During migration there are a lot of mmap/munmap calls,
because xc_get_pfn_type_batch() exceeds the default hypercall bounce
buffer cache size, and needs to allocate every time it is called.
munmap() is slow, especially in a PV Dom0 (takes an emulation fault),
so is best avoided.
Eventually it'd be good if the memory pool from xmalloc_tlsf.c
was reused here, but for now make it handle the commonly encountered
sizes (so far up to 4 pages).
Signed-off-by: Edwin Török <edwin.torok@citrix.com>
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
clang would duplicate the loop body and end up with a double definition
of the symbol:
```
/tmp/test_x86_emulator-0f3576.s:27823: Error: symbol `vmovsh_to_mem' is already defined
/tmp/test_x86_emulator-0f3576.s:27825: Error: symbol `.Lvmovsh_to_mem_end' is already defined
```
Until a better solution is found: reduce optimizations in the test runner.
Using -Os might also work, but we can't rely on the size optimization
always avoiding the duplication of asm blocks.
This is test code, not performance critical code, and -O0 is more future
proof.
However for debugging -Og is recommended over -O0, and this still avoids
the duplicate label problem.
Signed-off-by: Edwin Török <edwin.torok@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Fixes this `-fsanitize=undefined` error:
```
test_x86_emulator.c:614:12: runtime error: null pointer passed as argument 1, which is declared to never be null
/usr/include/string.h:44:28: note: nonnull attribute specified here
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior test_x86_emulator.c:614:12
```
Although this is more of a grey area: I don't see anything in the
standard that'd forbid calling `memcpy` with NULL and 0, but `glibc`
does specify it as non-null, which allows the compiler to make
optimizations assuming it never is NULL, so this is undefined behaviour
only on glibc.
Best to avoid the potential undefined behaviour though.
Signed-off-by: Edwin Török <edwin.torok@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Fixes this `-fsanitize=undefined` error:
```
test_x86_emulator.c:1103:32: runtime error: left shift of 573785183 by 2 places cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior test_x86_emulator.c:1103:32
```
Signed-off-by: Edwin Török <edwin.torok@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
clang-21 refuses to compile this:
```
test_x86_emulator.c:1164:24: error: shifting a negative signed value is undefined [-Werror,-Wshift-negative-value]
1164 | regs.r8 = (-1L << 40) + 1;
| ~~~ ^
1 error generated.
```
The shift could also exceed the width of the type on some systems.
I confirmed that both the old and the new code would produce the same value
with GCC on x86-64: `0xffffff0000000001`.
Signed-off-by: Edwin Török <edwin.torok@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Observed when attempting to boot a >4TiB VM:
After a call to domain_setmaxmem with 6370254848 (KiB), the domain's maxmem
got set to 2075287552, which is exactly 2^32 smaller.
xc_domain_setmaxmem takes an uint64_t as a parameter, and the OCaml value
is 64-bit already, so fix the C variable to match the type and avoid the
truncation.
Fixes: f5b43e95fa ("libxl: fix "xl mem-set" regression from 0c029c4da2")
Signed-off-by: Edwin Török <edwin.torok@citrix.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Edwin Török