While we've been diligent to ensure that the main text/data/rodata mappings
have suitable restrictions, their aliases via the directmap were left fully
read/write. Worse, we even had pieces of code making use of this as a
feature.
Restrict the permissions for .text/rodata, as we have no legitimate need for
writeability of these areas via the directmap alias. Note that the
compile-time allocated pagetables do get written through their directmap
alias, so need to remain writeable.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
These two early exits skipped re-enabling the watchdog, restoring the NMI
callback, and clearing the nmi_patch global pointer. Always execute the tail
of the function on the way out.
Fixes: 8dd4dfa92d ("x86/microcode: Synchronize late microcode loading")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
In VMX operation, the handling of INIT IPIs is changed. Instead of the CPU
resetting, the next VMEntry fails with EXIT_REASON_INIT. From the TXT spec,
the intent of this behaviour is so that an entity which cares can scrub
secrets from RAM before participating in an orderly shutdown.
Right now, Xen's behaviour is that when an INIT arrives, the HVM VM which
schedules next is killed (citing an unknown VMExit), *and* we ignore the INIT
and continue blindly onwards anyway.
This patch addresses only the first of these two problems by ignoring the INIT
and continuing without crashing the VM in question.
The second wants addressing too, just as soon as we've figured out something
better to do...
Discovered as collateral damage from when an AP triple faults on S3 resume on
Intel TigerLake platforms.
Link: https://github.com/QubesOS/qubes-issues/issues/7283
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
This reverts commit e1d7508444.
After spending ages sorting out Gitlab CI, it appears that OSSTest too has an
out-of-date Lets Encrypt cert. Revert again in the short term while we fix
this up.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
* Delete trailing whitespace
* Replace an opencoded DIV_ROUND_UP()
* Drop bogus smp_rmb() - spin_lock_irqsave() has full smp_mb() semantics.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
All three of these records have tail padding, leaking stack rubble into the
trace buffer. Introduce an explicit _pad field and have the compiler zero the
padding automatically.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
Four TRC_MEM_* records supply custom structures with tail padding, leaking
stack rubble into the trace buffer. Three of the records were fine in 32-bit
builds of Xen, due to the relaxed alignment of 64-bit integers, but
POD_SUPERPAGE_SPLITER was broken right from the outset.
We could pack the datastructures to remove the padding, but xentrace_format
has no way of rendering the upper half of a 16-bit field. Instead, expand all
16-bit fields to 32-bit.
For POD_SUPERPAGE_SPLINTER, introduce an order field as it is relevant
information, and to match DECREASE_RESERVATION, and so it doesn't require a
__packed attribute to drop tail padding.
Update xenalyze's structures to match, and introduce xentrace_format rendering
which was absent previously.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>
In the case that 'extra' isn't a multiple of uint32_t, the calculation rounds
the number of bytes up, causing later logic to read unrelated bytes beyond the
end of the object.
Also, asserting that the object is within TRACE_EXTRA_MAX, but truncating it
in release builds is rude. Instead, reject any out-of-spec records, leaving
enough of a message to identify the faulty caller.
There is one buggy trace record, TRC_RTDS_BUDGET_BURN. As it must remain
__packed (as cur_budget is misaligned), change bool has_extratime to uint32_t
to compensate.
It turns out that the new printk() can also be hit by HVMOP_xentrace, because
the hypercall is broken. It cannot be used outside of custom debugging, as
none of the tooling was ever updated to understand TRC_GUEST, nor is there any
evidence of hypercall ever being used in public.
While the hypercall was clearly intended to be used with units if uint32_t's,
that's not how the API/ABI works - Xen will in fact read the entire structure
rather than the initialised subset out of guest memory (most likely, stack
rubble), then copy up to 3 bytes of it (rounding up to the next uint32_t) into
the real tracebuffer.
There are several possible ways to fix this, but as the hypercall, and does
not plausibly have any users, go with the one that is least logic in Xen, by
rejecting tracing attempts that are not of uint32_t size.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Partly for clarity because there is a lot of subtle magic at work here.
Expand the commentary of what's going on.
Also because there is no need to double copy the stack (32kB). Spilled
content does need accounting for, but this can be sorted by only copying only
a handful of words.
No practical change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Gitlab Randconfig found:
arch/x86/mm/shadow/common.c: In function 'shadow_prealloc':
arch/x86/mm/shadow/common.c:1023:18: error: implicit declaration of function
'paging_logdirty_levels'; did you mean 'paging_log_dirty_init'? [-Werror=implicit-function-declaration]
1023 | count += paging_logdirty_levels();
| ^~~~~~~~~~~~~~~~~~~~~~
| paging_log_dirty_init
arch/x86/mm/shadow/common.c:1023:18: error: nested extern declaration of 'paging_logdirty_levels' [-Werror=nested-externs]
The '#if PG_log_dirty' expression is currently SHADOW_PAGING && !HVM &&
PV_SHIM_EXCLUSIVE. Move the declaration outside.
Fixes: 33fb3a6612 ("x86/shadow: account for log-dirty mode when pre-allocating")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Since c/s 73b13705af ("firmware: provide a stand alone set of headers"),
we've had a proper stddef.h. Actually use it.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
HVMLoader is not relocatable in memory, and 32bit PIC code has a large
overhead. Override the compilers choice of pic/no-pic and force it to be
non-relocatable.
Bloat-o-meter reports a net:
add/remove: 0/0 grow/shrink: 3/107 up/down: 14/-3370 (-3356)
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
There are two problems with domain_crash().
First, that it is frequently not preceded by a printk() at all, or only by a
dprintk(). Either way, critical diagnostic information is missing for an
event which is fatal to the guest.
Second, the embedded __LINE__ is an issue for livepatching, creating unwanted
churn in the binary diff. This is the final __LINE__ remaining in
livepatching-relevant contexts.
The end goal is to have domain_crash() require a print string which gets fed
to printk(), making it far less easy to omit relevant diagnostic information.
However, modifying all callers at once is far too big and complicated, so use
some macro magic to tolerate the old API (no print string) in the short term.
Adjust two callers in load_segments() to demonstrate the new API.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
It turns out that evaluate_nospec() code generation is not safe under Clang.
Given:
void eval_nospec_test(int x)
{
if ( evaluate_nospec(x) )
asm volatile ("nop #true" ::: "memory");
else
asm volatile ("nop #false" ::: "memory");
}
Clang emits:
<eval_nospec_test>:
0f ae e8 lfence
85 ff test %edi,%edi
74 02 je <eval_nospec_test+0x9>
90 nop
c3 ret
90 nop
c3 ret
which is not safe because the lfence has been hoisted above the conditional
jump. Clang concludes that both barrier_nospec_true()'s have identical side
effects and can safely be merged.
Clang can be persuaded that the side effects are different if there are
different comments in the asm blocks. This is fragile, but no more fragile
that other aspects of this construct.
Introduce barrier_nospec_false() with a separate internal comment to prevent
Clang merging it with barrier_nospec_true() despite the otherwise-identical
content. The generated code now becomes:
<eval_nospec_test>:
85 ff test %edi,%edi
74 05 je <eval_nospec_test+0x9>
0f ae e8 lfence
90 nop
c3 ret
0f ae e8 lfence
90 nop
c3 ret
which has the correct number of lfence's, and in the correct place.
Link: https://github.com/llvm/llvm-project/issues/55084
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>
We shouldn't be using two struct iovec's to write half of 'rec' each, and
there is no need to malloc() for two struct iovec's at all.
Simplify down to just two - one covering the whole of 'rec', and one covering
the pfns array.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Olaf Hering <olaf@aepfle.de>
OpenSBI already expands \n to \r\n. Don't repeat the expansion, as it doubles
the size of the resulting log with every other line being blank.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Rewrite argo_dprintk() so printk() format typechecking can always be
performed. This also fixes the fact that parameters are not evaulated at all
in the default case.
Emit the messages at XENLOG_DEBUG.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
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>
This removes most of the opencoded bit logic on the exit qualification.
Unfortunately, size is 1-based not 0-based, so need adjusting in a separate
variable.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This is mandated by the Fedora packaging guidelines because it is a security
vulnerability otherwise in suid scripts. While Xen doesn't have suid scripts,
it's a very good idea generally because it prevents the users local python
environment interfering from system packaged scripts.
pygrub is the odd-script-out, being installed by distutils rather than
manually with INSTALL_PYTHON_PROG. distutils has no nice way of editing the
shebang, so arrange to use INSTALL_PYTHON_PROG for pygrub too.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
* Add X86_{CPUID,MSR}_POLICY_FORMAT checks which were missed previously.
* Drop test_suite(). It hasn't been necessary since the Py2.3 era.
* Drop the __main__ logic. This can't be used without manually adjusting the
include path, and `make test` knows how to do the right thing.
* For `make test`, use `-v` to see which tests have been discovered and run.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
This script is not python3 compatible, but has its shebang altered to say
python3 by INSTALL_PYTHON_PROG.
The most recent reference I can find to this script (which isn't incidental
adjustments in the makefile) is from the Xen book, fileish 561e30b804 which
says
%% <snip> Alternatively, if the
%% Xen machine is connected to a serial-port server then we supply a
%% dumb TCP terminal client, {\tt xencons}.
So this a not-invented-here version of telnet. Delete it.
Resolves: xen-project/xen#159
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
This removes raw number manipulation, and makes the logic easier to follow.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Featuresets are supposed to be disappearing when the CPU policy infrastructure
is complete, but that has taken longer than expected, and isn't going to be
complete imminently either.
In the meantime, Xen does have proper default/max featuresets, and xen-cpuid
can even get them via the XEN_SYSCTL_cpu_policy_* interface, but only knows
now to render them nicely via the featureset interface.
Differences between default and max are a frequent source of errors,
frequently too in secret leading up to an embargo, so extend the featureset
sysctl to allow xen-cpuid to render them all nicely.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
struct fsinfo is the vestigial remnant of an older internal design which
didn't survive very long.
Simplify things by inlining get_featureset() and having a single memory
allocation that gets reused. This in turn changes featuresets[] to be a
simple list of names, so rename it to fs_names[].
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Xapi chose to render its featureset bitmaps with dashes rather than colons as
a separator. Have xen-cpuid support both forms, for convenience.
Fix a trivial style issue in the vicinity while here.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
This was an oversight when adding the Xen parts.
Fixes: cea9ae0622 ("x86/spec-ctrl: Enumeration for new Intel BHI controls")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
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>
Use a single fairly generic string as the "all done" message to look for,
which avoids the need to patch qemu-smoke-riscv64.sh each time a new feature
is added.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
struct nestedvm uses mostly plain integer types, except for virt_ext_t which
is a union wrapping two bitfield names.
However, it turns out that this is a write-only variable. Delete it, allowing
us to drop the include of vmcb.h
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
These days, this is just two length helpers. Move into the private svm.h
No functional change intended.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Fold svm_asid_g_invlpg() into its single caller, deleting the #if 0 which has
been present for the entire 16 years this helper has existed: c/s 322a078ab1
"[HVM][SVM] Reintroduce ASIDs."
Move the two remaining prototypes into the private svm.h, forward declaring
cpuinfo_x86 in preference to including asm/processor.h
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Xenia Ragiadakou <burzalodowa@gmail.com>
This is generally good practice, and necessary for livepatch binary diffing to
work.
With this, livepatching of the SVM entry path works. The only complication is
with svm_stgi_label which is only used by oprofile to guestimate (not
completely correctly) when an NMI hit guest context.
Livepatching of VMX is still an open question, because the logic doesn't form
anything remotely resembling functions. Both code fragments jump into each
other so need to be updated in tandem. Also, both code fragment entries need
trampolines in the case that patching actually occurs. For now, just treat it
as a single function.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Taking struct cpu_user_regs as a full object is bogus, and while what was
probably meant was to take a struct cpu_user_regs pointer, that's still wrong.
This isn't a function; its an address stored in the VMCS that the CPU resumes
from on VMExit, meaning that it doesn't conform to a normal C API/ABI.
Annotate it with `nocall`, and move the declaration into vmcs.c next to its
sole user.
Fixes: 9c3118a825 ("bitkeeper revision 1.1159.1.483 (41c0c417XYObowWqbfqU0cdLx30C9w)")
`-> "Initial Intel VMX support"
Reported-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
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>
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>
Also print the compiler version before starting. It's not easy to find
otherwise, and does change from time to time.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
It is easier just to make the functions void and let the compiler do the (not
very) hard work.
Passing regs is a bit weird for HVM guests anyway, because the resulting
pointer is invariant (this isn't native exception handling where the regs
pointers *are* important), and all functions calculate current themselves
which is another invariant.
Finally, the compiler can merge the get_cpu_info() calculation which is common
to both current and guest_cpu_user_regs(), meaning the delta in C really is
just one LEA, and not any more expensive than MOV's in ASM anyway.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Clang-15 (as seen in the FreeBSD 14 tests) complains:
xg_main.c:1248 error: a function declaration without a
prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
xg_init()
^
void
The error message is a bit confusing but appears to new as part of
-Wdeprecated-non-prototype which is part of supporting C2x which formally
removes K&R syntax.
Either way, fix the identified function.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Clang-15 (as seen in the FreeBSD 14 tests) complains:
arch/x86/time.c:1364:20: error: a function declaration without a
prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
s_time_t get_s_time()
^
void
The error message is a bit confusing but appears to new as part of
-Wdeprecated-non-prototype which is part of supporting C2x which formally
removes K&R syntax.
Either way, fix the identified functions.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
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>
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>
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>
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>
* Remove local integers when all we're returning is Val_int() of another
variable. The CAMLlocal*() can't be optimised automatically, as it's
registered with the GC.
* Rename "virq_type" to "virq" and "_port" to "port".
* In stub_eventchn_pending(), rename 'port' to 'rc', to be consistent with
all other stubs that return xenevtchn_port_or_error_t.
* In stub_eventchn_unmask(), check for rc == -1 to be consistent with all
other stubs.
No practical change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
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>
The OSSTest bisector identified an issue with c/s 1894049fa2 ("x86/shadow:
L2H shadow type is PV32-only") in !HVM builds.
The bug is ultimately caused by sh_type_to_size[] not actually being specific
to HVM guests, and it's position in shadow/hvm.c mislead the reasoning.
To fix the issue that OSSTest identified, SH_type_l2h_64_shadow must still
have the value 1 in any CONFIG_PV32 build. But simply adjusting this leaves
us with misleading logic, and a reasonable chance of making a related error
again in the future.
In hindsight, moving sh_type_to_size[] out of common.c in the first place a
mistake. Therefore, move sh_type_to_size[] back to living in common.c,
leaving a comment explaining why it happens to be inside an HVM conditional.
This effectively reverts the second half of 4fec945409 ("x86/shadow: adjust
and move sh_type_to_size[]") while retaining the other improvements from the
same changeset.
While making this change, also adjust the sh_type_to_size[] declaration to
match its definition.
Fixes: 4fec945409 ("x86/shadow: adjust and move sh_type_to_size[]")
Fixes: 1894049fa2 ("x86/shadow: L2H shadow type is PV32-only")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: George Dunlap <george.dunlap@cloud.com>
With all infrastructure in place, advertise the PKS CPUID bit to HAP guests,
and let them set CR4.PKS.
Experiment with a tweak to the layout of hvm_cr4_guest_valid_bits() so future
additions will be just a single added line.
The current context switching behaviour is tied to how VT-x works, so leave a
safety check in the short term.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
PKS is very similar to the existing PKU behaviour, operating on pagewalks for
any supervisor mapping.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Have guest_{rd,wr}msr(), via hvm_{get,set}_reg(), access either the live
register, or stashed state, depending on context. Include MSR_PKRS for
migration, and let the guest have full access.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Under PKS, MSR_PKRS is available and based on the CPUID policy alone, and
usable independently of CR4.PKS. See the large comment in prot-key.h for
details of the context switching arrangement.
Use WRMSRNS right away, as we don't care about serialsing properties for
context switching this MSR.
Sanitise MSR_PKRS on boot. In anticipation of wanting to use PKS for Xen in
the future, arrange for the sanitisation to occur prior to potentially setting
CR4.PKS; if PKEY0.{AD,WD} leak in from a previous context, we will triple
fault immediately on setting CR4.PKS.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <JBeulich@suse.com>
WRMSR Non-Serialising is an optimisation intended for cases where an MSR needs
updating, but architectural serialising properties are not needed.
In is anticipated that this will apply to most if not all MSRs modified on
context switch paths.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
asm/processor.h is in desperate need of splitting up, and protection key
functionality in only used in the emulator and pagewalk. Introduce a new
asm/prot-key.h and move the relevant content over.
Rename the PKRU_* constants to drop the user part and to use the architectural
terminology.
Drop the read_pkru_{ad,wd}() helpers entirely. The pkru infix is about to
become wrong, and the sole user is shorter and easier to follow without the
helpers.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Protection Key Supervisor works in a very similar way to Protection Key User,
except that instead of a PKRU register used by the {RD,WR}PKRU instructions,
the supervisor protection settings live in MSR_PKRS and is accessed using
normal {RD,WR}MSR instructions.
PKS has the same problematic interactions with PV guests as PKU (more infact,
given the guest kernel's CPL), so we'll only support this for HVM guests for
now.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
While the reset value of the register is 0, it might not be after kexec/etc.
If PKEY0.{WD,AD} have leaked in from an earlier context, construction of a PV
dom0 will explode.
Sequencing wise, this must come after setting CR4.PKE, and before we touch any
user mappings.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
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>
This is a global variable (actually 3, one per GUEST_PAGING_LEVEL), operated
on using atomics only (with no regard to what else shares the same cacheline),
which emits a diagnostic (in debug builds only) without changing any program
behaviour.
It is presumably left-over debugging, as it interlinks the behaviour of all
vCPUs in chronological order. Based on the read-only p2m types, this
diagnostic can be tripped by entirely legitimate guest behaviour.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Converting from PAT to PTE is trivial, and shorter to encode with bitwise
logic than the space taken by a table counting from 0 to 7 in non-adjacent
bits.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
A split in virtual address space is only applicable for x86 PV guests.
Furthermore, the information returned for x86 64bit PV guests is wrong.
Explain the problem in version.h, stating the other information that PV guests
need to know.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
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>
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>
kernel.c is mostly in an #ifndef COMPAT guard, because compat/kernel.c
re-includes kernel.c to recompile xen_version() in a compat form.
However, the xen_version hypercall is almost guest-ABI-agnostic; only
XENVER_platform_parameters has a compat split. Handle this locally, and do
away with the re-include entirely. Also drop the CHECK_TYPE()'s between types
that are simply char-arrays in their native and compat form.
In particular, this removed the final instances of obfuscation via the DO()
macro.
No functional change. Also saves 2k of of .text in the x86 build.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This is technically an ABI change, but Xen doesn't operate in any environment
where "unsigned int" is different to uint32_t, so switch to the explicit form.
This avoids the need to derive (identical) compat logic for handling the
subop.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>
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>
Each architecture's main trace.h is empty. Drop them all, so as not force all
new architectures to create an empty file too.
While moving the declaration of tb_init_done, change from int to bool.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>
There's no need to do ad-hoc string parsing. Use grep -q instead.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Some testcases use a cross compiler. Presently it's only arm32 and due to
previous cleanup the only thing which is now wrong is printing the compiler
version at the start of day.
Construct $cc to match what `make` will eventually choose given CROSS_COMPILE,
taking care not to modify $CC. Use $cc throughout the rest of the script.
Also correct the compiler detection logic. Plain "gcc" was wrong, and
"clang"* was a bodge highlighting the issue, but neither survive the
CROSS_COMPILE correction. Instead, construct cc_is_{gcc,clang} booleans like
we do elsewhere in the build system, by querying the --version text for gcc or
clang.
While making this change, adjust cc_ver to be calculated once at the same time
as cc_is_* are calculated.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Whether to build only Xen, or everything, is a property of container,
toolchain and/or testcase. It is not a property of XEN_TARGET_ARCH.
Capitalise HYPERVISOR_ONLY and have it set by all the
debian-unstable-gcc-arm32-* testcases at the point that arm32 get matched with
a container that can only build Xen.
To reduce the churn elsewhere, retain the RANDCONFIG implies HYPERVISOR_ONLY
property.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
This is purely code motion of the cfgargs construction, into the case where it
is used.
No practical change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Preserve the artefacts based on the `make` rune we actually ran, rather than
guesswork about which rune we would have run based on other settings.
Note that the ARM qemu smoke tests depend on finding binaries/xen even from
full builds. Also the Jessie-32 containers build tools but not Xen.
This means the x86_32 builds now store relevant artefacts. No change in other
configurations.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Having 3 extra hypervisor builds on the end of a full build is deeply
confusing to debug if one of them fails, because the .config file presented in
the artefacts is not the one which caused a build failure. Also, the log
tends to be truncated in the UI.
PV-only is tested as part of PV-Shim in a full build anyway, so doesn't need
repeating. HVM-only and neither appear frequently in randconfig, so drop all
the logic here to simplify things.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
We can relocate Xen by reading out of the virtual mapping that we're executing
on, and write directly into the directmap. In fact, this removes one
dependency on Xen being "at 0" (the XEN_IMG_OFFSET passed as src) for
relocation to occur.
This removes all the temporary pagetable handling under the covers of
move_memory(), and results in a forward copy rather than a chunked backwards
copy (caused by move_memory() always constructing src and dst in a way to
trigger memmove() to copy backwards).
With the penultimate caller of move_memory() dropped, clean up the API. Drop
the keep boolean, folding in 0 from the final caller, and drop the return
address which has been unused since c/s 0b76ce20de ("x86/setup: don't
relocate the VGA hole.") in 2007.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This check has existed in one form or another since c/s 369bafdb1c "xen: Big
changes to x86 start-of-day" in 2007.
c/s 0d31d16808 "x86/setup: do not relocate Xen over current Xen image
placement" demonstrates clearly that the logic was broken.
Without dissecting the myriad changes over the past 14 years, I'm pretty
certain Xen only booted by accident when l2_xenmap[0] was handled specially
and skipped the pte_update_limit check which would have left it corrupt.
The old logic was simply not safe, even if implemented as intended. TLB
entries can be lost for any reason; architectural (e.g. SMI), or uarch
(e.g. enough OoO execution to thrash the TLB). It is never safe to have
non-pagetable data in your live pagetables, for any period of time.
Either way, since c/s 0d31d16808 there is not a partial overlap of the Xen
image, so drop the vestigial remnants.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
To support CET Shadow Stacks, guard pages changed unilaterally from being
holes to being read-only (i.e. they're never holes any more).
Furthermore, being real shadow stacks in some cases, the frames explicitly
should be included in the integrity check.
Fixes: 6001660473 ("x86/shstk: Rework the stack layout to support shadow stacks")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.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>
The binding for xc_interface_close() free the underlying handle while leaving
the Ocaml object still in scope and usable. This would make it easy to suffer
a use-after-free, if it weren't for the fact that the typical usage is as a
singleton that lives for the lifetime of the program.
Ocaml 5 no longer permits storing a naked C pointer in an Ocaml value.
Therefore, use a Custom block. This allows us to use the finaliser callback
to call xc_interface_close(), if the Ocaml object goes out of scope.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
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>
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>
This will make the logic clearer when we plumb local_port through these
functions.
While doing this, rearrange the construct in Domains.create0 to separate the
remote port handling from the interface handling. (The interface logic is
dubious in several ways, but not altered by this cleanup.)
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>
Xenstored always needs to bind the DOM_EXC VIRQ.
Instead of doing it shortly after the call to Event.init(), do it in the
constructor directly. This removes the need for the field to be a mutable
option.
It will also simplify a future change to support live update. Rename the
field from virq_port (which could be any VIRQ) to it's proper name.
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>
This file has some style problems so severe that they interfere with the
readability of the subsequent bugfix patches.
Fix these issues ahead of time, to make the subsequent changes more readable.
No functional 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>
A debug statement got inserted into a single-expression if statement.
Insert brackets to give the intended meaning, rather than the actual meaning
where the "let con = Connections..." is outside and executed unconditionally.
This results in some unnecessary ring checks for domains which otherwise have
IO credit.
Fixes: 42f0581a91 ("tools/oxenstored: Implement live update for socket connections")
Reported-by: Edwin Török <edvin.torok@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
The error message accidentally printed the bytes value as if it were kB.
Furthermore, both b_info.shadow_memkb and shadow_mem are uint64_t, meaning
there is a risk of overflow if the user specified a stupidly large value in
the vm.cfg file. Check and reject such a condition.
Fixes: 7c3bbd940d ("xen/arm, libxl: Revert XEN_DOMCTL_shadow_op; use p2m mempool hypercalls")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Allocating or freeing p2m pages doesn't alter the size of the mempool; only
the split between free and used pages.
Right now, the hypercalls operate on the free subset of the pool, meaning that
XEN_DOMCTL_get_paging_mempool_size varies with time as the guest shuffles its
physmap, and XEN_DOMCTL_set_paging_mempool_size ignores the used subset of the
pool and lets the guest grow unbounded.
This fixes test-pagign-mempool on ARM so that the behaviour matches x86.
This is part of XSA-409 / CVE-2022-33747.
Fixes: cbea5a1149 ("xen/arm: Allocate and free P2M pages from the P2M pool")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
This reverts most of commit cf2a68d2ff, and bits
of cbea5a1149.
First of all, with ARM borrowing x86's implementation, the logic to set the
pool size should have been common, not duplicated. Introduce
libxl__domain_set_paging_mempool_size() as a shared implementation, and use it
from the ARM and x86 paths. It is left as an exercise to the reader to judge
how libxl/xl can reasonably function without the ability to query the pool
size...
Remove ARM's p2m_domctl() infrastructure now the functioanlity has been
replaced with a working and unit tested interface.
This is part of XSA-409 / CVE-2022-33747.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Andrew Cooper