* Yichen Wang (yichen.w...@bytedance.com) wrote:
> From: Hao Xiang <hao.xi...@linux.dev>
Please split the cpuid stuff out into a separate patch; it feels like
it should be in some x86 specific place.
> Intel DSA offloading is an optional feature that turns on if
> proper hardware and software stack is available. To turn on
> DSA offloading in multifd live migration by setting:
>
> zero-page-detection=dsa-accel
> dsa-accel-path=[dsa_dev_path1] [dsa_dev_path2] ... [dsa_dev_pathX]
I'd like to suggest changing that to:
accel-path=dsa:dev_path1 dsa:dev_path2 somethingelse:dev_path2 etc
that means we don't need a new option when someone adds a different
accelerator.
Dave
> This feature is turned off by default.
>
> Signed-off-by: Hao Xiang <hao.xi...@linux.dev>
> Signed-off-by: Yichen Wang <yichen.w...@bytedance.com>
> ---
> hmp-commands.hx | 2 +-
> include/qemu/dsa.h | 13 +++++++++++++
> migration/migration-hmp-cmds.c | 19 ++++++++++++++++++-
> migration/options.c | 30 ++++++++++++++++++++++++++++++
> migration/options.h | 1 +
> qapi/migration.json | 32 ++++++++++++++++++++++++++++----
> util/dsa.c | 31 +++++++++++++++++++++++++++++++
> 7 files changed, 122 insertions(+), 6 deletions(-)
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 06746f0afc..0e04eac7c7 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1009,7 +1009,7 @@ ERST
>
> {
> .name = "migrate_set_parameter",
> - .args_type = "parameter:s,value:s",
> + .args_type = "parameter:s,value:S",
Can you show the case you need this for?
Dave
> .params = "parameter value",
> .help = "Set the parameter for migration",
> .cmd = hmp_migrate_set_parameter,
> diff --git a/include/qemu/dsa.h b/include/qemu/dsa.h
> index a3b502ee41..b1bb6daad2 100644
> --- a/include/qemu/dsa.h
> +++ b/include/qemu/dsa.h
> @@ -100,6 +100,13 @@ void qemu_dsa_stop(void);
> */
> void qemu_dsa_cleanup(void);
>
> +/**
> + * @brief Check if DSA is supported.
> + *
> + * @return True if DSA is supported, otherwise false.
> + */
> +bool qemu_dsa_is_supported(void);
> +
> /**
> * @brief Check if DSA is running.
> *
> @@ -141,6 +148,12 @@ buffer_is_zero_dsa_batch_sync(QemuDsaBatchTask
> *batch_task,
>
> typedef struct QemuDsaBatchTask {} QemuDsaBatchTask;
>
> +static inline bool qemu_dsa_is_supported(void)
> +{
> + return false;
> +}
> +
> +
> static inline bool qemu_dsa_is_running(void)
> {
> return false;
> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
> index 20d1a6e219..983f13b73c 100644
> --- a/migration/migration-hmp-cmds.c
> +++ b/migration/migration-hmp-cmds.c
> @@ -312,7 +312,16 @@ void hmp_info_migrate_parameters(Monitor *mon, const
> QDict *qdict)
> monitor_printf(mon, "%s: '%s'\n",
> MigrationParameter_str(MIGRATION_PARAMETER_TLS_AUTHZ),
> params->tls_authz);
> -
> + if (params->has_dsa_accel_path) {
> + strList *dsa_accel_path = params->dsa_accel_path;
> + monitor_printf(mon, "%s:",
> + MigrationParameter_str(MIGRATION_PARAMETER_DSA_ACCEL_PATH));
> + while (dsa_accel_path) {
> + monitor_printf(mon, " '%s'", dsa_accel_path->value);
> + dsa_accel_path = dsa_accel_path->next;
> + }
> + monitor_printf(mon, "\n");
> + }
> if (params->has_block_bitmap_mapping) {
> const BitmapMigrationNodeAliasList *bmnal;
>
> @@ -563,6 +572,14 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict
> *qdict)
> p->has_x_checkpoint_delay = true;
> visit_type_uint32(v, param, &p->x_checkpoint_delay, &err);
> break;
> + case MIGRATION_PARAMETER_DSA_ACCEL_PATH:
> + p->has_dsa_accel_path = true;
> + g_autofree char **strv = g_strsplit(valuestr ? : "", " ", -1);
> + strList **tail = &p->dsa_accel_path;
> + for (int i = 0; strv[i]; i++) {
> + QAPI_LIST_APPEND(tail, strv[i]);
> + }
> + break;
> case MIGRATION_PARAMETER_MULTIFD_CHANNELS:
> p->has_multifd_channels = true;
> visit_type_uint8(v, param, &p->multifd_channels, &err);
> diff --git a/migration/options.c b/migration/options.c
> index 147cd2b8fd..a0b3a7d291 100644
> --- a/migration/options.c
> +++ b/migration/options.c
> @@ -13,6 +13,7 @@
>
> #include "qemu/osdep.h"
> #include "qemu/error-report.h"
> +#include "qemu/dsa.h"
> #include "exec/target_page.h"
> #include "qapi/clone-visitor.h"
> #include "qapi/error.h"
> @@ -832,6 +833,13 @@ const char *migrate_tls_creds(void)
> return s->parameters.tls_creds;
> }
>
> +const strList *migrate_dsa_accel_path(void)
> +{
> + MigrationState *s = migrate_get_current();
> +
> + return s->parameters.dsa_accel_path;
> +}
> +
> const char *migrate_tls_hostname(void)
> {
> MigrationState *s = migrate_get_current();
> @@ -945,6 +953,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error
> **errp)
> params->zero_page_detection = s->parameters.zero_page_detection;
> params->has_direct_io = true;
> params->direct_io = s->parameters.direct_io;
> + params->has_dsa_accel_path = true;
> + params->dsa_accel_path = QAPI_CLONE(strList,
> s->parameters.dsa_accel_path);
>
> return params;
> }
> @@ -953,6 +963,7 @@ void migrate_params_init(MigrationParameters *params)
> {
> params->tls_hostname = g_strdup("");
> params->tls_creds = g_strdup("");
> + params->dsa_accel_path = NULL;
>
> /* Set has_* up only for parameter checks */
> params->has_throttle_trigger_threshold = true;
> @@ -1165,6 +1176,14 @@ bool migrate_params_check(MigrationParameters *params,
> Error **errp)
> return false;
> }
>
> + if (params->has_zero_page_detection &&
> + params->zero_page_detection == ZERO_PAGE_DETECTION_DSA_ACCEL) {
> + if (!qemu_dsa_is_supported()) {
> + error_setg(errp, "DSA acceleration is not supported.");
> + return false;
> + }
> + }
> +
> return true;
> }
>
> @@ -1278,6 +1297,11 @@ static void
> migrate_params_test_apply(MigrateSetParameters *params,
> if (params->has_direct_io) {
> dest->direct_io = params->direct_io;
> }
> +
> + if (params->has_dsa_accel_path) {
> + dest->has_dsa_accel_path = true;
> + dest->dsa_accel_path = params->dsa_accel_path;
> + }
> }
>
> static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
> @@ -1410,6 +1434,12 @@ static void migrate_params_apply(MigrateSetParameters
> *params, Error **errp)
> if (params->has_direct_io) {
> s->parameters.direct_io = params->direct_io;
> }
> + if (params->has_dsa_accel_path) {
> + qapi_free_strList(s->parameters.dsa_accel_path);
> + s->parameters.has_dsa_accel_path = true;
> + s->parameters.dsa_accel_path =
> + QAPI_CLONE(strList, params->dsa_accel_path);
> + }
> }
>
> void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
> diff --git a/migration/options.h b/migration/options.h
> index a0bd6edc06..8198b220bd 100644
> --- a/migration/options.h
> +++ b/migration/options.h
> @@ -86,6 +86,7 @@ const char *migrate_tls_creds(void);
> const char *migrate_tls_hostname(void);
> uint64_t migrate_xbzrle_cache_size(void);
> ZeroPageDetection migrate_zero_page_detection(void);
> +const strList *migrate_dsa_accel_path(void);
>
> /* parameters helpers */
>
> diff --git a/qapi/migration.json b/qapi/migration.json
> index b66cccf107..d8b42ceae6 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -626,10 +626,14 @@
> # multifd migration is enabled, else in the main migration thread
> # as for @legacy.
> #
> +# @dsa-accel: Perform zero page checking with the DSA accelerator
> +# offloading in multifd sender thread if multifd migration is
> +# enabled, else in the main migration thread as for @legacy.
> +#
> # Since: 9.0
> ##
> { 'enum': 'ZeroPageDetection',
> - 'data': [ 'none', 'legacy', 'multifd' ] }
> + 'data': [ 'none', 'legacy', 'multifd', 'dsa-accel' ] }
>
> ##
> # @BitmapMigrationBitmapAliasTransform:
> @@ -837,6 +841,12 @@
> # See description in @ZeroPageDetection. Default is 'multifd'.
> # (since 9.0)
> #
> +# @dsa-accel-path: If enabled, use DSA accelerator offloading for
> +# certain memory operations. Enable DSA accelerator for zero
> +# page detection offloading by setting the @zero-page-detection
> +# to dsa-accel. This parameter defines the dsa device path, and
> +# defaults to an empty list. (Since 9.2)
> +#
> # @direct-io: Open migration files with O_DIRECT when possible. This
> # only has effect if the @mapped-ram capability is enabled.
> # (Since 9.1)
> @@ -855,7 +865,7 @@
> 'cpu-throttle-initial', 'cpu-throttle-increment',
> 'cpu-throttle-tailslow',
> 'tls-creds', 'tls-hostname', 'tls-authz', 'max-bandwidth',
> - 'avail-switchover-bandwidth', 'downtime-limit',
> + 'avail-switchover-bandwidth', 'downtime-limit', 'dsa-accel-path',
> { 'name': 'x-checkpoint-delay', 'features': [ 'unstable' ] },
> 'multifd-channels',
> 'xbzrle-cache-size', 'max-postcopy-bandwidth',
> @@ -1018,6 +1028,12 @@
> # See description in @ZeroPageDetection. Default is 'multifd'.
> # (since 9.0)
> #
> +# @dsa-accel-path: If enabled, use DSA accelerator offloading for
> +# certain memory operations. Enable DSA accelerator for zero
> +# page detection offloading by setting the @zero-page-detection
> +# to dsa-accel. This parameter defines the dsa device path, and
> +# defaults to an empty list. (Since 9.2)
> +#
> # @direct-io: Open migration files with O_DIRECT when possible. This
> # only has effect if the @mapped-ram capability is enabled.
> # (Since 9.1)
> @@ -1063,7 +1079,8 @@
> '*vcpu-dirty-limit': 'uint64',
> '*mode': 'MigMode',
> '*zero-page-detection': 'ZeroPageDetection',
> - '*direct-io': 'bool' } }
> + '*direct-io': 'bool',
> + '*dsa-accel-path': [ 'str' ] } }
>
> ##
> # @migrate-set-parameters:
> @@ -1228,6 +1245,12 @@
> # See description in @ZeroPageDetection. Default is 'multifd'.
> # (since 9.0)
> #
> +# @dsa-accel-path: If enabled, use DSA accelerator offloading for
> +# certain memory operations. Enable DSA accelerator for zero
> +# page detection offloading by setting the @zero-page-detection
> +# to dsa-accel. This parameter defines the dsa device path, and
> +# defaults to an empty list. (Since 9.2)
> +#
> # @direct-io: Open migration files with O_DIRECT when possible. This
> # only has effect if the @mapped-ram capability is enabled.
> # (Since 9.1)
> @@ -1270,7 +1293,8 @@
> '*vcpu-dirty-limit': 'uint64',
> '*mode': 'MigMode',
> '*zero-page-detection': 'ZeroPageDetection',
> - '*direct-io': 'bool' } }
> + '*direct-io': 'bool',
> + '*dsa-accel-path': [ 'str' ] } }
>
> ##
> # @query-migrate-parameters:
> diff --git a/util/dsa.c b/util/dsa.c
> index cbaa47c360..eeede3c0c7 100644
> --- a/util/dsa.c
> +++ b/util/dsa.c
> @@ -23,6 +23,7 @@
> #include "qemu/bswap.h"
> #include "qemu/error-report.h"
> #include "qemu/rcu.h"
> +#include <cpuid.h>
>
> #pragma GCC push_options
> #pragma GCC target("enqcmd")
> @@ -691,6 +692,36 @@ static void dsa_completion_thread_stop(void *opaque)
> qemu_sem_destroy(&thread_context->sem_init_done);
> }
>
> +/**
> + * @brief Check if DSA is supported.
> + *
> + * @return True if DSA is supported, otherwise false.
> + */
> +bool qemu_dsa_is_supported(void)
> +{
> + /*
> + * movdir64b is indicated by bit 28 of ecx in CPUID leaf 7, subleaf 0.
> + * enqcmd is indicated by bit 29 of ecx in CPUID leaf 7, subleaf 0.
> + * Doc: https://cdrdv2-public.intel.com/819680/architecture-instruction-\
> + * set-extensions-programming-reference.pdf
> + */
> + uint32_t eax, ebx, ecx, edx;
> + bool movedirb_enabled;
> + bool enqcmd_enabled;
> +
> + __get_cpuid_count(7, 0, &eax, &ebx, &ecx, &edx);
> + movedirb_enabled = (ecx >> 28) & 0x1;
> + if (!movedirb_enabled) {
> + return false;
> + }
> + enqcmd_enabled = (ecx >> 29) & 0x1;
> + if (!enqcmd_enabled) {
> + return false;
> + }
> +
> + return true;
> +}
> +
> /**
> * @brief Check if DSA is running.
> *
> --
> Yichen Wang
>
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ dave @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
