[Xen-devel] [PATCH v1] libxl: add helper function to set device_model_version

Olaf Hering posted 1 patch 1 week ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/xen tags/patchew/20190514072741.11760-1-olaf@aepfle.de
tools/libxl/libxl_create.c   | 90 +++++++++++++++++++++++++++-----------------
tools/libxl/libxl_dm.c       |  2 +
tools/libxl/libxl_internal.h |  2 +
3 files changed, 59 insertions(+), 35 deletions(-)

[Xen-devel] [PATCH v1] libxl: add helper function to set device_model_version

Posted by Olaf Hering 1 week ago
An upcoming change will set the value of device_model_version properly
also for the non-HVM case.

Move existing code to new function libxl__domain_set_device_model.
Move also initialization for device_model_stubdomain to that function.
Make sure libxl__domain_build_info_setdefault is called with
device_model_version set.

Update libxl__spawn_stub_dm() and initiate_domain_create() to call the
new function prior libxl__domain_build_info_setdefault() because
device_mode_version is expected to be initialzed.
libxl_domain_need_memory() needs no update because it does not have a
d_config available anyway, and the callers provide a populated b_info.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 tools/libxl/libxl_create.c   | 90 +++++++++++++++++++++++++++-----------------
 tools/libxl/libxl_dm.c       |  2 +
 tools/libxl/libxl_internal.h |  2 +
 3 files changed, 59 insertions(+), 35 deletions(-)

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 89fe80fc9c..3f0431cc84 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -27,6 +27,53 @@
 
 #include <xen-xsm/flask/flask.h>
 
+int libxl__domain_set_device_model(libxl__gc *gc, libxl_domain_config *d_config)
+{
+    libxl_domain_build_info *b_info = &d_config->b_info;
+    int ret;
+
+    libxl_defbool_setdefault(&b_info->device_model_stubdomain, false);
+
+    if (b_info->device_model_version)
+        return 0;
+
+    switch (b_info->type) {
+    case LIBXL_DOMAIN_TYPE_HVM:
+        if (libxl_defbool_val(b_info->device_model_stubdomain)) {
+            b_info->device_model_version =
+                LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL;
+        } else {
+            b_info->device_model_version = libxl__default_device_model(gc);
+        }
+        break;
+    default:
+        b_info->device_model_version =
+            LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL;
+        break;
+    }
+
+    if (b_info->device_model_version == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
+        const char *dm;
+
+        dm = libxl__domain_device_model(gc, b_info);
+        ret = access(dm, X_OK);
+        if (ret < 0) {
+            /* qemu-xen unavailable, use qemu-xen-traditional */
+            if (errno == ENOENT) {
+                LOGE(INFO, "qemu-xen is unavailable"
+                     ", using qemu-xen-traditional instead");
+                b_info->device_model_version =
+                    LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL;
+            } else {
+                LOGE(ERROR, "qemu-xen access error");
+                return ERROR_FAIL;
+            }
+        }
+    }
+
+    return 0;
+}
+
 int libxl__domain_create_info_setdefault(libxl__gc *gc,
                                          libxl_domain_create_info *c_info)
 {
@@ -73,6 +120,8 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
         return ERROR_INVAL;
     }
 
+    assert(b_info->device_model_version);
+
     /* Copy deprecated options to it's new position. */
     rc = libxl__domain_build_info_copy_deprecated(CTX, b_info);
     if (rc) {
@@ -80,45 +129,10 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
         return rc;
     }
 
-    libxl_defbool_setdefault(&b_info->device_model_stubdomain, false);
-
     if (libxl_defbool_val(b_info->device_model_stubdomain) &&
         !b_info->device_model_ssidref)
         b_info->device_model_ssidref = SECINITSID_DOMDM;
 
-    if (!b_info->device_model_version) {
-        if (b_info->type == LIBXL_DOMAIN_TYPE_HVM) {
-            if (libxl_defbool_val(b_info->device_model_stubdomain)) {
-                b_info->device_model_version =
-                    LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL;
-            } else {
-                b_info->device_model_version = libxl__default_device_model(gc);
-            }
-        } else {
-            b_info->device_model_version =
-                LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN;
-        }
-        if (b_info->device_model_version
-                == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
-            const char *dm;
-
-            dm = libxl__domain_device_model(gc, b_info);
-            rc = access(dm, X_OK);
-            if (rc < 0) {
-                /* qemu-xen unavailable, use qemu-xen-traditional */
-                if (errno == ENOENT) {
-                    LOGE(INFO, "qemu-xen is unavailable"
-                         ", using qemu-xen-traditional instead");
-                    b_info->device_model_version =
-                        LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL;
-                } else {
-                    LOGE(ERROR, "qemu-xen access error");
-                    return ERROR_FAIL;
-                }
-            }
-        }
-    }
-
     if (b_info->blkdev_start == NULL)
         b_info->blkdev_start = libxl__strdup(NOGC, "xvda");
 
@@ -938,6 +952,12 @@ static void initiate_domain_create(libxl__egc *egc,
         goto error_out;
     }
 
+    ret = libxl__domain_set_device_model(gc, d_config);
+    if (ret) {
+        LOGD(ERROR, domid, "Unable to set domain device model");
+        goto error_out;
+    }
+
     ret = libxl__domain_create_info_setdefault(gc, &d_config->c_info);
     if (ret) {
         LOGD(ERROR, domid, "Unable to set domain create info defaults");
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 2f19786bdd..086e566311 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -2168,6 +2168,8 @@ void libxl__spawn_stub_dm(libxl__egc *egc, libxl__stub_dm_spawn_state *sdss)
     dm_config->c_info.run_hotplug_scripts =
         guest_config->c_info.run_hotplug_scripts;
 
+    ret = libxl__domain_set_device_model(gc, dm_config);
+    if (ret) goto out;
     ret = libxl__domain_create_info_setdefault(gc, &dm_config->c_info);
     if (ret) goto out;
     ret = libxl__domain_build_info_setdefault(gc, &dm_config->b_info);
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 44e0221284..25f113404b 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1374,6 +1374,8 @@ _hidden int libxl__device_nextid(libxl__gc *gc, uint32_t domid,
 _hidden int libxl__resolve_domid(libxl__gc *gc, const char *name,
                                  uint32_t *domid);
 
+_hidden int libxl__domain_set_device_model(libxl__gc *gc,
+                                           libxl_domain_config *d_config);
 /*
  * For each aggregate type which can be used as an input we provide:
  *

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Re: [Xen-devel] [PATCH v1] libxl: add helper function to set device_model_version

Posted by Roger Pau Monné 1 week ago
On Tue, May 14, 2019 at 09:27:41AM +0200, Olaf Hering wrote:
> An upcoming change will set the value of device_model_version properly
> also for the non-HVM case.
> 
> Move existing code to new function libxl__domain_set_device_model.
> Move also initialization for device_model_stubdomain to that function.
> Make sure libxl__domain_build_info_setdefault is called with
> device_model_version set.
> 
> Update libxl__spawn_stub_dm() and initiate_domain_create() to call the
> new function prior libxl__domain_build_info_setdefault() because
> device_mode_version is expected to be initialzed.

That's all fine, but this just describes the changes performed below
without providing a reasoning on why those changes are needed. Why is
it not fine to set the device model version in
libxl__domain_build_info_setdefault?

> @@ -938,6 +952,12 @@ static void initiate_domain_create(libxl__egc *egc,
>          goto error_out;
>      }
>  
> +    ret = libxl__domain_set_device_model(gc, d_config);
> +    if (ret) {
> +        LOGD(ERROR, domid, "Unable to set domain device model");
> +        goto error_out;
> +    }

Can you place the call to libxl__domain_set_device_model at the top
(or a suitable place) of libxl__domain_build_info_setdefault instead
of adding a call in initiate_domain_create?

> +
>      ret = libxl__domain_create_info_setdefault(gc, &d_config->c_info);
>      if (ret) {
>          LOGD(ERROR, domid, "Unable to set domain create info defaults");
> diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
> index 2f19786bdd..086e566311 100644
> --- a/tools/libxl/libxl_dm.c
> +++ b/tools/libxl/libxl_dm.c
> @@ -2168,6 +2168,8 @@ void libxl__spawn_stub_dm(libxl__egc *egc, libxl__stub_dm_spawn_state *sdss)
>      dm_config->c_info.run_hotplug_scripts =
>          guest_config->c_info.run_hotplug_scripts;
>  
> +    ret = libxl__domain_set_device_model(gc, dm_config);
> +    if (ret) goto out;
>      ret = libxl__domain_create_info_setdefault(gc, &dm_config->c_info);
>      if (ret) goto out;
>      ret = libxl__domain_build_info_setdefault(gc, &dm_config->b_info);

Same here, AFAICT the call to libxl__domain_set_device_model could be
placed inside of libxl__domain_build_info_setdefault?

Thanks, Roger.

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Re: [Xen-devel] [PATCH v1] libxl: add helper function to set device_model_version

Posted by Olaf Hering 1 week ago
Am Tue, 14 May 2019 12:18:56 +0200
schrieb Roger Pau Monné <roger.pau@citrix.com>:

> Why is it not fine to set the device model version in
> libxl__domain_build_info_setdefault?

Because it receives just build_info, which lacks all the data to decide
if a device type needs a device model or not.

Olaf
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Re: [Xen-devel] [PATCH v1] libxl: add helper function to set device_model_version

Posted by Roger Pau Monné 1 week ago
On Tue, May 14, 2019 at 12:31:18PM +0200, Olaf Hering wrote:
> Am Tue, 14 May 2019 12:18:56 +0200
> schrieb Roger Pau Monné <roger.pau@citrix.com>:
> 
> > Why is it not fine to set the device model version in
> > libxl__domain_build_info_setdefault?
> 
> Because it receives just build_info, which lacks all the data to decide
> if a device type needs a device model or not.

Gah, thanks. Could you please add this to the commit message? Or else
it's likely I will ask again.

With that:

Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

Roger.

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Re: [Xen-devel] [PATCH v1] libxl: add helper function to set device_model_version

Posted by Wei Liu 1 week ago
On Tue, May 14, 2019 at 12:39:07PM +0200, Roger Pau Monné wrote:
> On Tue, May 14, 2019 at 12:31:18PM +0200, Olaf Hering wrote:
> > Am Tue, 14 May 2019 12:18:56 +0200
> > schrieb Roger Pau Monné <roger.pau@citrix.com>:
> > 
> > > Why is it not fine to set the device model version in
> > > libxl__domain_build_info_setdefault?
> > 
> > Because it receives just build_info, which lacks all the data to decide
> > if a device type needs a device model or not.
> 
> Gah, thanks. Could you please add this to the commit message? Or else
> it's likely I will ask again.
> 
> With that:
> 
> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

Olaf, if you can provide me with an updated version of the commit
message I can fold that in while committing. No need to resend this
patch.

Wei.

> 
> Roger.

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Re: [Xen-devel] [PATCH v1] libxl: add helper function to set device_model_version

Posted by Olaf Hering 1 week ago
Am Tue, 14 May 2019 15:32:27 +0100
schrieb Wei Liu <wei.liu2@citrix.com>:

> Olaf, if you can provide me with an updated version of the commit
> message I can fold that in while committing. No need to resend this
> patch.

Maybe just append this paragraph?

The upcoming change needs a full libxl_domain_config, and the existing
libxl__domain_build_info_setdefault has just a libxl_domain_build_info 
to work with.

Olaf
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