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linux-user: fix mmap_find_vma_reserved()

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The value given by mmap_find_vma_reserved() is used with mmap(),
so it is needed to be aligned with the host page size.

Since commit 18e80c55bb, reserved_va is only aligned to TARGET_PAGE_SIZE,
and it works well if this size is greater or equal to the host page size.

But ppc64 hosts have 64kB page size and when we start a 4kiB page size
guest (like i386), it fails when it tries to mmap the stack:

    mmap stack: Invalid argument

Fixes: 18e80c55bb (linux-user: Tidy and enforce reserved_va initialization)
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20180714193553.30846-1-laurent@vivier.eu>
This commit is contained in:
Laurent Vivier 2018-07-14 21:35:53 +02:00
parent af8ab2bf22
commit dc18baaef3
1 changed files with 12 additions and 7 deletions
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19
linux-user/main.c
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@ -78,14 +78,7 @@ int have_guest_base;
# endif # endif
#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; unsigned long reserved_va;
#endif
static void usage(int exitcode); static void usage(int exitcode);
@ -672,6 +665,18 @@ int main(int argc, char **argv, char **envp)
/* init tcg before creating CPUs and to get qemu_host_page_size */ /* init tcg before creating CPUs and to get qemu_host_page_size */
tcg_exec_init(0); tcg_exec_init(0);
/* 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 &&
reserved_va == 0) {
/* reserved_va must be aligned with the host page size
* as it is used with mmap()
*/
reserved_va = MAX_RESERVED_VA & qemu_host_page_mask;
}
cpu = cpu_create(cpu_type); cpu = cpu_create(cpu_type);
env = cpu->env_ptr; env = cpu->env_ptr;
cpu_reset(cpu); cpu_reset(cpu);