It's unsafe to disable IOMMU on a live system which is the case
if we're crashing since remapping hardware doesn't usually know what
to do with ongoing bus transactions and frequently raises NMI/MCE/SMI,
etc. (depends on the firmware configuration) to signal these abnormalities.
This, in turn, doesn't play well with kexec transition process as there is
no handling available at the moment for this kind of events resulting
in failures to enter the kernel.
Modern Linux kernels taught to copy all the necessary DMAR/IR tables
following kexec from the previous kernel (Xen in our case) - so it's
currently normal to keep IOMMU enabled. It might require minor changes to
kdump command line that enables IOMMU drivers (e.g. intel_iommu=on /
intremap=on) but recent kernels don't require any additional changes for
the transition to be transparent.
A fallback option is still left for compatibility with ancient crash
kernels which didn't like to have IOMMU active under their feet on boot.
Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
The behaviour of vpmu=<bool> being exclusive of vpmu=bts|ipc|arch is odd and
contrary to Xen's normal command line parsing behaviour. Rewrite the parsing
to use the normal form, but retain the previous behaviour where the use of
bts/ipc/arch implies vpmu=true.
Parts of the documenation are stale, most notibly the HVM-only statement.
Update it for consistency and correctness.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The register op is used by a domain to register a region of memory for
receiving messages from either a specified other domain, or, if specifying a
wildcard, any domain.
This operation creates a mapping within Xen's private address space that
will remain resident for the lifetime of the ring. In subsequent commits,
the hypervisor will use this mapping to copy data from a sending domain into
this registered ring, making it accessible to the domain that registered the
ring to receive data.
Wildcard any-sender rings are default disabled and registration will be
refused with EPERM unless they have been specifically enabled with the
new mac-permissive flag that is added to the argo boot option here. The
reason why the default for wildcard rings is 'deny' is that there is
currently no means to protect the ring from DoS by a noisy domain
spamming the ring, affecting other domains ability to send to it. This
will be addressed with XSM policy controls in subsequent work.
Since denying access to any-sender rings is a significant functional
constraint, the new option "mac-permissive" for the argo bootparam
enables overriding this. eg: "argo=1,mac-permissive=1"
The p2m type of the memory supplied by the guest for the ring must be
p2m_ram_rw and the memory will be pinned as PGT_writable_page while the ring
is registered.
This hypercall op and its interface currently only supports 4K-sized pages.
Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com>
Tested-by: Chris Patterson <pattersonc@ainfosec.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Initialises basic data structures and performs teardown of argo state
for domain shutdown.
Inclusion of the Argo implementation is dependent on CONFIG_ARGO.
Introduces a new Xen command line parameter 'argo': bool to enable/disable
the argo hypercall. Defaults to disabled.
New headers:
public/argo.h: with definions of addresses and ring structure, including
indexes for atomic update for communication between domain and hypervisor.
xen/argo.h: to expose the hooks for integration into domain lifecycle:
argo_init: per-domain init of argo data structures for domain_create.
argo_destroy: teardown for domain_destroy and the error exit
path of domain_create.
argo_soft_reset: reset of domain state for domain_soft_reset.
Adds a new field to struct domain: struct argo_domain *argo;
In accordance with recent work on _domain_destroy, argo_destroy is
idempotent. It will tear down: all rings registered by this domain, all
rings where this domain is the single sender (ie. specified partner,
non-wildcard rings), and all pending notifications where this domain is
awaiting signal about available space in the rings of other domains.
A count will be maintained of the number of rings that a domain has
registered in order to limit it below the fixed maximum limit defined here.
Macros are defined to verify the internal locking state within the argo
implementation. The macros are ASSERTed on entry to functions to validate
and document the required lock state prior to calling.
The hash function for the hashtables that hold ring state is derived from
the string hashing function djb2 (http://www.cse.yorku.ca/~oz/hash.html)
by Daniel J. Bernstein. Basic testing with a limited number of domains and
ports has shown reasonable distribution for the table size.
The software license on the public header is the BSD license, standard
procedure for the public Xen headers. The public header was originally
posted under a GPL license at: [1]:
https://lists.xenproject.org/archives/html/xen-devel/2013-05/msg02710.html
The following ACK by Lars Kurth is to confirm that only people being
employees of Citrix contributed to the header files in the series posted at
[1] and that thus the copyright of the files in question is fully owned by
Citrix. The ACK also confirms that Citrix is happy for the header files to
be published under a BSD license in this series (which is based on [1]).
Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com>
Acked-by: Lars Kurth <lars.kurth@citrix.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Tested-by: Chris Patterson <pattersonc@ainfosec.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Early version of Cortex-A76 can end-up with corrupt TLBs if they
speculate an AT instruction while the S1/S2 system registers are in an
inconsistent state.
This can happen during guest context switch and when invalidating the
TLBs for other than the current VMID.
The workaround implemented in Xen will:
- Use an empty stage-2 with a reserved VMID while context switching
between 2 guests
- Use an empty stage-2 with the VMID where TLBs need to be flushed
Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
For development purposes, it is very convenient to boot Xen as a PVH guest,
with an XTF PV or PVH "dom0". The edit-compile-go cycle is a matter of
seconds, and you can reasonably insert printk() debugging in places which
which would be completely infeasible when booting fully-fledged guests.
However, the PVH dom0 path insists on having a working IOMMU, which doesn't
exist when virtualised as a PVH guest, and isn't necessary for XTF anyway.
Introduce a developer mode to skip the IOMMU requirement.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
This option is unique to x86 PV dom0's, but it is not sensible to have a
catch-all which blindly maps all non-RAM regions into the IOMMU.
The map-reserved option remains, and covers all the buggy firmware issues that
I am aware of. The two common cases are legacy USB keyboard emulation, and
the BMC mailbox used by vendor firmware in NICs/HBAs to report information
back to the iLO/iDRAC/etc for remote remote management purposes.
A specific advantage of this change is that x86 dom0's IOMMU setup is now
consistent between PV and PVH.
This change is not expected to have any impact, due to map-reserved remaining.
In the unlikely case that it does cause an issue, we should introduce other
map-$SPECIFIC options rather than re-introducing this catch-all.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Update parse_efi_param() to use parse_boolean() for "rs", so it behaves
like other Xen booleans.
However, change "attr=uc" to not be a boolean. "no-attr=uc" is ambiguous and
shouldn't be accepted, but accept "attr=no" as an acceptable alternative.
Update the command line documentation for consistency.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Having a pvh boolean isn't ideal. If we gain a 3rd virtulsation mode,
what does `dom0=no-pvh` mean?
Change the syntax to be "dom0 = pv | pvh" which offers an option to more
obviously select PV mode. Hide both options behind the relevent
CONFIG_* settings, and default to PVH mode when CONFIG_PV is compiled
out.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Alter parse_pci_param() to use parse_boolean(), so the sub options
behave like other Xen booleans.
Update the command line documentation for consistency.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Update parse_iommu_param() to uniformly use parse_boolean(), so the sub
booleans behave like other Xen boolean options. Reposition the
custom_param() to avoid a forward declaration of parse_iommu_param().
Rewrite the command line documentation almost from scratch, including
far more detail.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Update to the latest metadata style, and discuss the options more
completely where appropriate.
Drop the redundant comment beside parse_dom0_param() - it is already out
of sync with the main documentation. Also drop the individual
documentation for deprecated options which refer to their newer
versions, for the same reason.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
As a short term alternative to deleting the code, default its building
to off (overridable in EXPERT mode only). Additionally make sure other
related baggage (LZO code) won't be carried when the option is off (with
TMEM scheduled to be deleted anyway, I didn't want to introduce a
separate Kconfig option to control the LZO compression code, and hence
CONFIG_TMEM is used directly there). Similarly I couldn't be bothered to
add actual content to the command line option doc for the two affected
options.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Add a verbose option to the dom0 command line, so that dom0 builder
can print extra debug information when required.
Use this new verbose mode to print statistics about memory allocations
when populating dom0 p2m.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
c/s a3a99df44 "docs/cmdline: Rewrite the cpuid_mask_* section" completely
forgot about how markdown gets rendered to HTML (as opposed to PDF), because
we use different translators depending on the destination format.
markdown and pandoc are very similar markup languages, but a couple of details
about pandoc cause it to have far more user-friendly inline markup.
Switch all markdown documents to be pandoc (so we are using a single
translator, and therefore a single flavour of markdown), which fixes the
rendered docs on xenbits.xen.org/docs.
While changing the format, fix the remainder of the escaped underscores in the
same mannor as the previous patch. The two problem cases here are __LINE__
and __FILE__ where the first underscore still needs escaping.
In addition, dmop.markdown and dom0less.markdown didn't used to get processed,
as only .markdown files in the misc/ directory got considered.
dom0less.pandoc gets picked up automatically now, due to being in the
features/ directory, but designs/ needs adding to the pandoc directory list
for dmop.pandoc to get processed.
While edting in appropriate areas, take the opportunity to fix some markup to
the surrounding style, and drop trailing whitespace.
No change in content - only formatting. This results in the text being easier
to read and grep.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Switch parse_ept_param() to use the parse_boolean() infrastructure for more
consistency with related command line parameters. Rename opt_pml_enabled to
opt_ept_pml for consistency with opt_ept_ad, and switch it to being bool
Drop the leading comment for parse_ept_param(). It is stale, and just repeats
the command line documentation.
For the command line documentation, rewrite it largely from scratch, updating
to the latest metadata style. Document A/D first, including a note about
AVR41, and modify PML to note its dependency on A/D.
No practical changes to behaviour.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
PVRDTSCP is believed-unused, and its implementation has adverse consequences
on unrelated functionality in the hypervisor. As a result, support is being
removed.
For more historical context, see
c/s c17b36d5dc
c/s 04656384a1
Modify libxl to provide a slightly more helpful error message if it encounters
PVRDTSCP being selected. While adjusting TSC handling, make libxl check for
errors from the set_tsc hypercall.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Today the memory size of dom0 can be specified only in terms of bytes
(either an absolute value or "host-mem - value"). When dom0 shouldn't
be auto-ballooned this requires nearly always a manual adaption of the
Xen boot parameters to reflect the actual host memory size.
Add more possibilities to specify memory sizes. Today we have:
dom0_mem= List of ( min:<size> | max:<size> | <size> )
with <size> being a positive or negative size value (e.g. 1G).
Modify that to:
dom0_mem= List of ( min:<sz> | max:<sz> | <sz> )
<sz>: <size> | [<size>+]<frac>%
<frac>: integer value < 100
With the following semantics:
<frac>% specifies a fraction of host memory size in percent.
<sz> is a percentage of host memory plus an offset.
So <sz> being 1G+25% on a 256G host would result in 65G.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
A large amount of the information here is obsolete since Xen 4.7
To being with, however, this patch marks a change in style for section
headings, due to how HTML anchors are generated. Having more than one
parameter per heading makes an awkward anchor, especially when brace globbing
is used. Furthermore, the misc suffixes such as (AMD only) get included, as
do the escaping for the underscores.
Markdown doesn't require escaped underscores in headings (I'm not entirely
sure how we ended up with that style), so remove them and fully expand the
glob syntax. Also adjust com1,com2 while at it, which is the only other
multi-parameter heading. Move the misc suffixes into an "Applicability:" note
alongside the information about defaults.
This results in the headings being unadorned, and identical to how they are
expressed on the command line and in code.
For cpuid_mask_cpu option, collapse the long line of almost identical strings
using [] globbing. The result is much shorter and clearer to read. Add a
warning that this option no longer masks all features on Fam15h and above, due
to not making use of the leaf 7 masks.
For the remainder of the cpuid_mask_* options, collapse them all together into
a single description.
Finally, leave an explicit note explaining that people should not be using
these options for migration safety.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Adjust the default line to note that the default is now selectable in Kconfig.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
* vwfi needs a closing `. rmrr needs one as well, and the opening ' switched
to `
* The com1/com2 example lines are already verbatim blocks and shouldn't
escape their underscores. This ends up in the rendered output.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Which, on x86, requires fiddling with the INTx bit in PCI config space,
since for internally used MSI we can't delegate this to Dom0.
ns16550_init_postirq() also needs (benign) re-ordering of its
operations.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
bti= was introduced with the original Spectre fixes (Jan 2018), but by the
time Speculative Store Bypass came along (May 2018), it was superceeded by the
more generic spec-ctrl=.
Since then, we've had LazyFPU (June 2018) and L1TF (August 2018), which means
noone will be using the option. Remove it entirely - anyone who happens to
accidentially be using it might now spot Xen complaining about an option it
doesn't understand.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Extend the existing device tree based multiboot protocol to include
information regarding multiple domains to boot.
Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Scrubbing RAM during boot may take a long time on machines with lots
of RAM. Add 'idle' option to bootscrub which marks all pages dirty
initially so they will eventually be scrubbed in idle-loop on every
online CPU.
It's guaranteed that the allocator will return scrubbed pages by doing
eager scrubbing during allocation (unless MEMF_no_scrub was provided).
Use the new 'idle' option as the default one.
Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
docs/qemu-deprivilege.txt had some basic instructions for using
dm_restrict, but it was incomplete, misleading, and stale.
Update the docs in a number of ways.
First, separate user-facing documentation and technical description
into docs/features and docs/design, respectively.
In the feature doc:
* Introduce a section mentioning minimim versions of Linux, Xen, and
qemu required (TBD)
* Fix the discussion of qemu userid. Mention xen-qemuuser-range-base,
and provide example shell code that actually has some hope of working
(instead of failing out after creating 900 userids).
* Describe how to enable restrictions, as well as features which
probably don't or definitely don't work.
In the design doc, introduce a "Technical Details" section which
describes specifically what restrictions are currently done, and also
what restrictions we are looking at doing in the future.
The idea here is that as we implement the various items for the
future, we move them from "Restrictions still to do" to "Restrictions
done". This can also act as a design document -- a place for public
discussion of what can or should be done and how.
Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
---
Changes since v4:
- Remove unnecessary FIXME
- Remove stale "Add SUPPORT.md"
Changes since v3:
- Fix typo (32->16)
- Use an example value not close to the `nobody` uids, but still a
multiple of 2^16.
- Mention that using a multiple of 2^16 may have advantages.
- Have the example create a group as well
- Reorganize two comments on the "range-base" method for clarity
Changes since v2:
- Extraneous privcmd / evtchn instances aren't closed
- Expand description of how to test fd deprivileging
- Rework and clarify two namespace sections, give reference for QEMU NAK
- Add more information about migration technical challenges
- In UID section, mention possibility of container ID collisions.
- Fix name of design document.
- Add SUPPORT.md statement. Specify Linux, to make sure that FreeBSD is
evaluated separately.
- Mention that `-sandbox` is a blacklist and why
Changes since v1:
- Break into two, and move into appropriate directories (rather than 'misc')
- Updated version requirements
- Distinguish between features which "don't yet work" and features which we never expect to work
- Update description of xen-restrict functionality
- Reorder and expand further restrictions
- Make it more clear which restrictions are available on Linux only
- Include detailed description of how to kill a process
- Add RLIMIT_NPROC as something we can do without further changes to qemu
- Document the need to check for the sandbox feature before using it
Thank you to Ross Lagerwall, whose description of what XenServer is
doing formed much of the basis for the text here.
CC: Ian Jackson <ian.jackson@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Jan Beulich <jbeulich@suse.com>
CC: Tim Deegan <tim@xen.org>
CC: Konrad Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@arm.com>
CC: Anthony Perard <anthony.perard@citrix.com>
CC: Ross Lagerwall <ross.lagerwall@citrix.com>
Backport commit 3714ce1d6655098ee69ede632883e5874d67e4ab
"iommu/arm-smmu: Disable stalling faults for all endpoints" from the
Linux kernel. This works-around Erratum #842869.
Original commit message:
Enabling stalling faults can result in hardware deadlock on poorly
designed systems, particularly those with a PCI root complex upstream of
the SMMU.
Although it's not really Linux's job to save hardware integrators from
their own misfortune, it *is* our job to stop userspace (e.g. VFIO
clients) from hosing the system for everybody else, even if they might
already be required to have elevated privileges.
Given that the fault handling code currently executes entirely in IRQ
context, there is nothing that can sensibly be done to recover from
things like page faults anyway, so let's rip this code out for now and
avoid the potential for deadlock.
Cc: <stable@vger.kernel.org>
Fixes: 48ec83bcbcf5 ("iommu/arm-smmu: Add initial driver support for ARM SMMUv3 devices")
Reported-by: Matt Evans <matt.evans@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
Acked-by: Julien Grall <julien.grall@arm.com>
The format identifier is consistent with Linux. The code is adapted from
bitmap_scn{,list}printf() but cleaned up.
This change allows all callers to avoid needing a secondary buffer to render a
cpumask/nodemask into.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: <jbeulich@suse.com>
When SILO is enabled, there would be no page-sharing or event notifications
between unprivileged VMs (no grant tables or event channels).
Signed-off-by: Xin Li <xin.li@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Introduce new boot parameter xsm to choose which xsm module is enabled,
and set default to dummy. And add new option in Kconfig to choose the
default XSM implementation.
Signed-off-by: Xin Li <xin.li@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
This allows all system domids to be printed by name, rather than special
casing the idle vcpus alone.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Several people have reported hardware issues (malfunctioning USB
controllers) due to iommu page faults on Intel hardware. Those faults
are caused by missing RMRR (VTd) entries in the ACPI tables. Those can
be worked around on VTd hardware by manually adding RMRR entries on
the command line, this is however limited to Intel hardware and quite
cumbersome to do.
In order to solve those issues add a new dom0-iommu=map-reserved
option that identity maps all regions marked as reserved in the memory
map. Note that regions used by devices emulated by Xen (LAPIC, IO-APIC
or PCIe MCFG regions) are specifically avoided. Note that this option
is available to all Dom0 modes (as opposed to the inclusive option
which only works for PV Dom0).
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To select the iommu configuration used by Dom0. This option supersedes
iommu=dom0-strict|dom0-passthrough.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
In order to have a simple and easy to remember means to suppress all the
more or less recent workarounds for hardware vulnerabilities, force
settings not controlled by "spec-ctrl=" also to their original defaults,
unless they've been forced to specific values already by earlier command
line options.
This is part of XSA-273.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
This mitigation requires up-to-date microcode, and is enabled by default on
affected hardware if available, and is used for HVM guests
The default for SMT/Hyperthreading is far more complicated to reason about,
not least because we don't know if the user is going to want to run any HVM
guests to begin with. If a explicit default isn't given, nag the user to
perform a risk assessment and choose an explicit default, and leave other
configuration to the toolstack.
This is part of XSA-273 / CVE-2018-3620.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Shadowing a PV guest is only available when shadow paging is compiled in.
When shadow paging isn't available, guests can be crashed instead as
mitigation from Xen's point of view.
Ideally, dom0 would also be potentially-shadowed-by-default, but dom0 has
never been shadowed before, and there are some stability issues under
investigation.
This is part of XSA-273 / CVE-2018-3620.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
It was never expected to work, the implementation is incomplete.
As a side effect, it also prevents guests from triggering a
"BUG_ON(page_get_owner(pg) != d)" in gnttab_unpopulate_status_frames().
This is XSA-268.
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Jan Beulich <jbeulich@suse.com>
Shared resources (L1 cache and TLB in particular) present a risk of
information leak via side channels. Provide a means to avoid use of
hyperthreads in such cases.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
During early boot timestamps aren't very useful, as they're all zero
(in "boot" mode) or absent altogether (in "date" and "datems" modes).
Log "boot" format timestamps when the date formats aren't available yet,
and log raw timestamps when boot ones are still all zero. Also add a
"raw" mode.
For the ARM side get_cycles() to produce a meaningful value, ARM's
cycle_t gets changed to uint64_t.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com>
In the shim case, the number of CPUs should be solely controlled by the
guest configuration file. Make sure the command line options are fully
(and not just partially) ignored.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
* Command line documentation for what the option does.
* Implement a canonicalise_addr() helper and replace the opencoded use in
sign_extend_msr()
* Canonicalise the ler pointers and print symbol information.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
The documentation for the iommu_inclusive_mapping Xen command line option
states:
"Use this to work around firmware issues providing incorrect RMRR entries"
Unfortunately this workaround does not function correctly if the dom0-strict
iommu option is also specified.
The documentation goes on to say:
"Rather than only mapping RAM pages for IOMMU accesses for Dom0, with this
option all pages up to 4GB, not marked as unusable in the E820 table, will
get a mapping established."
This patch modifies the VT-d hardware domain initialization code such that
the workaround will continue to function in dom0-strict mode, by mapping
all pages not marked as unusable *unless* they are RAM pages not assigned
to dom0.
NOTE: This patch modifies the test in drivers/passthrough/vtd/iommu.c from
need_iommu() to is_pv_domain() since dom0-strict implies need_iommu()
so we no longer want to gate invocation of vtd_set_hwdom_mapping()
on that.
It also exports the iommu_dom0_strict flag so that the implementation
of vtd_set_hwdom_mapping() can test it explicitly. It would be
possible to test need_iommu() instead, but it is more illustrative
to test the original flag rather than one of its side-effects.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Roger Pau Monne <roger.pau@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
It is hard to reconcile the comment at the top of the loop in
vtd_set_hwdom_mapping() with the if statement following it. This patch
re-phrases the logic, preserving the semantics, but making it easier
to read.
The patch also modifies the Xen command line documentation to make it
clear that iommu_inclusive_mapping only applies to pages up to the 4GB
boundary.
NOTE: This patch also corrects the indentation of the printk() towards
the end of vtd_set_hwdom_mapping().
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Roger Pau Monne <roger.pau@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
On a system where the firmware implements ARCH_WORKAROUND_2, it may be
useful to either permanently enable or disable the workaround for cases
where the user decides that they'd rather not get a trap overhead, and
keep the mitigation permanently on or off instead of switching it on
exception entry/exit. In any case, default to mitigation being enabled.
The new command line option is implemented as list of one option to
follow x86 option and also allow to extend it more easily in the future.
Note that for convenience, the full implemention of the workaround is
done in the .matches callback.
Lastly, a accessor is provided to know the state of the mitigation.
After this patch, there are 3 methods complementing each other to find the
state of the mitigation:
- The capability ARM_SSBD indicates the platform is affected by the
vulnerability. This will also return false if the user decide to force
disabled the mitigation (spec-ctrl="ssbd=force-disable"). The
capability is useful for putting shortcut in place using alternative.
- ssbd_state indicates the global state of the mitigation (e.g
unknown, force enable...). The global state is required to report
the state to a guest.
- The per-cpu ssbd_callback_required indicates whether a pCPU
requires to call the SMC. This allows to shortcut SMC call
and save an entry/exit to EL3.
This is part of XSA-263.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Intel Core processors since at least Nehalem speculate past #NM, which is the
mechanism by which lazy FPU context switching is implemented.
On affected processors, Xen must use fully eager FPU context switching to
prevent guests from being able to read FPU state (SSE/AVX/etc) from previously
scheduled vcpus.
This is part of XSA-267 / CVE-2018-3665
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Igor Druzhinin
Andrew Cooper
Christopher Clark
Julien Grall
Jan Beulich
Roger Pau Monné
Juergen Gross
Stefano Stabellini
Sergey Dyasli
George Dunlap
Stefano Stabellini
Xin Li
Wei Liu
Paul Durrant