lsmsr: Add support to show MSRs for which no description is provided

Of course no verbose information but only the plain value of the
register (if it's a valid MSR address) can be provided. Example:

  # lsmsr -r 0xdeadbeef -l
  warning: unknown MSR deadbeef
  unknown: 0xdeadbeef; (at your own risk)
  # lsmsr -r 0xdeadbeef
  warning: unknown MSR deadbeef
  could not read MSR 0xdeadbeef ((null)): Input/output error
  unknown = 0x0000000000000000

Artificial example (forcing use of family 0xf register description and
showing PstateControl MSR on a family 0x10 CPU):

  # ./lsmsr  -r 0xc0010062 -f 0xf
  warning: unknown MSR c0010062
  unknown = 0x0000000000000003

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/lsmsr.c b/lsmsr.c
index 1a00bc2..c03950e 100644
--- a/lsmsr.c
+++ b/lsmsr.c
@@ -308,6 +308,8 @@ static int set_msr_table(void)
 	return 0;
 }
 
+struct reg_spec unknown_msr = {0, "unknown", "(at your own risk)", NULL, NULL};
+
 #define OPT_MAX 32
 int main(int argc, char *argv[])
 {
@@ -400,8 +402,10 @@ int main(int argc, char *argv[])
 		reg = get_reg_spec(g.reg, g.msr_table);
 		if (!reg) {
 			fflush(stdout);
-			fprintf(stderr, "error: unknown MSR %x\n", g.reg);
-			goto out;
+			fprintf(stderr, "warning: unknown MSR %x\n", g.reg);
+			g.verbosity = 0;
+			unknown_msr.address = g.reg;
+			reg = &unknown_msr;
 		}
 		if (_show_msr(reg))
 			goto out;