[v3] linux-user: Improve host and guest page size handling

[PATCH v3 31/33] linux-user: Bound mmap_min_addr by host page size

Richard Henderson posted 33 patches 10 months, 4 weeks ago

Diff against v2 v4
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Maintainers: Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Riku Voipio <riku.voipio@iki.fi>, Warner Losh <imp@bsdimp.com>, Kyle Evans <kevans@freebsd.org>, Stefan Berger <stefanb@linux.vnet.ibm.com>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, Laurent Vivier <laurent@vivier.eu>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, David Hildenbrand <david@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Nicholas Piggin <npiggin@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, "Cédric Le Goater" <clg@kaod.org>, "Alex Bennée" <alex.bennee@linaro.org>, Yoshinori Sato <ysato@users.sourceforge.jp>

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[PATCH v3 31/33] linux-user: Bound mmap_min_addr by host page size

Posted by Richard Henderson 10 months, 4 weeks ago

Bizzarely, it is possible to set /proc/sys/vm/mmap_min_addr
to a value below the host page size.  Fix that.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/linux-user/main.c b/linux-user/main.c
index d00a0d7d1f..d5f3fa26c0 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -904,7 +904,7 @@ int main(int argc, char **argv, char **envp)
         if ((fp = fopen("/proc/sys/vm/mmap_min_addr", "r")) != NULL) {
             unsigned long tmp;
             if (fscanf(fp, "%lu", &tmp) == 1 && tmp != 0) {
-                mmap_min_addr = tmp;
+                mmap_min_addr = MAX(tmp, host_page_size);
                 qemu_log_mask(CPU_LOG_PAGE, "host mmap_min_addr=0x%lx\n",
                               mmap_min_addr);
             }
-- 
2.34.1

Re: [PATCH v3 31/33] linux-user: Bound mmap_min_addr by host page size

Posted by Ilya Leoshkevich 10 months ago

On Tue, Jan 02, 2024 at 12:58:06PM +1100, Richard Henderson wrote:
> Bizzarely, it is possible to set /proc/sys/vm/mmap_min_addr
> to a value below the host page size.  Fix that.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>

Re: [PATCH v3 31/33] linux-user: Bound mmap_min_addr by host page size

Posted by Philippe Mathieu-Daudé 10 months, 4 weeks ago

On 2/1/24 02:58, Richard Henderson wrote:
> Bizzarely, it is possible to set /proc/sys/vm/mmap_min_addr
> to a value below the host page size.  Fix that.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   linux-user/main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>