Under certain conditions guests can get the CPU stuck in an unbounded
loop without the possibility of an interrupt window to occur on
instruction boundary. This was the case with the scenarios described
in XSA-156.
Make use of the Notify VM Exit mechanism, that will trigger a VM Exit
if no interrupt window occurs for a specified amount of time. Note
that using the Notify VM Exit avoids having to trap #AC and #DB
exceptions, as Xen is guaranteed to get a VM Exit even if the guest
puts the CPU in a loop without an interrupt window, as such disable
the intercepts if the feature is available and enabled.
Setting the notify VM exit window to 0 is safe because there's a
threshold added by the hardware in order to have a sane window value.
Note the handling of EXIT_REASON_NOTIFY in the nested virtualization
case is passed to L0, and hence a nested guest being able to trigger a
notify VM exit with an invalid context would be able to crash the L1
hypervisor (by L0 destroying the domain). Since we don't expose VM
Notify support to L1 it should already enable the required
protections in order to prevent VM Notify from triggering in the first
place.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
x86/vmx: Partially revert "x86/vmx: implement Notify VM Exit"
The original patch tried to do two things - implement VMNotify, and
re-optimise VT-x to not intercept #DB/#AC by default.
The second part is buggy in multiple ways. Both GDBSX and Introspection need
to conditionally intercept #DB, which was not accounted for. Also, #DB
interception has nothing at all to do with cpu_has_monitor_trap_flag.
Revert the second half, leaving #DB/#AC intercepted unilaterally, but with
VMNotify active by default when available.
Fixes: 573279cde1 ("x86/vmx: implement Notify VM Exit")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: 573279cde1
master date: 2022-12-19 11:24:14 +0100
master commit: 5f08bc9404
master date: 2023-01-20 19:39:32 +0000
Introduce a small helper to OR VMX_INTR_SHADOW_NMI in
GUEST_INTERRUPTIBILITY_INFO in order to help dealing with the NMI
unblocked by IRET case. Replace the existing usage in handling
EXIT_REASON_EXCEPTION_NMI and also add such handling to EPT violations
and page-modification log-full events.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: d329b37d12
master date: 2022-12-19 11:23:34 +0100
Add support for enabling guest Bus Lock Detection on Intel systems.
Such detection works by triggering a vmexit, which ought to be enough
of a pause to prevent a guest from abusing of the Bus Lock.
Add an extra Xen perf counter to track the number of Bus Locks detected.
This is done because Bus Locks can also be reported by setting the bit
26 in the exit reason field, so also account for those.
Note EXIT_REASON_BUS_LOCK VMExits will always have bit 26 set in
exit_reason, and hence the performance counter doesn't need to be
increased for EXIT_REASON_BUS_LOCK handling.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: f7d07619d2
master date: 2022-12-19 11:22:43 +0100
As stated (correctly) by the comment next to SPEC_CTRL_ENTRY_FROM_PV, between
the two hunks visible in the patch, RET's are not safe prior to this point.
CR4_PV32_RESTORE hides a CALL/RET pair in certain configurations (PV32
compiled in, SMEP or SMAP active), and the RET can be attacked with one of
several known speculative issues.
Furthermore, CR4_PV32_RESTORE also hides a reference to the cr4_pv32_mask
global variable, which is not safe when XPTI is active before restoring Xen's
full pagetables.
This crash has gone unnoticed because it is only AMD CPUs which permit the
SYSCALL instruction in compatibility mode, and these are not vulnerable to
Meltdown so don't activate XPTI by default.
This is XSA-429 / CVE-2022-42331
Fixes: 5e79629011 ("x86/entry: Organise the use of MSR_SPEC_CTRL at each entry/exit point")
Fixes: 5784de3e20 ("x86: Meltdown band-aid against malicious 64-bit PV guests")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit df5b055b12116d9e63ced59ae5389e69a2a3de48)
While the RCU variants of list insertion and removal allow lockless list
traversal (with RCU just read-locked), insertions and removals still
need serializing amongst themselves. To keep things simple, use the
domain lock for this purpose.
This is CVE-2022-42334 / part of XSA-428.
Fixes: 642123c512 ("x86/hvm: provide XEN_DMOP_pin_memory_cacheattr")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
(cherry picked from commit 829ec245cf66560e3b50d140ccb3168e7fb7c945)
This is exposed via DMOP, i.e. to potentially not fully privileged
device models. With that we may not permit registration of an (almost)
unbounded amount of such regions.
This is CVE-2022-42333 / part of XSA-428.
Fixes: 642123c512 ("x86/hvm: provide XEN_DMOP_pin_memory_cacheattr")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit a5e768640f786b681063f4e08af45d0c4e91debf)
Pre-allocation is intended to ensure that in the course of constructing
or updating shadows there won't be any risk of just made shadows or
shadows being acted upon can disappear under our feet. The amount of
pages pre-allocated then, however, needs to account for all possible
subsequent allocations. While the use in sh_page_fault() accounts for
all shadows which may need making, so far it didn't account for
allocations coming from log-dirty tracking (which piggybacks onto the
P2M allocation functions).
Since shadow_prealloc() takes a count of shadows (or other data
structures) rather than a count of pages, putting the adjustment at the
call site of this function won't work very well: We simply can't express
the correct count that way in all cases. Instead take care of this in
the function itself, by "snooping" for L1 type requests. (While not
applicable right now, future new request sites of L1 tables would then
also be covered right away.)
It is relevant to note here that pre-allocations like the one done from
shadow_alloc_p2m_page() are benign when they fall in the "scope" of an
earlier pre-alloc which already included that count: The inner call will
simply find enough pages available then; it'll bail right away.
This is CVE-2022-42332 / XSA-427.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Tim Deegan <tim@xen.org>
(cherry picked from commit 91767a71061035ae42be93de495cd976f863a41a)
Currently late ucode loading is performed only on the first core of CPU
siblings. But according to the latest recommendation from AMD, late
ucode loading should happen on every logical thread/core on AMD CPUs.
To achieve that, introduce is_cpu_primary() helper which will consider
every logical cpu as "primary" when running on AMD CPUs. Also include
Hygon in the check for future-proofing.
Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: f1315e48a0
master date: 2023-02-28 14:51:28 +0100
From `man 2 realloc`:
If realloc() fails, the original block is left untouched; it is not freed or moved.
Found using GCC -fanalyzer:
| 184 | backup->entries = realloc(backup->entries,
| | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| | | | |
| | | | (91) when ‘realloc’ fails
| | | (92) ‘old_ptes.entries’ leaks here; was allocated at (44)
| | (90) ...to here
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 275d13184c
master date: 2023-02-27 15:51:23 +0000
Edwin, with the help of GCC's -fanalyzer, identified that p2m_frame_list_list
gets leaked. What fanalyzer can't see is that the live_p2m_frame_list_list
and live_p2m_frame_list foreign mappings are leaked too.
Rework the logic so the out path is executed unconditionally, which cleans up
all the intermediate allocations/mappings appropriately.
Fixes: bd7a29c3d0 ("tools/libs/ctrl: fix xc_core_arch_map_p2m() to support linear p2m table")
Reported-by: Edwin Török <edwin.torok@cloud.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
master commit: 1868d7f226
master date: 2023-02-27 15:51:23 +0000
Replace PKG_CONFIG variable name with PKG_CONFIG_FILE for the name of
the pkg-config file.
This is preventing a conflict in some build systems where PKG_CONFIG
actually contains the path to the pkg-config executable to use, as the
default assignment in libs.mk is using a weak assignment (?=).
This problem has been found when trying to build the latest version of
Xen tools using buildroot.
Fixes: d400dc5729 ("tools: tweak tools/libs/libs.mk for being able to support libxenctrl")
Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
master commit: b97e2fe7b9
master date: 2023-02-24 17:44:29 +0000
While trying to work around a different Clang-IAS bug (parent changeset), I
stumbled onto:
In file included from arch/x86/asm-macros.c:3:
./arch/x86/include/asm/spec_ctrl_asm.h:144:19: error: \u used with
no following hex digits; treating as '\' followed by identifier [-Werror,-Wunicode]
.L\@_fill_rsb_loop\uniq:
^
It turns out that Clang -E is sensitive to the file extension of the source
file it is processing. Furthermore, C explicitly permits the use of \u
escapes in identifier names, so the diagnostic would be reasonable in
principle if we trying to compile the result.
asm-macros should really have been .S from the outset, as it is ultimately
generating assembly, not C. Rename it, which causes Clang not to complain.
We need to introduce rules for generating a .i file from .S, and substituting
c_flags for a_flags lets us drop the now-redundant -D__ASSEMBLY__.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 53f0d02040
master date: 2023-02-24 17:44:29 +0000
https://github.com/llvm/llvm-project/issues/60792
It turns out that Clang-IAS does not expand \@ uniquely in a translaition
unit, and the XSA-426 change tickles this bug:
<instantiation>:4:1: error: invalid symbol redefinition
.L1_fill_rsb_loop:
^
make[3]: *** [Rules.mk:247: arch/x86/acpi/cpu_idle.o] Error 1
Extend DO_OVERWRITE_RSB with an optional parameter so C callers can mix %= in
too, which Clang does seem to expand properly.
Fixes: 63305e5392 ("x86/spec-ctrl: Mitigate Cross-Thread Return Address Predictions")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: a2adacff0b
master date: 2023-02-24 17:44:29 +0000
An assert failure has been observed in p2m_teardown when performing vm
forking and then destroying the forked VM (p2m-basic.c:173). The assert
checks whether the domain's shared pages counter is 0. According to the
patch that originally added the assert (7bedbbb5c3) the p2m_teardown
should only happen after mem_sharing already relinquished all shared pages.
In this patch we flip the order in which relinquish ops are called to avoid
tripping the assert. Conceptually sharing being torn down makes sense to
happen before paging is torn down.
Fixes: e7aa55c0aa ("x86/p2m: free the paging memory pool preemptively")
Signed-off-by: Tamas K Lengyel <tamas@tklengyel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 2869349f0c
master date: 2023-02-23 12:35:48 +0100
The original issue has been reported on AMD Bulldozer-based CPUs where
ucode loading loses the LWP feature bit in order to gain the IBPB bit.
LWP disabling is per-SMT/CMT core modification and needs to happen on
each sibling thread despite the shared microcode engine. Otherwise,
logical CPUs will end up with different cpuid capabilities.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216211
Guests running under Xen happen to be not affected because of levelling
logic for the feature masking/override MSRs which causes the LWP bit to
fall out and hides the issue. The latest recommendation from AMD, after
discussing this bug, is to load ucode on every logical CPU.
In Linux kernel this issue has been addressed by e7ad18d1169c
("x86/microcode/AMD: Apply the patch early on every logical thread").
Follow the same approach in Xen.
Introduce SAME_UCODE match result and use it for early AMD ucode
loading. Take this opportunity and move opt_ucode_allow_same out of
compare_revisions() to the relevant callers and also modify the warning
message based on it. Intel's side of things is modified for consistency
but provides no functional change.
Signed-off-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: f4ef8a41b8
master date: 2023-02-21 15:08:05 +0100
The FILE symbols in out-of-tree builds may be either a relative path to
the object dir or an absolute path depending on how the build is
invoked. Fix the paths for C files so that they are consistent with
in-tree builds - the path is relative to the "xen" directory (e.g.
common/irq.c).
This fixes livepatch builds when the original Xen build was out-of-tree
since livepatch-build always does in-tree builds. Note that this doesn't
fix the behaviour for Clang < 6 which always embeds full paths.
Fixes: 7115fa562f ("build: adding out-of-tree support to the xen build")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 5b9bb91abb
master date: 2023-02-15 16:13:49 +0100
Documentation for credit2_runqueue=all says it should create one queue
for all pCPUs on the host. But since introduction
sched_credit2_max_cpus_runqueue, it actually created separate runqueue
per socket, even if the CPUs count is below
sched_credit2_max_cpus_runqueue.
Adjust the condition to skip syblink check in case of
credit2_runqueue=all.
Fixes: 8e2aa76dc1 ("xen: credit2: limit the max number of CPUs in a runqueue")
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
master commit: 1f5747ee92
master date: 2023-02-15 16:12:42 +0100
Refer to Intel SDM Rev 70 (Dec 2022), Vol3 17.2.3 "Supervisor Shadow Stack
Token".
Architecturally, an event delivery which starts in CPL<3 and switches shadow
stack will first validate the Supervisor Shadow Stack Token (setting the busy
bit), then pushes CS/LIP/SSP. One example of this is an NMI interrupting Xen.
Some CPUs suffer from an issue called fracturing, whereby a fault/vmexit/etc
between setting the busy bit and completing the event injection renders the
action non-restartable, because when it comes time to restart, the busy bit is
found to be already set.
This is far more easily encountered under virt, yet it is not the fault of the
hypervisor, nor the fault of the guest kernel. The fault lies somewhere
between the architectural specification, and the uarch behaviour.
Intel have allocated CPUID.7[1].ecx[18] CET_SSS to enumerate that supervisor
shadow stacks are safe to use. Because of how Xen lays out its shadow stacks,
fracturing is not expected to be a problem on native.
Detect this case on boot and default to not using shstk if virtualised.
Specifying `cet=shstk` on the command line will override this heuristic and
enable shadow stacks irrespective.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 01e7477d1b
master date: 2023-02-09 18:26:17 +0000
We don't actually need ecx yet, but adding it in now will reduce the amount to
which leaf 7 is out of order in a featureset.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: b4a23bf629
master date: 2023-02-09 18:26:17 +0000
flex/bison generate two targets, and when those targets are
prerequisite of other rules they are considered independently by make.
We can have a situation where the .c file is out-of-date but not the
.h, git checkout for example. In this case, if a rule only have the .h
file as prerequiste, make will procced and start to build the object.
In parallel, another target can have the .c file as prerequisite and
make will find out it need re-generating and do so, changing the .h at
the same time. This parallel task breaks the first one.
To avoid this scenario, we put both the header and the source as
prerequisite for all object even if they only need the header.
Reported-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: bf652a50fb
master date: 2023-02-09 18:26:17 +0000
First, apt complain that it isn't the right way to add keys anymore,
but hopefully that's just a warning.
Second, we can't install clang-8:
The following packages have unmet dependencies:
clang-8 : Depends: libstdc++-8-dev but it is not installable
Depends: libgcc-8-dev but it is not installable
Depends: libobjc-8-dev but it is not installable
Recommends: llvm-8-dev but it is not going to be installed
Recommends: libomp-8-dev but it is not going to be installed
libllvm8 : Depends: libffi7 (>= 3.3~20180313) but it is not installable
E: Unable to correct problems, you have held broken packages.
clang on Debian unstable is now version 14.0.6.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit a6b1e2b80f)
All caml_alloc_*() functions can throw exceptions, and longjump out of
context. If this happens, we leak the xch/xce handle.
Reorder the logic to allocate the the Ocaml object first.
Fixes: 8b3c06a3e5 ("tools/ocaml/xenctrl: OCaml 5 support, fix use-after-free")
Fixes: 22d5affdf0 ("tools/ocaml/evtchn: OCaml 5 support, fix potential resource leak")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit d69ccf52ad)
The intf->{addr,len} references in the xc_map_foreign_range() call are unsafe.
From the manual:
https://ocaml.org/manual/intfc.html#ss:parallel-execution-long-running-c-code
"After caml_release_runtime_system() was called and until
caml_acquire_runtime_system() is called, the C code must not access any OCaml
data, nor call any function of the run-time system, nor call back into OCaml
code."
More than what the manual says, the intf pointer is (potentially) invalidated
by caml_enter_blocking_section() if another thread happens to perform garbage
collection at just the right (wrong) moment.
Rewrite the logic. There's no need to stash data in the Ocaml object until
the success path at the very end.
Fixes: 8b7ce06a2d ("ocaml: Add XC bindings.")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 9e7c74e6f9)
The patch adding this binding was plain broken, and unreviewed. It modified
the C stub to add a 4th parameter without an equivalent adjustment in the
Ocaml side of the bindings.
In 64bit builds, this causes us to dereference whatever dead value is in %rcx
when trying to interpret the rflags parameter.
This has gone unnoticed because Xapi doesn't use this binding (it has its
own), but unbreak the binding by passing RDM_RELAXED unconditionally for
now (matching the libxl default behaviour).
Fixes: 9b34056cb4 ("tools: extend xc_assign_device() to support rdm reservation policy")
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 4250683842)
The modification to the _H() macro for Ocaml 5 support introduced a subtle
bug. From the manual:
https://ocaml.org/manual/intfc.html#ss:parallel-execution-long-running-c-code
"After caml_release_runtime_system() was called and until
caml_acquire_runtime_system() is called, the C code must not access any OCaml
data, nor call any function of the run-time system, nor call back into OCaml
code."
Previously, the value was a naked C pointer, so dereferencing it wasn't
"accessing any Ocaml data", but the fix to avoid naked C pointers added a
layer of indirection through an Ocaml Custom object, meaning that the common
pattern of using _H() in a blocking section is unsafe.
In order to fix:
* Drop the _H() macro and replace it with a static inline xce_of_val().
* Opencode the assignment into Data_custom_val() in the two constructors.
* Rename "value xce" parameters to "value xce_val" so we can consistently
have "xenevtchn_handle *xce" on the stack, and obtain the pointer with the
GC lock still held.
Fixes: 22d5affdf0 ("tools/ocaml/evtchn: OCaml 5 support, fix potential resource leak")
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 2636d8ff7a)
caml_alloc() takes units of Wsize (word size), not bytes. As a consequence,
we're allocating 4 or 8 times too much memory.
Ocaml has a helper, Wsize_bsize(), but it truncates cases which aren't an
exact multiple. Use a BUILD_BUG_ON() to cover the potential for truncation,
as there's no rounding-up form of the helper.
Fixes: 8b7ce06a2d ("ocaml: Add XC bindings.")
Fixes: d3e649277a ("ocaml: add mmap bindings implementation.")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 36eb2de31b)
There is no such thing as an Ocaml function (C stub or otherwise) taking no
parameters. In the absence of any other parameters, unit is still passed.
This doesn't explode with any ABI we care about, but would malfunction for an
ABI environment such as stdcall.
Fixes: c3afd398ba ("ocaml: Add XS bindings.")
Fixes: 8b7ce06a2d ("ocaml: Add XC bindings.")
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit ff8b560be8)
The configuration file can contain typos or various errors that could prevent
live update from succeeding (e.g. a flag only valid on a different version).
Unknown entries in the config file would be ignored on startup normally,
add a strict --config-test that live-update can use to check that the config file
is valid *for the new binary*.
For compatibility with running old code during live update recognize
--live --help as an equivalent to --config-test.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit e6f07052ce)
This function is unusued (only Xs_ring.write_substring is used), and the
bytes/string conversion here is backwards: the C stub implements the bytes
version and then we use a Bytes.unsafe_of_string to convert a string into
bytes.
However the operation here really is read-only: we read from the string and
write it to the ring, so the C stub should implement the read-only string
version, and if needed we could use Bytes.unsafe_to_string to be able to send
'bytes'. However that is not necessary as the 'bytes' version is dropped above.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 01f139215e)
This is not strictly necessary since it is essentially a no-op currently: a
cast to void * and value *, even in OCaml 5.0.
However it does make it clearer that what we have here is not a regular OCaml
value, but one allocated with Abstract_tag or Custom_tag, and follows the
example from the manual more closely:
https://v2.ocaml.org/manual/intfc.html#ss:c-outside-head
It also makes it clearer that these modules have been reviewed for
compat with OCaml 5.0.
We cannot use OCaml finalizers here, because we want exact control over when
to unmap these pages from remote domains.
No functional change.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit d2ccc63711)
domain_getinfolist() is quadratic with the number of domains, because of the
behaviour of the underlying hypercall. Nevertheless, getting domain info in
blocks of 1024 is far more efficient than blocks of 2.
In a scalability testing scenario with ~1000 VMs, a combination of this and
the previous change takes xenopsd's wallclock time in domain_getinfolist()
down from 88% to 0.02%
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Tested-by: Pau Ruiz Safont <pau.safont@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 95db09b1b1)
domain_getinfolist() is quadratic with the number of domains, because of the
behaviour of the underlying hypercall. xenopsd was further observed to be
wasting excessive quantites of time manipulating the list of already-obtained
domains.
Implement a tail recursive `rev_concat` equivalent to `concat |> rev`, and use
it instead of calling `@` multiple times.
An incidental benefit is that the list of domains will now be in domid order,
instead of having pairs of 2 domains changing direction every time.
In a scalability testing scenario with ~1000 VMs, a combination of this and
the subsequent change takes xenopsd's wallclock time in domain_getinfolist()
down from 88% to 0.02%
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Tested-by: Pau Ruiz Safont <pau.safont@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit c3b6be714c)
When a domain performs a kexec (soft reset), libxl__build_pre() is
called with the existing domid. Calling libxl__cpuid_legacy() on the
existing domain fails since the cpuid policy has already been set, and
the guest isn't rebuilt and doesn't kexec.
xc: error: Failed to set d1's policy (err leaf 0xffffffff, subleaf 0xffffffff, msr 0xffffffff) (17 = File exists): Internal error
libxl: error: libxl_cpuid.c:494:libxl__cpuid_legacy: Domain 1:Failed to apply CPUID policy: File exists
libxl: error: libxl_create.c:1641:domcreate_rebuild_done: Domain 1:cannot (re-)build domain: -3
libxl: error: libxl_xshelp.c:201:libxl__xs_read_mandatory: xenstore read failed: `/libxl/1/type': No such file or directory
libxl: warning: libxl_dom.c:49:libxl__domain_type: unable to get domain type for domid=1, assuming HVM
During a soft_reset, skip calling libxl__cpuid_legacy() to avoid the
issue. Before commit 34990446ca, the libxl__cpuid_legacy() failure
would have been ignored, so kexec would continue.
Fixes: 34990446ca ("libxl: don't ignore the return value from xc_cpuid_apply_policy")
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
master commit: 1e454c2b5b
master date: 2023-01-26 10:58:23 +0100
uart->io_size represents the size in bytes. Thus, when serial_port.bit_width
is assigned to it, it should be converted to size in bytes.
Fixes: 17b516196c ("ns16550: add ACPI support for ARM only")
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
master commit: 352c89f72d
master date: 2023-01-24 16:54:38 +0100
Unfortunatly, adding prerequisite to "$(obj)/ss/built_in.o" doesn't
work because we have "$(obj)/%/built_in.o: $(obj)/% ;" in Rules.mk.
So, make is allow to try to build objects in "xsm/flask/ss/" before
generating the headers.
Adding a prerequisite on "$(obj)/ss" instead will fix the issue as
that's the target used to run make in this subdirectory.
Unfortunatly, that target is also used when running `make clean`, so
we want to ignore it in this case. $(MAKECMDGOALS) can't be used in
this case as it is empty, but we can guess which operation is done by
looking at the list of loaded makefiles.
Fixes: 7a3bcd2bab ("build: build everything from the root dir, use obj=$subdir")
Reported-by: "Daniel P. Smith" <dpsmith@apertussolutions.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: d60324d8af
master date: 2023-01-23 15:03:58 +0100
Clearly within the for_each_vcpu() the vCPU of this loop is meant, not
the (loop invariant) one the fault occurred on.
Fixes: 3d5e6a3ff3 ("x86 hvm: implement HVMOP_pagetable_dying")
Fixes: ef3b0d8d2c ("x86/shadow: shadow_table[] needs only one entry for PV-only configs")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: f8fdceefbb
master date: 2023-01-20 09:23:42 +0100
Ice Lake (server at least) has both architectural LBR and model-specific LBR.
Sapphire Rapids does not have model-specific LBR at all. I.e. On SPR and
later, model_specific_lbr will always be NULL, so we must make changes to
avoid reliably hitting the domain_crash().
The Arch LBR spec states that CPUs without model-specific LBR implement
MSR_DBG_CTL.LBR by discarding writes and always returning 0.
Do this for any CPU for which we lack model-specific LBR information.
Adjust the now-stale comment, now that the Arch LBR spec has created a way to
signal "no model specific LBR" to guests.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: 3edca52ce7
master date: 2023-01-12 18:42:00 +0000
There is no point repeating this calculation at runtime, especially as it is
in the fallback path of the WRSMR/RDMSR handlers.
Move the infrastructure higher in vmx.c to avoid forward declarations,
renaming last_branch_msr_get() to get_model_specific_lbr() to highlight that
these are model-specific only.
No practical change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: e94af0d58f
master date: 2023-01-12 18:42:00 +0000
Public headers can include other public headers. Such interdependencies
are retained in their compat counterparts. Since some compat headers are
generated only in certain configurations, the referenced headers still
need to exist. The lack thereof was observed with hvm/hvm_op.h needing
trace.h, where generation of the latter depends on TRACEBUFFER=y. Make
empty stubs in such cases (as generating the extra headers is relatively
slow and hence better to avoid). Changes to .config and incrementally
(re-)building is covered by the respective .*.cmd then no longer
matching the command to be used, resulting in the necessary re-creation
of the (possibly stub) header.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
master commit: 6bec713f87
master date: 2023-01-12 16:17:54 +0100
The configure option "--enable-trace-backend" isn't accepted anymore
and we should use "--enable-trace-backends" instead which was
introduce in 2014 and allow multiple backends.
"--enable-trace-backends" was introduced by:
5b808275f3bb ("trace: Multi-backend tracing")
The backward compatible option "--enable-trace-backend" is removed by
10229ec3b0ff ("configure: remove backwards-compatibility and obsolete options")
As we already use ./configure options that wouldn't be accepted by
older version of QEMU's configure, we will simply use the new spelling
for the option and avoid trying to detect which spelling to use.
We already make use if "--firmwarepath=" which was introduced by
3d5eecab4a5a ("Add --firmwarepath to configure")
which already include the new spelling for "--enable-trace-backends".
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
master commit: e66d450b6e
master date: 2023-01-11 10:45:29 +0100
There are two paths in the trampoline, and Xen's PAT needs setting up in both,
not just the boot path.
Fixes: 4304ff420e ("x86/S3: Drop {save,restore}_rest_processor_state() completely")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 4d975798e1
master date: 2023-01-10 21:21:30 +0000
I'm observing guest kexec trigger xenstored to abort on a double free.
gdb output:
Program received signal SIGABRT, Aborted.
__pthread_kill_implementation (no_tid=0, signo=6, threadid=140645614258112) at ./nptl/pthread_kill.c:44
44 ./nptl/pthread_kill.c: No such file or directory.
(gdb) bt
at ./nptl/pthread_kill.c:44
at ./nptl/pthread_kill.c:78
at ./nptl/pthread_kill.c:89
at ../sysdeps/posix/raise.c:26
at talloc.c:119
ptr=ptr@entry=0x559fae724290) at talloc.c:232
at xenstored_core.c:2945
(gdb) frame 5
at talloc.c:119
119 TALLOC_ABORT("Bad talloc magic value - double free");
(gdb) frame 7
at xenstored_core.c:2945
2945 talloc_increase_ref_count(conn);
(gdb) p conn
$1 = (struct connection *) 0x559fae724290
Looking at a xenstore trace, we have:
IN 0x559fae71f250 20230120 17:40:53 READ (/local/domain/3/image/device-model-dom
id )
wrl: dom 0 1 msec 10000 credit 1000000 reserve 100 disc
ard
wrl: dom 3 1 msec 10000 credit 1000000 reserve 100 disc
ard
wrl: dom 0 0 msec 10000 credit 1000000 reserve 0 disc
ard
wrl: dom 3 0 msec 10000 credit 1000000 reserve 0 disc
ard
OUT 0x559fae71f250 20230120 17:40:53 ERROR (ENOENT )
wrl: dom 0 1 msec 10000 credit 1000000 reserve 100 disc
ard
wrl: dom 3 1 msec 10000 credit 1000000 reserve 100 disc
ard
IN 0x559fae71f250 20230120 17:40:53 RELEASE (3 )
DESTROY watch 0x559fae73f630
DESTROY watch 0x559fae75ddf0
DESTROY watch 0x559fae75ec30
DESTROY watch 0x559fae75ea60
DESTROY watch 0x559fae732c00
DESTROY watch 0x559fae72cea0
DESTROY watch 0x559fae728fc0
DESTROY watch 0x559fae729570
DESTROY connection 0x559fae724290
orphaned node /local/domain/3/device/suspend/event-channel deleted
orphaned node /local/domain/3/device/vbd/51712 deleted
orphaned node /local/domain/3/device/vkbd/0 deleted
orphaned node /local/domain/3/device/vif/0 deleted
orphaned node /local/domain/3/control/shutdown deleted
orphaned node /local/domain/3/control/feature-poweroff deleted
orphaned node /local/domain/3/control/feature-reboot deleted
orphaned node /local/domain/3/control/feature-suspend deleted
orphaned node /local/domain/3/control/feature-s3 deleted
orphaned node /local/domain/3/control/feature-s4 deleted
orphaned node /local/domain/3/control/sysrq deleted
orphaned node /local/domain/3/data deleted
orphaned node /local/domain/3/drivers deleted
orphaned node /local/domain/3/feature deleted
orphaned node /local/domain/3/attr deleted
orphaned node /local/domain/3/error deleted
orphaned node /local/domain/3/console/backend-id deleted
and no further output.
The trace shows that DESTROY was called for connection 0x559fae724290,
but that is the same pointer (conn) main() was looping through from
connections. So it wasn't actually removed from the connections list?
Reverting commit e8e6e42279 "tools/xenstore: simplify loop handling
connection I/O" fixes the abort/double free. I think the use of
list_for_each_entry_safe is incorrect. list_for_each_entry_safe makes
traversal safe for deleting the current iterator, but RELEASE/do_release
will delete some other entry in the connections list. I think the
observed abort is because list_for_each_entry has next pointing to the
deleted connection, and it is used in the subsequent iteration.
Add a comment explaining the unsuitability of list_for_each_entry_safe.
Also notice that the old code takes a reference on next which would
prevents a use-after-free.
This reverts commit e8e6e42279.
This is XSA-425/CVE-2022-42330.
Fixes: e8e6e42279 ("tools/xenstore: simplify loop handling connection I/O")
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
fallback_exception_handler feeds a string with embedded newlines directly into
syslog(). While this is an improvement on getting nothing, syslogd escapes
all control characters it gets, and emits one (long) log line.
Fix the problem generally in the syslog stub. As we already have a local copy
of the string, split it in place and emit one syslog() call per line.
Also tweak Logging.msg_of to avoid putting an extra newline on a string which
already ends with one.
Fixes: ee7815f49f ("tools/oxenstored: Set uncaught exception handler")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit d2162d884c)
strdup() may return NULL. Check for this before passing to syslog().
Drop const from c_msg. It is bogus, as demonstrated by the need to cast to
void * in order to free the memory.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit acd3fb6d65)
Unhandled exceptions go to stderr by default, but this doesn't typically work
for oxenstored because:
* daemonize reopens stderr as /dev/null
* systemd redirects stderr to /dev/null too
Debugging an unhandled exception requires reproducing the issue locally when
using --no-fork, and is not conducive to figuring out what went wrong on a
remote system.
Install a custom handler which also tries to render the backtrace to the
configured syslog facility, and DAEMON|ERR otherwise.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit ee7815f49f)
During live update, oxenstored tries a best effort approach to recover as many
domains and information as possible even if it encounters errors restoring
some domains.
However, logging about misunderstood input is more severe than simply info.
Log it at warning instead.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 3f02e0a70f)
Closing the evtchn handle will unbind and free all local ports. The new
xenstored would need to rebind all evtchns, which is work that we don't want
or need to be doing during the critical handover period.
However, it turns out that the Windows PV drivers also rebind their local port
too across suspend/resume, leaving (o)xenstored with a stale idea of the
remote port to use. In this case, reusing the established connection is the
only robust option.
Therefore:
* Have oxenstored open /dev/xen/evtchn without CLOEXEC at start of day.
* Extend the handover information with the evtchn fd, domexc virq local port,
and the local port number for each domain connection.
* Have (the new) oxenstored recover the open handle using Xeneventchn.fdopen,
and use the provided local ports rather than trying to rebind them.
When this new information isn't present (i.e. live updating from an oxenstored
prior to this change), the best-effort status quo will have to do.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 9b224c2529)
Inter-domain event channels are always a pair of local and remote ports.
Right now the handling is asymmetric, caused by the fact that the evtchn is
bound after the associated Domain object is constructed.
First, move binding of the event channel into the Domain.make() constructor.
This means the local port no longer needs to be an option. It also removes
the final callers of Domain.bind_interdomain.
Next, introduce a new port_pair type to encapsulate the fact that these two
should be updated together, and replace the previous port and remote_port
fields. This refactoring also changes the Domain.get_port interface (removing
an option) so take the opportunity to name it get_local_port instead.
Also, this fixes a use-after-free risk with Domain.close. Once the evtchn has
been unbound, the same local port number can be reused for a different
purpose, so explicitly invalidate the ports to prevent their accidental misuse
in the future.
This also cleans up some of the debugging, to always print a port pair.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit df2db174b3)
Generally speaking, the event channel local/remote port is fixed for the
lifetime of the associated domain object. The exception to this is a
secondary XS_INTRODUCE (defined to re-bind to a new event channel) which pokes
around at the domain object's internal state.
We need to refactor the evtchn handling to support live update, so start by
moving the relevant manipulation into Domain.
No practical change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Edwin Török <edvin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit aecdc28d95)
Roger Pau Monné
Andrew Cooper
Jan Beulich
Sergey Dyasli
Edwin Török
Bertrand Marquis
Tamas K Lengyel
Ross Lagerwall
Marek Marczykowski-Górecki
Anthony PERARD
Edwin Török
Jason Andryuk
Ayan Kumar Halder