From d77e1a9642fe1efe9aa5f737a640354c27d04e02 Mon Sep 17 00:00:00 2001 From: Daniel Veillard Date: Wed, 2 Nov 2005 12:50:21 +0000 Subject: [PATCH] Initial revision --- COPYING.LIB | 510 +++++++++++++++++++++++++++++++++++++++++++++++ ChangeLog | 4 + Makefile.am | 9 + configure.in | 35 ++++ docs/Plan | 4 + docs/analysis | 33 +++ docs/library.xen | 101 ++++++++++ include/libxen.h | 80 ++++++++ src/Makefile.am | 8 + src/libxen.c | 76 +++++++ 10 files changed, 860 insertions(+) create mode 100644 COPYING.LIB create mode 100644 ChangeLog create mode 100644 Makefile.am create mode 100644 configure.in create mode 100644 docs/Plan create mode 100644 docs/analysis create mode 100644 docs/library.xen create mode 100644 include/libxen.h create mode 100644 src/Makefile.am create mode 100644 src/libxen.c diff --git a/COPYING.LIB b/COPYING.LIB new file mode 100644 index 0000000000..cf9b6b9972 --- /dev/null +++ b/COPYING.LIB @@ -0,0 +1,510 @@ + + GNU LESSER GENERAL PUBLIC LICENSE + Version 2.1, February 1999 + + Copyright (C) 1991, 1999 Free Software Foundation, Inc. + 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + +[This is the first released version of the Lesser GPL. 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Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the + library `Frob' (a library for tweaking knobs) written by James + Random Hacker. + + , 1 April 1990 + Ty Coon, President of Vice + +That's all there is to it! + + diff --git a/ChangeLog b/ChangeLog new file mode 100644 index 0000000000..3d4bf1d586 --- /dev/null +++ b/ChangeLog @@ -0,0 +1,4 @@ +Wed Nov 2 13:44:47 CET 2005 Daniel Veillard + + * src/libxen.c src/Makefile.am include/libxen.h configure.in + Makefile.am COPYING.LIB: creation diff --git a/Makefile.am b/Makefile.am new file mode 100644 index 0000000000..ed0f60398e --- /dev/null +++ b/Makefile.am @@ -0,0 +1,9 @@ +## Process this file with automake to produce Makefile.in + +SUBDIRS = src #docs +EXTRA_DIST = libxen.spec.in libxen.spec COPYING.LIB \ + libxen.pc.in libxen.pc + +pkgconfigdir = $(libdir)/pkgconfig +pkgconfig_DATA = libxen.pc + diff --git a/configure.in b/configure.in new file mode 100644 index 0000000000..5b5c9c92b1 --- /dev/null +++ b/configure.in @@ -0,0 +1,35 @@ +dnl Process this file with autoconf to produce a configure script. +AC_INIT(entities.c) +AM_CONFIG_HEADER(config.h) +AC_CANONICAL_HOST + +LIBXEN_MAJOR_VERSION=0 +LIBXEN_MINOR_VERSION=0 +LIBXEN_MICRO_VERSION=1 +LIBXEN_MICRO_VERSION_SUFFIX= +LIBXEN_VERSION=$LIBXEN_MAJOR_VERSION.$LIBXEN_MINOR_VERSION.$LIBXEN_MICRO_VERSION$LIBXEN_MICRO_VERSION_SUFFIX +LIBXEN_VERSION_INFO=`expr $LIBXEN_MAJOR_VERSION + $LIBXEN_MINOR_VERSION`:$LIBXEN_MICRO_VERSION:$LIBXEN_MINOR_VERSION + +LIBXEN_VERSION_NUMBER=`expr $LIBXEN_MAJOR_VERSION \* 10000 + $LIBXEN_MINOR_VERSION \* 100 + $LIBXEN_MICRO_VERSION` + +if test -f CVS/Entries; then + extra=`grep ChangeLog CVS/Entries | grep -v LIBXEN | sed -e s\%/ChangeLog/1\.%% -e s\%/.*$%%` + echo extra=$extra + if test "$extra" != "" + then + LIBXEN_VERSION_EXTRA="-CVS$extra" + fi +fi + +AC_SUBST(LIBXEN_MAJOR_VERSION) +AC_SUBST(LIBXEN_MINOR_VERSION) +AC_SUBST(LIBXEN_MICRO_VERSION) +AC_SUBST(LIBXEN_VERSION) +AC_SUBST(LIBXEN_VERSION_INFO) +AC_SUBST(LIBXEN_VERSION_NUMBER) +AC_SUBST(LIBXEN_VERSION_EXTRA) + +VERSION=${LIBXEN_VERSION} + +AM_INIT_AUTOMAKE(libxen, $VERSION) + diff --git a/docs/Plan b/docs/Plan new file mode 100644 index 0000000000..35e00f8397 --- /dev/null +++ b/docs/Plan @@ -0,0 +1,4 @@ +1/ go for a minimal library first, expand on use cases +2/ reuse xenctrl.h / libxenctrl in a first implementation, but make + sure to clearly isolate the bits calling them +3/ diff --git a/docs/analysis b/docs/analysis new file mode 100644 index 0000000000..35e22d0469 --- /dev/null +++ b/docs/analysis @@ -0,0 +1,33 @@ +arch/xen/kernel/evtchn.c: Communication via Xen event channels +->HYPERVISOR_xen_version call +->HYPERVISOR_physdev_op call +->HYPERVISOR_event_channel_op call +-> global HYPERVISOR_shared_info + +arch/xen/kernel/fixup.c: binary rewrinting for threads TLS +-> message to suppress... + boot delay + +arch/xen/kernel/gnttab.c: memory access and sharing + inline assemby from privcmd.c using TRAP_INSTR macro to do an hypervisor + call apparently. + +arch/xen/kernel/reboot.c: +-> HYPERVISOR_suspend call + +include/asm-xen/asm-i386/hypercall.h: +-> assembly macro for the hypervisor calls + +tools/libxc/xc_*.c: library for xen control + +tools/libxc/xc_private.h: + -> Xen hypervisor call is an ioctl() with an privcmd_hypercall_t parameter + xc_domain.c: + -> API for all domain supervisor calls, create, memory, cpu weight, destroy + +=> Fraser all over the place ... + +/Xen/xen-unstable.hg/tools/libxc + + + The hypervisor calls are defined as inlined functions in xc_private.h +This is GPL and not installed. diff --git a/docs/library.xen b/docs/library.xen new file mode 100644 index 0000000000..aa2c822f76 --- /dev/null +++ b/docs/library.xen @@ -0,0 +1,101 @@ + + About a libxen library + ====================== + +Functional description: +----------------------- + + Small C library to be able to control Xen Linux guest, i.e. + provide the following operations for Xen guest domains running Linux + from domain 0 code linked to the library (running as root): + - start + - stop + - suspend + - resume + - monitor + More advanced features should be allowed as future extensions, but + are not expected to be provided in first shipment. + + Open enough Licence that customers can link their apps to it (LGPL) + + Small and contained enough that we can use it as a way to + provide API and ABI stability in spite if the evolution of Xen + existing API and hypervisor calls. + +The current state of Xen userland: +---------------------------------- + + the existing Xen 3.0 userland code is mostly based on tiny C functions +using direct hypervisor calls (or /proc/xen/ interfaces) and a lot of +Python code on top driving the hypervisor. + The C code is relatively hairy, functions with 10 parameters or more +are not uncommon, and it is very low level usually without comment about +the function or its arguments. They are usually only called once in the +whole tree by the python bindings. In essence it looks like the Xen project +was not implemented with the idea of reusing that part of the code by +applications. + Indeed most of the userland code coming with Xen is built on Python, +like xend the xen daemon running on domain 0 or the xenstored daemon which +manage the state of the domains launched. + +Rebuilding a library ?: +----------------------- + + Providing a library at the C level to drive domain execution is in a +very large part a rimplementation of existing code but in a different way +and somehow with different goals for the code. The existing Licence (GPL) +makes it uneasy, we can't copy GPL code to put it in a LGPL'ed library, +and rewriting everything while looking at the Xen code will inevitably +lead to code similarities especially with this kind of system code. Plus +we will still need to run xend and probably xenstored to not diverge +completely from Xen existing code base. + +The IBM way: +------------ + + Here is supposition about code that I can't instanciate except by looking +at said code but it looks that IBM also needed a C programmatic API to +manage the Xen domain definitions. Their solution was to build (Rusty +Russell did this) an LGPL C API connecting directly to the xenstore +daemon (./tools/xenstore/*). In a way this is quite more fragile as it depends +on the whole existing stack of the Xen code, but it isolate the API +from the implementation details of the current Xen source (API in +./tools/xenstore/xs.h). The goal seems to be more about testing and controlling +the xen store daemon, but it shows a different approach to decouple client +API/ABI from the Xen existing code. + +Open question: +--------------- + + To what extent should libxen be a rewrite or an isolation layer around +some of the existing code ? + + Rewrite: + + Pros: + - avoid the GPL Licence problem potentially more users + - allow do build a cleaner more stable layer + - the existing code is frigthening + Cons: + - awful lot of work debugging very hard + - will still require existing Xen code to be running + - splitting interfaces is hard politically and lower the + Open Source efforts toward the project + + Wrappers on top of existing code: + + Pros: + - much smaller code rewrite + - benefits from the bugfixes injected by other patchers upstream + Cons: + - Licence constraint GPL only for apps + - API/ABI isolation may not be easier in that way + + Potentially the API could be implemented as a layer on top of the existing +libxc C code library and then progressively migrating out the existing +dependance to Xen code as the interfaces stabilize. + +Daniel Veillard + +Mon Oct 24 18:40:19 CEST 2005 + diff --git a/include/libxen.h b/include/libxen.h new file mode 100644 index 0000000000..1f74d75ab2 --- /dev/null +++ b/include/libxen.h @@ -0,0 +1,80 @@ +/* + * libxen.h: interface for the libxen library to handle Xen domains + * from a process running in domain 0 + * + * Copyright (C) 2005 Red Hat, Inc. + * + * See COPYING.LIB for the License of this software + * + * Daniel Veillard + */ + +#ifndef __XEN_XENLIB_H__ +#define __XEN_XENLIB_H__ + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * xenConnect: + * + * a xenConnect is a private structure representing a connection to + * the Xen Hypervisor. + */ +typedef struct _xenConnect xenConnect; + +/** + * xenConnectPtr: + * + * a xenConnectPtr is pointer to a xenConnect private structure, this is the + * type used to reference a connection to the Xen Hypervisor in the API. + */ +typedef xenConnect *xenConnectPtr; + +/** + * xenDomain: + * + * a xenDomain is a private structure representing a Xen domain. + */ +typedef struct _xenDomain xenDomain; + +/** + * xenDomainPtr: + * + * a xenDomainPtr is pointer to a xenDomain private structure, this is the + * type used to reference a Xen domain in the API. + */ +typedef xenDomain *xenDomainPtr; + + +/** + * xenDomainFlags: + * + * Flags OR'ed together to provide specific behaviour when creating a + * Domain. + */ +typedef enum { + XEN_DOMAIN_NONE = 0 +} xenDomainFlags; + +/* + * Connection and disconnections to the Hypervisor + */ +xenConnectPtr xenOpenConnect (const char *name); +int xenCloseConnect (xenConnectPtr conn); +unsigned long xenGetVersion (xenConnectPtr conn); + +/* + * Domain creation and destruction + */ +xenDomainPtr xenCreateLinuxDomain (xenConnectPtr conn, + const char *kernel_path, + const char *initrd_path, + const char *cmdline, + unsigned int flags); +#ifdef __cplusplus +} +#endif + +#endif /* __XEN_XENLIB_H__ */ diff --git a/src/Makefile.am b/src/Makefile.am new file mode 100644 index 0000000000..c848c79d0f --- /dev/null +++ b/src/Makefile.am @@ -0,0 +1,8 @@ +## Process this file with automake to produce Makefile.in + +INCLUDES = -I$(top_builddir)/include -I@srcdir@/include + +lib_LTLIBRARIES = libxen.la +libxen_la_LIBADD = +libxen_la_LDFLAGS = -version-info @LIBXML_VERSION_INFO@ +libxen_la_SOURCES = libxen.c diff --git a/src/libxen.c b/src/libxen.c new file mode 100644 index 0000000000..e7d56088b9 --- /dev/null +++ b/src/libxen.c @@ -0,0 +1,76 @@ +/* + * libxen.h: Main interfaces for the libxen library to handle virtualization + * domains from a process running in domain 0 + * + * Copyright (C) 2005 Red Hat, Inc. + * + * See COPYING.LIB for the License of this software + * + * Daniel Veillard + */ + +#include "libxen.h" + +#include "memory.h" +#include "internal.h" + +/* + * TODO: + * - use lock to protect against concurrent accesses ? + * - use reference counting to garantee coherent pointer state ? + */ + +#define XEN_CONNECT_MAGIC 0x4F23DEAD +/** + * _xenConnect: + * + * Internal structure associated to a connection + */ +struct _xenConnect { + unsigned int magic; /* specific value to check */ + int handle; /* internal handle used for hypercall */ +} + +/** + * xenGetConnect: + * @name: optional argument currently unused, pass NULL + * + * This function should be called first to get a connection to the + * Hypervisor + * + * Returns a pointer to the hypervisor connection or NULL in case of error + */ +xenConnectPtr +xenOpenConnect(const char *name ATTRIBUTE_UNUSED) { + return(NULL); +} + +/** + * xenCloseConnect: + * @conn: pointer to the hypervisor connection + * + * This function closes the connection to the Hypervisor. This should + * not be called if further interaction with the Hypervisor are needed + * especially if there is running domain which need further monitoring by + * the application. + * + * Returns 0 in case of success or -1 in case of error. + */ +int +xenCloseConnect(xenConnectPtr conn) { + if ((conn == NULL) || (conn->magic != XEN_CONNECT_MAGIC)) + return(-1); + /* + * TODO: + * Free the domain pointers associated to this connection + */ + conn->magic = -1; + free(conn); + return(0); +} + +/** + * xenGetVersion: + * @conn: pointer to the hypervisor connection + * + * Get the version level of the Hypervisor running