Commit Graph
1070 Commits
Author SHA1 Message Date
Wei Liu e1b03b03b1 xl.conf: Add global affinity masks
XSA-273 involves one hyperthread being able to use Spectre-like
techniques to "spy" on another thread.  The details are somewhat
complicated, but the upshot is that after all Xen-based mitigations
have been applied:

* PV guests cannot spy on sibling threads
* HVM guests can spy on sibling threads

(NB that for purposes of this vulnerability, PVH and HVM guests are
identical.  Whenever this comment refers to 'HVM', this includes PVH.)

There are many possible mitigations to this, including disabling
hyperthreading entirely.  But another solution would be:

* Specify some cores as PV-only, others as PV or HVM
* Allow HVM guests to only run on thread 0 of the "HVM-or-PV" cores
* Allow PV guests to run on the above cores, as well as any thread of the PV-only cores.

For example, suppose you had 16 threads across 8 cores (0-7).  You
could specify 0-3 as PV-only, and 4-7 as HVM-or-PV.  Then you'd set
the affinity of the HVM guests as follows (binary representation):

0000000010101010

And the affinity of the PV guests as follows:

1111111110101010

In order to make this easy, this patches introduces three "global affinity
masks", placed in xl.conf:

    vm.cpumask
    vm.hvm.cpumask
    vm.pv.cpumask

These are parsed just like the 'cpus' and 'cpus_soft' options in the
per-domain xl configuration files.  The resulting mask is AND-ed with
whatever mask results at the end of the xl configuration file.
`vm.cpumask` would be applied to all guest types, `vm.hvm.cpumask`
would be applied to HVM and PVH guest types, and `vm.pv.cpumask`
would be applied to PV guest types.

The idea would be that to implement the above mask across all your
VMs, you'd simply add the following two lines to the configuration
file:

    vm.hvm.cpumask=8,10,12,14
    vm.pv.cpumask=0-8,10,12,14

See xl.conf manpage for details.

This is part of XSA-273 / CVE-2018-3646.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit aa67b97ed3)

PVH guest type in toolstack is not available in this version of Xen.
Change code and manpage to cope. Also xl is still part of libxl in
thsi version, manually backport code to relevant places.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
2018-08-14 17:39:57 +01:00
Jan Beulich 1ecb0d46d3 x86: Make "spec-ctrl=no" a global disable of all mitigations
In order to have a simple and easy to remember means to suppress all the
more or less recent workarounds for hardware vulnerabilities, force
settings not controlled by "spec-ctrl=" also to their original defaults,
unless they've been forced to specific values already by earlier command
line options.

This is part of XSA-273.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit d8800a82c3)
2018-08-14 17:39:57 +01:00
Andrew Cooper 4b12b44b21 x86/spec-ctrl: Introduce an option to control L1D_FLUSH for HVM HAP guests
This mitigation requires up-to-date microcode, and is enabled by default on
affected hardware if available, and is used for HVM guests

The default for SMT/Hyperthreading is far more complicated to reason about,
not least because we don't know if the user is going to want to run any HVM
guests to begin with.  If a explicit default isn't given, nag the user to
perform a risk assessment and choose an explicit default, and leave other
configuration to the toolstack.

This is part of XSA-273 / CVE-2018-3620.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 3bd36952da)
2018-08-14 17:39:57 +01:00
Andrew Cooper b2449f57ae x86/spec-ctrl: CPUID/MSR definitions for L1D_FLUSH
This is part of XSA-273 / CVE-2018-3646.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 3563fc2b27)
2018-08-14 17:39:57 +01:00
Andrew Cooper 2b1e6a4868 x86/spec-ctrl: Introduce an option to control L1TF mitigation for PV guests
Shadowing a PV guest is only available when shadow paging is compiled in.
When shadow paging isn't available, guests can be crashed instead as
mitigation from Xen's point of view.

Ideally, dom0 would also be potentially-shadowed-by-default, but dom0 has
never been shadowed before, and there are some stability issues under
investigation.

This is part of XSA-273 / CVE-2018-3620.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 66a4e98681)
2018-08-14 17:39:56 +01:00
Stefano Stabellini 45f6a2777c ARM: disable grant table v2
It was never expected to work, the implementation is incomplete.

As a side effect, it also prevents guests from triggering a
"BUG_ON(page_get_owner(pg) != d)" in gnttab_unpopulate_status_frames().

This is XSA-268.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 9a5c16a3e7)
2018-08-14 17:39:56 +01:00
Andrew Cooper 4c8d9f87bd common/gnttab: Introduce command line feature controls
This patch was originally released as part of XSA-226.  It retains the same
command line syntax (as various downstreams are mitigating XSA-226 using this
mechanism) but the defaults have been updated due to the revised XSA-226
patched, after which transitive grants are believed to functioning
properly.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit dc96c65ed6)
2018-08-14 17:39:56 +01:00
Jan Beulich e0981f6087 x86: command line option to avoid use of secondary hyper-threads
Shared resources (L1 cache and TLB in particular) present a risk of
information leak via side channels. Provide a means to avoid use of
hyperthreads in such cases.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: d8f974f1a6
master date: 2018-07-19 13:43:33 +0100
2018-07-30 14:21:07 +02:00
Andrew Cooper 542f711567 x86/spec-ctrl: Mitigations for LazyFPU
Intel Core processors since at least Nehalem speculate past #NM, which is the
mechanism by which lazy FPU context switching is implemented.

On affected processors, Xen must use fully eager FPU context switching to
prevent guests from being able to read FPU state (SSE/AVX/etc) from previously
scheduled vcpus.

This is part of XSA-267 / CVE-2018-3665

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 243435bf67)
2018-06-13 22:01:37 +01:00
Juergen Gross 365ecffbb6 xen/x86: use PCID feature
Avoid flushing the complete TLB when switching %cr3 for mitigation of
Meltdown by using the PCID feature if available.

We are using 4 PCID values for a 64 bit pv domain subject to XPTI and
2 values for the non-XPTI case:

- guest active and in kernel mode
- guest active and in user mode
- hypervisor active and guest in user mode (XPTI only)
- hypervisor active and guest in kernel mode (XPTI only)

We use PCID only if PCID _and_ INVPCID are supported. With PCID in use
we disable global pages in cr4. A command line parameter controls in
which cases PCID is being used.

As the non-XPTI case has shown not to perform better with PCID at least
on some machines the default is to use PCID only for domains subject to
XPTI.

With PCID enabled we always disable global pages. This avoids having to
either flush the complete TLB or do a cycle through all PCID values
when invalidating a single global page.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2018-05-29 11:31:34 +02:00
Juergen Gross cb0230a637 xen/x86: use invpcid for flushing the TLB
If possible use the INVPCID instruction for flushing the TLB instead of
toggling cr4.pge for that purpose.

While at it remove the dependency on cr4.pge being required for mtrr
loading, as this will be required later anyway.

Add a command line option "invpcid" for controlling the use of
INVPCID (default to true).

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2018-05-29 11:28:53 +02:00
Juergen Gross 4336ffad91 xen/x86: support per-domain flag for xpti
Instead of switching XPTI globally on or off add a per-domain flag for
that purpose. This allows to modify the xpti boot parameter to support
running dom0 without Meltdown mitigations. Using "xpti=no-dom0" as boot
parameter will achieve that.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2018-05-29 11:28:24 +02:00
Andrew Cooper bfe8f3e884 x86/Intel: Mitigations for GPZ SP4 - Speculative Store Bypass
To combat GPZ SP4 "Speculative Store Bypass", Intel have extended their
speculative sidechannel mitigations specification as follows:

 * A feature bit to indicate that Speculative Store Bypass Disable is
   supported.
 * A new bit in MSR_SPEC_CTRL which, when set, disables memory disambiguation
   in the pipeline.
 * A new bit in MSR_ARCH_CAPABILITIES, which will be set in future hardware,
   indicating that the hardware is not susceptible to Speculative Store Bypass
   sidechannels.

For contemporary processors, this interface will be implemented via a
microcode update.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 9df52a25e0
master date: 2018-05-21 14:20:06 +0100
2018-05-29 11:08:34 +02:00
Andrew Cooper 4f0509d9bf x86/AMD: Mitigations for GPZ SP4 - Speculative Store Bypass
AMD processors will execute loads and stores with the same base register in
program order, which is typically how a compiler emits code.

Therefore, by default no mitigating actions are taken, despite there being
corner cases which are vulnerable to the issue.

For performance testing, or for users with particularly sensitive workloads,
the `spec-ctrl=ssbd` command line option is available to force Xen to disable
Memory Disambiguation on applicable hardware.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 8c0e338086
master date: 2018-05-21 14:20:06 +0100
2018-05-29 11:08:10 +02:00
Andrew Cooper 2f99d683f8 x86/spec_ctrl: Introduce a new spec-ctrl= command line argument to replace bti=
In hindsight, the options for `bti=` aren't as flexible or useful as expected
(including several options which don't appear to behave as intended).
Changing the behaviour of an existing option is problematic for compatibility,
so introduce a new `spec-ctrl=` in the hopes that we can do better.

One common way of deploying Xen is with a single PV dom0 and all domUs being
HVM domains.  In such a setup, an administrator who has weighed up the risks
may wish to forgo protection against malicious PV domains, to reduce the
overall performance hit.  To cater for this usecase, `spec-ctrl=no-pv` will
disable all speculative protection for PV domains, while leaving all
speculative protection for HVM domains intact.

For coding clarity as much as anything else, the suboptions are grouped by
logical area; those which affect the alternatives blocks, and those which
affect Xen's in-hypervisor settings.  See the xen-command-line.markdown for
full details of the new options.

While changing the command line options, take the time to change how the data
is reported to the user.  The three DEBUG printks are upgraded to unilateral,
as they are all relevant pieces of information, and the old "mitigations:"
line is split in the two logical areas described above.

Sample output from booting with `spec-ctrl=no-pv` looks like:

  (XEN) Speculative mitigation facilities:
  (XEN)   Hardware features: IBRS/IBPB STIBP IBPB
  (XEN)   Compiled-in support: INDIRECT_THUNK
  (XEN)   Xen settings: BTI-Thunk RETPOLINE, SPEC_CTRL: IBRS-, Other: IBPB
  (XEN)   Support for VMs: PV: None, HVM: MSR_SPEC_CTRL RSB
  (XEN)   XPTI (64-bit PV only): Dom0 enabled, DomU enabled

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 3352afc26c
master date: 2018-05-16 12:19:10 +0100
2018-05-29 11:07:29 +02:00
Andrew Cooper 8994cf3cf7 x86/ctxt: Issue a speculation barrier between vcpu contexts
Issuing an IBPB command flushes the Branch Target Buffer, so that any poison
left by one vcpu won't remain when beginning to execute the next.

The cost of IBPB is substantial, and skipped on transition to idle, as Xen's
idle code is robust already.  All transitions into vcpu context are fully
serialising in practice (and under consideration for being retroactively
declared architecturally serialising), so a cunning attacker cannot use SP1 to
try and skip the flush.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: a2ed643ed7
master date: 2018-01-26 14:10:21 +0000
2018-02-14 13:44:01 +01:00
Andrew Cooper 642c6037bb x86/boot: Calculate the most appropriate BTI mitigation to use
See the logic and comments in init_speculation_mitigations() for further
details.

There are two controls for RSB overwriting, because in principle there are
cases where it might be safe to forego rsb_native (Off the top of my head,
SMEP active, no 32bit PV guests at all, no use of vmevent/paging subsystems
for HVM guests, but I make no guarantees that this list of restrictions is
exhaustive).

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

x86/spec_ctrl: Fix determination of when to use IBRS

The original version of this logic was:

    /*
     * On Intel hardware, we'd like to use retpoline in preference to
     * IBRS, but only if it is safe on this hardware.
     */
    else if ( boot_cpu_has(X86_FEATURE_IBRSB) )
    {
        if ( retpoline_safe() )
            thunk = THUNK_RETPOLINE;
        else
            ibrs = true;
    }

but it was changed by a request during review.  Sadly, the result is buggy as
it breaks the later fallback logic by allowing IBRS to appear as available
when in fact it isn't.

This in practice means that on repoline-unsafe hardware without IBRS, we
select THUNK_JUMP despite intending to select THUNK_RETPOLINE.

Reported-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 2713715305
master date: 2018-01-26 14:10:21 +0000
master commit: 30cbd0c83e
master date: 2018-02-06 18:32:58 +0000
2018-02-14 13:43:36 +01:00
Andrew Cooper 4d2154914e x86/cmdline: Introduce a command line option to disable IBRS/IBPB, STIBP and IBPB
Instead of gaining yet another top level boolean, introduce a more generic
cpuid= option.  Also introduce a helper function to parse a generic boolean
value.

This is part of XSA-254.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/cmdline: Fix parse_boolean() for unadorned values

A command line such as "cpuid=no-ibrsb,no-stibp" tickles a bug in
parse_boolean() because the separating comma fails the NUL case.

Instead, check for slen == nlen which accounts for the boundary (if any)
passed via the 'e' parameter.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 7850b1c007
master date: 2018-01-16 17:45:50 +0000
master commit: ac37ec1dde
master date: 2018-01-31 10:47:12 +0000
2018-02-14 12:44:17 +01:00
Andrew Cooper 2613a1bc70 x86: Introduce alternative indirect thunks
Depending on hardware and microcode availability, we will want to replace
IND_THUNK_REPOLINE with other implementations.

For AMD hardware, choose IND_THUNK_LFENCE in preference to retpoline if lfence
is known to be (or was successfully made) dispatch serialising.

This is part of XSA-254.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 858cba0d4c
master date: 2018-01-16 17:45:50 +0000
2018-02-14 12:43:05 +01:00
Jan Beulich 44ad7f6895 x86: allow Meltdown band-aid to be disabled
First of all we don't need it on AMD systems. Additionally allow its use
to be controlled by command line option. For best backportability, this
intentionally doesn't use alternative instruction patching to achieve
the intended effect - while we likely want it, this will be later
follow-up.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: e871e80c38
master date: 2018-01-16 17:50:59 +0100
2018-01-17 17:32:03 +01:00
George Dunlap be63d665b8 x86/mm: Make PV linear pagetables optional
Allowing pagetables to point to other pagetables of the same level
(often called 'linear pagetables') has been included in Xen since its
inception; but recently it has been the source of a number of subtle
reference-counting bugs.

It is not used by Linux or MiniOS; but it is used by NetBSD and Novell
Netware.  There are significant numbers of people who are never going
to use the feature, along with significant numbers who need the
feature.

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2017-11-16 12:13:11 +01:00
Jan Beulich f974d3211e gnttab: split maptrack lock to make it fulfill its purpose again
The way the lock is currently being used in get_maptrack_handle(), it
protects only the maptrack limit: The function acts on current's list
only, so races on list accesses are impossible even without the lock.

Otoh list access races are possible between __get_maptrack_handle() and
put_maptrack_handle(), due to the invocation of the former for other
than current from steal_maptrack_handle(). Introduce a per-vCPU lock
for list accesses to become race free again. This lock will be
uncontended except when it becomes necessary to take the steal path,
i.e. in the common case there should be no meaningful performance
impact.

When in get_maptrack_handle adds a stolen entry to a fresh, empty,
freelist, we think that there is probably no concurrency.  However,
this is not a fast path and adding the locking there makes the code
clearly correct.

Also, while we are here: the stolen maptrack_entry's tail pointer was
not properly set.  Set it.

This is CVE-2017-12136 / XSA-228.

Reported-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
master commit: 02cbeeb620
master date: 2017-08-15 15:07:25 +0200
2017-08-15 15:30:26 +02:00
Stefano Stabellini 82fde4fa36 xen/arm: introduce vwfi parameter
Introduce new Xen command line parameter called "vwfi", which stands for
virtual wfi. The default is "trap": Xen traps guest wfi and wfe
instructions. In the case of wfi, Xen calls vcpu_block on the guest
vcpu; in the case of guest wfe, Xen calls vcpu_yield on the guest vcpu.
The behavior can be changed by setting vwfi to "native", in that case
Xen doesn't trap neither wfi nor wfe, running them in guest context.

The result is strong reduction in irq latency (from 5000ns to 2000ns,
measured using https://github.com/edgarigl/tbm, the physical timer, and
1 pcpu dedicated to 1 vcpu). The downside is that the scheduler thinks
that the guest is busy when actually is sleeping, leading to suboptimal
scheduling decisions.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
2017-03-07 11:26:58 -08:00
Ian Jackson 44d8545ba6 libxl: Document ~/serial/ correctly
xenstore-paths.markdown talked about ~/device/serial/, but that's not
used.

(It is very wrong for this value, which contains a driver domain
filesystem path, to be in the guest's area of xenstore.  However, it
is only ever created by libxl and ready by xenconsoled.  When it is
created, it inherits the read-only permissions of /local/domain/DOMID.
So there is no security bug.)

This is a followup to XSA-175.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
2016-06-06 15:08:59 +01:00
Ian Jackson 866bea560b libxl: Make copy of every xs backend in /libxl in _generic_add
We want to stop libxl trustingly reading information from the backend
directory (since this is, of course, writeable by the backend, which
might be a semi-trusted driver domain).

In principle it is wrong in current libxl for anything to try to
divine virtual device configuration from xenstore: the JSON domain
config ought to supply that, and xenstore should only tell us which
devices actually exist.

However:

Firstly, there are several existing places where configuration
information is retrieved from xenstore rather than JSON.  We do not
want to reen gineer this in a security patch.

Secondly, we want to make a security patch which can be backported to
versions of libxl without the JSON configuration machinery.

So we take the expedient approach of keeping a copy of the
configuration somewhere we trust, namely /libxl.  This is obviously
fairly low-risk, although it does write significantly more keys in
xenstore.

In this patch we make this change in libxl__device_generic_add.  This
is responsible for actually writing the vast majority of device
information to xenstore.  There are a few loose ends which will be
dealt with in a moment.

Likewise, changes to readers to use the new location will appear in
further patches.

This is part of XSA-178.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
2016-06-06 14:47:35 +01:00
Ian Jackson 71bdf79ede libxl: Record backend/frontend paths in /libxl/$DOMID
This gives us a record of all the backends we have set up for a
domain, which is separate from the frontends in
  /local/domain/$DOMID/device.

In particular:

1. A guest has write permission for the frontend path:
  /local/domain/$DOMID/device/$KIND/$DEVID
which means that the guest can completely delete the frontend.
(They can't recreate it because they don't have write permission
on the containing directory.)

2. A guest has write permission for the backend path recorded in the
frontend, ie, it can write to
  /local/domain/$DOMID/device/$KIND/$DEVID/backend
which means that the guest can break the association between
frontend and backend.

So we can't rely on iterating over the frontends to find all the
backends, or examining a frontend to discover how a device is
configured.

So, have libxl__device_generic_add record the frontend and backend
paths in /libxl/$DOMID/device, and have libxl__device_destroy remove
them again.

Create the containing directory /libxl/GUEST/device in
libxl__domain_make.  The already existing xs_rm in devices_destroy_cb
will take care of removing it.

This is part of XSA-175.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
2016-06-06 13:56:33 +01:00
Jan Beulich 6d03c9e4f2 x86: enforce consistent cachability of MMIO mappings
We've been told by Intel that inconsistent cachability between
multiple mappings of the same page can affect system stability only
when the affected page is an MMIO one. Since the stale data issue is
of no relevance to the hypervisor (since all guest memory accesses go
through proper accessors and validation), handling of RAM pages
remains unchanged here. Any MMIO mapped by domains however needs to be
done consistently (all cachable mappings or all uncachable ones), in
order to avoid Machine Check exceptions. Since converting existing
cachable mappings to uncachable (at the time an uncachable mapping
gets established) would in the PV case require tracking all mappings,
allow MMIO to only get mapped uncachable (UC, UC-, or WC).

This also implies that in the PV case we mustn't use the L1 PTE update
fast path when cachability flags get altered.

Since in the HVM case at least for now we want to continue honoring
pinned cachability attributes for pages not mapped by the hypervisor,
special case handling of r/o MMIO pages (forcing UC) gets added there.
Arguably the counterpart change to p2m-pt.c may not be necessary, since
UC- (which already gets enforced there) is probably strict enough.

Note that the shadow code changes include fixing the write protection
of r/o MMIO ranges: shadow_l1e_remove_flags() and its siblings, other
than l1e_remove_flags() and alike, return the new PTE (and hence
ignoring their return values makes them no-ops).

This is CVE-2016-2270 / XSA-154.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: c61a6f74f8
master date: 2016-02-17 16:16:53 +0100
2016-02-17 16:31:16 +01:00
Ian Campbell 5929e25d98 docs: correct descriptions of gnttab_max_{, maptrack}_frames
gnttab_max_frames incorrectly referred to numbers of grant tab
operations and gnttab_max_maptrack_frames was confusingly worded.

Add the default for gnttab_max_frames while here (it's currently the
same on all arches since no arch uses the available arch override) and
adjust the default for gnttab_max_maptrack_frames to match the normal
form.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: ef17887d84
master date: 2016-01-19 16:24:44 +0000
2016-01-20 13:59:02 +01:00
Jan Beulich 499886c800 x86/vPMU: document as unsupported
This is XSA-163.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
master commit: c03480cf5c
master date: 2015-11-24 18:32:20 +0100
2015-12-15 15:22:58 +01:00
Jan Beulich 2ce580f21f memory: split and tighten maximum order permitted in memops
Introduce and enforce separate limits for ordinary DomU, DomU with
pass-through device(s), control domain, and hardware domain.

The DomU defaults were determined based on what so far was allowed by
multipage_allocation_permitted().

The x86 hwdom default was chosen based on linux-2.6.18-xen.hg c/s
1102:82782f1361a9 indicating 2Mb is not enough, plus some slack.

The ARM hwdom default was chosen to allow 2Mb (order-9) mappings, plus
a little bit of slack.

This is CVE-2015-8338 / XSA-158.

Reported-by: Julien Grall <julien.grall@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
master commit: 4a578b316e
master date: 2015-12-08 14:00:33 +0100
2015-12-08 14:05:20 +01:00
Ian Campbell e4a1dcbfae docs: xl.cfg: permissive option is not PV only.
Since XSA-131 qemu-xen has defaulted to non-permissive mode and the
option was extended to cover that case in 015a373351 "tools: libxl:
allow permissive qemu-upstream pci passthrough".

Since I was rewrapping to adjust the text anyway I've split the safety
warning into a separate paragraph to make it more obvious.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Eric <epretorious@yahoo.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 7f25baba1c)
2015-10-22 16:03:10 +01:00
Ross Lagerwall 9204673fc6 x86/EPT: work around hardware erratum setting A bit
Since commit 191b3f3344 ("p2m/ept: enable PML in p2m-ept for
log-dirty"), the A and D bits of EPT paging entries are set
unconditionally, regardless of whether PML is enabled or not. This
causes a regression in Xen 4.6 on some processors due to Intel Errata
AVR41 -- HVM guests get severe memory corruption when the A bit is set
due to incorrect TLB flushing on mov to cr3. The erratum affects the
Atom C2000 family (Avoton).

To fix, do not set the A bit on this processor family.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>

Move feature suppression to feature detection code. Add command line
override.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
master commit: 33b55dc103
master date: 2015-10-02 13:39:12 +0200
2015-10-02 13:53:27 +02:00
Chao Peng fc39c88241 docs/man: resort sections
Section 'IGNORED FOR COMPATIBILITY WITH XM' separates 'CACHE MONITORING
TECHNOLOGY' and 'CACHE ALLOCATION TECHNOLOGY' but they really should be
put together.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 61598449ae)
2015-09-29 10:59:54 +01:00
Chao Peng 41c46dd10b docs: make xl-psr.markdown more precise
Drop the chapter number as it can be confusing when it gets changed in
the referred document.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
[ ijc -- dropped hunk changing URL to specific revision, this is not
         needed now that the references do not include a specific
         chapter number ]

(cherry picked from commit 7f732ffa2b)
2015-09-29 10:59:54 +01:00
Andrew Cooper ec6462ed3f docs: Migration feature document
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 112e5346b0)
2015-09-21 12:28:09 +01:00
Andrew Cooper 17588f6352 docs: Template for feature documents
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit d02bed2a39)
2015-09-21 12:28:09 +01:00
Wei Liu ed9926ecf0 xl/libxl: disallow saving a guest with vNUMA configured
This is because the migration stream does not preserve node information.

Note this is not a regression for migration v2 vs legacy migration
because neither of them preserves node information.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
[ ijc -- some grammar fixes to the doc and fixed a comment ]

(cherry picked from commit fa6b5490be)
2015-09-11 16:36:56 +01:00
Andrew Cooper 6a05af2459 docs: Fix installation of man8 pages
c/s a430436 "docs: Support for generating man(8) pages" accidentally
failed to update to the install and clean rules for man8 pages, meaning
that c/s 7b21214 "docs: Move xentrace.8 to docs/man/xentrace.pod.8"
caused a packaging regression when it came to xentop.8

To avoid similar bugs in the future, move the generation of the build,
install and clean rules into the manpage metarule.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
2015-08-28 10:49:41 +01:00
Andrew Cooper 7b21214a3a docs: Move xentrace.8 to docs/man/xentrace.pod.8
And transform to POD to match our other manpages.

The content is identical, although the formatting was altered slightly
to conform to more usual manpage layout.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2015-08-27 19:14:35 +01:00
Andrew Cooper a4304367c4 docs: Support for generating man(8) pages
The manpage rules are very repetative, because of the section number being
present in the filenames.

Instead of adding another set of 3 rules, switch to using a metarule to
automate the repetative action.  New rules for different manpage sections can
be added simply by extending the $(foreach)

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2015-08-27 19:14:31 +01:00
Andrew Cooper 014b165f9b docs: Move xentrace_format.1 to docs/man/xentrace_format.pod.1
And transform to POD to match our other manpages.

The content is identical (other than one correction), although the
layout differs slightly with certain indentation.

As a correction, remove the reference to xentrace_cpusplit(1) which was
removed in c/s 9b9ca98b6a, more than 10 years ago!

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2015-08-27 19:14:27 +01:00
Andrew Cooper 570de9c384 docs: Move xentop.1 to docs/man/xentop.pod.1
And transform to POD to match our other manpages.

The content is identical, although the layout differs slightly with
certain indentation.

In addition, adjust the MAN{1,5}SRC-y `find` runes to be more general.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2015-08-27 19:14:20 +01:00
Andrew Cooper c85d3d1d98 docs: Move misc README's into docs/misc/
To live with the other documentation.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2015-08-27 19:14:17 +01:00
Ting-Wei Lan 146341187a VT-d: add iommu=igfx option to workaround graphics issues
When using Linux >= 3.19 (commit 47591df) as dom0 on some Intel Ironlake
devices, It is possible to encounter graphics issues that make screen
unreadable or crash the system. It was reported in freedesktop bugzilla:

https://bugs.freedesktop.org/show_bug.cgi?id=90037

As we still cannot find a proper fix for this problem, this patch adds
iommu=igfx option to control whether Intel graphics IOMMU is enabled.
Running Xen with iommu=no-igfx is similar to running Linux with
intel_iommu=igfx_off, which disables IOMMU for Intel GPU. This can be
used by users to manually workaround the problem before a fix is
available for i915 driver.

Signed-off-by: Ting-Wei Lan <lantw44@gmail.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
2015-08-06 10:03:53 +01:00
Andrew Cooper 47801b0451 docs/libxl: Re-specify XENSTORE_DATA as EMULATOR_XENSTORE_DATA
The legacy "toolstack" record as implemented in libxl turns out not to
be 32/64bit safe.  As migration v2 has not shipped yet, take this
opportunity to adjust the specification and fix the incompatibility.

Libxl shall loose all knowledge of the old "toolstack" blob and use this
EMULATOR_XENSTORE_DATA record instead.  Compatibility shall be handled
by the legacy conversion script.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
2015-08-05 10:46:30 +01:00
Wei Liu 27524b5e15 xl/libxl: disable PV vNUMA
Update xl manual and disable PV vNUMA in libxl.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2015-07-31 10:15:17 +01:00
Andrew Cooper 5850b0317d docs: Migration v2 is now no longer draft
Add further instructions to the libxc "Future Extensions" section, and
provide such a section for libxl.

In addition, drop the "In experimental __func__" IPRINTF()s from the
libxc implementations.

Finally, a correction to libxl's "Not Yet Included" section which
should have been amended in c/s 7eaec00 when libxl Remus support was
introduced into the protocol.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2015-07-28 11:11:52 +01:00
Andrew Cooper 2591383a50 tools/libx{l, c}: Remove the toolstack_{save, restore} callbacks
Update the libxc spec to indicate more sternly that TOOLSTACK records
should no longer be used.

Also, trim further toolstack infrastructure which should have gone in
c/s 39bf4e9 "tools/libxl: Drop all knowledge of toolstack callbacks"

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2015-07-28 11:11:52 +01:00
Ed White ea21400128 x86/altp2m: add altp2mhvm HVM domain parameter
The altp2mhvm and nestedhvm parameters are mutually
exclusive and cannot be set together.

Signed-off-by: Ed White <edmund.h.white@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
2015-07-24 13:38:28 +02:00
Ed White fce42d9ad7 x86/HVM: hardware alternate p2m support detection
As implemented here, only supported on platforms with VMX HAP.

By default this functionality is force-disabled, it can be enabled
by specifying altp2m=1 on the Xen command line.

Signed-off-by: Ed White <edmund.h.white@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
2015-07-24 13:26:02 +02:00