livepatch: introduce --force option

Introduce a xen-livepatch tool --force option, that's propagated into the
hyerpvisor for livepatch operations.  The intention is for the option to be
used to bypass some checks that would otherwise prevent the patch from being
loaded.

Re purpose the pad field in xen_sysctl_livepatch_op to be a flags field that
applies to all livepatch operations.  The flag is currently only set by the
hypercall wrappers for the XEN_SYSCTL_LIVEPATCH_UPLOAD operation, as that's so
far the only one where it will be used initially.  Other uses can be added as
required.

Note that helpers would set the .pad field to 0, that's been removed since the
structure is already zero initialized at definition.

No functional usages of the new flag introduced in this patch.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>

diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 2ef8b4e05422379730331e5d93fdcc385cbb24ac..499685594427e90feaa33eeb6ef9c4345693a1f9 100644 (file)
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -2555,7 +2555,8 @@ int xc_psr_get_hw_info(xc_interface *xch, uint32_t socket,
 #endif
 
 int xc_livepatch_upload(xc_interface *xch,
-                        char *name, unsigned char *payload, uint32_t size);
+                        char *name, unsigned char *payload, uint32_t size,
+                        bool force);
 
 int xc_livepatch_get(xc_interface *xch,
                      char *name,

diff --git a/tools/libs/ctrl/xc_misc.c b/tools/libs/ctrl/xc_misc.c
index 5ecdfa2c7934983b7a99ced6c23e8e7f309e5fa0..50282fd60dccb14c17db6c31ff9df65d4a1194b6 100644 (file)
--- a/tools/libs/ctrl/xc_misc.c
+++ b/tools/libs/ctrl/xc_misc.c
@@ -576,7 +576,8 @@ int xc_getcpuinfo(xc_interface *xch, int max_cpus,
 int xc_livepatch_upload(xc_interface *xch,
                         char *name,
                         unsigned char *payload,
-                        uint32_t size)
+                        uint32_t size,
+                        bool force)
 {
     int rc;
     struct xen_sysctl sysctl = {};
@@ -612,7 +613,7 @@ int xc_livepatch_upload(xc_interface *xch,
 
     sysctl.cmd = XEN_SYSCTL_livepatch_op;
     sysctl.u.livepatch.cmd = XEN_SYSCTL_LIVEPATCH_UPLOAD;
-    sysctl.u.livepatch.pad = 0;
+    sysctl.u.livepatch.flags = force ? LIVEPATCH_FLAG_FORCE : 0;
     sysctl.u.livepatch.u.upload.size = size;
     set_xen_guest_handle(sysctl.u.livepatch.u.upload.payload, local);
 
@@ -656,7 +657,6 @@ int xc_livepatch_get(xc_interface *xch,
 
     sysctl.cmd = XEN_SYSCTL_livepatch_op;
     sysctl.u.livepatch.cmd = XEN_SYSCTL_LIVEPATCH_GET;
-    sysctl.u.livepatch.pad = 0;
 
     sysctl.u.livepatch.u.get.status.state = 0;
     sysctl.u.livepatch.u.get.status.rc = 0;
@@ -985,7 +985,6 @@ static int _xc_livepatch_action(xc_interface *xch,
 
     sysctl.cmd = XEN_SYSCTL_livepatch_op;
     sysctl.u.livepatch.cmd = XEN_SYSCTL_LIVEPATCH_ACTION;
-    sysctl.u.livepatch.pad = 0;
     sysctl.u.livepatch.u.action.cmd = action;
     sysctl.u.livepatch.u.action.timeout = timeout;
     sysctl.u.livepatch.u.action.flags = flags;

diff --git a/tools/misc/xen-livepatch.c b/tools/misc/xen-livepatch.c
index 2c4f69e596fafc816384c34782f2275a1641700d..c16fb6862d6c0ef5e0b187d4be9a395019aa5a2e 100644 (file)
--- a/tools/misc/xen-livepatch.c
+++ b/tools/misc/xen-livepatch.c
@@ -19,11 +19,15 @@
 
 static xc_interface *xch;
 
+/* Global option to disable checks. */
+static bool force;
+
 void show_help(void)
 {
     fprintf(stderr,
             "xen-livepatch: live patching tool\n"
-            "Usage: xen-livepatch <command> [args] [command-flags]\n"
+            "Usage: xen-livepatch [--force] <command> [args] [command-flags]\n"
+            " Use --force option to bypass some checks.\n"
             " <name> An unique name of payload. Up to %d characters.\n"
             "Commands:\n"
             "  help                   display this help\n"
@@ -240,7 +244,7 @@ static int upload_func(int argc, char *argv[])
         return saved_errno;
     }
     printf("Uploading %s... ", filename);
-    rc = xc_livepatch_upload(xch, name, fbuf, len);
+    rc = xc_livepatch_upload(xch, name, fbuf, len, force);
     if ( rc )
     {
         rc = errno;
@@ -571,6 +575,19 @@ int main(int argc, char *argv[])
         show_help();
         return 0;
     }
+
+    if ( strcmp("--force", argv[1]) )
+    {
+        if ( argc <= 2 )
+        {
+            show_help();
+            return EXIT_FAILURE;
+        }
+        force = true;
+        argv++;
+        argc--;
+    }
+
     for ( i = 0; i < ARRAY_SIZE(main_options); i++ )
         if (!strcmp(main_options[i].name, argv[1]))
             break;

diff --git a/xen/common/livepatch.c b/xen/common/livepatch.c
index 351a3e0b9a6061991bbbb24749b58d5279b91a52..502e264bc6fe180330c436b5c924f426ee9f1156 100644 (file)
--- a/xen/common/livepatch.c
+++ b/xen/common/livepatch.c
@@ -2125,7 +2125,8 @@ int livepatch_op(struct xen_sysctl_livepatch_op *livepatch)
 {
     int rc;
 
-    if ( livepatch->pad )
+    if ( (livepatch->flags & ~LIVEPATCH_FLAGS_MASK) &&
+         !(livepatch->flags & LIVEPATCH_FLAG_FORCE) )
         return -EINVAL;
 
     switch ( livepatch->cmd )

diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 9b19679caeb18ecff6ad38ae76072e2e754de604..febaa4b16ab74e2fd8da94f9c4b47a07b5a59e07 100644 (file)
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -1139,7 +1139,9 @@ struct xen_sysctl_livepatch_action {
 
 struct xen_sysctl_livepatch_op {
     uint32_t cmd;                           /* IN: XEN_SYSCTL_LIVEPATCH_*. */
-    uint32_t pad;                           /* IN: Always zero. */
+    uint32_t flags;                         /* IN, flags. */
+#define LIVEPATCH_FLAG_FORCE      (1u << 0) /* Skip some checks. */
+#define LIVEPATCH_FLAGS_MASK      LIVEPATCH_FLAG_FORCE
     union {
         struct xen_sysctl_livepatch_upload upload;
         struct xen_sysctl_livepatch_list list;