On Tue, Jan 02, 2024 at 12:57:40PM +1100, Richard Henderson wrote:
> If reserved_va, then we have already reserved the entire
> guest virtual address space; no need to remap page.
> If !reserved_va, then use MAP_FIXED_NOREPLACE.
>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> ---
> linux-user/elfload.c | 23 ++++++++++++++---------
> 1 file changed, 14 insertions(+), 9 deletions(-)
>
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index c166faabab..96d8d4f84c 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -1969,16 +1969,21 @@ static inline void init_thread(struct target_pt_regs
> *regs,
>
> static bool init_guest_commpage(void)
> {
> - void *want = g2h_untagged(LO_COMMPAGE);
> - void *addr = mmap(want, qemu_host_page_size, PROT_NONE,
> - MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
> + /* If reserved_va, then we have already mapped 0 page on the host. */
> + if (!reserved_va) {
> + int host_page_size = qemu_real_host_page_size();
> + void *want, *addr;
>
> - if (addr == MAP_FAILED) {
> - perror("Allocating guest commpage");
> - exit(EXIT_FAILURE);
> - }
> - if (addr != want) {
> - return false;
> + want = g2h_untagged(LO_COMMPAGE);
> + addr = mmap(want, host_page_size, PROT_NONE,
> + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED_NOREPLACE, -1,
> 0);
> + if (addr == MAP_FAILED) {
> + perror("Allocating guest commpage");
> + exit(EXIT_FAILURE);
> + }
> + if (addr != want) {
> + return false;
> + }
> }
>
> /*
> --
> 2.34.1
Reviewed-by: Ilya Leoshkevich <i...@linux.ibm.com>
