Message ID | 20180714193553.30846-1-laurent@vivier.eu |
---|---|
State | New |
Headers | show |
Series | [v3] linux-user: fix mmap_find_vma_reserved() | expand |
On 07/14/2018 02:35 PM, Laurent Vivier wrote: > 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> > --- > > Notes: > v3: > move initialization of reserved_va to main() > > v2: > fix typo s/has/as/ > > linux-user/main.c | 19 ++++++++++++------- > 1 file changed, 12 insertions(+), 7 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
diff --git a/linux-user/main.c b/linux-user/main.c index 52b5a618fe..ea00dd9057 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -78,14 +78,7 @@ int have_guest_base; # 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 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 */ 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); env = cpu->env_ptr; cpu_reset(cpu);
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> --- Notes: v3: move initialization of reserved_va to main() v2: fix typo s/has/as/ linux-user/main.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)