kmod-setup: Add early loading for virtio_console

getty-generator enables serial-getty@.service for virtualizer consoles
that it can find in /sys/class/tty. To make sure this works for
virtio consoles, let's make sure we load the module is loaded early
so that the /sys/class/tty/hvc0 exists before we run getty-generator.

1 files changed, 33 insertions, 8 deletions

diff --git a/src/core/kmod-setup.c b/src/core/kmod-setup.c
index d7abf4b7d8..c09e17f568 100644
--- a/src/core/kmod-setup.c
+++ b/src/core/kmod-setup.c
@@ -86,6 +86,27 @@ static bool has_virtio_rng(void) {
         return r > 0;
 }
 
+static bool has_virtio_console(void) {
+        int r;
+
+        /* Directory traversal might be slow, hence let's do a cheap check first if it's even worth it */
+        if (detect_vm() == VIRTUALIZATION_NONE)
+                return false;
+
+        r = recurse_dir_at(
+                        AT_FDCWD,
+                        "/sys/devices/pci0000:00",
+                        /* statx_mask= */ 0,
+                        /* n_depth_max= */ 3,
+                        RECURSE_DIR_ENSURE_TYPE,
+                        match_modalias_recurse_dir_cb,
+                        STRV_MAKE("virtio:d00000003v", "virtio:d0000000Bv"));
+        if (r < 0)
+                log_debug_errno(r, "Failed to determine whether host has virtio-console device, ignoring: %m");
+
+        return r > 0;
+}
+
 static bool in_qemu(void) {
         return IN_SET(detect_vm(), VIRTUALIZATION_KVM, VIRTUALIZATION_QEMU);
 }
@@ -103,31 +124,35 @@ int kmod_setup(void) {
         } kmod_table[] = {
                 /* This one we need to load explicitly, since auto-loading on use doesn't work
                  * before udev created the ghost device nodes, and we need it earlier than that. */
-                { "autofs4",     "/sys/class/misc/autofs",    true,  false, NULL           },
+                { "autofs4",         "/sys/class/misc/autofs",    true,  false, NULL               },
 
                 /* This one we need to load explicitly, since auto-loading of IPv6 is not done when
                  * we try to configure ::1 on the loopback device. */
-                { "ipv6",        "/sys/module/ipv6",          false, true,  NULL           },
+                { "ipv6",            "/sys/module/ipv6",          false, true,  NULL               },
 
                 /* This should never be a module */
-                { "unix",        "/proc/net/unix",            true,  true,  NULL           },
+                { "unix",            "/proc/net/unix",            true,  true,  NULL               },
 
 #if HAVE_LIBIPTC
                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
-                { "ip_tables",   "/proc/net/ip_tables_names", false, false, NULL           },
+                { "ip_tables",       "/proc/net/ip_tables_names", false, false, NULL               },
 #endif
                 /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
-                { "virtio_rng",  NULL,                        false, false, has_virtio_rng },
+                { "virtio_rng",      NULL,                        false, false, has_virtio_rng     },
+
+                /* we want early logging to hvc consoles if possible, and make sure systemd-getty-generator
+                 * can rely on all consoles being probed already.*/
+                { "virtio_console",  NULL,                        false, false, has_virtio_console },
 
                 /* qemu_fw_cfg would be loaded by udev later, but we want to import credentials from it super early */
-                { "qemu_fw_cfg", "/sys/firmware/qemu_fw_cfg", false, false, in_qemu        },
+                { "qemu_fw_cfg",     "/sys/firmware/qemu_fw_cfg", false, false, in_qemu            },
 
                 /* dmi-sysfs is needed to import credentials from it super early */
-                { "dmi-sysfs",   "/sys/firmware/dmi/entries", false, false, NULL           },
+                { "dmi-sysfs",       "/sys/firmware/dmi/entries", false, false, NULL               },
 
 #if HAVE_TPM2
                 /* Make sure the tpm subsystem is available which ConditionSecurity=tpm2 depends on. */
-                { "tpm",         "/sys/class/tpmrm",          false, false, efi_has_tpm2   },
+                { "tpm",             "/sys/class/tpmrm",          false, false, efi_has_tpm2       },
 #endif
         };
         _cleanup_(kmod_unrefp) struct kmod_ctx *ctx = NULL;