x86: add support for STAC/CLAC instructions

The STAC/CLAC instructions are only available when SMAP feature is
available, but on the other hand they aren't needed if SMAP is not
enabled, or before we start to run userspace, in that case, the
functions and macros do nothing.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
x86: clear AC bit in RFLAGS to protect Xen itself by SMAP

Clear AC bit in RFLAGS at the beginning of exception, interrupt, hypercall,
so Xen itself can be protected by SMAP mechanism. This patch also sets AC
bit at the beginning of double_fault and fatal_trap() to reduce the likelihood
of taking a further fault while trying to dump state.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
x86: temporarily disable SMAP to legally access user pages in kernel mode

Use STAC/CLAC to temporarily disable SMAP to allow legal accesses to
user pages in kernel mode

STAC/CLAC is not needed for compat_create_bounce_frame, since in this
chunk of code, it only accesses the pv guest's kernel stack, which is
in ring 1 for 32-bit pv guests.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
VMX: disable SMAP feature when guest is in non-paging mode

SMAP is disabled if CPU is in non-paging mode in hardware.
However Xen always uses paging mode to emulate guest non-paging
mode with HAP. To emulate this behavior, SMAP needs to be manually
disabled when guest switches to non-paging mode.

This logic is similiar with SMEP.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
x86: enable Supervisor Mode Access Prevention (SMAP) for Xen

Supervisor Mode Access Prevention (SMAP) is a new security
feature disclosed by Intel, please refer to the following
document:

http://software.intel.com/sites/default/files/319433-014.pdf

If CR4.SMAP = 1, supervisor-mode data accesses are not allowed
to linear addresses that are accessible in user mode. If CPL < 3,
SMAP protections are disabled if EFLAGS.AC = 1. If CPL = 3, SMAP
applies to all supervisor-mode data accesses (these are implicit
supervisor accesses) regardless of the value of EFLAGS.AC.

This patch enables SMAP in Xen to prevent Xen hypervisor from
accessing pv guest data, whose translation paging-structure
entries' U/S flags are all set.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
x86/hvm: add SMAP support to HVM guest

Intel new CPU supports SMAP (Supervisor Mode Access Prevention).
SMAP prevents supervisor-mode accesses to any linear address with
a valid translation for which the U/S flag (bit 2) is 1 in every
paging-structure entry controlling the translation for the linear
address.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Tim Deegan <tim@xen.org>
x86/tools: expose SMAP to HVM guests

This patch exposes SMAP festure to HVM guests

Signed-off-by: Feng Wu <feng.wu@intel.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
x86/traps: do not inline do_trap() into 10 different handlers

Furthermore, trapnr can be pulled from regs->entry_vector to avoid a risk of
mismatching the trap number with the underlying exception state.

This nets 2K of code reduction.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
libxl: add option for discard support to xl disk configuration

Handle new boolean option discard/no-discard for disk configuration. It
is supposed to disable discard support if file based backing storage was
intentionally created non-sparse to avoid fragmentation of the file.

The option intended for the backend driver. A new boolean property
"discard-enable" is written to the backend node. An upcoming patch for
qemu will make use of this property. The kernel blkback driver may be
updated as well to disable discard for phy based backing storage.

v5:
replace option discard=0|1 with boolean discard/no-discard
adjust wording in xl-disk-configuration.txt and blkif.h
call libxl_defbool_setdefault directly
adjust linewarapping in device_disk_add
v4:
rebase ontop of commit 6ec48cf4 (direct_io_safe)
rebase ontop of fixup commit for 6ec48cf4 (direct_io_safe)
add testcases to tools/libxl/check-xl-disk-parse
v3:
enable discard unconditionally by always writing discard-enable=1 to xenstore
fix typos in xl-disk-configuration.txt
update description in blkif.h, property should be ignored if unsupported
v2:
rename xenstore property from discard_enable to discard-enable
update description in xl-disk-configuration.txt
use libxl_defbool as type for discard_enable
update check-xl-disk-parse to use "<default>"
add LIBXL_HAVE_LIBXL_DEVICE_DISK_DISCARD_ENABLE to libxl.h

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
tools/mkrpm: allow different rpm package name

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Config.mk: move directory list into BUILD_MAKE_VARS

To maintain the list of directories in a single place, move the existing
list into its own variable and use it in buildmakevars2file.
Required for upcoming changes.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Config.mk: replace dependency to genpath with actual target

genpath is a detail of buildmakevars2file. Replace the dependency to
genpath with the actual buildmakevars2file target. This change by itself
does not fix any bug. Upcoming changes will add dependencies to
$(target), but no rule exist to create $(target).

With this change a rule for $(target) is added, which in turn depends on
genpath. No change in behaviour is expected by this patch.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Config.mk: add new macro buildmakevars2header

This macro is similar to buildmakevars2file, it just creates a C header
file instead of shell style syntax. Upcoming changes will use this macro
in libxl and libxc.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
tools/libxl: use buildmakevars2header to create _paths.h

Replace usage of buildmakevars2file with buildmakevars2header. The macro
generates a C header file, so remove code which converts shell variables
into C defines. Also update the dependency, the macro itself creates a
dependency to genpath for _paths.h. A temporary file is not needed
anymore.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
tools/libxc: provide variable paths to libxc

In preparation to remove hardcoded /var/run/xen paths, provide
XEN_RUN_DIR and related directories to xc_private.h. Similar code exists
already for libxl, stubdom and other parts.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
tools/libxc: use XEN_RUN_DIR for SUSPEND_LOCK_FILE

Remove hardcoded /var/run/xen directory path, use XEN_RUN_DIR instead.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
tools/pygrub: store kernels in /var/run/xen/pygrub

Move location of temporary bootfiles from /var/run/xend/boot to
/var/run/xen/pygrub. Create the subdirectory if does not exist, unless
--output-directory=<dir> was specified.

The reason for this change is that all entrys below /var/run have to be
created at runtime in case /var/run is cleared on every boot.

v4:
 update mkdir exception handling
v3:
 use /var/run/xen/pygrub instead of /var/run/pygrub
v2:
 update exception handling for python 2.4

Signed-off-by: Olaf Hering <olaf@aepfle.de>
tools/hotplug: use XEN_SCRIPT_DIR instead of hardcoded path

Helper scripts get installed into XEN_SCRIPT_DIR, but initscripts,
helper scripts and udev rules still refer to the hardcoded location
/etc/xen/scripts/. Update scripts, rules and Makefile to refer to
@@XEN_SCRIPT_DIR@@ instead.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
tools/hotplug: create XEN_RUN_DIR at runtime

Create XEN_RUN_DIR instead of hardcoded path at runtime.
/var/run might be empty on startup.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
tools/hotplug: create XEN_LOCK_DIR at runtime

XEN_LOCK_DIR is a compile-time setting and may not exist on the target
host.

Signed-off-by: Olaf Hering <olaf@aepfle.de>