AMD have updated the SRSO whitepaper[1] with further information. These
features exist on AMD Zen5 CPUs and are necessary for Xen to use.
The two features are in principle unrelated:
* SRSO_U/S_NO is an enumeration saying that SRSO attacks can't cross the
User(CPL3) / Supervisor(CPL<3) boundary. i.e. Xen don't need to use
IBPB-on-entry for PV64. PV32 guests are explicitly unsupported for
speculative issues, and excluded from consideration for simplicity.
* SRSO_MSR_FIX is an enumeration identifying that the BP_SPEC_REDUCE bit is
available in MSR_BP_CFG. When set, SRSO attacks can't cross the host/guest
boundary. i.e. Xen don't need to use IBPB-on-entry for HVM.
Extend ibpb_calculations() to account for these when calculating
opt_ibpb_entry_{pv,hvm} defaults. Add a `bp-spec-reduce=<bool>` option to
control the use of BP_SPEC_REDUCE, with it active by default.
Because MSR_BP_CFG is core-scoped with a race condition updating it, repurpose
amd_check_erratum_1485() into amd_check_bp_cfg() and calculate all updates at
once.
Xen also needs to to advertise SRSO_U/S_NO to guests to allow the guest kernel
to skip SRSO mitigations too:
* This is trivial for HVM guests. It is also is accurate for PV32 guests
too, but we have already excluded them from consideration, and do so again
here to simplify the policy logic.
* As written, SRSO_U/S_NO does not help for the PV64 user->kernel boundary.
However, after discussing with AMD, an implementation detail of having
BP_SPEC_REDUCE active causes the PV64 user->kernel boundary to have the
property described by SRSO_U/S_NO, so we can advertise SRSO_U/S_NO to
guests when the BP_SPEC_REDUCE precondition is met.
Finally, fix a typo in the SRSO_NO's comment.
[1] https://www.amd.com/content/dam/amd/en/documents/corporate/cr/speculative-return-stack-overflow-whitepaper.pdf
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: a1746cd443
master date: 2025-01-02 18:44:49 +0000
Rename all instances of ECLAIR MISRA C:2012 service identifiers,
identified by the prefix MC3R1, to use the prefix MC3A2, which
refers to MISRA C:2012 Amendment 2 guidelines.
This update is motivated by the need to upgrade ECLAIR GitLab runners
that use the new naming scheme for MISRA C:2012 Amendment 2 guidelines.
Changes to the docs/misra directory are needed in order to keep
comment-based deviation up to date.
Signed-off-by: Alessandro Zucchelli <alessandro.zucchelli@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 631f535a3d)
(cherry picked from commit 8b584c97f8)
Right now, Xen clobbers the value at 0xffc when performing it's load-base
calculation. We've got plenty of free registers at this point, so the value
can be preserved easily.
This fixes a real bug booting under Coreboot+SeaBIOS, where 0xffc happens to
be the cbmem pointer (e.g. Coreboot's dmesg ring, among other things).
However, there's also a better choice of memory location to use than 0xffc, as
all our supported boot protocols have a pointer to an info structure in %ebx.
Update the documentation to match.
Fixes: 1695e53851 ("x86/boot: Fix the boot time relocation calculations")
Fixes: d96bb172e8 ("x86/entry: Early PVH boot code")
Signed-off-by: Frediano Ziglio <frediano.ziglio@cloud.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: e58a2858d5
master date: 2024-08-27 18:08:19 +0100
PHYSDEVOP_pirq_eoi_gmfn_v<N> accepting just a single GFN implies that no
more than 32k pIRQ-s can be used by a domain on x86. Document this upper
bound.
To also enforce the limit, (ab)use both arch_hwdom_irqs() (changing its
parameter type) and setup_system_domains(). This is primarily to avoid
exposing the two static variables or introducing yet further arch hooks.
While touching arch_hwdom_irqs() also mark it hwdom-init.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
amend 'cmdline: document and enforce "extra_guest_irqs" upper bounds'
Address late review comments for what is now commit 17f6d398f7:
- bound max_irqs right away against nr_irqs
- introduce a #define for a constant used twice
Requested-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 17f6d398f7
master date: 2024-07-02 12:00:27 +0200
master commit: 1f56accba3
master date: 2024-07-03 14:03:27 +0200
Out of an abudnance of caution, implement the long loop too, and allowing for
it to be opted in to.
This is part of XSA-456 / CVE-2024-2201.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit d5887c0dec)
In the absence of BHI_DIS_S, mitigating Native-BHI requires the use of a
software sequence.
Introduce a new bhb-seq= option to select between avaialble sequences and
bhb-entry= to control the per-PV/HVM actions like we have for other blocks.
Activate the short sequence by default for PV and HVM guests on affected
hardware if BHI_DIS_S isn't present.
This is part of XSA-456 / CVE-2024-2201.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 689ad48ce9)
Introduce a "bhi-dis-s" boolean to match the other options we have for
MSR_SPEC_CTRL values. Also introduce bhi_calculations().
Use BHI_DIS_S whenever possible.
Guests which are levelled to be migration compatible with older CPUs can't see
BHI_DIS_S, and Xen must fill in the difference to make the guest safe. Use
the virt MSR_SPEC_CTRL infrastructure to force BHI_DIS_S behind the guest's
back.
This is part of XSA-456 / CVE-2024-2201.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 62a1106415)
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)
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)
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
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
sphinx-build reports:
docs/designs/launch/hyperlaunch.rst: WARNING: document isn't included in any toctree
docs/designs/launch/hyperlaunch-devicetree.rst: WARNING: document isn't included in any toctree
docs/misc/xen-makefiles/makefiles.rst: WARNING: document isn't included in any toctree
docs/misra/C-language-toolchain.rst: WARNING: document isn't included in any toctree
docs/misra/C-runtime-failures.rst: WARNING: document isn't included in any toctree
docs/misra/documenting-violations.rst: WARNING: document isn't included in any toctree
docs/misra/exclude-list.rst: WARNING: document isn't included in any toctree
docs/misra/xen-static-analysis.rst: WARNING: document isn't included in any toctree
Create an up-to-date index.rst in misra/ create an "unsorted docs" section at
the top level to contain everything else. They can be re-filed at a later
date.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
(cherry picked from commit fb41228ece)
sphinx-build reports:
docs/misra/exclude-list.rst:50: WARNING: Inline emphasis start-string without end-string.
'*' either needs escaping, or put in a literal block.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
(cherry picked from commit ab03b284b4)
sphinx-build reports:
docs/designs/launch/hyperlaunch.rst:111: WARNING: Title underline too short.
docs/designs/launch/hyperlaunch.rst:203: WARNING: Unexpected indentation.
docs/designs/launch/hyperlaunch.rst:216: WARNING: Unexpected indentation.
Nested lists require newlines as delimiters.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
(cherry picked from commit 93ad5dd974)
These 3 Kconfig docs were imported from Linux erroneously. They are
GPL-2.0-only in Linux, but have no SPDX tag and were placed in such a way to
be included by the blanket statement saying that all RST files are CC-BY-4.0.
We should not be carrying a shadow copy of these docs. They aren't even wired
into our Sphinx docs, and anyone wanting to refer to Kconfig docs is going to
look at the Linux docs anyway. These, and more docs can be found at:
https://www.kernel.org/doc/html/latest/kbuild/
which also have corrections vs the snapshot we took.
Fixes: f80fe2b34f ("xen: Update Kconfig to Linux v5.4")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
(cherry picked from commit 044503f61c)
One file is missing an SDPX tag, but is covered by the blanketing license
statement in docs/README.sources saying that RST files are CC-BY-4.0
Fixes: 3c911be55f ("docs/misra: document the C dialect and translation toolchain assumptions.")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
(cherry picked from commit 8ee1a332b4)
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>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
(cherry picked from commit 850382254b)
In commit 9d267c049d ("xen/arm64: Rework the memory layout"),
we decided to require Xen to be loaded below 2 TiB to simplify
the logic to enable the MMU. The limit was decided based on
how known platform boot plus some slack.
We had a recent report that this is not sufficient on the AVA
platform with a old firmware [1]. But the restriction is not
going to change in Xen 4.18. So document the limit clearly
in docs/misc/arm/booting.txt.
[1] https://lore.kernel.org/20231013122658.1270506-3-leo.yan@linaro.org
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
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>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
This file contains the deviation that are not marked by
a deviation comment, as specified in
docs/misra/documenting-violations.rst.
Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
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>
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>
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>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
During the discussions that led to the acceptance of Rule 2.1, we
decided on a few exceptions that were not properly recorded in
rules.rst. Add them now.
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Bertrand Marquis <bertrand.marquis@arm.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Add 14.3, with project-wide deviations.
Also take the opportunity to clarify that parameters of function pointer
types are expected to have names (Rule 8.2).
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Bertrand Marquis <bertrand.marquis@arm.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
The credit scheduler tries as hard as it can to ensure that it always
runs scheduling units with positive credit (PRI_TS_UNDER) before
running those with negative credit (PRI_TS_OVER). If the next
runnable scheduling unit is of priority OVER, it will always run the
load balancer, which will scour the system looking for another
scheduling unit of the UNDER priority.
Unfortunately, as the number of cores on a system has grown, the cost
of the work-stealing algorithm has dramatically increased; a recent
trace on a system with 128 cores showed this taking over 50
microseconds.
Add a parameter, load_balance_ratelimit, to limit the frequency of
load balance operations on a given pcpu. Default this to 1
millisecond.
Invert the load balancing conditional to make it more clear, and line
up more closely with the comment above it.
Overall it might be cleaner to have the last_load_balance checking
happen inside csched_load_balance(), but that would require either
passing both now and spc into the function, or looking them up again;
both of which seemed to be worse than simply checking and setting the
values before calling it.
On a system with a vcpu:pcpu ratio of 2:1, running Windows guests
(which will end up calling YIELD during spinlock contention), this
patch increased performance significantly.
Signed-off-by: George Dunlap <george.dunlap@cloud.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Python distutils is deprecated and is going to be removed in Python
3.12. distutils.sysconfig is available as the sysconfig module in
stdlib since Python 2.7 and Python 3.2, so use that directly.
Update the README to reflect that we now depend on Python 2.7.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Javi Merino <javi.merino@cloud.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
[Regen ./configure]
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
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>
As per the last MISRA C group discussion, let's accept 11.7 (for which
we have no violations) and 11.8.
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
As stated in 'docs/misra/rules.rst' the functions that are used only by
asm modules do not need to conform to MISRA C:2012 Rule 8.4.
The deviations are carried out with a SAF comment.
Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Jan Beulich <jbeulich@suse.com>
10.1 with several caveats, described in the notes.
10.3 and 10.4 as "aspirational" guidelines, as clarified in the notes.
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Not displaying INFO messages by default on release builds is not
helpful, as messages of that level are relevant for hypervisor
operation. For example messages related to livepatches applied and
reverted are of INFO level.
Custom builds that require less verbose output can adjust it using the
command line, but attempt to provide all relevant information by
default on release builds.
Adjust the loglevel of printks that don't have an associated level to
INFO instead of WARNING, since INFO will now be printed by default on
all builds.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
During the discussions that led to the acceptance of the Rules, we
decided on a few exceptions that were not properly recorded in
rules.rst. Other times, the exceptions were decided later when it came
to enabling a rule in ECLAIR.
Either way, update rules.rst with appropriate notes.
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
From the Intel SDM: "Hardware-Controlled Performance States (HWP), which
autonomously selects performance states while utilizing OS supplied
performance guidance hints."
Enable HWP to run in autonomous mode by poking the correct MSRs. HWP is
disabled by default, and cpufreq=hwp enables it.
cpufreq= parsing is expanded to allow cpufreq=hwp;xen. This allows
trying HWP and falling back to xen if not available. Only hwp and xen
are supported for this fallback feature. hdc is a sub-option under hwp
(i.e. cpufreq=hwp,hdc=0) as is verbose.
There is no interface to configure - xen_sysctl_pm_op/xenpm will
be extended to configure in subsequent patches. It will run with the
default values, which should be the default 0x80 (out of 0x0-0xff)
energy/performance preference.
Unscientific powertop measurement of an mostly idle, customized OpenXT
install:
A 10th gen 6-core laptop showed battery discharge drop from ~9.x to
~7.x watts.
A 8th gen 4-core laptop dropped from ~10 to ~9
Power usage depends on many factors, especially display brightness, but
this does show a power saving in balanced mode when CPU utilization is
low.
HWP isn't compatible with an external governor - it doesn't take
explicit frequency requests. Therefore a minimal internal governor,
hwp, is also added as a placeholder.
While adding to the xen-command-line.pandoc entry, un-nest verbose from
minfreq. They are independent.
With cpufreq=hwp,verbose, HWP prints processor capabilities that are not
used by the code, like HW_FEEDBACK. This is done because otherwise
there isn't a convenient way to query the information.
Xen doesn't use the HWP interrupt, so it is disabled like in the Linux
pstate driver.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Add entries to the exclude-list.json for those files that need to be
excluded from the analysis scan.
Signed-off-by: Federico Serafini <federico.serafini@bugseng.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
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>
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>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
This option is particularly dubious as Xen does not use Protection Keys, owing
to the sharing of pagetables with PV guests. All this option does is hide PKU
by default from HVM guests, and is therefore redundant with the more generic
cpuid=no-pku.
The variable ought to be in __initdata given it's single user, but deleting it
entirely looks to be a better course of action.
Visibility of PKU to guests should be handled via its vm.cfg file.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Henry Wang <Henry.Wang@arm.com>
Add -e argument to xl console and pass to new escape_character argument
of libxl_console_exec.
Introduce a new API version to support this new argument and advertise
the new functionality in libxl.h
In libxl_console_exec, there are currently two call sites to execl,
which uses varargs, in order to support optionally passing
'start-notify-fd' to the console client. In order to support passing
the 'escape' argument optionally too, refactor to instead have a single
call site to execv, which has the same behavior but takes an array of
arguments.
If -e is not specified, --escape is not passed to the console client and
the existing value (^]) is used as a default.
Update the xl docs.
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
The documented option --usage worked because every unknown option
showed the help.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: George Dunlap <george.dunlap@cloud.com>
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>
Andrew Cooper