Commit Graph
1771 Commits
Author SHA1 Message Date
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
Oleksandr Tyshchenko 66dd1c62b2 libxl: Add support for Virtio disk configuration
This patch adds basic support for configuring and assisting virtio-mmio
based virtio-disk backend (emulator) which is intended to run out of
Qemu and could be run in any domain.
Although the Virtio block device is quite different from traditional
Xen PV block device (vbd) from the toolstack's point of view:
 - as the frontend is virtio-blk which is not a Xenbus driver, nothing
   written to Xenstore are fetched by the frontend currently ("vdev"
   is not passed to the frontend). But this might need to be revised
   in future, so frontend data might be written to Xenstore in order to
   support hotplugging virtio devices or passing the backend domain id
   on arch where the device-tree is not available.
 - the ring-ref/event-channel are not used for the backend<->frontend
   communication, the proposed IPC for Virtio is IOREQ/DM
it is still a "block device" and ought to be integrated in existing
"disk" handling. So, re-use (and adapt) "disk" parsing/configuration
logic to deal with Virtio devices as well.

For the immediate purpose and an ability to extend that support for
other use-cases in future (Qemu, virtio-pci, etc) perform the following
actions:
- Add new disk backend type (LIBXL_DISK_BACKEND_STANDALONE) and reflect
  that in the configuration
- Introduce new disk "specification" and "transport" fields to struct
  libxl_device_disk. Both are written to the Xenstore. The transport
  field is only used for the specification "virtio" and it assumes
  only "mmio" value for now.
- Introduce new "specification" option with "xen" communication
  protocol being default value.
- Add new device kind (LIBXL__DEVICE_KIND_VIRTIO_DISK) as current
  one (LIBXL__DEVICE_KIND_VBD) doesn't fit into Virtio disk model

An example of domain configuration for Virtio disk:
disk = [ 'phy:/dev/mmcblk0p3, xvda1, backendtype=standalone, specification=virtio']

Nothing has changed for default Xen disk configuration.

Please note, this patch is not enough for virtio-disk to work
on Xen (Arm), as for every Virtio device (including disk) we need
to allocate Virtio MMIO params (IRQ and memory region) and pass
them to the backend, also update Guest device-tree. The subsequent
patch will add these missing bits. For the current patch,
the default "irq" and "base" are just written to the Xenstore.
This is not an ideal splitting, but this way we avoid breaking
the bisectability.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
Tested-by: Jiamei Xie <jiamei.xie@arm.com>
2022-07-28 19:25:43 +01:00
Jan Beulich 6fc03330cd IOMMU/x86: new command line option to suppress use of superpage mappings
Before actually enabling their use, provide a means to suppress it in
case of problems. Note that using the option can also affect the sharing
of page tables in the VT-d / EPT combination: If EPT would use large
page mappings but the option is in effect, page table sharing would be
suppressed (to properly fulfill the admin request).

Requested-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Paul Durrant <paul@xen.org>
2022-07-25 15:34:55 +02:00
Stefano Stabellini 52196c8cd9 docs: document dom0less + PV drivers
Document how to use the feature and how the implementation works.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-07-20 19:06:33 +01:00
Jan Beulich 0a85463954 Revert "tools/xenstore: add documentation for ..."
This reverts commits 3db29e8fac,
6574f38779, and
1a564e4b3b. They were committed
by mistake (newer version pending).
2022-07-19 11:16:02 +02:00
Jan Beulich c3cad613dd EFI: strip xen.efi when putting it on the EFI partition
With debug info retained, xen.efi can be quite large. Unlike for xen.gz
there's no intermediate step (mkelf32 there) involved which would strip
debug info kind of as a side effect. While the installing of xen.efi on
the EFI partition is an optional step (intended to be a courtesy to the
developer), adjust it also for the purpose of documenting what distros
would be expected to do during boot loader configuration (which is what
would normally put xen.efi into the EFI partition).

Model the control over stripping after Linux'es module installation,
except that the stripped executable is constructed in the build area
instead of in the destination location. This is to conserve on space
used there - EFI partitions tend to be only a few hundred Mb in size.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Henry Wang <Henry.Wang@arm.com>
Tested-by: Wei Chen <Wei.Chen@arm.com> # arm
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
2022-07-18 17:48:40 +02:00
Juergen Gross 3db29e8fac 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: Luca Fancellu <luca.fancellu@arm.com>
2022-07-18 17:47:23 +02:00
Juergen Gross 6574f38779 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 Xenstore quota of a given domain.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
2022-07-18 17:47:04 +02:00
Juergen Gross 1a564e4b3b 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: Luca Fancellu <luca.fancellu@arm.com>
2022-07-18 17:46:47 +02:00
Andrew Cooper d8cb7e0f06 x86/spec-ctrl: Mitigate Branch Type Confusion when possible
Branch Type Confusion affects AMD/Hygon CPUs on Zen2 and earlier.  To
mitigate, we require SMT safety (STIBP on Zen2, no-SMT on Zen1), and to issue
an IBPB on each entry to Xen, to flush the BTB.

Due to performance concerns, dom0 (which is trusted in most configurations) is
excluded from protections by default.

Therefore:
 * Use STIBP by default on Zen2 too, which now means we want it on by default
   on all hardware supporting STIBP.
 * Break the current IBPB logic out into a new function, extending it with
   IBPB-at-entry logic.
 * Change the existing IBPB-at-ctxt-switch boolean to be tristate, and disable
   it by default when IBPB-at-entry is providing sufficient safety.

If all PV guests on the system are trusted, then it is recommended to boot
with `spec-ctrl=ibpb-entry=no-pv`, as this will provide an additional marginal
perf improvement.

This is part of XSA-407 / CVE-2022-23825.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2022-07-12 16:23:00 +01:00
Andrew Cooper 27357c394b x86/spec-ctrl: Add fine-grained cmdline suboptions for primitives
Support controling the PV/HVM suboption of msr-sc/rsb/md-clear, which
previously wasn't possible.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
2022-07-11 15:21:35 +01:00
Jane Malalane 2ce11ce249 x86/HVM: allow per-domain usage of hardware virtualized APIC
Introduce a new per-domain creation x86 specific flag to
select whether hardware assisted virtualization should be used for
x{2}APIC.

A per-domain option is added to xl in order to select the usage of
x{2}APIC hardware assisted virtualization, as well as a global
configuration option.

Having all APIC interaction exit to Xen for emulation is slow and can
induce much overhead. Hardware can speed up x{2}APIC by decoding the
APIC access and providing a VM exit with a more specific exit reason
than a regular EPT fault or by altogether avoiding a VM exit.

On the other hand, being able to disable x{2}APIC hardware assisted
virtualization can be useful for testing and debugging purposes.

Note:

- vmx_install_vlapic_mapping doesn't require modifications regardless
of whether the guest has "Virtualize APIC accesses" enabled or not,
i.e., setting the APIC_ACCESS_ADDR VMCS field is fine so long as
virtualize_apic_accesses is supported by the CPU.

- Both per-domain and global assisted_x{2}apic options are not part of
the migration stream, unless explicitly set in the respective
configuration files. Default settings of assisted_x{2}apic done
internally by the toolstack, based on host capabilities at create
time, are not migrated.

Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jane Malalane <jane.malalane@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
Reviewed-by: "Roger Pau Monné" <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
2022-07-11 12:15:05 +02:00
Juergen Gross a58fca51ab docs: add reference to release cycle discussion
As it is coming up basically every release cycle of Xen, add a
reference to the discussion why the current release scheme has been
selected in the release management documentation.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
2022-07-11 12:13:40 +02:00
Roger Pau Monne 54d8f27d04 tools/libxl: report trusted backend status to frontends
Allow administrators to notify a frontend driver that it's backend
counterpart is not to be trusted, so the frontend can deploy whatever
mitigations required in order to secure itself.

Allow such option for disk and network frontends only, as those are
the only hardened ones currently supported.

This is part of XSA-403

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
2022-07-05 14:16:26 +02:00
Luca Fancellu 4a0da1c741 docs/misra: Add instructions for cppcheck
Add instructions on how to build cppcheck, the version currently used
and an example to use the cppcheck integration to run the analysis on
the Xen codebase

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-07-04 14:45:39 +02:00
Andrew Cooper fef244b179 x86/spec-ctrl: Knobs for STIBP and PSFD, and follow hardware STIBP hint
STIBP and PSFD are slightly weird bits, because they're both implied by other
bits in MSR_SPEC_CTRL.  Add fine grain controls for them, and take the
implications into account when setting IBRS/SSBD.

Rearrange the IBPB text/variables/logic to keep all the MSR_SPEC_CTRL bits
together, for consistency.

However, AMD have a hardware hint CPUID bit recommending that STIBP be set
unilaterally.  This is advertised on Zen3, so follow the recommendation.
Furthermore, in such cases, set STIBP behind the guest's back for now.  This
has negligible overhead for the guest, but saves a WRMSR on vmentry.  This is
the only default change.

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>
2022-06-30 18:07:13 +01:00
Juergen Gross 53e5d2166a tools/xenstore: modify feature bit specification in xenstore-ring.txt
Instead of specifying the feature bits in xenstore-ring.txt as a mask
value use bit numbers. This will make the specification easier to read
when adding more features.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
2022-06-28 17:06:14 +02:00
Andrew Cooper 8c24b70fed x86/spec-ctrl: Add spec-ctrl=unpriv-mmio
Per Xen's support statement, PCI passthrough should be to trusted domains
because the overall system security depends on factors outside of Xen's
control.

As such, Xen, in a supported configuration, is not vulnerable to DRPW/SBDR.

However, users who have risk assessed their configuration may be happy with
the risk of DoS, but unhappy with the risk of cross-domain data leakage.  Such
users should enable this option.

On CPUs vulnerable to MDS, the existing mitigations are the best we can do to
mitigate MMIO cross-domain data leakage.

On CPUs fixed to MDS but vulnerable MMIO stale data leakage, this option:

 * On CPUs susceptible to FBSDP, mitigates cross-domain fill buffer leakage
   using FB_CLEAR.
 * On CPUs susceptible to SBDR, mitigates RNG data recovery by engaging the
   srb-lock, previously used to mitigate SRBDS.

Both mitigations require microcode from IPU 2022.1, May 2022.

This is part of XSA-404.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
2022-06-16 12:10:37 +01:00
Andrew Cooper e06b95c1d4 x86/spec-ctrl: Make VERW flushing runtime conditional
Currently, VERW flushing to mitigate MDS is boot time conditional per domain
type.  However, to provide mitigations for DRPW (CVE-2022-21166), we need to
conditionally use VERW based on the trustworthiness of the guest, and the
devices passed through.

Remove the PV/HVM alternatives and instead issue a VERW on the return-to-guest
path depending on the SCF_verw bit in cpuinfo spec_ctrl_flags.

Introduce spec_ctrl_init_domain() and d->arch.verw to calculate the VERW
disposition at domain creation time, and context switch the SCF_verw bit.

For now, VERW flushing is used and controlled exactly as before, but later
patches will add per-domain cases too.

No change in behaviour.

This is part of XSA-404.

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>
2022-06-16 12:10:37 +01:00
Stefano Stabellini 162dea4e76 add 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.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
2022-06-14 16:14:14 -07:00
Michal Orzel 7ac12e3634 xen/arm: Allow setting the number of CPUs to activate at runtime
Introduce a command line parameter "maxcpus" on Arm to allow adjusting
the number of CPUs to activate. Currently the limit is defined by the
config option CONFIG_NR_CPUS. Such parameter already exists on x86.

Define a parameter "maxcpus" and a corresponding static variable
max_cpus in Arm smpboot.c. Modify function smp_get_max_cpus to take
max_cpus as a limit and to return proper unsigned int instead of int.

Take the opportunity to remove redundant variable cpus from start_xen
function and to directly assign the return value from smp_get_max_cpus
to nr_cpu_ids (global variable in Xen used to store the number of CPUs
actually activated).

Signed-off-by: Michal Orzel <michal.orzel@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
2022-06-08 11:16:38 +01:00
Stefano Stabellini 8c1cc69748 docs/misra: add Rule 5.1
Add Rule 5.1, with the additional note that the character limit for Xen
is 40 characters.

The max length identifiers found by ECLAIR are:

__mitigate_spectre_bhb_clear_insn_start
domain_pause_by_systemcontroller_nosync

Both of them are 40 characters long.

Explicitly mention that public headers might have longer identifiers.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-06-07 17:44:03 -07:00
Stefano Stabellini 4b08435f58 docs/misra: introduce rules.rst
Introduce a list of MISRA C rules that apply to the Xen hypervisor. The
list is in RST format.

Specify that rules deviations need to be documented. Introduce a
documentation tag for in-code comments to mark them as deviations. Also
mention that other documentation mechanisms are work-in-progress.

Add a mention of the new list to CODING_STYLE.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-06-07 17:43:47 -07:00
Luca Miccio fc2b57c9af xenstored: send an evtchn notification on introduce_domain
When xs_introduce_domain is called, send out a notification on the
xenstore event channel so that any (dom0less) domain waiting for the
xenstore interface to be ready can continue with the initialization.
Before sending the notification, clear XENSTORE_RECONNECTING.

The extra notification is harmless for domains that don't require it.

In xs_wire.h update the commment on top of XENSTORE_RECONNECTING to
generalize its meaning to suit the dom0less use-case better. Also
improve docs/misc/xenstore-ring.txt.

Signed-off-by: Luca Miccio <lucmiccio@gmail.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
2022-05-24 16:18:08 -07:00
Stefano Stabellini 5eedfe7728 xen: introduce xen,enhanced dom0less property
Introduce a new "xen,enhanced" dom0less property to enable/disable PV
driver interfaces for dom0less guests. Currently only "enabled" and
"disabled" are supported property values (and empty). Leave the option
open to implement further possible values in the future (e.g.
"xenstore" to enable only xenstore.) Dom0 presence is required for now
to use "xen,enhanced" on a domU.

The configurable option is for domUs only. For dom0 we always set the
corresponding property in the Xen code to true (PV interfaces enabled.)

This patch only parses the property. Next patches will make use of it.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Acked-by: Julien Grall <jgrall@amazon.com>
CC: Julien Grall <julien@xen.org>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
CC: Bertrand Marquis <bertrand.marquis@arm.com>
2022-05-24 16:16:42 -07:00
Stefano Stabellini 2a2447757b xen/arm: implement domU extended regions
Implement extended regions for dom0less domUs. The implementation is
based on the libxl implementation.

Also update docs for the ext_regions command line option.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Acked-by: Julien Grall <jgrall@amazon.com>
2022-05-24 16:12:09 -07:00
Juergen Gross 77bbea1baf tools/libs/light: update xenstore entry when setting max domain memory
libxl_domain_setmaxmem() called during "xl mem-max" should update the
domain's memory/static-max Xenstore node, as otherwise "xl mem-set"
won't be able to set the memory size to the new maximum.

Adjust the related comments and documentation accordingly.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
2022-05-20 12:18:50 +02:00
Anthony PERARD 17060df97c docs: fix path to code in migration doc
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
2022-05-16 18:16:47 +01:00
Luca Fancellu 92ea9c54fc arm/dom0less: assign dom0less guests to cpupools
Introduce domain-cpupool property of a xen,domain device tree node,
that specifies the cpupool device tree handle of a xen,cpupool node
that identifies a cpupool created at boot time where the guest will
be assigned on creation.

Add member to the xen_domctl_createdomain public interface so the
XEN_DOMCTL_INTERFACE_VERSION version is bumped.

Add public function to retrieve a pool id from the device tree
cpupool node.

Update documentation about the property.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
2022-05-09 13:32:57 -07:00