Fixes warnings such as:
File "config.ml", line 102, characters 12-27:
102 | | Failure "int_of_string" -> append (k, "expect int arg")
^^^^^^^^^^^^^^^
Warning 52: Code should not depend on the actual values of
this constructor's arguments. They are only for information
and may change in future versions. (See manual section 9.5)
Do not rely on the string values of the `Failure` exception, but use the
`_opt` functions instead.
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Tested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Now that we no longer have a hashtable inside we can make Quota.t pure, and
push the mutable update to its callers. Store.t already had a mutable Quota.t
field.
No functional change.
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
On a stress test running 1000 VMs flamegraphs have shown that
`oxenstored` spends a large amount of time in `Hashtbl.copy` and the GC.
Hashtable complexity:
* read/write: O(1) average
* copy: O(domains) -- copying the entire table
Map complexity:
* read/write: O(log n) worst case
* copy: O(1) -- a word copy
We always perform at least one 'copy' when processing each xenstore
packet (regardless whether it is a readonly operation or inside a
transaction or not), so the actual complexity per packet is:
* Hashtbl: O(domains)
* Map: O(log domains)
Maps are the clear winner, and a better fit for the immutable xenstore
tree.
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Char.lowercase got removed in OCaml 5.0 (it has been deprecated since 2014),
and doesn't build any more.
Char.lowercase_ascii has existed since OCaml 4.03, so that is the new
minimum version for oxenstored.
However, OCaml 4.05 is the oldest new-enough version found in common distros,
so pick this as a baseline.
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
[Update CHANGELOG.md]
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
`Tag_cons` is `0` and is meant to be used as the tag argument for
`caml_alloc`/`caml_alloc_small` when constructing a non-empty list.
The empty list is `Val_emptylist` instead, which is really just `Val_int(0)`.
Assigning `0` to a list value like this is equivalent to assigning the naked
pointer `NULL` to the field. Naked pointers are not valid in OCaml 5, however
even in OCaml <5.x any attempt to iterate on the list will lead to a segfault.
The list currently only has an opaque type, so no code would have reason to
iterate on it currently, but we shouldn't construct invalid OCaml values that
might lead to a crash when exploring the type.
`Val_emptylist` is available since OCaml 3.01 as a constant.
Fixes: e5ac68a011 ("x86/hvm: Revert per-domain APIC acceleration support")
Signed-off-by: Edwin Török <edwin.torok@cloud.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
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>
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 xch_of_val().
* Opencode the assignment into Data_custom_val() in the constructors.
* Rename "value xch" parameters to "value xch_val" so we can consistently
have "xc_interface *xch" on the stack, and obtain the pointer with the GC
lock still held.
* Drop the _D() macro while at it, because it's just pointless indirection.
Fixes: 8b3c06a3e5 ("tools/ocaml/xenctrl: OCaml 5 support, fix use-after-free")
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>
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>
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>
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>
Edwin Török