Commit Graph
1805 Commits
Author SHA1 Message Date
Julien Grall e1d08321ef docs/proces: branching-checklist: Update the section "add to patchbot"
Make clear the patchbot is accessible from the user "xen" on xenbits.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>

----
    Changes in v2:
        - Add Henry's reviewed-by
        - Add George's acked-by
2023-02-19 18:44:02 +00:00
Julien Grall 7708b13acf docs/process: branching-checklist: Remove section about the cambridge colo
The cambridge colo was internal to Citrix (now Cloud) and hasn't been used
by the community for a while.

So remove the section.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: George Dunlap <george.dunlap@cloud.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>

----
    Changes in v2:
        - Add George's acked-by
        - Add Henry's reviewed-by
2023-02-19 18:44:02 +00:00
Julien Grall 163b3cf7af docs/process: branching-checklist: Reword the section about Config.mk
Since at least Xen 4.12, the revision for external trees don't contain
the word "unstable". So explicitly list the *_REVISION variables that
need to be updated as part of the branching process.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>

----
    Changes in v2:
        * Explain what should be the tag format for each variables
2023-02-19 18:44:02 +00:00
Marek Marczykowski-Górecki 1f5747ee92 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>
2023-02-15 16:12:42 +01:00
Andrew Cooper 63305e5392 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>
2023-02-14 17:53:32 +00:00
Andrew Cooper 01e7477d1b 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>
2023-02-09 18:26:17 +00:00
Juergen Gross 789ed08abb docs: clarify xenstore permission documentation
In docs/misc/xenstore.txt the description of the Xenstore node access
permissions is missing one important aspect, which can be found only
in the code or in the wiki [1]:

The first permission entry is defining the owner of the node via the
domid, and the access rights for all domains NOT having a dedicated
permission entry.

Make that aspect clear in the official documentation.

[1]: https://wiki.xenproject.org/wiki/XenBus#Permissions

Reported-by: Edwin Török <edwin.torok@cloud.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2023-02-09 18:26:17 +00:00
Julien Grall 4e0e7a29d2 docs/process: branching-checklist: Clarify steps to add the branch in osstest
The steps to add the new branch in osstest doesn't mention the change
should be committed.

Update the steps to clarify that. Take the opportunity to switch to
use $v instead hardcoded version.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>
2023-02-09 17:07:28 +00:00
Julien Grall 6a6ae4ac34 docs/process: branching-checklist: Remove reference to root
The steps to generate the documentation for the new branch requires
to ssh as root and then su to run with the user xendocs.

The release technician may not (and should not) have access to root.
So update the step to directly ssh as xendocs.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: George Dunlap <george.dunlap@cloud.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>
2023-02-09 17:07:13 +00:00
Julien Grall f87a15f5cc docs/process: branching-checklist: Remove reference to qemu-ijw.git
Per [1], qemu-iwj.git was a clone of QEMU traditional on Ian's computer
for tagging QEMU trad.

The next section will provide tag for the official tree. So remove
the section about qemu-ijw.git.

[1] 25482.10006.140155.984629@chiark.greenend.org.uk

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: George Dunlap <george.dunlap@cloud.com>
Acked-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>
2023-02-09 17:04:41 +00:00
Julien Grall 5dbe775c2b docs/process: branching-checklist: Use consistent indentation
At the moment, branch-checklist.txt is using a mix of soft and hard
tab. They are both meant to be represented using 8 characters.

In Xen we tend to use 4-space softtab represented with 4 characters. So
to avoid  having to use a different editor configuration, switch all
the indentation to 4-space softtab.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: George Dunlap <george.dunlap@cloud.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>
2023-02-09 17:04:30 +00:00
Michal Orzel 6d317b10f8 xen/arm: Add support for booting gzip compressed uImages
At the moment, Xen does not support booting gzip compressed uImages.
This is because we are trying to decompress the kernel before probing
the u-boot header. This leads to a failure as the header always appears
at the top of the image (and therefore obscuring the gzip header).

Move the call to kernel_uimage_probe before kernel_decompress and make
the function self-containing by taking the following actions:
 - take a pointer to struct bootmodule as a parameter,
 - check the comp field of a u-boot header to determine compression type,
 - in case of compressed image, call kernel_decompress passing uImage
   header size as an offset to gzip header,
 - set up zimage.{kernel_addr,len} accordingly,
 - return -ENOENT in case of a u-boot header not found to distinguish it
   amongst other return values and make it the only case for falling
   through to try to probe other image types.

Modify kernel_decompress to take an additional parameter being an offset
to a gzip header from start address. This is needed so that a function
can first operate on a region containing actually compressed kernel (in case
of compressed uImage, size of u-boot header is an offset to a gzip header)
and then at the end pass the entire region (as it was before taking an offset
into account) to fw_unreserved_regions for freeing.

This approach avoids splitting the uImage probing into 2 stages (executed
before and after decompression) which otherwise would be necessary to
properly parse header, update boot module start and size before
decompression and update zimage.{kernel_addr,len} afterwards.

Remove the limitation from the booting.txt documentation.

Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewwed-by: Julien Grall <jgrall@amazon.com>
2023-02-08 13:57:57 +00:00
Juergen Gross ad58142e73 xen/public: move xenstore related doc into 9pfs.h
The Xenstore related documentation is currently to be found in
docs/misc/9pfs.pandoc, instead of the related header file
xen/include/public/io/9pfs.h like for most other paravirtualized
device protocols.

There is a comment in the header pointing at the document, but the
given file name is wrong. Additionally such headers are meant to be
copied into consuming projects (Linux kernel, qemu, etc.), so pointing
at a doc file in the Xen git repository isn't really helpful for the
consumers of the header.

This situation is far from ideal, which is already being proved by the
fact that neither qemu nor the Linux kernel are implementing the
device attach/detach protocol correctly.

Change that by moving the Xenstore related 9pfs documentation from
docs/misc/9pfs.pandoc into xen/include/public/io/9pfs.h.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2023-02-06 08:52:15 +01:00
Stefano Stabellini 4a1bceded2 Add more rules to docs/misra/rules.rst
As agreed during the last MISRA C discussion, I am adding the following
MISRA C rules: 7.1, 7.3, 18.3.

I am also adding 13.1 that was "agreed pending an analysis on the amount
of violations". There are zero violations reported by cppcheck.

Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2023-02-02 12:01:10 -08:00
Ayan Kumar Halder 78e93e6e57 xen/arm: Probe the load/entry point address of an uImage correctly
Currently, kernel_uimage_probe() does not read the load/entry point address
set in the uImge header. Thus, info->zimage.start is 0 (default value). This
causes, kernel_zimage_place() to treat the binary (contained within uImage)
as position independent executable. Thus, it loads it at an incorrect
address.

The correct approach would be to read "uimage.load" and set
info->zimage.start. This will ensure that the binary is loaded at the
correct address. Also, read "uimage.ep" and set info->entry (ie kernel entry
address).

If user provides load address (ie "uimage.load") as 0x0, then the image is
treated as position independent executable. Xen can load such an image at
any address it considers appropriate. A position independent executable
cannot have a fixed entry point address.

This behavior is applicable for both arm32 and arm64 platforms.

Earlier for arm32 and arm64 platforms, Xen was ignoring the load and entry
point address set in the uImage header. With this commit, Xen will use them.
This makes the behavior of Xen consistent with uboot for uimage headers.

Users who want to use Xen with statically partitioned domains, can provide
non zero load address and entry address for the dom0/domU kernel. It is
required that the load and entry address provided must be within the memory
region allocated by Xen.

A deviation from uboot behaviour is that we consider load address == 0x0,
to denote that the image supports position independent execution. This
is to make the behavior consistent across uImage and zImage.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
[stefano: minor doc improvement]
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2023-01-30 12:54:47 -08:00
Juergen Gross 1d2355d1c6 tools/xenstore: introduce trace classes
Make the xenstored internal trace configurable by adding classes
which can be switched on and off independently from each other.

Define the following classes:

- obj: Creation and deletion of interesting "objects" (watch,
  transaction, connection)
- io: incoming requests and outgoing responses
- wrl: write limiting

Per default "obj" and "io" are switched on.

Entries written via trace() will always be printed (if tracing is on
at all).

Add the capability to control the trace settings via the "log"
command and via a new "--log-control" command line option.

Add a missing trace_create() call for creating a transaction.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2023-01-20 09:23:51 +00:00
Michal Orzel 9c57a29737 xen/arm: Allow to set grant table related limits for dom0less domUs
At the moment, for dom0less domUs, we do not have a way to specify
per domain grant table related limits (unlike when using xl), namely
max version, max number of grant frames, max number of maptrack frames.
This means that such domains always use the values specified by the Xen
command line parameters or their default values if unspecified.

In order to have more control over dom0less domUs, introduce the
following device-tree properties that can be set under domUs nodes:
 - max_grant_version to set the maximum grant table version the domain
   is allowed to use,
 - max_grant_frames to set the maximum number of grant frames the domain
   is allowed to have,
 - max_maptrack_frames to set the maximum number of grant maptrack frames
   the domain is allowed to have.

Update documentation accordingly.

Note that the values obtained from device tree are of type uint32_t,
whereas the d_cfg.max_{grant_frames,maptrack_frames} are of type int32_t.
Call panic in case of overflow. Other sanity checks are already there in
grant_table_init() resulting in panic in case of errors, therefore no
need to repeat them in create_domUs().

Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2022-12-21 17:20:43 -08:00
Roger Pau Monné 573279cde1 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>
2022-12-19 11:24:14 +01:00
Viresh Kumar dd54ea500b docs: add documentation for generic virtio devices
This patch updates xl.cfg man page with details of generic Virtio device
related information.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
2022-12-14 12:03:38 +01:00
Luca Fancellu bc19af0bd4 xen: Justify linker script defined symbols in include/xen/kernel.h
Eclair and Coverity found violation of the MISRA rule 8.6 for the
symbols _start, _end, start, _stext, _etext, _srodata, _erodata,
_sinittext, _einittext which are declared in
xen/include/xen/kernel.h.
All those symbols are defined by the liker script so we can deviate
from the rule 8.6 for these cases.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
2022-12-12 14:19:20 -08:00
Luca Fancellu 02b26c02c7 xen/scripts: add cppcheck tool to the xen-analysis.py script
Add Cppcheck analysis to the xen-analysis.py script using the
arguments --run-cppcheck.

Now cppcheck analysis will build Xen while the analysis is performed
on the source files, it will produce a text report and an additional
html output when the script is called with --cppcheck-html.

With this patch cppcheck will benefit of platform configuration files
that will help it to understand the target of the compilation and
improve the analysis. These are XML files placed in
xen/tools/cppcheck-plat/, describing to cppcheck the length of basic
types to help it in the analysis.

To do so:
 - Update xen-analysis.py with the code to integrate cppcheck.
 - add platform configuration files for cppcheck..
 - add cppcheck-cc.sh script that is a wrapper for cppcheck and it's
   used as Xen compiler, it will intercept all flags given from the
   make build system and it will execute cppcheck on the compiled
   file together with the file compilation.
 - guarded hypercall-defs.c with CPPCHECK define because cppcheck
   gets confused as the file does not contain c code.
 - add false-positive-cppcheck.json file
 - update documentation.
 - update .gitignore

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
2022-12-12 14:19:11 -08:00
Luca Fancellu b4465e73b1 xen/scripts: add xen-analysis.py for coverity and eclair analysis
Add new script for coverity/eclair analysis tool that will enable
the procedure to suppress findings when these tool are used.
The procedure is documented in docs/misra/documenting-violations.rst
and the script is documented in docs/misra/xen-static-analysis.rst.

Add in docs/misra/ the files safe.json and
false-positive-{coverity,eclair}.json that are JSON files containing
the data structures for the justifications, they are used by the
analysis script to link the Xen tags to the proprietary tool comment.

Add docs/misra/documenting-violations.rst to explain how to add
justifications.

Add docs/misra/xen-static-analysis.rst to explain how to use the
script to analyse Xen.

Add analysis artifacts files to .gitignore.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
2022-12-12 14:19:04 -08:00
Marek Marczykowski-Górecki 9699351942 docs: do not install .deps files
It isn't really part of the documentation. Furthermore, entries there
are in not determined order, which breaks build reproducibility.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2022-12-12 12:29:09 +01:00
Julien Grall 15241c9267 process/release-technician-checklist: Explain how the banner in README is generated
Explain how the banner in README is generated and take the opportunity
to mention what it should look like for RC.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2022-12-05 11:20:33 +00:00
Juergen Gross 6b09ca19d9 xen/locks: add dynamic lock recursion checks
Add checking of lock recursion to the hypervisor. This is done by using
a percpu data array for storing the address of each taken lock. Any
attempt to take a lock twice (with the exception of recursive
spinlocks) will result in a crash. This is especially meant for
detecting attempts to take a rwlock multiple times as a reader, which
will only result in a deadlock in case of another cpu trying to get the
lock as a writer in between.

The additional checks are not performance neutral, so they are enabled
only in debug builds per default, as the checks are active only with
CONFIG_DEBUG_LOCKS enabled. The size of the percpu data array can be
selected via a boot parameter.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2022-12-02 10:26:55 +01:00
Stefano Stabellini 1527066a7e Introduce more MISRA C rules to docs/misra/rules.rst
Add the new MISRA C rules agreed by the MISRA C working group to
docs/misra/rules.rst.

Add a comment for Rule 19.1 to explain that Eclair's findings are
"caution" reports, not violations.

Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
2022-12-01 17:04:24 -08:00
Julien Grall 72269801cc Set version to 4.18; return ./autogen.sh
Signed-off-by: Julien Grall <jgrall@amazon.com>
2022-12-01 14:05:45 +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