bsd-user: Catch up to run-time reserved_va math

Catch up to linux-user's 8f67b9c694, 13c1339755, 2f7828b572, and
95059f9c31 by Richard Henderson which made reserved_va a run-time
calculation, defaulting to nothing except in the case of 64-bit host
32-bit target. Also include the adjustment of the comment heading that
work submitted in the same patch stream. Since this is a direct copy,
squash it into one patch rather than follow the Linux evolution since
breaking this down further at this point doesn't make sense for this
"new code".

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Warner Losh 2024-06-06 22:01:41 -06:00
parent ba379542bf
commit cb4c259052

View file

@ -77,25 +77,16 @@ bool have_guest_base;
# if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
# if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \
(TARGET_LONG_BITS == 32 || defined(TARGET_ABI32))
# define MAX_RESERVED_VA 0xfffffffful
# define MAX_RESERVED_VA(CPU) 0xfffffffful
# else
# define MAX_RESERVED_VA ((1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
# define MAX_RESERVED_VA(CPU) ((1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
# endif
# else
# define MAX_RESERVED_VA 0
# define MAX_RESERVED_VA(CPU) 0
# endif
#endif
/*
* That said, reserving *too* much vm space via mmap can run into problems
* with rlimits, oom due to page table creation, etc. We will still try it,
* if directed by the command-line option, but not by default.
*/
#if HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32
unsigned long reserved_va = MAX_RESERVED_VA;
#else
unsigned long reserved_va;
#endif
const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;
const char *qemu_uname_release;
@ -293,6 +284,7 @@ int main(int argc, char **argv)
envlist_t *envlist = NULL;
char *argv0 = NULL;
int host_page_size;
unsigned long max_reserved_va;
adjust_ssize();
@ -493,6 +485,29 @@ int main(int argc, char **argv)
cpu_reset(cpu);
thread_cpu = cpu;
/*
* Reserving too much vm space via mmap can run into problems with rlimits,
* oom due to page table creation, etc. We will still try it, if directed
* by the command-line option, but not by default. Unless we're running a
* target address space of 32 or fewer bits on a host with 64 bits.
*/
max_reserved_va = MAX_RESERVED_VA(cpu);
if (reserved_va != 0) {
if ((reserved_va + 1) % host_page_size) {
char *s = size_to_str(host_page_size);
fprintf(stderr, "Reserved virtual address not aligned mod %s\n", s);
g_free(s);
exit(EXIT_FAILURE);
}
if (max_reserved_va && reserved_va > max_reserved_va) {
fprintf(stderr, "Reserved virtual address too big\n");
exit(EXIT_FAILURE);
}
} else if (HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32) {
/* MAX_RESERVED_VA + 1 is a large power of 2, so is aligned. */
reserved_va = max_reserved_va;
}
if (getenv("QEMU_STRACE")) {
do_strace = 1;
}