[PATCH v6 3/4] x86/ucode: Introduce --force option to xen-ucode

[Fouad Hilly <fouad.hilly@xxxxxxxxx>]

Introduce --force option to xen-ucode to force skipping microcode version 
check, which
allows the user to update x86 microcode even if both versions are the same or 
downgrade.
xc_microcode_update() refactored to accept flags and utilize 
xenpf_microcode_update2.

Signed-off-by: Fouad Hilly <fouad.hilly@xxxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
[v6]
1- Fix usage() output for -f option to be explicitly wrapped for 80 character 
width
[v5]
1- Update commit message.
2- Re-phrase --force option description.
[v4]
1- Add --force to xen-ucode options.
2- Update xc_microcode_update() to accept and handle flags.
---
 tools/include/xenctrl.h   |  3 ++-
 tools/libs/ctrl/xc_misc.c | 12 +++++++-----
 tools/misc/xen-ucode.c    | 15 ++++++++++++---
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 9ceca0cffc2f..2c4608c09ab0 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -1171,7 +1171,8 @@ typedef uint32_t xc_node_to_node_dist_t;
 int xc_physinfo(xc_interface *xch, xc_physinfo_t *info);
 int xc_cputopoinfo(xc_interface *xch, unsigned *max_cpus,
                    xc_cputopo_t *cputopo);
-int xc_microcode_update(xc_interface *xch, const void *buf, size_t len);
+int xc_microcode_update(xc_interface *xch, const void *buf,
+                        size_t len, unsigned int flags);
 int xc_get_cpu_version(xc_interface *xch, struct xenpf_pcpu_version *cpu_ver);
 int xc_get_ucode_revision(xc_interface *xch,
                           struct xenpf_ucode_revision *ucode_rev);
diff --git a/tools/libs/ctrl/xc_misc.c b/tools/libs/ctrl/xc_misc.c
index 50282fd60dcc..6a60216bda03 100644
--- a/tools/libs/ctrl/xc_misc.c
+++ b/tools/libs/ctrl/xc_misc.c
@@ -203,11 +203,12 @@ int xc_physinfo(xc_interface *xch,
     return 0;
 }
 
-int xc_microcode_update(xc_interface *xch, const void *buf, size_t len)
+int xc_microcode_update(xc_interface *xch, const void *buf,
+                        size_t len, unsigned int flags)
 {
     int ret;
     struct xen_platform_op platform_op = {};
-    DECLARE_HYPERCALL_BUFFER(struct xenpf_microcode_update, uc);
+    DECLARE_HYPERCALL_BUFFER(struct xenpf_microcode_update2, uc);
 
     uc = xc_hypercall_buffer_alloc(xch, uc, len);
     if ( uc == NULL )
@@ -215,9 +216,10 @@ int xc_microcode_update(xc_interface *xch, const void 
*buf, size_t len)
 
     memcpy(uc, buf, len);
 
-    platform_op.cmd = XENPF_microcode_update;
-    platform_op.u.microcode.length = len;
-    set_xen_guest_handle(platform_op.u.microcode.data, uc);
+    platform_op.cmd = XENPF_microcode_update2;
+    platform_op.u.microcode2.length = len;
+    platform_op.u.microcode2.flags = flags;
+    set_xen_guest_handle(platform_op.u.microcode2.data, uc);
 
     ret = do_platform_op(xch, &platform_op);
 
diff --git a/tools/misc/xen-ucode.c b/tools/misc/xen-ucode.c
index 2c9f337b86cb..688e540943b1 100644
--- a/tools/misc/xen-ucode.c
+++ b/tools/misc/xen-ucode.c
@@ -13,6 +13,8 @@
 #include <xenctrl.h>
 #include <getopt.h>
 
+#include <xen/platform.h>
+
 static xc_interface *xch;
 
 static const char intel_id[] = "GenuineIntel";
@@ -79,7 +81,9 @@ static void usage(FILE *stream, const char *name)
             "options:\n"
             "  -h, --help            display this help\n"
             "  -s, --show-cpu-info   show CPU information\n"
-            "Usage: %s [microcode file | options]\n", name, name);
+            "  -f, --force           skip certain checks; do not use unless\n"
+            "you know exactly what you are doing\n"
+            "Usage: %s [microcode file [-f,--force] | options]\n", name, name);
     show_curr_cpu(stream);
 }
 
@@ -88,6 +92,7 @@ int main(int argc, char *argv[])
     static const struct option options[] = {
         {"help", no_argument, NULL, 'h'},
         {"show-cpu-info", no_argument, NULL, 's'},
+        {"force", no_argument, NULL, 'f'},
         {NULL, no_argument, NULL, 0}
     };
     int fd, ret;
@@ -95,6 +100,7 @@ int main(int argc, char *argv[])
     size_t len;
     struct stat st;
     int opt;
+    uint32_t ucode_flags = 0;
 
     xch = xc_interface_open(NULL, NULL, 0);
     if ( xch == NULL )
@@ -104,7 +110,7 @@ int main(int argc, char *argv[])
         exit(1);
     }
 
-    while ( (opt = getopt_long(argc, argv, "hs", options, NULL)) != -1 )
+    while ( (opt = getopt_long(argc, argv, "hsf", options, NULL)) != -1 )
     {
         switch ( opt )
         {
@@ -116,6 +122,9 @@ int main(int argc, char *argv[])
             show_curr_cpu(stdout);
             exit(EXIT_SUCCESS);
 
+        case 'f':
+            ucode_flags = XENPF_UCODE_FORCE;
+            break;
         default:
             goto ext_err;
         }
@@ -156,7 +165,7 @@ int main(int argc, char *argv[])
     }
 
     errno = 0;
-    ret = xc_microcode_update(xch, buf, len);
+    ret = xc_microcode_update(xch, buf, len, ucode_flags);
     if ( ret == -1 && errno == EEXIST )
         printf("Microcode already up to date\n");
     else if ( ret )
-- 
2.42.0