[libvirt PATCH 2/4] include: define constants for resetting NVRAM state

[Daniel P. Berrangé]

When starting a guest with pflash based firmware, we will initialize
NVRAM from a template if it does not already exist. In theory if the
firmware code file is updated, the existing NVRAM variables should
continue to work correctly. It is inevitable that this could break
accidentally one day. Or a bug in the firmware might corrupt the
NVRAM storage. Or user might make bad changes to the settings that
prevent booting. Or the user might have re-configured the XML to
point to a different firmware file incompatible with the current
variables.

In all these cases it would be useful to delete the existing NVRAM
and initialize it from the pristine template.

To support this introduce a VIR_DOMAIN_START_RESET_NVRAM constant
for use with virDomainCreate / virDomainCreateXML, along with  a
VIR_DOMAIN_SAVE_RESET_NVRAM constant for use with virDomainRestore.

Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
---
 include/libvirt/libvirt-domain-snapshot.h |  1 +
 include/libvirt/libvirt-domain.h          |  2 ++
 src/libvirt-domain.c                      | 16 ++++++++++++++++
 3 files changed, 19 insertions(+)

diff --git a/include/libvirt/libvirt-domain-snapshot.h b/include/libvirt/libvirt-domain-snapshot.h
index 90673ed0fb..d729d1a532 100644
--- a/include/libvirt/libvirt-domain-snapshot.h
+++ b/include/libvirt/libvirt-domain-snapshot.h
@@ -198,6 +198,7 @@ typedef enum {
     VIR_DOMAIN_SNAPSHOT_REVERT_RUNNING = 1 << 0, /* Run after revert */
     VIR_DOMAIN_SNAPSHOT_REVERT_PAUSED  = 1 << 1, /* Pause after revert */
     VIR_DOMAIN_SNAPSHOT_REVERT_FORCE   = 1 << 2, /* Allow risky reverts */
+    VIR_DOMAIN_SNAPSHOT_REVERT_RESET_NVRAM = 1 << 3, /* Re-initialize NVRAM from template */
 } virDomainSnapshotRevertFlags;
 
 /* Revert the domain to a point-in-time snapshot.  The
diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 374859fdff..8c16598817 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -302,6 +302,7 @@ typedef enum {
     VIR_DOMAIN_START_BYPASS_CACHE = 1 << 2, /* Avoid file system cache pollution */
     VIR_DOMAIN_START_FORCE_BOOT   = 1 << 3, /* Boot, discarding any managed save */
     VIR_DOMAIN_START_VALIDATE     = 1 << 4, /* Validate the XML document against schema */
+    VIR_DOMAIN_START_RESET_NVRAM  = 1 << 5, /* Re-initialize NVRAM from template */
 } virDomainCreateFlags;
 
 
@@ -1268,6 +1269,7 @@ typedef enum {
     VIR_DOMAIN_SAVE_BYPASS_CACHE = 1 << 0, /* Avoid file system cache pollution */
     VIR_DOMAIN_SAVE_RUNNING      = 1 << 1, /* Favor running over paused */
     VIR_DOMAIN_SAVE_PAUSED       = 1 << 2, /* Favor paused over running */
+    VIR_DOMAIN_SAVE_RESET_NVRAM  = 1 << 3, /* Re-initialize NVRAM from template */
 } virDomainSaveRestoreFlags;
 
 int                     virDomainSave           (virDomainPtr domain,
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index 5912551a49..75796affc7 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -154,6 +154,10 @@ virDomainGetConnect(virDomainPtr dom)
  * block attempts at migration. Hypervisors may also block save-to-file,
  * or snapshots.
  *
+ * If @flags includes VIR_DOMAIN_START_RESET_NVRAM, then libvirt will
+ * discard any existing NVRAM file and re-initialize NVRAM from the
+ * pristine template.
+ *
  * virDomainFree should be used to free the resources after the
  * domain object is no longer needed.
  *
@@ -1015,6 +1019,10 @@ virDomainRestore(virConnectPtr conn, const char *from)
  * @flags will override the default read from the file.  These two
  * flags are mutually exclusive.
  *
+ * If @flags includes VIR_DOMAIN_SAVE_RESET_NVRAM, then libvirt will
+ * discard any existing NVRAM file and re-initialize NVRAM from the
+ * pristine template.
+ *
  * Returns 0 in case of success and -1 in case of failure.
  */
 int
@@ -6764,6 +6772,10 @@ virDomainCreate(virDomainPtr domain)
  * If the VIR_DOMAIN_START_FORCE_BOOT flag is set, then any managed save
  * file for this domain is discarded, and the domain boots from scratch.
  *
+ * If @flags includes VIR_DOMAIN_START_RESET_NVRAM, then libvirt will
+ * discard any existing NVRAM file and re-initialize NVRAM from the
+ * pristine template.
+ *
  * Returns 0 in case of success, -1 in case of error
  */
 int
@@ -6836,6 +6848,10 @@ virDomainCreateWithFlags(virDomainPtr domain, unsigned int flags)
  * If the VIR_DOMAIN_START_FORCE_BOOT flag is set, then any managed save
  * file for this domain is discarded, and the domain boots from scratch.
  *
+ * If @flags includes VIR_DOMAIN_START_RESET_NVRAM, then libvirt will
+ * discard any existing NVRAM file and re-initialize NVRAM from the
+ * pristine template.
+ *
  * Returns 0 in case of success, -1 in case of error
  */
 int
-- 
2.34.1