Re: [PATCH] xen/argo: Command line handling improvements

[Christopher Clark <christopher.w.clark@xxxxxxxxx>]

On Tue, May 20, 2025 at 3:10 PM Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:

Treat "argo" on the command line as a positive boolean, rather than requiring
the user to pass "argo=1/on/enable/true".

Move both opt_argo* variables into __ro_after_init.  They're set during
command line parsing and never modified thereafter.

Instead of binding to static values set at boot, would boolean_runtime_param be acceptable? This allows the system administrator to adjust the Argo settings if the hypervisor has been compiled with it enabled and booted with the default settings, and avoid having to reboot and modify the bootloader configuration.

I agree with Daniel's request for a doc update where affected.

thanks,

Christopher

 

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Christopher Clark <christopher.w.clark@xxxxxxxxx>
CC: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
CC: Denis Mukhin <dmkhn@xxxxxxxxx>

Found while
---
 xen/common/argo.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/common/argo.c b/xen/common/argo.c
index cbe8911a4364..027b37b18a6c 100644
--- a/xen/common/argo.c
+++ b/xen/common/argo.c
@@ -79,8 +79,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_argo_unregister_ring_t);
 DEFINE_COMPAT_HANDLE(compat_argo_iov_t);
 #endif

-static bool __read_mostly opt_argo;
-static bool __read_mostly opt_argo_mac_permissive;
+static bool __ro_after_init opt_argo;
+static bool __ro_after_init opt_argo_mac_permissive;

 static int __init cf_check parse_argo(const char *s)
 {
@@ -92,7 +92,10 @@ static int __init cf_check parse_argo(const char *s)
         if ( !ss )
             ss = strchr(s, '\0');

-        if ( (val = parse_bool(s, ss)) >= 0 )
+        /* Intepret "argo" as a positive boolean. */
+        if ( *s == '\0' )
+            opt_argo = true;
+        else if ( (val = parse_bool(s, ss)) >= 0 )
             opt_argo = val;
         else if ( (val = parse_boolean("mac-permissive", s, ss)) >= 0 )
             opt_argo_mac_permissive = val;

base-commit: 293abb9e0c5e8df96cc5dfe457c62dfcb7542b19
--
2.39.5