From e4901a4e83f0ab59a525095d2fe1c7f1a38c0aac Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Wed, 4 May 2022 15:41:52 +0200
Subject: [PATCH] lib: launch-direct: ignore drive "iface" parameter

Rich said in <https://bugzilla.redhat.com/show_bug.cgi?id=1844341#c1>:

> The libvirt backend has never allowed the iface parameter.  We should
> probably ignore it in the direct backend since it's never been possible
> to use this parameter correctly.

Remove the handling of "iface" in the direct (QEMU) backend. Refresh the
documentation regarding both backends.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1844341
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20220504134155.11832-2-lersek@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
(cherry picked from commit 3eb830dbaee12c8dc4566cab226ed2af0e0f2d8c)
---
 generator/actions_core_deprecated.ml |  8 +++-
 lib/launch-direct.c                  | 59 ++++++----------------------
 2 files changed, 19 insertions(+), 48 deletions(-)

diff --git a/generator/actions_core_deprecated.ml b/generator/actions_core_deprecated.ml
index 00dde3d2a..f1040a0e9 100644
--- a/generator/actions_core_deprecated.ml
+++ b/generator/actions_core_deprecated.ml
@@ -73,7 +73,9 @@ of C<guestfs_add_drive_ro>." };
     shortdesc = "add a drive specifying the QEMU block emulation to use";
     longdesc = "\
 This is the same as C<guestfs_add_drive> but it allows you
-to specify the QEMU interface emulation to use at run time." };
+to specify the QEMU interface emulation to use at run time.
+The libvirt backend rejects a non-empty C<iface> argument.
+The direct backend ignores C<iface>." };
 
   { defaults with
     name = "add_drive_ro_with_if"; added = (1, 0, 84);
@@ -83,7 +85,9 @@ to specify the QEMU interface emulation to use at run time." };
     shortdesc = "add a drive read-only specifying the QEMU block emulation to use";
     longdesc = "\
 This is the same as C<guestfs_add_drive_ro> but it allows you
-to specify the QEMU interface emulation to use at run time." };
+to specify the QEMU interface emulation to use at run time.
+The libvirt backend rejects a non-empty C<iface> argument.
+The direct backend ignores C<iface>." };
 
   { defaults with
     name = "lstatlist"; added = (1, 0, 77);
diff --git a/lib/launch-direct.c b/lib/launch-direct.c
index b292b9c26..ff0eaeb62 100644
--- a/lib/launch-direct.c
+++ b/lib/launch-direct.c
@@ -296,52 +296,19 @@ static int
 add_drive (guestfs_h *g, struct backend_direct_data *data,
            struct qemuopts *qopts, size_t i, struct drive *drv)
 {
-  /* If there's an explicit 'iface', use it.  Otherwise default to
-   * virtio-scsi.
-   */
-  if (drv->iface && STREQ (drv->iface, "virtio")) { /* virtio-blk */
-    start_list ("-drive") {
-      if (add_drive_standard_params (g, data, qopts, i, drv) == -1)
-        return -1;
-      append_list ("if=none");
-    } end_list ();
-    start_list ("-device") {
-      append_list (VIRTIO_DEVICE_NAME ("virtio-blk"));
-      append_list_format ("drive=hd%zu", i);
-      if (drv->disk_label)
-        append_list_format ("serial=%s", drv->disk_label);
-      if (add_device_blocksize_params (g, qopts, drv) == -1)
-        return -1;
-    } end_list ();
-  }
-#if defined(__arm__) || defined(__aarch64__) || defined(__powerpc__)
-  else if (drv->iface && STREQ (drv->iface, "ide")) {
-    error (g, "'ide' interface does not work on ARM or PowerPC");
-    return -1;
-  }
-#endif
-  else if (drv->iface) {
-    start_list ("-drive") {
-      if (add_drive_standard_params (g, data, qopts, i, drv) == -1)
-        return -1;
-      append_list_format ("if=%s", drv->iface);
-    } end_list ();
-  }
-  else /* default case: virtio-scsi */ {
-    start_list ("-drive") {
-      if (add_drive_standard_params (g, data, qopts, i, drv) == -1)
-        return -1;
-      append_list ("if=none");
-    } end_list ();
-    start_list ("-device") {
-      append_list ("scsi-hd");
-      append_list_format ("drive=hd%zu", i);
-      if (drv->disk_label)
-        append_list_format ("serial=%s", drv->disk_label);
-      if (add_device_blocksize_params (g, qopts, drv) == -1)
-        return -1;
-    } end_list ();
-  }
+  start_list ("-drive") {
+    if (add_drive_standard_params (g, data, qopts, i, drv) == -1)
+      return -1;
+    append_list ("if=none");
+  } end_list ();
+  start_list ("-device") {
+    append_list ("scsi-hd");
+    append_list_format ("drive=hd%zu", i);
+    if (drv->disk_label)
+      append_list_format ("serial=%s", drv->disk_label);
+    if (add_device_blocksize_params (g, qopts, drv) == -1)
+      return -1;
+  } end_list ();
 
   return 0;
 
-- 
2.31.1