x86: Implement SMEP and SMAP

This patch implements Supervisor Mode Execution Prevention (SMEP) and
Supervisor Mode Access Prevention (SMAP) for x86.  The purpose of the
patch, obviously, is to help kernel developers debug the support for
those features.

A fair bit of the code relates to the handling of CPUID features.  The
CPUID code probably would get greatly simplified if all the feature
bit words were unified into a single vector object, but in the
interest of producing a minimal patch for SMEP/SMAP, and because I had
very limited time for this project, I followed the existing style.

[ v2: don't change the definition of the qemu64 CPU shorthand, since
  that breaks loading old snapshots.  Per Anthony Liguori this can be
  fixed once the CPU feature set is snapshot.

  Change the coding style slightly to conform to checkpatch.pl. ]

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Update kernel header script to include vfio

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Update Linux kernel headers

Based on Linux as of 1a95620.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
vfio: vfio-pci device assignment driver

This adds the core of the QEMU VFIO-based PCI device assignment driver.
To make use of this driver, enable CONFIG_VFIO, CONFIG_VFIO_IOMMU_TYPE1,
and CONFIG_VFIO_PCI in your host Linux kernel config.  Load the vfio-pci
module.  To assign device 0000:05:00.0 to a guest, do the following:

for dev in $(ls /sys/bus/pci/devices/0000:05:00.0/iommu_group/devices); do
    vendor=$(cat /sys/bus/pci/devices/$dev/vendor)
    device=$(cat /sys/bus/pci/devices/$dev/device)
    if [ -e /sys/bus/pci/devices/$dev/driver ]; then
        echo $dev > /sys/bus/pci/devices/$dev/driver/unbind
    fi
    echo $vendor $device > /sys/bus/pci/drivers/vfio-pci/new_id
done

See Documentation/vfio.txt in the Linux kernel tree for further
description of IOMMU groups and VFIO.

Then launch qemu including the option:

-device vfio-pci,host=0000:05:00.0

Legacy PCI interrupts (INTx) currently makes use of a kludge where we
trap BAR accesses and assume the access is in response to an interrupt,
therefore de-asserting and unmasking the interrupt.  It's not quite as
targetted as using the EOI for this, but it's self contained and seems
to work across all architectures.  The side-effect is a significant
performance slow-down for device in INTx mode.  Some devices, like
graphics cards, don't really use their interrupt, so this can be turned
off with the x-intx=off option, which disables INTx alltogether.  This
should be considered an experimental option until we refine this code.
Both MSI and MSI-X are supported and avoid these issues.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
vfio: Enable vfio-pci and mark supported

Enabled for all softmmu guests supporting PCI on Linux hosts.  Note
that currently only x86 hosts have the kernel side VFIO IOMMU support
for this.  PPC (g3beige) is the only non-x86 guest known to work.
ARM (veratile) hangs in firmware, others untested.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
vfio_pci: fix build on 32-bit systems

We cannot cast directly from pointer to uint64.

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alex Barcelo <abarcelo@ac.upc.edu>
Reported-by: Alex Barcelo <abarcelo@ac.upc.edu>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
fpu/softfloat.c: Remove pointless shift of always-zero value

In float16_to_float32, when returning an infinity, just pass zero
as the mantissa argument to packFloat32(), rather than shifting
a value which we know must be zero.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
fpu/softfloat.c: Return correctly signed values from uint64_to_float32

The uint64_to_float32() conversion function was incorrectly always
returning numbers with the sign bit set (ie negative numbers). Correct
this so we return positive numbers instead.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
target-i386: return Error from cpu_x86_find_by_name()

it will allow to use property setters there later.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Don Slutz <Don@CloudSwitch.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
--
v2:
    - style change, add braces (reqested by Blue Swirl)
    - removed unused error_is_set(errp) in properties set loop
target-i386: cpu_x86_register(): report error from property setter

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
target-i386: if x86_cpu_realize() failed report error and do cleanup

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Andreas Färber <afaerber@suse.de>
target-i386: filter out not TCG features if running without kvm at realize time

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
target-i386: move out CPU features initialization in separate func

later it could be used in cpu_x86_find_by_name() to init
CPU from found cpu_def

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
--
v2:
   - rebased on top of  "i386: cpu: remove duplicate feature names"
      http://www.mail-archive.com/qemu-devel@nongnu.org/msg129458.html
target-i386: xlevel should be more than 0x80000000, move fixup into setter

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
target-i386: convert cpuid features into properties

add property accessors for cpuid feature bits defined by
*_feature_name arrays.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
target-i386: add stubs for hyperv_(vapic_recommended|relaxed_timing_enabled|get_spinlock_retries)()

It's needed for the next 3 patches to avoid build breakage when qemu is built
with --disable-kvm option.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reported-by: Eduardo Habkost <ehabkost@redhat.com>
target-i386: convert 'hv_spinlocks' feature into property

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
target-i386: convert 'hv_relaxed' feature into property

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
target-i386: convert 'hv_vapic' feature into property

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
target-i386: convert 'check' and 'enforce' features into properties

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
--
v2:
  * restore original behavior, check features against host before
    they might be filtered out by TCG masks. spotted-by: Eduardo Habkost