Message ID | 20191213022919.5934-1-precinct@mail.ustc.edu.cn |
---|---|
State | New |
Headers | show |
Series | linux-user:Fix align mistake when mmap guest space | expand |
Le 13/12/2019 à 03:29, Xinyu Li a écrit : > In init_guest_space, we need to mmap guest space. If the return address > of first mmap is not aligned with align, which was set to MAX(SHMLBA, > qemu_host_page_size), we need unmap and a new mmap(space is larger than > first size). The new size is named real_size, which is aligned_size + > qemu_host_page_size. alugned_size is the guest space size. And add a > qemu_host_page_size to avoid memory error when we align real_start > manually (ROUND_UP(real_start, align)). But when SHMLBA > > qemu_host_page_size, the added size will smaller than the size to align, > which can make a mistake(in a mips machine, it appears). So change > real_size from aligned_size +qemu_host_page_size > to aligned_size + align will solve it. > > Signed-off-by: Xinyu Li <precinct@mail.ustc.edu.cn> > --- > linux-user/elfload.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index f6693e5760..312ded0779 100644 > --- a/linux-user/elfload.c > +++ b/linux-user/elfload.c > @@ -2189,7 +2189,7 @@ unsigned long init_guest_space(unsigned long host_start, > * to where we need to put the commpage. > */ > munmap((void *)real_start, host_size); > - real_size = aligned_size + qemu_host_page_size; > + real_size = aligned_size + align; > real_start = (unsigned long) > mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0); > if (real_start == (unsigned long)-1) { > Your change seems correct to me. Richard did you miss this in your patch 30ab9ef2967d ("linux-user: Fix shmat emulation by honoring host SHMLBA") or was it voluntary to keep it? Thanks, Laurent
On 12/12/19 11:00 PM, Laurent Vivier wrote: > Le 13/12/2019 à 03:29, Xinyu Li a écrit : >> In init_guest_space, we need to mmap guest space. If the return address >> of first mmap is not aligned with align, which was set to MAX(SHMLBA, >> qemu_host_page_size), we need unmap and a new mmap(space is larger than >> first size). The new size is named real_size, which is aligned_size + >> qemu_host_page_size. alugned_size is the guest space size. And add a >> qemu_host_page_size to avoid memory error when we align real_start >> manually (ROUND_UP(real_start, align)). But when SHMLBA > >> qemu_host_page_size, the added size will smaller than the size to align, >> which can make a mistake(in a mips machine, it appears). So change >> real_size from aligned_size +qemu_host_page_size >> to aligned_size + align will solve it. >> >> Signed-off-by: Xinyu Li <precinct@mail.ustc.edu.cn> >> --- >> linux-user/elfload.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/linux-user/elfload.c b/linux-user/elfload.c >> index f6693e5760..312ded0779 100644 >> --- a/linux-user/elfload.c >> +++ b/linux-user/elfload.c >> @@ -2189,7 +2189,7 @@ unsigned long init_guest_space(unsigned long host_start, >> * to where we need to put the commpage. >> */ >> munmap((void *)real_start, host_size); >> - real_size = aligned_size + qemu_host_page_size; >> + real_size = aligned_size + align; >> real_start = (unsigned long) >> mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0); >> if (real_start == (unsigned long)-1) { >> > > Your change seems correct to me. > > Richard did you miss this in your patch > 30ab9ef2967d ("linux-user: Fix shmat emulation by honoring host SHMLBA") > or was it voluntary to keep it? Looks like I missed it. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
Le 13/12/2019 à 03:29, Xinyu Li a écrit : > In init_guest_space, we need to mmap guest space. If the return address > of first mmap is not aligned with align, which was set to MAX(SHMLBA, > qemu_host_page_size), we need unmap and a new mmap(space is larger than > first size). The new size is named real_size, which is aligned_size + > qemu_host_page_size. alugned_size is the guest space size. And add a > qemu_host_page_size to avoid memory error when we align real_start > manually (ROUND_UP(real_start, align)). But when SHMLBA > > qemu_host_page_size, the added size will smaller than the size to align, > which can make a mistake(in a mips machine, it appears). So change > real_size from aligned_size +qemu_host_page_size > to aligned_size + align will solve it. > > Signed-off-by: Xinyu Li <precinct@mail.ustc.edu.cn> > --- > linux-user/elfload.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index f6693e5760..312ded0779 100644 > --- a/linux-user/elfload.c > +++ b/linux-user/elfload.c > @@ -2189,7 +2189,7 @@ unsigned long init_guest_space(unsigned long host_start, > * to where we need to put the commpage. > */ > munmap((void *)real_start, host_size); > - real_size = aligned_size + qemu_host_page_size; > + real_size = aligned_size + align; > real_start = (unsigned long) > mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0); > if (real_start == (unsigned long)-1) { > Applied to my linux-user branch. Thanks, Laurent
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index f6693e5760..312ded0779 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2189,7 +2189,7 @@ unsigned long init_guest_space(unsigned long host_start, * to where we need to put the commpage. */ munmap((void *)real_start, host_size); - real_size = aligned_size + qemu_host_page_size; + real_size = aligned_size + align; real_start = (unsigned long) mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0); if (real_start == (unsigned long)-1) {
In init_guest_space, we need to mmap guest space. If the return address of first mmap is not aligned with align, which was set to MAX(SHMLBA, qemu_host_page_size), we need unmap and a new mmap(space is larger than first size). The new size is named real_size, which is aligned_size + qemu_host_page_size. alugned_size is the guest space size. And add a qemu_host_page_size to avoid memory error when we align real_start manually (ROUND_UP(real_start, align)). But when SHMLBA > qemu_host_page_size, the added size will smaller than the size to align, which can make a mistake(in a mips machine, it appears). So change real_size from aligned_size +qemu_host_page_size to aligned_size + align will solve it. Signed-off-by: Xinyu Li <precinct@mail.ustc.edu.cn> --- linux-user/elfload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)