Adds a new compile-time flag to allow disabling PDX compression and
compiles out compression-related code/data. It also shorts the pdx<->pfn
conversion macros and creates stubs for masking functions.
While at it, removes the old arch-defined CONFIG_HAS_PDX flag. Despite the
illusion of choice, it was not optional.
There are ARM and PPC platforms with sparse RAM banks - leave compression
active by default there. However, there are no known production x86 systems
with sparse RAM banks, so disable compression. RISC-V platforms are unknown
right now. These decisions can be revisited if our understanding changes.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
At the moment, we do not check a return code from scan_pfdt_node()
called recursively. This means that any issue that may occur while
parsing and copying the passthrough nodes is hidden and Xen continues
to boot a domain despite errors. This may lead to incorrect device tree
generation and various guest issues (e.g. trap on attempt to access MMIO
not mapped in P2M). Fix it.
Fixes: 669ecdf8d6 ("xen/arm: copy dtb fragment to guest dtb")
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Commit fc2b57c9a ("xenstored: send an evtchn notification on
introduce_domain") introduced the sending of an event channel to the
guest when first introduced, so that dom0less domains waiting for the
connection would know that xenstore was ready to use.
Unfortunately, it was introduced in introduce_domain(), which 1) is
called by other functions, where such functionality is unneeded, and
2) after the main XS_INTRODUCE call, calls domain_conn_reset(). This
introduces a race condition, whereby if xenstored is delayed, a domain
can wake up, send messages to the buffer, only to have them deleted by
xenstore before finishing its processing of the XS_INTRODUCE message.
Move the connect-and-notfy call into do_introduce() instead, after the
domain_conn_rest(); predicated on the state being in the
XENSTORE_RECONNECT state.
(We don't need to check for "restoring", since that value is always
passed as "false" from do_domain_introduce()).
Also take the opportunity to add a missing wmb barrier after resetting
the indexes of the ring in domain_conn_reset.
This change will also remove an extra event channel notification for
dom0 (because the notification is now done by do_introduce which is not
called for dom0.) The extra dom0 event channel notification was only
introduced by fc2b57c9a and was never present before. It is not needed
because dom0 is the one to tell xenstored the connection parameters, so
dom0 has to know that the ring page is setup correctly by the time
xenstored starts looking at it. It is dom0 that performs the ring page
init.
Signed-off-by: George Dunlap <george.dunlap@cloud.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
CC: jgross@suse.com
CC: julien@xen.org
CC: wl@xen.org
Sometime, a contributer would like to be CCed on part of the changes,
and it could happen that we end-up with a section that doesn't have
any maintainer, but a Ack from a maintainer would still be needed.
Rework get_maintainer so if there's no maintainers beside THE REST, it
doesn't drop THE REST emails.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
We warn when we see data for a vcpu moving into a non-RUNNING state,
just so that people know why we're ignoring it. On full traces, this
happens only once. However, if the trace was limited to a subset of
pcpus, then this will happen every time the domain in question is
woken on that pcpu.
Add a 'delayed_init' flag to the vcpu struct to indicate when a vcpu
has experienced a delayed init. Print a warning message once when
entering the state, and once when leaving it.
Signed-off-by: George Dunlap <george.dunlap@cloud.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
EIP lists are generalized across several use cases. For many of them,
it make sense to have a cycle per sample; but not really for interrupt
EIP lists. For this reason, it normally just passes 0 as for the tsc
value, which will in turn down at the bottom of update_cycles(),
update only the summary.event_count, but nothing else.
The dump_eip() function attempted to handle this by calling the generic
cycle print handler if the summary contained *any* cycles, and by collecting
and printing its own stats, based solely on counts, if not.
Unfortunately, it used the wrong element for this: it collected the
total from samples.count rather samples.event_count; in the case that
there are no cycles, this will always be zero. It then divided by
this zero value. This results in output that looked like this:
```
ffff89d29656 : 0 -nan%
ffff89d298b6 : 0 -nan%
ffff89d298c0 : 0 -nan%
```
It's better than nothing, but a lot less informative than one would
like.
Use event_count rather than count for collecting the total, and the
reporting when there are no cycles in the summary information. This results
in output that looks like this:
```
ffff89d29656 : 2 1.21%
ffff89d298b6 : 1 0.61%
ffff89d298c0 : 1 0.61%
```
Signed-off-by: George Dunlap <george.dunlap@cloud.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
If a vmentry/exit arc unexpectedly doesn't have a handler, we throw an
error, and then log the information under HVM event 0; thus those
particular traces within the vmexit reason will have stats gathered,
and will show up with "(no handler)". This is useful in the event
that there are unusual paths through the hypervisor which don't have
trace points.
However, if there are more than one of these, then although we detect and warn
that this is happening, we subsequently continue to stuff data about all exits
into that one exit, even though we only show it in one place.
Instead, refator things to only allow a single exit reason to be
accumulated into any given event.
Also put a comment explaining what's going on, and how to fix it.
Signed-off-by: George Dunlap <george.dunlap@cloud.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Following a conversation with Bob Eschleman, it was agreed that
Bobby would prefer to return to being a Reviewer.
Signed-off-by: George Dunlap <george.dunlap@cloud.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Per ACPI 6.5 section 5.2.25 ("Generic Timer Description Table (GTDT)"),
the fields "Secure EL1 Timer GSIV/Flags" are optional and an OS running
in non-secure world is meant to ignore the values.
However, Xen is trying to reserve the value. The ACPI tables for Graviton
2 metal instances will provide the value 0 which is not a correct PPI
(PPIs start at 16) and would have in fact been already reserved by Xen
as this is an SGI. Xen will hit the BUG() and panic().
For the Device-Tree case, I couldn't find a statement suggesting
that the secure physical timer interrupt is ignored. In fact, I have
found some code in Linux using it as a fallback. That said, it should
never be used.
As I am not aware of any issue when booting using Device-Tree, the
physical timer interrupt is only ignored for ACPI.
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
This file contains the deviation that are not marked by
a deviation comment, as specified in
docs/misra/documenting-violations.rst.
Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Generic timer dt node property "clock-frequency" (refer Linux dt binding
Documentation/devicetree/bindings/timer/arm,arch_timer.yaml) is used to
override the incorrect value set by firmware in CNTFRQ_EL0. If the value
of this property is 0 (i.e. by mistake), Xen would continue to work and
use the value from the sysreg instead. The logic is thus incorrect and
results in inconsistency when creating timer node for domUs:
- libxl domUs: clock_frequency member of struct xen_arch_domainconfig
is set to 0 and libxl ignores setting the "clock-frequency" property,
- dom0less domUs: "clock-frequency" property is taken from dt_host and
thus set to 0.
Property "clock-frequency" is used to override the value from sysreg,
so if it is also invalid, there is nothing we can do and we shall panic
to let user know about incorrect setting. Going even further, we operate
under assumption that the frequency must be at least 1KHz (i.e. cpu_khz
not 0) in order for Xen to boot. Therefore, introduce a new helper
validate_timer_frequency() to verify this assumption and use it to check
the frequency obtained either from dt property or from sysreg.
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
The use of access_ok() is buggy, because it permits access to the compat
translation area. 64bit PV guests don't use the XLAT area, but on AMD
hardware, the DBEXT feature allows a breakpoint to match up to a 4G aligned
region, allowing the breakpoint to reach outside of the XLAT area.
Prior to c/s cda16c1bb2 ("x86: mirror compat argument translation area for
32-bit PV"), the live GDT was within 4G of the XLAT area.
All together, this allowed a malicious 64bit PV guest on AMD hardware to place
a breakpoint over the live GDT, and trigger a #DB livelock (CVE-2015-8104).
Introduce breakpoint_addr_ok() and explain why __addr_ok() happens to be an
appropriate check in this case.
For Xen 4.14 and later, this is a latent bug because the XLAT area has moved
to be on its own with nothing interesting adjacent. For Xen 4.13 and older on
AMD hardware, this fixes a PV-trigger-able DoS.
This is part of XSA-444 / CVE-2023-34328.
Fixes: 65e3554908 ("x86/PV: support data breakpoint extension registers")
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>
The handling of MSR_DR{0..3}_MASK is asymmetric between PV and HVM guests.
HVM guests context switch in based on the guest view of DBEXT, whereas PV
guest switch in base on the host capability. Both guest types leave the
context dirty for the next vCPU.
This leads to the following issue:
* PV or HVM vCPU has debugging active (%dr7 + mask)
* Switch out deactivates %dr7 but leaves other state stale in hardware
* HVM vCPU with debugging activate but can't see DBEXT is switched in
* Switch in loads %dr7 but leaves the mask MSRs alone
Now, the HVM vCPU is operating in the context of the prior vCPU's mask MSR,
and furthermore in a case where it genuinely expects there to be no masking
MSRs.
As a stopgap, adjust the HVM path to switch in/out the masks based on host
capabilities rather than guest visibility (i.e. like the PV path). Adjustment
of the of the intercepts still needs to be dependent on the guest visibility
of DBEXT.
This is part of XSA-444 / CVE-2023-34327
Fixes: c097f54912 ("x86/SVM: support data breakpoint extension registers")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Introduce a timeout for bootloader execution when running in restricted mode.
Allow overwriting the default time out with an environment provided value.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Much like the device model depriv mode, add the same kind of support for the
bootloader. Such feature allows passing a UID as a parameter for the
bootloader to run as, together with the bootloader itself taking the necessary
actions to isolate.
Note that the user to run the bootloader as must have the right permissions to
access the guest disk image (in read mode only), and that the bootloader will
be run in non-interactive mode when restricted.
If enabled bootloader restrict mode will attempt to re-use the user(s) from the
QEMU depriv implementation if no user is provided on the configuration file or
the environment. See docs/features/qemu-deprivilege.pandoc for more
information about how to setup those users.
Bootloader restrict mode is not enabled by default as it requires certain
setup to be done first (setup of the user(s) to use in restrict mode).
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Introduce a --runas=<uid> flag to deprivilege pygrub on Linux and *BSDs. It
also implicitly creates a chroot env where it drops a deprivileged forked
process. The chroot itself is cleaned up at the end.
If the --runas arg is present, then pygrub forks, leaving the child to
deprivilege itself, and waiting for it to complete. When the child exists,
the parent performs cleanup and exits with the same error code.
This is roughly what the child does:
1. Initialize libfsimage (this loads every .so in memory so the chroot
can avoid bind-mounting /{,usr}/lib*
2. Create a temporary empty chroot directory
3. Mount tmpfs in it
4. Bind mount the disk inside, because libfsimage expects a path, not a
file descriptor.
5. Remount the root tmpfs to be stricter (ro,nosuid,nodev)
6. Set RLIMIT_FSIZE to a sensibly high amount (128 MiB)
7. Depriv gid, groups and uid
With this scheme in place, the "output" files are writable (up to
RLIMIT_FSIZE octets) and the exposed filesystem is immutable and contains
the single only file we can't easily get rid of (the disk).
If running on Linux, the child process also unshares mount, IPC, and
network namespaces before dropping its privileges.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
This is work required in order to let pygrub operate in highly deprivileged
chroot mode. This patch adds a function that preloads every plugin, hence
ensuring that a on function exit, every shared library is loaded in memory.
The new "init" function is supposed to be used before depriv, but that's
fine because it's not acting on untrusted data.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
This patch allows pygrub to get ahold of every RW file descriptor it needs
early on. A later patch will clamp the filesystem it can access so it can't
obtain any others.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Small tidy up to ensure output_directory always has a trailing '/' to ease
concatenating paths and that `output` can only be a filename or None.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
There's a hypercall being issued in order to determine whether PV64 is
supported, but since Xen 4.3 that's strictly true so it's not required.
Plus, this way we can avoid mapping the privcmd interface altogether in the
depriv pygrub.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Adds the common tools include folder to the -I compile flags
of libfsimage. This allows us to use:
xen-tools/common-macros.h:BUILD_BUG_ON()
With it, statically assert a sanitized "blocklog - SECTOR_BITS" cannot
underflow.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Sanity-check the XFS superblock for wellformedness at the mount handler.
This forces pygrub to abort parsing a potentially malformed filesystem and
ensures the invariants assumed throughout the rest of the code hold.
Also, derive parameters from previously sanitized parameters where possible
(rather than reading them off the superblock)
The code doesn't try to avoid overflowing the end of the disk, because
that's an unlikely and benign error. Parameters used in calculations of
xfs_daddr_t (like the root inode index) aren't in critical need of being
sanitized.
The sanitization of agblklog is basically checking that no obvious
overflows happen on agblklog, and then ensuring agblocks is contained in
the range (2^(sb_agblklog-1), 2^sb_agblklog].
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
agblklog could plausibly be 32, but that would overflow this shift.
Perform the shift as ULL and cast to u32 at the end instead.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
xfs_info.agnolog (and related code) and XFS_INO_AGBNO_BITS are dead code
that serve no purpose.
This is part of XSA-443 / CVE-2023-34325
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The caching invalidation guidelines from the AMD-Vi specification (48882—Rev
3.07-PUB—Oct 2022) seem to be misleading on some hardware, as devices will
malfunction (see stale DMA mappings) if some fields of the DTE are updated but
the IOMMU TLB is not flushed. This has been observed in practice on AMD
systems. Due to the lack of guidance from the currently published
specification this patch aims to increase the flushing done in order to prevent
device malfunction.
In order to fix, issue an INVALIDATE_IOMMU_PAGES command from
amd_iommu_flush_device(), flushing all the address space. Note this requires
callers to be adjusted in order to pass the DomID on the DTE previous to the
modification.
Some call sites don't provide a valid DomID to amd_iommu_flush_device() in
order to avoid the flush. That's because the device had address translations
disabled and hence the previous DomID on the DTE is not valid. Note the
current logic relies on the entity disabling address translations to also flush
the TLB of the in use DomID.
Device I/O TLB flushing when ATS are enabled is not covered by the current
change, as ATS usage is not security supported.
This is XSA-442 / CVE-2023-34326
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The list is out of date and does not specify all the hypercalls/sub-ops
we support, so update it.
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
The x86 hypercall ABI really used to have 6-argument hypercalls. V4V, the
downstream predecessor to Argo did take 6th args.
However, the 6th arg being %ebp in the 32bit ABI makes it unusable in
practice, because that's the frame pointer in builds with frame pointers
enabled. Therefore Argo was altered to being a 5-arg hypercall when it was
upstreamed.
c/s 2f531c122e ("x86: limit number of hypercall parameters to 5") removed
the ability for hypercalls to take 6 arguments.
Update the documentation to match reality.
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
The script heavily relies on the urlgrabber python module, which doesn't seem
to be packaged by all distros; it's missing from newer Debian versions at
least.
Also the usage of the commands module has been deprecated since Python 2.6, and
removed in Python 3, so the code would need to be re-written to not rely on
urlgrabber and the commands modules.
Arguably the purpose of the xenpvnetboot bootloader can also be achieved with
an isolated script that fetches the kernel and ramdisk before attempting to
launch the domain, without having to run in libxl context. There are no xl.cfg
options consumed by the bootloader apart from the base location and the
subpaths of the kernel and ramdisk to fetch.
Any interested parties in keeping such functionality are free to submit an
updated script that works with Python 3.
Resolves: xen-project/xen#172
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
XENFEAT_runstate_phys_area is exposed to all architectures, while
XENFEAT_vcpu_time_phys_area is currently only implemented for x86, and hence
the feature flag is also only exposed on x86.
Additionally add dummy guards with TODOs in the respective hypercall
implementations, to signal the intention to control the availability of those
hypercalls on a guest-by-guest basis from the toolstack.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
unmap_domain_page_global() expects the provided address to be page aligned, or
else some of the called functions will trigger assertions, like
modify_xen_mappings() on x86 or destroy_xen_mappings() on Arm.
The following assert has been reported by osstest arm 32bit tests:
(XEN) Assertion 'IS_ALIGNED(s, PAGE_SIZE)' failed at arch/arm/mm.c:1243
(XEN) ----[ Xen-4.18-rc arm32 debug=y Not tainted ]----
(XEN) CPU: 0
(XEN) PC: 00271a38 destroy_xen_mappings+0x50/0x5c
[...]
(XEN) Xen call trace:
(XEN) [<00271a38>] destroy_xen_mappings+0x50/0x5c (PC)
(XEN) [<00235aa8>] vunmap+0x30/0x1a0 (LR)
(XEN) [<0026ad88>] unmap_domain_page_global+0x10/0x20
(XEN) [<00208e38>] unmap_guest_area+0x90/0xec
(XEN) [<00208f98>] domain_kill+0x104/0x180
(XEN) [<00239e3c>] do_domctl+0x8ac/0x14fc
(XEN) [<0027ae34>] do_trap_guest_sync+0x570/0x66c
(XEN) [<002019f0>] arch/arm/arm32/entry.o#return_from_trap+0/0x4
Fixes: eadc288cbb ('domain: map/unmap GADDR based shared guest areas')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
For read operations, there's a potential issue when the data field
of the ioreq struct is partially updated in the response. To address
this, zero data field during read operations. This modification
serves as a safeguard against implementations that may inadvertently
partially update the data field in response to read requests.
For instance, consider an 8-bit read operation. In such cases, QEMU,
returns the same content of the data field with only 8 bits of
updated data. This behavior could potentially result in the
propagation of incorrect or unintended data to ioreq clients.
During a write access, the Device Model only need to know the content
of the bits associated with the access size (e.g. for 8-bit, the lower
8-bits). During a read access, the Device Model don't need to know any
value. So restrict the value it can access.
Signed-off-by: Andrii Chepurnyi <andrii_chepurnyi@epam.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Switch to using map_guest_area(). Noteworthy differences from
map_vcpu_info():
- remote vCPU-s are paused rather than checked for being down (which in
principle can change right after the check),
- the domain lock is taken for a much smaller region,
- the error code for an attempt to re-register the area is now -EBUSY,
- we could in principle permit de-registration when no area was
previously registered (which would permit "probing", if necessary for
anything).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
The registration by virtual/linear address has downsides: The access is
expensive for HVM/PVH domains. Furthermore for 64-bit PV domains the area
is inaccessible (and hence cannot be updated by Xen) when in guest-user
mode.
Introduce a new vCPU operation allowing to register the secondary time
area by guest-physical address.
An at least theoretical downside to using physically registered areas is
that PV then won't see dirty (and perhaps also accessed) bits set in its
respective page table entries.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
The registration by virtual/linear address has downsides: At least on
x86 the access is expensive for HVM/PVH domains. Furthermore for 64-bit
PV domains the area is inaccessible (and hence cannot be updated by Xen)
when in guest-user mode.
Introduce a new vCPU operation allowing to register the runstate area by
guest-physical address.
An at least theoretical downside to using physically registered areas is
that PV then won't see dirty (and perhaps also accessed) bits set in its
respective page table entries.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
The registration by virtual/linear address has downsides: At least on
x86 the access is expensive for HVM/PVH domains. Furthermore for 64-bit
PV domains the areas are inaccessible (and hence cannot be updated by
Xen) when in guest-user mode, and for HVM guests they may be
inaccessible when Meltdown mitigations are in place. (There are yet
more issues.)
In preparation of the introduction of new vCPU operations allowing to
register the respective areas (one of the two is x86-specific) by
guest-physical address, flesh out the map/unmap functions.
Noteworthy differences from map_vcpu_info():
- areas can be registered more than once (and de-registered),
- remote vCPU-s are paused rather than checked for being down (which in
principle can change right after the check),
- the domain lock is taken for a much smaller region.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
In preparation of the introduction of new vCPU operations allowing to
register the respective areas (one of the two is x86-specific) by
guest-physical address, add the necessary fork handling (with the
backing function yet to be filled in).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Tamas K Lengyel <tamas@tklengyel.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Before adding a new vCPU operation to register the secondary time area
by guest-physical address, add code to actually keep such areas up-to-
date.
Note that pages aren't marked dirty when written to (matching the
handling of space mapped by map_vcpu_info()), on the basis that the
registrations are lost anyway across migration (or would need re-
populating at the target for transparent migration). Plus the contents
of the areas in question have to be deemed volatile in the first place
(so saving a "most recent" value is pretty meaningless even for e.g.
snapshotting).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Before adding a new vCPU operation to register the runstate area by
guest-physical address, add code to actually keep such areas up-to-date.
Note that updating of the area will be done exclusively following the
model enabled by VMASST_TYPE_runstate_update_flag for virtual-address
based registered areas.
Note further that pages aren't marked dirty when written to (matching
the handling of space mapped by map_vcpu_info()), on the basis that the
registrations are lost anyway across migration (or would need re-
populating at the target for transparent migration). Plus the contents
of the areas in question have to be deemed volatile in the first place
(so saving a "most recent" value is pretty meaningless even for e.g.
snapshotting).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
In preparation of the introduction of new vCPU operations allowing to
register the respective areas (one of the two is x86-specific) by
guest-physical address, add the necessary domain cleanup hooks.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
While likely the guest would just re-register the same areas after
a possible resume, let's not take this for granted and avoid the risk of
otherwise corrupting guest memory.
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>
Instead let map_vcpu_info() and it's call to get_page_from_gfn()
populate the page in the child as needed. Also remove the bogus
copy_domain_page(): should be placed before the call to map_vcpu_info(),
as the later can update the contents of the vcpu_info page.
Note that this eliminates a bug in copy_vcpu_settings(): The function did
allocate a new page regardless of the GFN already having a mapping, thus in
particular breaking the case of two vCPU-s having their info areas on the same
page.
Fixes: 41548c5472 ('mem_sharing: VM forking')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Tamas K Lengyel <tamas@tklengyel.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
The feature is not commonly used, and we don't have hardware to test it,
not in OSSTest, not in Gitlab, and not even ad-hoc manually by community
members. We could use QEMU to test it, but even that it is known not to
work on our end.
Also take the opportunity to rename the feature to "ACPI CPU Hotplug"
for clarity.
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Alejandro Vallejo