Commit Graph
1799 Commits
Author SHA1 Message Date
Roger Pau Monné 9d2f136328 x86/spinlock: introduce support for blocking speculation into critical regions
Introduce a new Kconfig option to block speculation into lock protected
critical regions.  The Kconfig option is enabled by default, but the mitigation
won't be engaged unless it's explicitly enabled in the command line using
`spec-ctrl=lock-harden`.

Convert the spinlock acquire macros into always-inline functions, and introduce
a speculation barrier after the lock has been taken.  Note the speculation
barrier is not placed inside the implementation of the spin lock functions, as
to prevent speculation from falling through the call to the lock functions
resulting in the barrier also being skipped.

trylock variants are protected using a construct akin to the existing
evaluate_nospec().

This patch only implements the speculation barrier for x86.

Note spin locks are the only locking primitive taken care in this change,
further locking primitives will be adjusted by separate changes.

This is part of XSA-453 / CVE-2024-2193

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 7ef0084418)
2024-03-12 16:13:03 +00:00
Andrew Cooper d55d52961d x86/spec-ctrl: Rename VERW related options
VERW is going to be used for a 3rd purpose, and the existing nomenclature
didn't survive the Stale MMIO issues terribly well.

Rename the command line option from `md-clear=` to `verw=`.  This is more
consistent with other options which tend to be named based on what they're
doing, not which feature enumeration they use behind the scenes.  Retain
`md-clear=` as a deprecated alias.

Rename opt_md_clear_{pv,hvm} and opt_fb_clear_mmio to opt_verw_{pv,hvm,mmio},
which has a side effect of making spec_ctrl_init_domain() rather clearer to
follow.

No functional change.

This is part of XSA-452 / CVE-2023-28746.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit f7603ca252)
2024-03-12 16:13:03 +00:00
Roger Pau Monné 693455c3c3 x86/spec: fix INDIRECT_THUNK option to only be set when build-enabled
Attempt to provide a more helpful error message when the user attempts to set
spec-ctrl=bti-thunk option but the support is build-time disabled.

While there also adjust the command line documentation to mention
CONFIG_INDIRECT_THUNK instead of INDIRECT_THUNK.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 8441fa806a
master date: 2024-02-27 14:58:20 +0100
2024-03-05 11:58:04 +01:00
Roger Pau Monné 83ae677d2a x86/x2apic: introduce a mixed physical/cluster mode
The current implementation of x2APIC requires to either use Cluster Logical or
Physical mode for all interrupts.  However the selection of Physical vs Logical
is not done at APIC setup, an APIC can be addressed both in Physical or Logical
destination modes concurrently.

Introduce a new x2APIC mode called Mixed, which uses Logical Cluster mode for
IPIs, and Physical mode for external interrupts, thus attempting to use the
best method for each interrupt type.

Using Physical mode for external interrupts allows more vectors to be used, and
interrupt balancing to be more accurate.

Using Logical Cluster mode for IPIs allows fewer accesses to the ICR register
when sending those, as multiple CPUs can be targeted with a single ICR register
write.

A simple test calling flush_tlb_all() 10000 times on a tight loop on AMD EPYC
9754 with 512 CPUs gives the following figures in nano seconds:

x mixed
+ phys
* cluster
    N           Min           Max        Median           Avg        Stddev
x  25 3.5131328e+08 3.5716441e+08 3.5410987e+08 3.5432659e+08     1566737.4
+  12  1.231082e+09  1.238824e+09 1.2370528e+09 1.2357981e+09     2853892.9
Difference at 95.0% confidence
	8.81472e+08 +/- 1.46849e+06
	248.774% +/- 0.96566%
	(Student's t, pooled s = 2.05985e+06)
*  11 3.5099276e+08 3.5561459e+08 3.5461234e+08 3.5415668e+08     1415071.9
No difference proven at 95.0% confidence

So Mixed has no difference when compared to Cluster mode, and Physical mode is
248% slower when compared to either Mixed or Cluster modes with a 95%
confidence.

Note that Xen uses Cluster mode by default, and hence is already using the
fastest way for IPI delivery at the cost of reducing the amount of vectors
available system-wide.

Make the newly introduced mode the default one.

Note the printing of the APIC addressing mode done in connect_bsp_APIC() has
been removed, as with the newly introduced mixed mode this would require more
fine grained printing, or else would be incorrect.  The addressing mode can
already be derived from the APIC driver in use, which is printed by different
helpers.

Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Henry Wang <Henry.Wang@arm.com>
master commit: e3c409d59a
master date: 2023-11-07 09:59:48 +0000
2023-12-12 14:47:02 +01:00
Andrew Cooper 011d20a69c docs: Fix IOMMU command line docs some more
Make the command line docs match the actual implementation, and state that the
default behaviour is selected at compile time.

Fixes: 980d6acf15 ("IOMMU: make DMA containment of quarantined devices optional")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 850382254b
master date: 2023-10-31 15:48:07 +0000
2023-11-14 13:59:40 +01:00
Jan Beulich bb13e63143 x86: support data operand independent timing mode
[1] specifies a long list of instructions which are intended to exhibit
timing behavior independent of the data they operate on. On certain
hardware this independence is optional, controlled by a bit in a new
MSR. Provide a command line option to control the mode Xen and its
guests are to operate in, with a build time control over the default.
Longer term we may want to allow guests to control this.

Since Arm64 supposedly also has such a control, put command line option
and Kconfig control in common files.

[1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/best-practices/data-operand-independent-timing-isa-guidance.html

Requested-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: bad1ac345b
master date: 2023-10-20 15:50:05 +0200
2023-11-14 13:58:18 +01:00
Roger Pau Monné ee4ce01198 iommu: fix quarantine mode command line documentation
With the addition of per-device quarantine page tables the sink page is now
exclusive for each device, and thus writable.  Update the documentation to
reflect the current implementation.

Fixes: 14dd241aad ('IOMMU/x86: use per-device page tables for quarantining')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 94a5127ebe
master date: 2023-10-19 21:52:52 +0100
2023-11-14 13:56:13 +01:00
Michal Orzel 6384cdf0c3 x86: Clarify that only 5 hypercall parameters are supported
The x86 hypercall ABI really used to have 6-argument hypercalls.  V4V, the
downstream predecessor to Argo did take 6th args.

However, the 6th arg being %ebp in the 32bit ABI makes it unusable in
practice, because that's the frame pointer in builds with frame pointers
enabled.  Therefore Argo was altered to being a 5-arg hypercall when it was
upstreamed.

c/s 2f531c122e ("x86: limit number of hypercall parameters to 5") removed
the ability for hypercalls to take 6 arguments.

Update the documentation to match reality.

Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
master commit: c035151902
master date: 2023-10-10 10:03:49 +0100
2023-11-14 13:52:01 +01:00
Andrew Cooper 2e87f3a03a docs/sphinx: Switch hypercall-abi.rst to named footnotes
This will simplify inserting a new one in the middle.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 1357f1fa58
master date: 2023-10-10 10:03:49 +0100
2023-11-14 13:51:41 +01:00
Roger Pau Monne 46d00dbf4c libxl: limit bootloader execution in restricted mode
Introduce a timeout for bootloader execution when running in restricted mode.

Allow overwriting the default time out with an environment provided value.

This is part of XSA-443 / CVE-2023-34325

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
(cherry picked from commit 9c114178ff)
2023-09-29 15:54:00 +02:00
Roger Pau Monne 42bf49d74b libxl: add support for running bootloader in restricted mode
Much like the device model depriv mode, add the same kind of support for the
bootloader.  Such feature allows passing a UID as a parameter for the
bootloader to run as, together with the bootloader itself taking the necessary
actions to isolate.

Note that the user to run the bootloader as must have the right permissions to
access the guest disk image (in read mode only), and that the bootloader will
be run in non-interactive mode when restricted.

If enabled bootloader restrict mode will attempt to re-use the user(s) from the
QEMU depriv implementation if no user is provided on the configuration file or
the environment.  See docs/features/qemu-deprivilege.pandoc for more
information about how to setup those users.

Bootloader restrict mode is not enabled by default as it requires certain
setup to be done first (setup of the user(s) to use in restrict mode).

This is part of XSA-443 / CVE-2023-34325

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
(cherry picked from commit 1f762642d2)
2023-09-29 15:54:00 +02:00
Andrew Cooper 9ac2f49f5f x86/spec-ctrl: Mitigate the Zen1 DIV leakage
In the Zen1 microarchitecure, there is one divider in the pipeline which
services uops from both threads.  In the case of #DE, the latched result from
the previous DIV to execute will be forwarded speculatively.

This is an interesting covert channel that allows two threads to communicate
without any system calls.  In also allows userspace to obtain the result of
the most recent DIV instruction executed (even speculatively) in the core,
which can be from a higher privilege context.

Scrub the result from the divider by executing a non-faulting divide.  This
needs performing on the exit-to-guest paths, and ist_exit-to-Xen.

Alternatives in IST context is believed safe now that it's done in NMI
context.

This is XSA-439 / CVE-2023-20588.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit b5926c6ecf)
2023-09-19 19:36:49 +01:00
Andrew Cooper b9ade05cbb x86/spec-ctrl: Mitigate Gather Data Sampling
This is part of XSA-435 / CVE-2022-40982

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 56d690efd3)
2023-08-08 16:02:17 +01:00
Andrew Cooper 24b37f9538 x86/spec-ctrl: Mitigate Speculative Return Stack Overflow
On native, synthesise the SRSO bits by probing various hardware properties as
given by AMD.

Extend the IBPB-on-entry mitigations to Zen3/4 CPUs.  There is a microcode
prerequisite to make this an effective mitigation.

This is part of XSA-434 / CVE-2023-20569

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 220c06e6fe)
2023-08-08 16:02:17 +01:00
Roger Pau Monne 7374a8d770 libxl: use the cpuid feature names from cpufeatureset.h
The current implementation in libxl_cpuid_parse_config() requires
keeping a list of cpuid feature bits that should be mostly in sync
with the contents of cpufeatureset.h.

Avoid such duplication by using the automatically generated list of
cpuid features in INIT_FEATURE_NAMES in order to map feature names to
featureset bits, and then translate from featureset bits into cpuid
leaf, subleaf, register tuple.

Note that the full contents of the previous cpuid translation table
can't be removed.  That's because some feature names allowed by libxl
are not described in the featuresets, or because naming has diverged
and the previous nomenclature is preserved for compatibility reasons.

Should result in no functional change observed by callers, albeit some
new cpuid features will be available as a result of the change.

While there constify cpuid_flags name field.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
(cherry picked from commit d638fe233c)
2023-08-08 16:02:17 +01:00
Luca Fancellu 3d0aa6f23d xen/arm: Add Cortex-A77 erratum 1508412 handling
Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence of a
store-exclusive or read of PAR_EL1 and a load with device or non-cacheable
memory attributes.
A workaround is available, but it depends on a firmware counterpart.

The proposed workaround from the errata document is to modify the software
running at EL1 and above to include a DMB SY before and after accessing
PAR_EL1.

In conjunction to the above, the firmware needs to use a specific write
sequence to several IMPLEMENTATION DEFINED registers to have the hardware
insert a DMB SY after all load-exclusive and store-exclusive instructions.

Apply the workaround to Xen where PAR_EL1 is read, implementing an helper
function to do that.
Since Xen can be interrupted by irqs in any moment, add a barrier on
entry/exit when we are running on the affected cores.

A guest without the workaround can deadlock the system, so warn the users
of Xen with the above type of cores to use only trusted guests, by
printing a message on Xen startup.

This is XSA-436 / CVE-2023-34320.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
[stefano: add XSA-436 to commit message]
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2023-08-01 16:05:31 -07:00
Yann Dirson 1ca795ae8a docs/man: fix xenstore-write synopsis
Reported-by: zithro <slack@rabbit.lu>
Signed-off-by: Yann Dirson <yann.dirson@vates.fr>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 8b1ac353b4
master date: 2023-05-09 10:37:29 +0100
2023-05-23 14:55:11 +02:00
Roger Pau Monné b745ff3011 x86/vmx: implement Notify VM Exit
Under certain conditions guests can get the CPU stuck in an unbounded
loop without the possibility of an interrupt window to occur on
instruction boundary.  This was the case with the scenarios described
in XSA-156.

Make use of the Notify VM Exit mechanism, that will trigger a VM Exit
if no interrupt window occurs for a specified amount of time.  Note
that using the Notify VM Exit avoids having to trap #AC and #DB
exceptions, as Xen is guaranteed to get a VM Exit even if the guest
puts the CPU in a loop without an interrupt window, as such disable
the intercepts if the feature is available and enabled.

Setting the notify VM exit window to 0 is safe because there's a
threshold added by the hardware in order to have a sane window value.

Note the handling of EXIT_REASON_NOTIFY in the nested virtualization
case is passed to L0, and hence a nested guest being able to trigger a
notify VM exit with an invalid context would be able to crash the L1
hypervisor (by L0 destroying the domain).  Since we don't expose VM
Notify support to L1 it should already enable the required
protections in order to prevent VM Notify from triggering in the first
place.

Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>

x86/vmx: Partially revert "x86/vmx: implement Notify VM Exit"

The original patch tried to do two things - implement VMNotify, and
re-optimise VT-x to not intercept #DB/#AC by default.

The second part is buggy in multiple ways.  Both GDBSX and Introspection need
to conditionally intercept #DB, which was not accounted for.  Also, #DB
interception has nothing at all to do with cpu_has_monitor_trap_flag.

Revert the second half, leaving #DB/#AC intercepted unilaterally, but with
VMNotify active by default when available.

Fixes: 573279cde1 ("x86/vmx: implement Notify VM Exit")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: 573279cde1
master date: 2022-12-19 11:24:14 +0100
master commit: 5f08bc9404
master date: 2023-01-20 19:39:32 +0000
2023-03-21 13:42:43 +01:00
Marek Marczykowski-Górecki 74b76704fd credit2: respect credit2_runqueue=all when arranging runqueues
Documentation for credit2_runqueue=all says it should create one queue
for all pCPUs on the host. But since introduction
sched_credit2_max_cpus_runqueue, it actually created separate runqueue
per socket, even if the CPUs count is below
sched_credit2_max_cpus_runqueue.

Adjust the condition to skip syblink check in case of
credit2_runqueue=all.

Fixes: 8e2aa76dc1 ("xen: credit2: limit the max number of CPUs in a runqueue")
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
master commit: 1f5747ee92
master date: 2023-02-15 16:12:42 +0100
2023-03-03 07:57:39 +01:00
Andrew Cooper 8202b9cf84 x86/shskt: Disable CET-SS on parts susceptible to fractured updates
Refer to Intel SDM Rev 70 (Dec 2022), Vol3 17.2.3 "Supervisor Shadow Stack
Token".

Architecturally, an event delivery which starts in CPL<3 and switches shadow
stack will first validate the Supervisor Shadow Stack Token (setting the busy
bit), then pushes CS/LIP/SSP.  One example of this is an NMI interrupting Xen.

Some CPUs suffer from an issue called fracturing, whereby a fault/vmexit/etc
between setting the busy bit and completing the event injection renders the
action non-restartable, because when it comes time to restart, the busy bit is
found to be already set.

This is far more easily encountered under virt, yet it is not the fault of the
hypervisor, nor the fault of the guest kernel.  The fault lies somewhere
between the architectural specification, and the uarch behaviour.

Intel have allocated CPUID.7[1].ecx[18] CET_SSS to enumerate that supervisor
shadow stacks are safe to use.  Because of how Xen lays out its shadow stacks,
fracturing is not expected to be a problem on native.

Detect this case on boot and default to not using shstk if virtualised.
Specifying `cet=shstk` on the command line will override this heuristic and
enable shadow stacks irrespective.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 01e7477d1b
master date: 2023-02-09 18:26:17 +0000
2023-03-03 07:56:16 +01:00
Andrew Cooper 3685e754e6 x86/spec-ctrl: Mitigate Cross-Thread Return Address Predictions
This is XSA-426 / CVE-2022-27672

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 63305e5392)
2023-02-14 17:53:49 +00:00
Michal Orzel ddcc208ccd docs/misc/arm: Update references to Linux kernel docs
Some time ago, Linux switched the format of docs to ReST and the format
of device-tree bindings to json-schema.

Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
2022-12-01 10:43:05 +00:00
Andrew Cooper e5ac68a011 x86/hvm: Revert per-domain APIC acceleration support
I was really hoping to avoid this, but its now too late in the 4.17 freeze and
we still don't have working fixes.

The in-Xen calculations for assistance capabilities are buggy.  For the
avoidance of doubt, the original intention was to be able to control every
aspect of a APIC acceleration so we could comprehensively test Xen's support,
as it has proved to be buggy time and time again.

Even after a protracted discussion on what the new API ought to mean, attempts
to apply it to the existing logic have been unsuccessful, proving that the
API/ABI is too complicated for most people to reason about.

This reverts most of:
  2ce11ce249
  6b2b9b3405

leaving in place the non-APIC specific changes (minimal as they are).

This takes us back to the behaviour of Xen 4.16 where APIC acceleration is
configured on a per system basis.

This work will be revisted in due course.

Fixes: 2ce11ce249 ("x86/HVM: allow per-domain usage of hardware virtualized APIC")
Fixes: 6b2b9b3405 ("x86: report Interrupt Controller Virtualization capabilities")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
2022-11-17 16:51:51 +00:00
Roger Pau Monne b2030e6730 amd/virt_ssbd: set SSBD at vCPU context switch
This fixes an issue with running C code in a GIF=0 region, that's
problematic when using UBSAN or other instrumentation techniques.

The current logic for AMD SSBD context switches it on every
vm{entry,exit} if the Xen and guest selections don't match.  This is
expensive when not using SPEC_CTRL, and hence should be avoided as
much as possible.

When SSBD is not being set from SPEC_CTRL on AMD don't context switch
at vm{entry,exit} and instead only context switch SSBD when switching
vCPUs.  This has the side effect of running Xen code with the guest
selection of SSBD, the documentation is updated to note this behavior.
Also note that then when `ssbd` is selected on the command line guest
SSBD selection will not have an effect, and the hypervisor will run
with SSBD unconditionally enabled when not using SPEC_CTRL itself.

As a result of no longer running the code to set SSBD in a GIF=0
region the locking of amd_set_legacy_ssbd() can be done using normal
spinlocks, and some more checks can be added to assure it works as
intended.

Finally it's also worth noticing that since the guest SSBD selection
is no longer set on vmentry the VIRT_SPEC_MSR handling needs to
propagate the value to the hardware as part of handling the wrmsr.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

Extend the msrs->virt_spec_ctrl context switching comment.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
2022-11-16 00:18:42 +00:00
Juergen Gross 1283af6465 tools/xenstore: remove XEN_LIB_STORED and XENSTORED_ROOTDIR
XEN_LIB_STORED is serving no real purpose, as it is a mount point for
a tmpfs, so it can be replaced easily by XEN_RUN_STORED.

XENSTORED_ROOTDIR is basically unused already, there is just a single
reference in xs_daemon_rootdir() with a fallback to XEN_LIB_STORED,
and a .gdbinit file setting it.

Remove the .gdbinit file, as it is not known having been used since
ages, and make xs_daemon_rootdir() an alias of xs_daemon_rundir().

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
2022-11-02 12:07:57 +01:00
Juergen Gross d084d2c6df docs: enhance xenstore.txt with permissions description
The permission scheme of Xenstore nodes is not really covered by
docs/misc/xenstore.txt, other than referring to the Xen wiki.

Add a paragraph explaining the permissions of nodes, and especially
mentioning removal of nodes when a domain has been removed from
Xenstore.

This is part of XSA-419.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-11-01 13:05:44 +00:00
Juergen Gross 9c484bef83 tools/xenstore: add control command for setting and showing quota
Add a xenstore-control command "quota" to:
- show current quota settings
- change quota settings
- show current quota related values of a domain

Note that in the case the new quota is lower than existing one,
Xenstored may continue to handle requests from a domain exceeding the
new limit (depends on which one has been broken) and the amount of
resource used will not change. However the domain will not be able to
create more resource (associated to the quota) until it is back to below
the limit.

This is part of XSA-326.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-11-01 13:05:44 +00:00
Artem Bityutskiy 9fc9a5c216 x86/mwait-idle: add 'preferred-cstates' command line option
On Sapphire Rapids Xeon (SPR) the C1 and C1E states are basically mutually
exclusive - only one of them can be enabled. By default, 'intel_idle' driver
enables C1 and disables C1E. However, some users prefer to use C1E instead of
C1, because it saves more energy.

This patch adds a new module parameter ('preferred_cstates') for enabling C1E
and disabling C1. Here is the idea behind it.

1. This option has effect only for "mutually exclusive" C-states like C1 and
   C1E on SPR.
2. It does not have any effect on independent C-states, which do not require
   other C-states to be disabled (most states on most platforms as of today).
3. For mutually exclusive C-states, the 'intel_idle' driver always has a
   reasonable default, such as enabling C1 on SPR by default. On other
   platforms, the default may be different.
4. Users can override the default using the 'preferred_cstates' parameter.
5. The parameter accepts the preferred C-states bit-mask, similarly to the
   existing 'states_off' parameter.
6. This parameter is not limited to C1/C1E, and leaves room for supporting
   other mutually exclusive C-states, if they come in the future.

Today 'intel_idle' can only be compiled-in, which means that on SPR, in order
to disable C1 and enable C1E, users should boot with the following kernel
argument: intel_idle.preferred_cstates=4

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Origin: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git da0e58c038e6

Enable C1E (if requested) not only on the BSP's socket / package. Alter
command line option to fit our model, and extend it to also accept
string form arguments.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
2022-10-13 17:52:36 +02:00
Henry Wang cbea5a1149 xen/arm: Allocate and free P2M pages from the P2M pool
This commit sets/tearsdown of p2m pages pool for non-privileged Arm
guests by calling `p2m_set_allocation` and `p2m_teardown_allocation`.

- For dom0, P2M pages should come from heap directly instead of p2m
pool, so that the kernel may take advantage of the extended regions.

- For xl guests, the setting of the p2m pool is called in
`XEN_DOMCTL_shadow_op` and the p2m pool is destroyed in
`domain_relinquish_resources`. Note that domctl->u.shadow_op.mb is
updated with the new size when setting the p2m pool.

- For dom0less domUs, the setting of the p2m pool is called before
allocating memory during domain creation. Users can specify the p2m
pool size by `xen,domain-p2m-mem-mb` dts property.

To actually allocate/free pages from the p2m pool, this commit adds
two helper functions namely `p2m_alloc_page` and `p2m_free_page` to
`struct p2m_domain`. By replacing the `alloc_domheap_page` and
`free_domheap_page` with these two helper functions, p2m pages can
be added/removed from the list of p2m pool rather than from the heap.

Since page from `p2m_alloc_page` is cleaned, take the opportunity
to remove the redundant `clean_page` in `p2m_create_table`.

This is part of CVE-2022-33747 / XSA-409.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2022-10-11 14:28:44 +02:00
Henry Wang 156a239ea2 libxl, docs: Add per-arch extra default paging memory
This commit adds a per-arch macro `EXTRA_DEFAULT_PAGING_MEM_MB`
to the default paging memory size, in order to cover the p2m
pool for extended regions of a xl-based guest on Arm.

For Arm, the extra default paging memory is 128MB.
For x86, the extra default paging memory is zero, since there
are no extended regions on x86.

Also update the xl.cfg documentation to add Arm documentation
according to code changes.

This is part of CVE-2022-33747 / XSA-409.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-10-11 14:28:37 +02:00
Marek Marczykowski-Górecki bebaf7c296 drivers/char: add console=ehci as an alias for console=dbgp
Make it consistent with console=xhci.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2022-09-26 11:13:31 +02:00
Marek Marczykowski-Górecki 72cab2289e drivers/char: allow driving the rest of XHCI by a domain while Xen uses DbC
That's possible, because the capability was designed specifically to
allow separate driver handle it, in parallel to unmodified xhci driver
(separate set of registers, pretending the port is "disconnected" for
the main xhci driver etc). It works with Linux dom0, although requires
an awful hack - re-enabling bus mastering behind dom0's backs.
Linux driver does similar thing - see
drivers/usb/early/xhci-dbc.c:xdbc_handle_events().

When controller sharing is enabled in kconfig (option marked as
experimental), dom0 is allowed to use the controller even if Xen uses it
for debug console. Additionally, option `dbgp=xhci,share=` is available
to either prevent even dom0 from using it (`no` value), or allow any
domain using it (`any` value).

In any case, to avoid Linux messing with the DbC, mark this MMIO area as
read-only. This might cause issues for Linux's driver (if it tries to
write something on the same page - like anoter xcap), but makes Xen's
use safe. In practice, as of Linux 5.18, it seems to work without
issues.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2022-09-26 11:13:06 +02:00
Marek Marczykowski-Górecki d88e2aa4ea drivers/char: add RX support to the XHCI driver
Add another work ring buffer for received data, and point IN TRB at it.
Ensure there is always at least one pending IN TRB, so the controller
has a way to send incoming data to the driver.
Note that both "success" and "short packet" completion codes are okay -
in fact it will be "short packet" most of the time, as the TRB length is
about maximum size, not required size.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2022-09-26 11:12:03 +02:00
Marek Marczykowski-Górecki 022e40edd4 drivers/char: allow using both dbgp=xhci and dbgp=ehci
This allows configuring EHCI and XHCI consoles separately,
simultaneously, such that e.g. one can be used for the console and the
other by the debugger.

This changes string_param() to custom_param() in both ehci and xhci
drivers. Both drivers parse only values applicable to them.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2022-09-26 11:09:19 +02:00
Henry Wang 942ac5fc15 xen/arm, device-tree: Make static-mem use #{address,size}-cells
In order to keep consistency in the device tree binding, there is
no need for static memory allocation feature to define a specific
set of address and size cells for "xen,static-mem" property.

Therefore, this commit reuses the regular #{address,size}-cells
for parsing the device tree "xen,static-mem" property. Update
the documentation accordingly.

Also, take the chance to remove the unnecessary "#address-cells"
and "#size-cells" in the domU1 node of the device tree to only
emphasize the related part that the example is showing.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
2022-09-09 13:49:02 -07:00
Penny Zheng 1d98281adf xen/arm: introduce static shared memory
This patch series introduces a new feature: setting up static
shared memory on a dom0less system, through device tree configuration.

This commit parses shared memory node at boot-time, and reserve it in
bootinfo.reserved_mem to avoid other use.

This commits proposes a new Kconfig CONFIG_STATIC_SHM to wrap
static-shm-related codes, and this option depends on static memory(
CONFIG_STATIC_MEMORY). That's because that later we want to reuse a few
helpers, guarded with CONFIG_STATIC_MEMORY, like acquire_staticmem_pages, etc,
on static shared memory.

Signed-off-by: Penny Zheng <penny.zheng@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2022-09-09 12:57:57 -07:00
Henry Wang 9066d877bf docs/device-tree: Place the static-heap dt-binding in proper place
The static-heap dt-binding should be placed after the last feature,
namely static-evtchn.

Fixes: 4596329291 ("docs, xen/arm: Introduce static heap memory")
Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-09-09 10:07:34 +01:00
Juergen Gross 6bc1c1aba0 tools/xenstore: add migration stream extensions for new features
Extend the definition of the Xenstore migration stream to cover new
features:

- per domain features
- extended watches (watch depth)
- per domain quota

Some of those additions (per domain features and extended watches)
require bumping the migration stream version to "2", as usage of those
features will require to transport mandatory new information in the
migration stream.

One note regarding the GLOBAL_QUOTA_DATA record: the split of quota
between global and per-domain ones is meant to support the possibility
to pass on unknown quota settings for newly created domains to other
Xenstore instances:

Imagine Xenstore A knows about global quota g and domain quota d, while
Xenstore B doesn't know both. Initially I'm running Xenstore A on a
host, then I'm live-updating to B.

B gets the information that g is global, and d is per-domain, but has
no other idea what to do with the values of g and d. OTOH it knows that
each new domain should get d with the related value, so it can set d
for each newly created domain.

When B is either downgraded to A again, or a domain is migrated to
another host running A, B can add the quota information of d for all
domains.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-09-08 12:28:54 +01:00
Henry Wang 4596329291 docs, xen/arm: Introduce static heap memory
This commit introduces the static heap memory, which is parts of RAM
reserved in the beginning of the boot time for heap.

Firstly, since a new type of memory bank is needed for marking the
memory bank solely as the heap, this commit defines `enum membank_type`
and use this enum in function device_tree_get_meminfo(). Changes of
code are done accordingly following the introduction of this enum.

Also, this commit introduces the logic to parse the static heap
configuration in device tree. If the memory bank is reserved as heap
through `xen,static-heap` property in device tree `chosen` node, the
memory will be marked as static heap type.

A documentation section is added, describing the definition of static
heap memory and the method of enabling the static heap memory through
device tree at boot time.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Signed-off-by: Penny Zheng <penny.zheng@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-09-08 12:27:15 +01:00
Rahul Singh 1fe16b3ed7 xen/arm: introduce xen-evtchn dom0less property
Introduce a new sub-node under /chosen node to establish static event
channel communication between domains on dom0less systems.

An event channel will be created beforehand to allow the domains to
send notifications to each other.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2022-09-08 12:21:59 +01:00
Rahul Singh 4a6d155a84 xen/arm: introduce new xen,enhanced property value
Introduce a new "xen,enhanced" dom0less property value "no-xenstore" to
disable xenstore interface for dom0less guests.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2022-09-08 12:21:59 +01:00
Juergen Gross 3a2feae17e tools/xenstore: add documentation for extended watch command
Add documentation for an extension of the WATCH command used to limit
the scope of watched paths. Additionally it enables to receive more
information in the events related to special watches (@introduceDomain
or @releaseDomain).

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-09-08 09:28:30 +02:00
Juergen Gross 4d4cf97d41 tools/xenstore: add documentation for new set/get-quota commands
Add documentation for two new Xenstore wire commands SET_QUOTA and
GET_QUOTA used to set or query the global Xenstore quota or those of
a given domain.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-09-08 09:27:59 +02:00
Juergen Gross ace1d2eff8 tools/xenstore: minor fix of the migration stream doc
Drop mentioning the non-existent read-only socket in the migration
stream description document.

The related record field was removed in commit 8868a0e3f6 ("docs:
update the xenstore migration stream documentation).

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-09-08 09:25:58 +02:00
Anthony PERARD 62ca138c2c tools/libxl: Replace deprecated -soundhw on QEMU command line
-soundhw is deprecated since 825ff02911c9 ("audio: add soundhw
deprecation notice"), QEMU v5.1, and is been remove for upcoming v7.1
by 039a68373c45 ("introduce -audio as a replacement for -soundhw").

Instead we can just add the sound card with "-device", for most option
that "-soundhw" could handle. "-device" is an option that existed
before QEMU 1.0, and could already be used to add audio hardware.

The list of possible option for libxl's "soundhw" is taken the list
from QEMU 7.0.

The list of options for "soundhw" are listed in order of preference in
the manual. The first three (hda, ac97, es1370) are PCI devices and
easy to test on Linux, and the last four are ISA devices which doesn't
seems to work out of the box on linux.

The sound card 'pcspk' isn't listed even if it used to be accepted by
'-soundhw' because QEMU crash when trying to add it to a Xen domain.
Also, it wouldn't work with "-device" might need to be "-machine
pcspk-audiodev=default" instead.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
2022-08-18 09:25:50 +02:00
Marek Marczykowski-Górecki deb23751e1 drivers/char: add support for selecting specific xhci
Handle parameters similar to dbgp=ehci.

Implement this by not resettting dbc->sbdf again in dbc_init_xhc(), but
using a value found there if non-zero. Additionally, add xue->xhc_num to
select n-th controller.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2022-08-16 11:22:54 +02:00
Connor Davis 791f216361 drivers/char: add support for USB3 DbC debugger
[Connor]
Xue is a cross-platform USB 3 debugger that drives the Debug
Capability (DbC) of xHCI-compliant host controllers. This patch
implements the operations needed for xue to initialize the host
controller's DbC and communicate with it. It also implements a struct
uart_driver that uses xue as a backend. Note that only target -> host
communication is supported for now. To use Xue as a console, add
'console=dbgp dbgp=xhci' to the command line.

[Marek]
The Xue driver is taken from https://github.com/connojd/xue and heavily
refactored to fit into Xen code base. Major changes include:
- rename to xhci_dbc
- drop support for non-Xen systems
- drop xue_ops abstraction
- use Xen's native helper functions for PCI access
- move all the code to xue.c, drop "inline"
- build for x86 only
- annotate functions with cf_check
- adjust for Xen's code style

At this stage, only the first xHCI is considered, and only output is
supported. Later patches add support for choosing specific device, and
input handling.
The driver is initiallized before memory allocator works, so all the
transfer buffers (about 230KiB of them) are allocated statically and will
use memory even if XUE console is not selected. The driver can be
disabled build time to reclaim this memory.
Most of this memory is shared with the controller via DMA. Later patch
will adjust structures placement to avoid anything else to be placed on
those DMA-reachable pages. This also means str_buf cannot use static
initializer, without reserving (at least) a whole page page in .data (or
more, when combined with other structures).

Signed-off-by: Connor Davis <davisc@ainfosec.com>
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2022-08-16 11:20:01 +02:00
Jan Beulich 3caa5a3f03 docs: correct x86 MCE command line option info
Not even the types were correct, let alone defaults being spelled out or
the purpose of the options actually mentioned in any way.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2022-08-09 11:52:49 +02:00
Juergen Gross e2bd45f4ca tools/xenstore: add documentation for new set/get-feature commands
Add documentation for two new Xenstore wire commands SET_FEATURE and
GET_FEATURE used to set or query the Xenstore features visible in the
ring page of a given domain.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-08-05 08:36:54 +02:00
Bertrand Marquis 8a5116371d doc: Add git commands to generate Fixes
Add git commands examples that can be used to generate fixes and how to
use the pretty configuration for git.
This should make it easier for contributors to have the right format.

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-08-04 17:48:01 +01:00