avoids having filp->f_op and the corresponding inode->i_fop different,
which is a little unorthodox.

The ioctl list is split into two: global kvm ioctls and per-vm ioctls.  A new
ioctl, KVM_CREATE_VM, is used to create VMs and return the VM fd.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The kvmfs inodes will represent virtual machines and vcpus, as necessary,
reducing cacheline bouncing due to inodes and filps being shared.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

This adds a special MSR based hypercall API to KVM. This is to be
used by paravirtual kernels and virtual drivers.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Besides using an established api, this allows using kvm in older kernels.
Signed-off-by: NMarkus Rechberger <markus.rechberger@amd.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

This gives it more chances of surviving suspend.
Signed-off-by: NJeremy Katz <katzj@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Add the necessary callbacks to suspend and resume a host running kvm.  This is
just a repeat of the cpu hotplug/unplug work.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On hotplug, we execute the hardware extension enable sequence.  On unplug, we
decache any vcpus that last ran on the exiting cpu, and execute the hardware
extension disable sequence.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This will allow us to iterate over all vcpus and see which cpus they are
running on.

[akpm@osdl.org: use standard (ugly) initialisers]
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

vcpu_load() can return NULL and it sometimes does in failure paths (for
example when the userspace ABI version is too old) - causing a preemption
count underflow in the ->vcpu_free() later on.  So check for NULL.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We report the value of cr8 to userspace on an exit.  Also let userspace change
cr8 when we re-enter the guest.  The lets 64-bit guest code maintain the tpr
correctly.

Thanks for Yaniv Kamay for the idea.
Signed-off-by: NDor Laor <dor.laor@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This allows netbsd 3.1 i386 to get further along installing.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This makes the vmwrite errors on vm shutdown go away.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>