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[PATCH 2/2] linux-user: Adjust guest page protection for the host
From: |
Richard Henderson |
Subject: |
[PATCH 2/2] linux-user: Adjust guest page protection for the host |
Date: |
Tue, 19 May 2020 11:56:45 -0700 |
Executable guest pages are never directly executed by
the host, but do need to be readable for translation.
Signed-off-by: Richard Henderson <address@hidden>
---
linux-user/mmap.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 36fd1e2250..84662c3311 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -76,8 +76,12 @@ static int validate_prot_to_pageflags(int *host_prot, int
prot)
* don't bother transforming guest bit to host bit. Any other
* target-specific prot bits will not be understood by the host
* and will need to be encoded into page_flags for qemu emulation.
+ *
+ * Pages that are executable by the guest will never be executed
+ * by the host, but the host will need to be able to read them.
*/
- *host_prot = prot & (PROT_READ | PROT_WRITE | PROT_EXEC);
+ *host_prot = (prot & (PROT_READ | PROT_WRITE))
+ | (prot & PROT_EXEC ? PROT_READ : 0);
return prot & ~valid ? 0 : page_flags;
}
--
2.20.1