hw/accel: add a per-accelerator callback to change VM accelerator handle
When a confidential virtual machine is reset, a new guest context in the accelerator must be generated post reset. Therefore, the old accelerator guest file handle must be closed and a new one created. To this end, a per-accelerator callback, "rebuild_guest" is introduced that would get called when a confidential guest is reset. Subsequent patches will introduce specific implementation of this callback for KVM accelerator. Signed-off-by: Ani Sinha <anisinha@redhat.com> Link: https://lore.kernel.org/r/20260225035000.385950-4-anisinha@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ani Sinha committed
Feb 25, 2026 at 09:19 UTC
4003e5e65fe0a497705275eba73aef6c89870c82
2 files changed
+39
-1
include/accel/accel-ops.h
+2
@@ -23,6 +23,8 @@ struct AccelClass {
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AccelOpsClass *ops;
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int (*init_machine)(AccelState *as, MachineState *ms);
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+ /* used mainly by confidential guests to rebuild guest state upon reset */
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+ int (*rebuild_guest)(MachineState *ms);
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bool (*cpu_common_realize)(CPUState *cpu, Error **errp);
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void (*cpu_common_unrealize)(CPUState *cpu);
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/* get_stats: Append statistics to @buf */
system/runstate.c
+37
-1
@@ -42,6 +42,7 @@
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#include "qapi/qapi-commands-run-state.h"
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#include "qapi/qapi-events-run-state.h"
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#include "qemu/accel.h"
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+#include "accel/accel-ops.h"
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#include "qemu/error-report.h"
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#include "qemu/job.h"
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#include "qemu/log.h"
@@ -509,6 +510,9 @@ void qemu_system_reset(ShutdownCause reason)
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{
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MachineClass *mc;
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ResetType type;
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+ AccelClass *ac = ACCEL_GET_CLASS(current_accel());
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+ bool guest_state_rebuilt = false;
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+ int ret;
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mc = current_machine ? MACHINE_GET_CLASS(current_machine) : NULL;
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@@ -521,6 +525,29 @@ void qemu_system_reset(ShutdownCause reason)
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default:
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type = RESET_TYPE_COLD;
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}
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+
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+ if (!cpus_are_resettable() &&
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+ (reason == SHUTDOWN_CAUSE_GUEST_RESET ||
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+ reason == SHUTDOWN_CAUSE_HOST_QMP_SYSTEM_RESET)) {
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+ if (ac->rebuild_guest) {
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+ ret = ac->rebuild_guest(current_machine);
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+ if (ret < 0) {
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+ error_report("unable to rebuild guest: %s(%d)",
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+ strerror(-ret), ret);
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+ vm_stop(RUN_STATE_INTERNAL_ERROR);
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+ } else {
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+ info_report("virtual machine state has been rebuilt with new "
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+ "guest file handle.");
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+ guest_state_rebuilt = true;
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+ }
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+ } else if (!cpus_are_resettable()) {
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+ error_report("accelerator does not support reset!");
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+ } else {
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+ error_report("accelerator does not support rebuilding guest state,"
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+ " proceeding with normal reset!");
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+ }
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+ }
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+
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if (mc && mc->reset) {
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mc->reset(current_machine, type);
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} else {
@@ -543,7 +570,16 @@ void qemu_system_reset(ShutdownCause reason)
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* it does _more_ than cpu_synchronize_all_post_reset().
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*/
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if (cpus_are_resettable()) {
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- cpu_synchronize_all_post_reset();
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+ if (guest_state_rebuilt) {
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+ /*
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+ * If guest state has been rebuilt, then we
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+ * need to sync full cpu state for non confidential guests post
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+ * reset.
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+ */
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+ cpu_synchronize_all_post_init();
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+ } else {
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+ cpu_synchronize_all_post_reset();
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+ }
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}
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vm_set_suspended(false);