On Thu, Feb 22, 2024 at 05:03:09PM -1000, Richard Henderson wrote:
> Handle combined host and guest alignment requirements.
> Handle host and guest page size differences.
> Handle SHM_EXEC.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/115
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> ---
> linux-user/mmap.c | 146 ++++++++++++++++++++++++++++++++++------------
> 1 file changed, 110 insertions(+), 36 deletions(-)
[...]
> - /* find out the length of the shared memory segment */
> + /*
> + * Because we can't use host shmat() unless the address is sufficiently
> + * aligned for the host, we'll need to check both.
> + * TODO: Could be fixed with softmmu.
> + */
Are there any plans to introduce softmmu to qemu-user?
[...]
Reviewed-by: Ilya Leoshkevich <i...@linux.ibm.com>
Please consider adding the reproducer to the series:
>From 964164ada4de55ac01a56613f7b759e538803fc9 Mon Sep 17 00:00:00 2001
From: Ilya Leoshkevich <i...@linux.ibm.com>
Date: Fri, 23 Feb 2024 12:31:40 +0100
Subject: [PATCH] tests/tcg: Check that shmat() does not break /proc/self/maps
Add a regression test for a recently fixed issue, where shmat()
desynced the guest and the host view of the address space and caused
open("/proc/self/maps") to SEGV.
Signed-off-by: Ilya Leoshkevich <i...@linux.ibm.com>
---
tests/tcg/multiarch/linux/linux-shmat-maps.c | 40 ++++++++++++++++++++
1 file changed, 40 insertions(+)
create mode 100644 tests/tcg/multiarch/linux/linux-shmat-maps.c
diff --git a/tests/tcg/multiarch/linux/linux-shmat-maps.c
b/tests/tcg/multiarch/linux/linux-shmat-maps.c
new file mode 100644
index 00000000000..4090bc77ba7
--- /dev/null
+++ b/tests/tcg/multiarch/linux/linux-shmat-maps.c
@@ -0,0 +1,40 @@
+/*
+ * Test that shmat() does not break /proc/self/maps.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include <assert.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <unistd.h>
+
+int main(void)
+{
+ char buf[128];
+ int err, fd;
+ int shmid;
+ ssize_t n;
+ void *p;
+
+ shmid = shmget(IPC_PRIVATE, 0x400, IPC_CREAT | 0600);
+ assert(shmid != -1);
+ p = shmat(shmid, (void *)0x800000, 0);
+ assert(p != (void *)-1);
+
+ fd = open("/proc/self/maps", O_RDONLY);
+ assert(fd != -1);
+ do {
+ n = read(fd, buf, sizeof(buf));
+ assert(n >= 0);
+ } while (n != 0);
+ close(fd);
+
+ err = shmdt(p);
+ assert(err == 0);
+ err = shmctl(shmid, IPC_RMID, NULL);
+ assert(err == 0);
+
+ return EXIT_SUCCESS;
+}
--
2.34.1
