| Submitter | Michael Roth |
|---|---|
| Date | Jan. 17, 2012, 4:37 p.m. |
| Message ID | <1326818263-21528-2-git-send-email-mdroth@linux.vnet.ibm.com> |
| Download | mbox | patch |
| Permalink | /patch/136499/ |
| State | New |
| Headers | show |
Comments
On Tue, 17 Jan 2012 10:37:43 -0600 Michael Roth <mdroth@linux.vnet.ibm.com> wrote: > Recently commands where introduced on the mailing that involved adding > commands to the guest agent that could potentially break older versions > of QEMU. While it's okay to expect that qemu-ga can be updated to support > newer host features, it's unrealistic to require a host to be updated to > support qemu-ga features, or to expect that qemu-ga should be downgraded > in these circumstances, especially considering that a large mix of > guests/agents may be running on a particular host. > > To address this, we introduce here a mechanism to set qemu-ga's > feature-set to one that is known to be compatible with > the host/QEMU running the guest. As new commands/options are added, we > can maintain backward-compatibility by adding conditional checks to filter > out host-incompatible functionality based on the host-specified support > level (generally analogous to the host QEMU version) set by the > client. > > The current default/minimum support level supports all versions of QEMU > that have had qemu-ga in-tree (0.15.0, 1.0.0) and so should be > backward-compatible with existing hosts/clients. > > Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com> > --- > qapi-schema-guest.json | 67 +++++++++++++++++++++++++++++++++++++++++++- > qemu-ga.c | 46 ++++++++++++++++++++++++++++++ > qga/guest-agent-commands.c | 13 ++++++++ > qga/guest-agent-core.h | 11 +++++++ > 4 files changed, 136 insertions(+), 1 deletions(-) > > diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json > index 706925d..81cd773 100644 > --- a/qapi-schema-guest.json > +++ b/qapi-schema-guest.json > @@ -51,6 +51,27 @@ > 'data': { 'name': 'str', 'enabled': 'bool' } } > > ## > +# @GuestAgentSupportLevel > +# > +# Guest agent support/compatability level (as configured by > +# guest agent defaults of guest-set-support-level command) > +# > +# Three numerical fields describe the support level: > +# > +# <major>.<minor>.<micro> > +# > +# @major: As above > +# > +# @minor: As above > +# > +# @micro: As above > +# > +# Since 1.1.0 > +## > +{ 'type': 'GuestAgentSupportLevel', > + 'data': { 'major': 'int', 'minor': 'int', 'micro': 'int' } } > + > +## > # @GuestAgentInfo > # > # Information about guest agent. > @@ -59,11 +80,17 @@ > # > # @supported_commands: Information about guest agent commands > # > +# @support_level: Current support/compatability level, as set by > +# guest agent defaults or guest-set-support-level > +# command. > +# > # Since 0.15.0 > ## > { 'type': 'GuestAgentInfo', > 'data': { 'version': 'str', > - 'supported_commands': ['GuestAgentCommandInfo'] } } > + 'supported_commands': ['GuestAgentCommandInfo'] > + 'support_level': 'GuestAgentSupportLevel' } } > + > ## > # @guest-info: > # > @@ -77,6 +104,44 @@ > 'returns': 'GuestAgentInfo' } > > ## > +# @guest-set-support-level: > +# > +# Set guest agent feature-set to one that is compatible with/supported by > +# the host. > +# > +# Certain commands/options may have dependencies on host > +# version/support-level, such as specific QEMU features (such > +# dependencies will be noted in this schema). By default we assume 1.0.0, > +# which is backward-compatible with QEMU 0.15.0/1.0, and should be compatible > +# with later versions of QEMU as well. To enable newer guest agent features, > +# this command must be issued to raise the support-level to one corresponding > +# to supported host QEMU/KVM/etc capabilities. > +# > +# The host support-level is generally <= host QEMU version > +# level. Note that undefined behavior may occur if a support-level is > +# provided that exceeds the capabilities of the version of QEMU currently > +# running the guest. Any level specified below 1.0.0 will default to 1.0.0. > +# > +# The currently set support level is obtainable via the guest-info command. > +# > +# Three numerical fields describe the host support/compatability level: > +# > +# <major>.<minor>.<micro> > +# > +# @major: As above > +# > +# @minor: As above > +# > +# @micro: As above > +# > +# Returns: Nothing on success > +# > +# Since: 1.1.0 > +## > +{ 'command': 'guest-set-support-level', > + 'data': { 'major': 'int', 'minor': 'int', '*micro': 'int' } } > + > +## > # @guest-shutdown: > # > # Initiate guest-activated shutdown. Note: this is an asynchronous > diff --git a/qemu-ga.c b/qemu-ga.c > index 29e4f64..8e5b075 100644 > --- a/qemu-ga.c > +++ b/qemu-ga.c > @@ -28,6 +28,7 @@ > #include "qerror.h" > #include "error_int.h" > #include "qapi/qmp-core.h" > +#include "qga-qapi-types.h" > > #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0" > #define QGA_PIDFILE_DEFAULT "/var/run/qemu-ga.pid" > @@ -102,6 +103,45 @@ static void usage(const char *cmd) > > static void conn_channel_close(GAState *s); > > +static GuestAgentSupportLevel ga_support_level; > + > +static int ga_cmp_support_levels(GuestAgentSupportLevel a, > + GuestAgentSupportLevel b) > +{ > + if (a.major == b.major) { > + if (a.minor == b.minor) { > + return a.micro - b.micro; > + } > + return a.minor - b.minor; > + } > + return a.major - b.major; > +} > + > +bool ga_has_support_level(int major, int minor, int micro) > +{ > + const GuestAgentSupportLevel level = { major, minor, micro }; > + return ga_cmp_support_levels(ga_support_level, level) >= 0; > +} > + > +void ga_set_support_level(GuestAgentSupportLevel level) > +{ > + const GuestAgentSupportLevel min_support_level = { > + QGA_SUPPORT_LEVEL_MAJOR_MIN, > + QGA_SUPPORT_LEVEL_MINOR_MIN, > + QGA_SUPPORT_LEVEL_MICRO_MIN > + }; > + if (ga_cmp_support_levels(level, min_support_level) <= 0) { > + ga_support_level = min_support_level; > + } else { > + ga_support_level = level; > + } > +} > + > +GuestAgentSupportLevel ga_get_support_level(void) > +{ > + return ga_support_level; > +} > + > static const char *ga_log_level_str(GLogLevelFlags level) > { > switch (level & G_LOG_LEVEL_MASK) { > @@ -569,6 +609,11 @@ int main(int argc, char **argv) > GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL; > FILE *log_file = stderr; > GAState *s; > + const GuestAgentSupportLevel default_support_level = { > + QGA_SUPPORT_LEVEL_MAJOR_DEFAULT, > + QGA_SUPPORT_LEVEL_MINOR_DEFAULT, > + QGA_SUPPORT_LEVEL_MICRO_DEFAULT > + }; > > module_call_init(MODULE_INIT_QAPI); > > @@ -642,6 +687,7 @@ int main(int argc, char **argv) > become_daemon(pidfile); > } > > + ga_set_support_level(default_support_level); > s = g_malloc0(sizeof(GAState)); > s->conn_channel = NULL; > s->path = path; > diff --git a/qga/guest-agent-commands.c b/qga/guest-agent-commands.c > index a09c8ca..656dde8 100644 > --- a/qga/guest-agent-commands.c > +++ b/qga/guest-agent-commands.c > @@ -62,6 +62,8 @@ struct GuestAgentInfo *qmp_guest_info(Error **err) > char **cmd_list_head, **cmd_list; > > info->version = g_strdup(QGA_VERSION); > + info->support_level = g_malloc0(sizeof(GuestAgentSupportLevel)); > + *info->support_level = ga_get_support_level(); > > cmd_list_head = cmd_list = qmp_get_command_list(); > if (*cmd_list_head == NULL) { > @@ -87,6 +89,17 @@ out: > return info; > } > > +void qmp_guest_set_support_level(int64_t major, int64_t minor, bool has_micro, > + int64_t micro, Error **errp) > +{ > + GuestAgentSupportLevel level = { > + major, > + minor, > + has_micro ? micro : 0 > + }; > + ga_set_support_level(level); > +} > + > void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err) > { > int ret; > diff --git a/qga/guest-agent-core.h b/qga/guest-agent-core.h > index e42b91d..7327e73 100644 > --- a/qga/guest-agent-core.h > +++ b/qga/guest-agent-core.h > @@ -12,8 +12,16 @@ > */ > #include "qapi/qmp-core.h" > #include "qemu-common.h" > +#include "qga-qapi-types.h" > > #define QGA_VERSION "1.0" > +#define QGA_SUPPORT_LEVEL_MAJOR_DEFAULT 1 > +#define QGA_SUPPORT_LEVEL_MINOR_DEFAULT 0 > +#define QGA_SUPPORT_LEVEL_MICRO_DEFAULT 0 > +/* lowest possible support level */ > +#define QGA_SUPPORT_LEVEL_MAJOR_MIN 1 > +#define QGA_SUPPORT_LEVEL_MINOR_MIN 0 > +#define QGA_SUPPORT_LEVEL_MICRO_MIN 0 > #define QGA_READ_COUNT_DEFAULT 4 << 10 > > typedef struct GAState GAState; > @@ -29,3 +37,6 @@ GACommandState *ga_command_state_new(void); > bool ga_logging_enabled(GAState *s); > void ga_disable_logging(GAState *s); > void ga_enable_logging(GAState *s); > +bool ga_has_support_level(int major, int minor, int micro); > +void ga_set_support_level(GuestAgentSupportLevel level); > +GuestAgentSupportLevel ga_get_support_level(void);
Patch
diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json index 706925d..81cd773 100644 --- a/qapi-schema-guest.json +++ b/qapi-schema-guest.json @@ -51,6 +51,27 @@ 'data': { 'name': 'str', 'enabled': 'bool' } } ## +# @GuestAgentSupportLevel +# +# Guest agent support/compatability level (as configured by +# guest agent defaults of guest-set-support-level command) +# +# Three numerical fields describe the support level: +# +# <major>.<minor>.<micro> +# +# @major: As above +# +# @minor: As above +# +# @micro: As above +# +# Since 1.1.0 +## +{ 'type': 'GuestAgentSupportLevel', + 'data': { 'major': 'int', 'minor': 'int', 'micro': 'int' } } + +## # @GuestAgentInfo # # Information about guest agent. @@ -59,11 +80,17 @@ # # @supported_commands: Information about guest agent commands # +# @support_level: Current support/compatability level, as set by +# guest agent defaults or guest-set-support-level +# command. +# # Since 0.15.0 ## { 'type': 'GuestAgentInfo', 'data': { 'version': 'str', - 'supported_commands': ['GuestAgentCommandInfo'] } } + 'supported_commands': ['GuestAgentCommandInfo'] + 'support_level': 'GuestAgentSupportLevel' } } + ## # @guest-info: # @@ -77,6 +104,44 @@ 'returns': 'GuestAgentInfo' } ## +# @guest-set-support-level: +# +# Set guest agent feature-set to one that is compatible with/supported by +# the host. +# +# Certain commands/options may have dependencies on host +# version/support-level, such as specific QEMU features (such +# dependencies will be noted in this schema). By default we assume 1.0.0, +# which is backward-compatible with QEMU 0.15.0/1.0, and should be compatible +# with later versions of QEMU as well. To enable newer guest agent features, +# this command must be issued to raise the support-level to one corresponding +# to supported host QEMU/KVM/etc capabilities. +# +# The host support-level is generally <= host QEMU version +# level. Note that undefined behavior may occur if a support-level is +# provided that exceeds the capabilities of the version of QEMU currently +# running the guest. Any level specified below 1.0.0 will default to 1.0.0. +# +# The currently set support level is obtainable via the guest-info command. +# +# Three numerical fields describe the host support/compatability level: +# +# <major>.<minor>.<micro> +# +# @major: As above +# +# @minor: As above +# +# @micro: As above +# +# Returns: Nothing on success +# +# Since: 1.1.0 +## +{ 'command': 'guest-set-support-level', + 'data': { 'major': 'int', 'minor': 'int', '*micro': 'int' } } + +## # @guest-shutdown: # # Initiate guest-activated shutdown. Note: this is an asynchronous diff --git a/qemu-ga.c b/qemu-ga.c index 29e4f64..8e5b075 100644 --- a/qemu-ga.c +++ b/qemu-ga.c @@ -28,6 +28,7 @@ #include "qerror.h" #include "error_int.h" #include "qapi/qmp-core.h" +#include "qga-qapi-types.h" #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0" #define QGA_PIDFILE_DEFAULT "/var/run/qemu-ga.pid" @@ -102,6 +103,45 @@ static void usage(const char *cmd) static void conn_channel_close(GAState *s); +static GuestAgentSupportLevel ga_support_level; + +static int ga_cmp_support_levels(GuestAgentSupportLevel a, + GuestAgentSupportLevel b) +{ + if (a.major == b.major) { + if (a.minor == b.minor) { + return a.micro - b.micro; + } + return a.minor - b.minor; + } + return a.major - b.major; +} + +bool ga_has_support_level(int major, int minor, int micro) +{ + const GuestAgentSupportLevel level = { major, minor, micro }; + return ga_cmp_support_levels(ga_support_level, level) >= 0; +} + +void ga_set_support_level(GuestAgentSupportLevel level) +{ + const GuestAgentSupportLevel min_support_level = { + QGA_SUPPORT_LEVEL_MAJOR_MIN, + QGA_SUPPORT_LEVEL_MINOR_MIN, + QGA_SUPPORT_LEVEL_MICRO_MIN + }; + if (ga_cmp_support_levels(level, min_support_level) <= 0) { + ga_support_level = min_support_level; + } else { + ga_support_level = level; + } +} + +GuestAgentSupportLevel ga_get_support_level(void) +{ + return ga_support_level; +} + static const char *ga_log_level_str(GLogLevelFlags level) { switch (level & G_LOG_LEVEL_MASK) { @@ -569,6 +609,11 @@ int main(int argc, char **argv) GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL; FILE *log_file = stderr; GAState *s; + const GuestAgentSupportLevel default_support_level = { + QGA_SUPPORT_LEVEL_MAJOR_DEFAULT, + QGA_SUPPORT_LEVEL_MINOR_DEFAULT, + QGA_SUPPORT_LEVEL_MICRO_DEFAULT + }; module_call_init(MODULE_INIT_QAPI); @@ -642,6 +687,7 @@ int main(int argc, char **argv) become_daemon(pidfile); } + ga_set_support_level(default_support_level); s = g_malloc0(sizeof(GAState)); s->conn_channel = NULL; s->path = path; diff --git a/qga/guest-agent-commands.c b/qga/guest-agent-commands.c index a09c8ca..656dde8 100644 --- a/qga/guest-agent-commands.c +++ b/qga/guest-agent-commands.c @@ -62,6 +62,8 @@ struct GuestAgentInfo *qmp_guest_info(Error **err) char **cmd_list_head, **cmd_list; info->version = g_strdup(QGA_VERSION); + info->support_level = g_malloc0(sizeof(GuestAgentSupportLevel)); + *info->support_level = ga_get_support_level(); cmd_list_head = cmd_list = qmp_get_command_list(); if (*cmd_list_head == NULL) { @@ -87,6 +89,17 @@ out: return info; } +void qmp_guest_set_support_level(int64_t major, int64_t minor, bool has_micro, + int64_t micro, Error **errp) +{ + GuestAgentSupportLevel level = { + major, + minor, + has_micro ? micro : 0 + }; + ga_set_support_level(level); +} + void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err) { int ret; diff --git a/qga/guest-agent-core.h b/qga/guest-agent-core.h index e42b91d..7327e73 100644 --- a/qga/guest-agent-core.h +++ b/qga/guest-agent-core.h @@ -12,8 +12,16 @@ */ #include "qapi/qmp-core.h" #include "qemu-common.h" +#include "qga-qapi-types.h" #define QGA_VERSION "1.0" +#define QGA_SUPPORT_LEVEL_MAJOR_DEFAULT 1 +#define QGA_SUPPORT_LEVEL_MINOR_DEFAULT 0 +#define QGA_SUPPORT_LEVEL_MICRO_DEFAULT 0 +/* lowest possible support level */ +#define QGA_SUPPORT_LEVEL_MAJOR_MIN 1 +#define QGA_SUPPORT_LEVEL_MINOR_MIN 0 +#define QGA_SUPPORT_LEVEL_MICRO_MIN 0 #define QGA_READ_COUNT_DEFAULT 4 << 10 typedef struct GAState GAState; @@ -29,3 +37,6 @@ GACommandState *ga_command_state_new(void); bool ga_logging_enabled(GAState *s); void ga_disable_logging(GAState *s); void ga_enable_logging(GAState *s); +bool ga_has_support_level(int major, int minor, int micro); +void ga_set_support_level(GuestAgentSupportLevel level); +GuestAgentSupportLevel ga_get_support_level(void);
Recently commands where introduced on the mailing that involved adding commands to the guest agent that could potentially break older versions of QEMU. While it's okay to expect that qemu-ga can be updated to support newer host features, it's unrealistic to require a host to be updated to support qemu-ga features, or to expect that qemu-ga should be downgraded in these circumstances, especially considering that a large mix of guests/agents may be running on a particular host. To address this, we introduce here a mechanism to set qemu-ga's feature-set to one that is known to be compatible with the host/QEMU running the guest. As new commands/options are added, we can maintain backward-compatibility by adding conditional checks to filter out host-incompatible functionality based on the host-specified support level (generally analogous to the host QEMU version) set by the client. The current default/minimum support level supports all versions of QEMU that have had qemu-ga in-tree (0.15.0, 1.0.0) and so should be backward-compatible with existing hosts/clients. Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> --- qapi-schema-guest.json | 67 +++++++++++++++++++++++++++++++++++++++++++- qemu-ga.c | 46 ++++++++++++++++++++++++++++++ qga/guest-agent-commands.c | 13 ++++++++ qga/guest-agent-core.h | 11 +++++++ 4 files changed, 136 insertions(+), 1 deletions(-)