[RFC Qemu PATCH v2 1/2] spapr: drc: Add support for async hcalls at the drc level
Shivaprasad G Bhat
sbhat at linux.ibm.com
Tue Dec 1 02:16:39 AEDT 2020
The patch adds support for async hcalls at the DRC level for the
spapr devices. To be used by spapr-scm devices in the patch/es to follow.
Signed-off-by: Shivaprasad G Bhat <sbhat at linux.ibm.com>
---
hw/ppc/spapr_drc.c | 149 ++++++++++++++++++++++++++++++++++++++++++++
include/hw/ppc/spapr_drc.h | 25 +++++++
2 files changed, 174 insertions(+)
diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index 77718cde1f..4ecd04f686 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -15,6 +15,7 @@
#include "qapi/qmp/qnull.h"
#include "cpu.h"
#include "qemu/cutils.h"
+#include "qemu/guest-random.h"
#include "hw/ppc/spapr_drc.h"
#include "qom/object.h"
#include "migration/vmstate.h"
@@ -421,6 +422,148 @@ void spapr_drc_detach(SpaprDrc *drc)
spapr_drc_release(drc);
}
+
+/*
+ * @drc : device DRC targetting which the async hcalls to be made.
+ *
+ * All subsequent requests to run/query the status should use the
+ * unique token returned here.
+ */
+uint64_t spapr_drc_get_new_async_hcall_token(SpaprDrc *drc)
+{
+ Error *err = NULL;
+ uint64_t token;
+ SpaprDrcDeviceAsyncHCallState *tmp, *next, *state;
+
+ state = g_malloc0(sizeof(*state));
+ state->pending = true;
+
+ qemu_mutex_lock(&drc->async_hcall_states_lock);
+retry:
+ if (qemu_guest_getrandom(&token, sizeof(token), &err) < 0) {
+ error_report_err(err);
+ g_free(state);
+ qemu_mutex_unlock(&drc->async_hcall_states_lock);
+ return 0;
+ }
+
+ if (!token) /* Token should be non-zero */
+ goto retry;
+
+ if (!QLIST_EMPTY(&drc->async_hcall_states)) {
+ QLIST_FOREACH_SAFE(tmp, &drc->async_hcall_states, node, next) {
+ if (tmp->continue_token == token) {
+ /* If the token already in use, get a new one */
+ goto retry;
+ }
+ }
+ }
+
+ state->continue_token = token;
+ QLIST_INSERT_HEAD(&drc->async_hcall_states, state, node);
+
+ qemu_mutex_unlock(&drc->async_hcall_states_lock);
+
+ return state->continue_token;
+}
+
+static void *spapr_drc_async_hcall_runner(void *opaque)
+{
+ int response = -1;
+ SpaprDrcDeviceAsyncHCallState *state = opaque;
+
+ /*
+ * state is freed only after this thread finishes(after pthread_join()),
+ * don't worry about it becoming NULL.
+ */
+
+ response = state->func(state->data);
+
+ state->hcall_ret = response;
+ state->pending = 0;
+
+ return NULL;
+}
+
+/*
+ * @drc : device DRC targetting which the async hcalls to be made.
+ * token : The continue token to be used for tracking as recived from
+ * spapr_drc_get_new_async_hcall_token
+ * @func() : the worker function which needs to be executed asynchronously
+ * @data : data to be passed to the asynchronous function. Worker is supposed
+ * to free/cleanup the data that is passed here
+ */
+void spapr_drc_run_async_hcall(SpaprDrc *drc, uint64_t token,
+ SpaprDrcAsyncHcallWorkerFunc *func, void *data)
+{
+ SpaprDrcDeviceAsyncHCallState *state;
+
+ qemu_mutex_lock(&drc->async_hcall_states_lock);
+ QLIST_FOREACH(state, &drc->async_hcall_states, node) {
+ if (state->continue_token == token) {
+ state->func = func;
+ state->data = data;
+ qemu_thread_create(&state->thread, "sPAPR Async HCALL",
+ spapr_drc_async_hcall_runner, state,
+ QEMU_THREAD_JOINABLE);
+ break;
+ }
+ }
+ qemu_mutex_unlock(&drc->async_hcall_states_lock);
+}
+
+/*
+ * spapr_drc_finish_async_hcalls
+ * Waits for all pending async requests to complete
+ * thier execution and free the states
+ */
+static void spapr_drc_finish_async_hcalls(SpaprDrc *drc)
+{
+ SpaprDrcDeviceAsyncHCallState *state, *next;
+
+ if (QLIST_EMPTY(&drc->async_hcall_states)) {
+ return;
+ }
+
+ qemu_mutex_lock(&drc->async_hcall_states_lock);
+ QLIST_FOREACH_SAFE(state, &drc->async_hcall_states, node, next) {
+ qemu_thread_join(&state->thread);
+ QLIST_REMOVE(state, node);
+ g_free(state);
+ }
+ qemu_mutex_unlock(&drc->async_hcall_states_lock);
+}
+
+/*
+ * spapr_drc_get_async_hcall_status
+ * Fetches the status of the hcall worker and returns H_BUSY
+ * if the worker is still running.
+ */
+int spapr_drc_get_async_hcall_status(SpaprDrc *drc, uint64_t token)
+{
+ int ret = H_PARAMETER;
+ SpaprDrcDeviceAsyncHCallState *state, *node;
+
+ qemu_mutex_lock(&drc->async_hcall_states_lock);
+ QLIST_FOREACH_SAFE(state, &drc->async_hcall_states, node, node) {
+ if (state->continue_token == token) {
+ if (state->pending) {
+ ret = H_BUSY;
+ break;
+ } else {
+ ret = state->hcall_ret;
+ qemu_thread_join(&state->thread);
+ QLIST_REMOVE(state, node);
+ g_free(state);
+ break;
+ }
+ }
+ }
+ qemu_mutex_unlock(&drc->async_hcall_states_lock);
+
+ return ret;
+}
+
void spapr_drc_reset(SpaprDrc *drc)
{
SpaprDrcClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
@@ -448,6 +591,7 @@ void spapr_drc_reset(SpaprDrc *drc)
drc->ccs_offset = -1;
drc->ccs_depth = -1;
}
+ spapr_drc_finish_async_hcalls(drc);
}
static bool spapr_drc_unplug_requested_needed(void *opaque)
@@ -558,6 +702,7 @@ SpaprDrc *spapr_dr_connector_new(Object *owner, const char *type,
drc->owner = owner;
prop_name = g_strdup_printf("dr-connector[%"PRIu32"]",
spapr_drc_index(drc));
+
object_property_add_child(owner, prop_name, OBJECT(drc));
object_unref(OBJECT(drc));
qdev_realize(DEVICE(drc), NULL, NULL);
@@ -577,6 +722,10 @@ static void spapr_dr_connector_instance_init(Object *obj)
object_property_add(obj, "fdt", "struct", prop_get_fdt,
NULL, NULL, NULL);
drc->state = drck->empty_state;
+
+ qemu_mutex_init(&drc->async_hcall_states_lock);
+ QLIST_INIT(&drc->async_hcall_states);
+
}
static void spapr_dr_connector_class_init(ObjectClass *k, void *data)
diff --git a/include/hw/ppc/spapr_drc.h b/include/hw/ppc/spapr_drc.h
index 165b281496..77f6e4386c 100644
--- a/include/hw/ppc/spapr_drc.h
+++ b/include/hw/ppc/spapr_drc.h
@@ -18,6 +18,7 @@
#include "sysemu/runstate.h"
#include "hw/qdev-core.h"
#include "qapi/error.h"
+#include "block/thread-pool.h"
#define TYPE_SPAPR_DR_CONNECTOR "spapr-dr-connector"
#define SPAPR_DR_CONNECTOR_GET_CLASS(obj) \
@@ -168,6 +169,21 @@ typedef enum {
SPAPR_DRC_STATE_PHYSICAL_CONFIGURED = 8,
} SpaprDrcState;
+typedef struct SpaprDrc SpaprDrc;
+
+typedef int SpaprDrcAsyncHcallWorkerFunc(void *opaque);
+typedef struct SpaprDrcDeviceAsyncHCallState {
+ uint64_t continue_token;
+ bool pending;
+
+ int hcall_ret;
+ SpaprDrcAsyncHcallWorkerFunc *func;
+ void *data;
+
+ QemuThread thread;
+
+ QLIST_ENTRY(SpaprDrcDeviceAsyncHCallState) node;
+} SpaprDrcDeviceAsyncHCallState;
typedef struct SpaprDrc {
/*< private >*/
DeviceState parent;
@@ -182,6 +198,10 @@ typedef struct SpaprDrc {
int ccs_offset;
int ccs_depth;
+ /* async hcall states */
+ QemuMutex async_hcall_states_lock;
+ QLIST_HEAD(, SpaprDrcDeviceAsyncHCallState) async_hcall_states;
+
/* device pointer, via link property */
DeviceState *dev;
bool unplug_requested;
@@ -241,6 +261,11 @@ void spapr_drc_detach(SpaprDrc *drc);
/* Returns true if a hot plug/unplug request is pending */
bool spapr_drc_transient(SpaprDrc *drc);
+uint64_t spapr_drc_get_new_async_hcall_token(SpaprDrc *drc);
+void spapr_drc_run_async_hcall(SpaprDrc *drc, uint64_t token,
+ SpaprDrcAsyncHcallWorkerFunc, void *data);
+int spapr_drc_get_async_hcall_status(SpaprDrc *drc, uint64_t token);
+
static inline bool spapr_drc_unplug_requested(SpaprDrc *drc)
{
return drc->unplug_requested;
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