[RFC] Host and guest capabilities

["Richard W.M. Jones" <rjones@xxxxxxxxxx>]

I've been looking into the parts of virtinst which try to probe the 
capabilities of the host directly, rather than being abstracted through 
libvirt (for example, opening and parsing 
/sys/hypervisor/properties/capabilities directly).

Attached is a proposed API for probing the capabilities and supported 
guest architectures of the hypervisor / driver.

I've implemented the virCapabilities part already.  My original 
implementation of the guest architectures had virCapabilities containing 
a list of supported architectures, but that doesn't nearly cover the 
richness of what the underlying drivers could support, so I'm currently 
separating that out into a separate virConnectGetGuestArchitectures call.

Let me know your opinions of this API.

As an aside, the current virt-manager "choose paravirt / fullvirt" 
screen doesn't really capture the full, shall I say, ugliness of the 
possible choices for architecture, particularly when we add qemu, kqemu, 
and emulation in the mix.  I suspect that presenting a list of 
architectures here, perhaps with some options to show only paravirt, 
show only fullvirt, show only accelerated ...

Rich.

--
Emerging Technologies, Red Hat  http://et.redhat.com/~rjones/
64 Baker Street, London, W1U 7DF     Mobile: +44 7866 314 421
 "[Negative numbers] darken the very whole doctrines of the equations
 and make dark of the things which are in their nature excessively
 obvious and simple" (Francis Maseres FRS, mathematician, 1759)

diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index bd8f6a1..5a84bf5 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -188,6 +188,52 @@ struct _virNodeInfo {
 typedef virNodeInfo *virNodeInfoPtr;
 
 /**
+ * virCapabilitiesPtr:
+ *
+ * a virCapabilitiesPtr contains the capabilities of the hypervisor or
+ * driver that we have connected to, returned by virConnectGetCapabilities.
+ * Use virCapabilitiesFree to free the structure after use.
+ */
+
+struct _virCapabilities;
+typedef struct _virCapabilities virCapabilities;
+typedef virCapabilities *virCapabilitiesPtr;
+
+int virCapabilitiesFree (virCapabilitiesPtr caps);
+
+/* Accessors for fields in the virCapabilitiesPtr structure. */
+int virCapabilitiesGetHostSupportsHVM (virCapabilitiesPtr caps);
+int virCapabilitiesGetHostHVMDisabledByBIOS (virCapabilitiesPtr caps);
+  /* XXX Other things which virtinst needs:
+   * blktap
+   * KVM/KQEMU available in kernel
+   */
+
+/**
+ * virGuestArchitecturesPtr
+ *
+ * a virGuestArchitecturesPtr contains a list of the guest architectures
+ * supported by the driver, returned by virConnectGetGuestArchitectures.
+ * Use virGuestArchitecturesFree to free the structure after use.
+ */
+
+struct _virGuestArchitectures;
+typedef struct _virGuestArchitectures virGuestArchitectures;
+typedef struct virGuestArchitectures *virGuestArchitecturesPtr;
+
+int virGuestArchitecturesFree (virGuestArchitecturesPtr archs);
+
+/* Accessors for elements in the virGuestArchitecturesPtr structure. */
+int virGuestArchitecturesGetCount (virGuestArchitecturesPtr archs);
+char *virGuestArchitecturesGetName (virGuestArchitecturesPtr archs, int n);
+int virGuestArchitecturesGetIsHVM (virGuestArchitecturesPtr archs, int n);
+int virGuestArchitecturesGetIsAccelerated (virGuestArchitecturesPtr archs, int n);
+int virGuestArchitecturesGetIsEmulated (virGuestArchitecturesPtr archs, int n);
+int virGuestArchitecturesGetIsBigEndian (virGuestArchitecturesPtr archs, int n);
+int virGuestArchitecturesGetBits (virGuestArchitecturesPtr archs, int n);
+int virGuestArchitecturesGetIsPAE (virGuestArchitecturesPtr archs, int n);
+
+/**
  * VIR_UUID_STRING_BUFLEN:
  *
  * This macro provides the length of the buffer required
@@ -231,8 +277,14 @@ int			virConnectClose		(virConnectPtr conn);
 const char *		virConnectGetType	(virConnectPtr conn);
 int			virConnectGetVersion	(virConnectPtr conn,
 						 unsigned long *hvVer);
+/*
+ * Capabilities of the connection / driver.
+ */
+
 int			virNodeGetInfo		(virConnectPtr conn,
 						 virNodeInfoPtr info);
+virCapabilitiesPtr      virConnectGetCapabilities (virConnectPtr conn);
+virGuestArchitecturesPtr virConnectGetGuestArchitectures (virConnectPtr conn);
 
 /*
  * Gather list of running domains

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature