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>

When auditing a 32-bit guest on a 64-bit host, sign extension of the page
table directory pointer table index caused bogus addresses to be shown on
audit errors.

Fix by declaring the index unsigned.
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>

Instead of twiddling the rip registers directly, use the
skip_emulated_instruction() function to do that for us.
Signed-off-by: NDor Laor <dor.laor@qumranet.com>
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>

Nonpae guest pdes are shadowed by two pae ptes, so we double the offset
twice: once to account for the pte size difference, and once because we
need to shadow pdes for a single guest pde.

But when writing to the upper guest pde we also need to truncate the
lower bits, otherwise the multiply shifts these bits into the pde index
and causes an access to the wrong shadow pde.  If we're at the end of the
page (accessing the very last guest pde) we can even overflow into the
next host page and oops.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

failed VM entry on VMX might still change %fs or %gs, thus make sure
that KVM always reloads the segment selectors. This is crutial on both
x86 and x86_64: x86 has __KERNEL_PDA in %fs on which things like
'current' depends and x86_64 has 0 there and needs MSR_GS_BASE to work.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Intel virtualization extensions do not support virtualizing real mode.  So
kvm uses virtualized vm86 mode to run real mode code.  Unfortunately, this
virtualized vm86 mode does not support the so called "big real" mode, where
the segment selector and base do not agree with each other according to the
real mode rules (base == selector << 4).

To work around this, kvm checks whether a selector/base pair violates the
virtualized vm86 rules, and if so, forces it into conformance.  On a
transition back to protected mode, if we see that the guest did not touch
a forced segment, we restore it back to the original protected mode value.

This pile of hacks breaks down if the gdt has changed in real mode, as it
can cause a segment selector to point to a system descriptor instead of a
normal data segment.  In fact, this happens with the Windows bootloader
and the qemu acpi bios, where a protected mode memcpy routine issues an
innocent 'pop %es' and traps on an attempt to load a system descriptor.

"Fix" by checking if the to-be-restored selector points at a system segment,
and if so, coercing it into a normal data segment.  The long term solution,
of course, is to abandon vm86 mode and use emulation for big real mode.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

PAGE_MASK is an unsigned long, so using it to mask physical addresses on
i386 (which are 64-bit wide) leads to truncation.  This can result in
page->private of unrelated memory pages being modified, with disasterous
results.

Fix by not using PAGE_MASK for physical addresses; instead calculate
the correct value directly from PAGE_SIZE.  Also fix a similar BUG_ON().
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

KVM shadow page tables are always in pae mode, regardless of the guest
setting.  This means that a guest pde (mapping 4MB of memory) is mapped
to two shadow pdes (mapping 2MB each).

When the guest writes to a pte or pde, we intercept the write and emulate it.
We also remove any shadowed mappings corresponding to the write.  Since the
mmu did not account for the doubling in the number of pdes, it removed the
wrong entry, resulting in a mismatch between shadow page tables and guest
page tables, followed shortly by guest memory corruption.

This patch fixes the problem by detecting the special case of writing to
a non-pae pde and adjusting the address and number of shadow pdes zapped
accordingly.
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The vmx code currently treats the guest's sysenter support msrs as 32-bit
values, which breaks 32-bit compat mode userspace on 64-bit guests.  Fix by
using the native word width of the machine.
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>

This patch changes the SVM code to intercept SMIs and handle it
outside the guest.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

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

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: NAhmed S. Darwish <darwish.07@gmail.com>
Signed-off-by: NDor Laor <dor.laor@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The whole thing is rotten, but this allows vmx to boot with the guest reboot
fix.
Signed-off-by: NMarkus Rechberger <markus.rechberger@amd.com>
Signed-off-by: NJoerg Roedel <joerg.roedel@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>