diff options
| author | Michael Kelly <mike@weatherwax.co.uk> | 2025-08-31 23:35:56 +0200 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2025-08-31 23:37:01 +0200 |
| commit | 2ccdc970f7d83a4a5fc3c2c6e89f94a10e36d2ac (patch) | |
| tree | 981a3c4210e700814a5eba2c091b3587bf9e3cf6 | |
| parent | a632f784548f910522e13b7cdb683249b27712bd (diff) | |
rumpdisk: Set USER_DEVICE ktype on device ports
so that IPC messages destined for rumpdisk will use page lists rather than
page map entries, to make them safe against swapping out.
| -rw-r--r-- | configure.ac | 1 | ||||
| -rw-r--r-- | rumpdisk/block-rump.c | 22 |
2 files changed, 23 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index d7e33e56..4ddb1fe9 100644 --- a/configure.ac +++ b/configure.ac @@ -153,6 +153,7 @@ AC_CACHE_CHECK([for libio], # Check if libc contains these functions. AC_CHECK_FUNCS(file_exec_paths exec_exec_paths _hurd_exec_paths) AC_CHECK_FUNCS(_hurd_libc_proc_init) +AC_CHECK_FUNCS(mach_port_set_ktype) # Compatibility with glibc < 2.28 AC_CHECK_FUNCS(file_utimens) diff --git a/rumpdisk/block-rump.c b/rumpdisk/block-rump.c index d2fc0f1c..aa8afb4f 100644 --- a/rumpdisk/block-rump.c +++ b/rumpdisk/block-rump.c @@ -27,6 +27,7 @@ #include <mach.h> #include <mach/gnumach.h> +#include <mach/port.h> #include <hurd.h> #include <hurd/ports.h> #include <device/device.h> @@ -329,6 +330,27 @@ rumpdisk_device_open (mach_port_t reply_port, mach_msg_type_name_t reply_port_ty return err; } +#ifdef HAVE_MACH_PORT_SET_KTYPE + /* Configure the receive port as a USER_DEVICE so that IPC messages + destined for rumpdisk will use page lists rather than page map + entries. This strategy prevents pages that are referenced in the + message body from being swapped out until the message has been + processed. + */ + err = mach_port_set_ktype (master_host, + mach_task_self (), + bd->port.port_right, + MACH_PORT_RIGHT_RECEIVE, + MACH_PORT_KTYPE_USER_DEVICE); + if (err != 0) + { + fprintf (stderr, + "Warning: mach_port_set_ktype failed, swapping will be unreliable: %s\n", + strerror (err)); + fflush (stderr); + } +#endif + bd->taken = 1; snprintf (bd->name, DISK_NAME_LEN, "%s", name); bd->rump_fd = fd; |