[PULL 0/6] Host Memory Backends and Memory devices queue 2024-09-24

[PULL 0/6] Host Memory Backends and Memory devices queue 2024-09-24

[David Hildenbrand]

Hi,

due to reset changes this contains a bit of churn that touches various
architectures, but it's all fairly minimal and straight-forward.

The following changes since commit 01dc65a3bc262ab1bec8fe89775e9bbfa627becb:

  Merge tag 'pull-target-arm-20240919' of https://git.linaro.org/people/pmaydell/qemu-arm into staging (2024-09-19 14:15:15 +0100)

are available in the Git repository at:

  https://github.com/davidhildenbrand/qemu.git tags/mem-2024-09-24

for you to fetch changes up to 78c8f780d3f0d6d17aa93d6f99ff72960080fdd7:

  hostmem: Apply merge property after the memory region is initialized (2024-09-24 11:33:35 +0200)

----------------------------------------------------------------
Hi,

"Host Memory Backends" and "Memory devices" queue ("mem"):
- Kconfig fix for virtio-based memory devices
- virtio-mem support for suspend+wake-up with plugged memory
- hostmem fix when specifying "merge=off"

----------------------------------------------------------------
Gavin Shan (1):
      hostmem: Apply merge property after the memory region is initialized

Juraj Marcin (4):
      reset: Use ResetType for qemu_devices_reset() and MachineClass::reset()
      reset: Add RESET_TYPE_WAKEUP
      virtio-mem: Use new Resettable framework instead of LegacyReset
      virtio-mem: Add support for suspend+wake-up with plugged memory

Paolo Bonzini (1):
      virtio: kconfig: memory devices are PCI only

 backends/hostmem.c             |  2 +-
 docs/devel/reset.rst           | 12 ++++++++++-
 hw/arm/aspeed.c                |  4 ++--
 hw/arm/mps2-tz.c               |  4 ++--
 hw/core/reset.c                |  5 +----
 hw/hppa/machine.c              |  4 ++--
 hw/i386/microvm.c              |  4 ++--
 hw/i386/pc.c                   |  6 +++---
 hw/ppc/pegasos2.c              |  4 ++--
 hw/ppc/pnv.c                   |  4 ++--
 hw/ppc/spapr.c                 |  6 +++---
 hw/s390x/s390-virtio-ccw.c     |  4 ++--
 hw/virtio/Kconfig              | 11 ++++++++++
 hw/virtio/virtio-mem.c         | 48 ++++++++++++++++++++++++++++++------------
 hw/virtio/virtio-qmp.c         |  3 +++
 include/hw/boards.h            |  3 ++-
 include/hw/resettable.h        |  2 ++
 include/hw/virtio/virtio-mem.h |  4 ++++
 include/sysemu/reset.h         |  5 +++--
 system/runstate.c              | 13 ++++++++++--
 20 files changed, 103 insertions(+), 45 deletions(-)
-- 
2.46.1

[PULL 1/6] virtio: kconfig: memory devices are PCI only

[David Hildenbrand]

From: Paolo Bonzini <pbonzini@redhat.com>

Virtio memory devices rely on PCI BARs to expose the contents of memory.
Because of this they cannot be used (yet) with virtio-mmio or virtio-ccw.
In fact the code that is common to virtio-mem and virtio-pmem, which
is in hw/virtio/virtio-md-pci.c, is only included if CONFIG_VIRTIO_PCI
is set.  Reproduce the same condition in the Kconfig file, only allowing
VIRTIO_MEM and VIRTIO_PMEM to be defined if the transport supports it.

Without this patch it is possible to create a configuration with
CONFIG_VIRTIO_PCI=n and CONFIG_VIRTIO_MEM=y, but that causes a
linking failure.

Message-ID: <20240906101658.514470-1-pbonzini@redhat.com>
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/virtio/Kconfig | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig
index aa63ff7fd4..0afec2ae92 100644
--- a/hw/virtio/Kconfig
+++ b/hw/virtio/Kconfig
@@ -16,6 +16,7 @@ config VIRTIO_PCI
     default y if PCI_DEVICES
     depends on PCI
     select VIRTIO
+    select VIRTIO_MD_SUPPORTED
 
 config VIRTIO_MMIO
     bool
@@ -35,10 +36,17 @@ config VIRTIO_CRYPTO
     default y
     depends on VIRTIO
 
+# not all virtio transports support memory devices; if none does,
+# no need to include the code
+config VIRTIO_MD_SUPPORTED
+    bool
+
 config VIRTIO_MD
     bool
+    depends on VIRTIO_MD_SUPPORTED
     select MEM_DEVICE
 
+# selected by the board if it has the required support code
 config VIRTIO_PMEM_SUPPORTED
     bool
 
@@ -46,9 +54,11 @@ config VIRTIO_PMEM
     bool
     default y
     depends on VIRTIO
+    depends on VIRTIO_MD_SUPPORTED
     depends on VIRTIO_PMEM_SUPPORTED
     select VIRTIO_MD
 
+# selected by the board if it has the required support code
 config VIRTIO_MEM_SUPPORTED
     bool
 
@@ -57,6 +67,7 @@ config VIRTIO_MEM
     default y
     depends on VIRTIO
     depends on LINUX
+    depends on VIRTIO_MD_SUPPORTED
     depends on VIRTIO_MEM_SUPPORTED
     select VIRTIO_MD
 
-- 
2.46.1

[PULL 2/6] reset: Use ResetType for qemu_devices_reset() and MachineClass::reset()

[David Hildenbrand]

From: Juraj Marcin <jmarcin@redhat.com>

Currently, both qemu_devices_reset() and MachineClass::reset() use
ShutdownCause for the reason of the reset. However, the Resettable
interface uses ResetState, so ShutdownCause needs to be translated to
ResetType somewhere. Translating it qemu_devices_reset() makes adding
new reset types harder, as they cannot always be matched to a single
ShutdownCause here, and devices may need to check the ResetType to
determine what to reset and if to reset at all.

This patch moves this translation up in the call stack to
qemu_system_reset() and updates all MachineClass children to use the
ResetType instead.

Message-ID: <20240904103722.946194-2-jmarcin@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/arm/aspeed.c            |  4 ++--
 hw/arm/mps2-tz.c           |  4 ++--
 hw/core/reset.c            |  5 +----
 hw/hppa/machine.c          |  4 ++--
 hw/i386/microvm.c          |  4 ++--
 hw/i386/pc.c               |  6 +++---
 hw/ppc/pegasos2.c          |  4 ++--
 hw/ppc/pnv.c               |  4 ++--
 hw/ppc/spapr.c             |  6 +++---
 hw/s390x/s390-virtio-ccw.c |  4 ++--
 include/hw/boards.h        |  3 ++-
 include/sysemu/reset.h     |  5 +++--
 system/runstate.c          | 13 +++++++++++--
 13 files changed, 37 insertions(+), 29 deletions(-)

diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c
index 3d13b16768..cf0c6c580b 100644
--- a/hw/arm/aspeed.c
+++ b/hw/arm/aspeed.c
@@ -1529,12 +1529,12 @@ static void aspeed_machine_bletchley_class_init(ObjectClass *oc, void *data)
     aspeed_machine_class_init_cpus_defaults(mc);
 }
 
-static void fby35_reset(MachineState *state, ShutdownCause reason)
+static void fby35_reset(MachineState *state, ResetType type)
 {
     AspeedMachineState *bmc = ASPEED_MACHINE(state);
     AspeedGPIOState *gpio = &bmc->soc->gpio;
 
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
 
     /* Board ID: 7 (Class-1, 4 slots) */
     object_property_set_bool(OBJECT(gpio), "gpioV4", true, &error_fatal);
diff --git a/hw/arm/mps2-tz.c b/hw/arm/mps2-tz.c
index aec57c0d68..8edf57a66d 100644
--- a/hw/arm/mps2-tz.c
+++ b/hw/arm/mps2-tz.c
@@ -1254,7 +1254,7 @@ static void mps2_set_remap(Object *obj, const char *value, Error **errp)
     }
 }
 
-static void mps2_machine_reset(MachineState *machine, ShutdownCause reason)
+static void mps2_machine_reset(MachineState *machine, ResetType type)
 {
     MPS2TZMachineState *mms = MPS2TZ_MACHINE(machine);
 
@@ -1264,7 +1264,7 @@ static void mps2_machine_reset(MachineState *machine, ShutdownCause reason)
      * reset see the correct mapping.
      */
     remap_memory(mms, mms->remap);
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
 }
 
 static void mps2tz_class_init(ObjectClass *oc, void *data)
diff --git a/hw/core/reset.c b/hw/core/reset.c
index 58dfc8db3d..14a2639fbf 100644
--- a/hw/core/reset.c
+++ b/hw/core/reset.c
@@ -170,11 +170,8 @@ void qemu_unregister_resettable(Object *obj)
     resettable_container_remove(get_root_reset_container(), obj);
 }
 
-void qemu_devices_reset(ShutdownCause reason)
+void qemu_devices_reset(ResetType type)
 {
-    ResetType type = (reason == SHUTDOWN_CAUSE_SNAPSHOT_LOAD) ?
-        RESET_TYPE_SNAPSHOT_LOAD : RESET_TYPE_COLD;
-
     /* Reset the simulation */
     resettable_reset(OBJECT(get_root_reset_container()), type);
 }
diff --git a/hw/hppa/machine.c b/hw/hppa/machine.c
index 5d0a8739de..8259fe2e38 100644
--- a/hw/hppa/machine.c
+++ b/hw/hppa/machine.c
@@ -642,12 +642,12 @@ static void machine_HP_C3700_init(MachineState *machine)
     machine_HP_common_init_tail(machine, pci_bus, translate);
 }
 
-static void hppa_machine_reset(MachineState *ms, ShutdownCause reason)
+static void hppa_machine_reset(MachineState *ms, ResetType type)
 {
     unsigned int smp_cpus = ms->smp.cpus;
     int i;
 
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
 
     /* Start all CPUs at the firmware entry point.
      *  Monarch CPU will initialize firmware, secondary CPUs
diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index 40edcee7af..8ae4dff7f2 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -462,7 +462,7 @@ static void microvm_machine_state_init(MachineState *machine)
     microvm_devices_init(mms);
 }
 
-static void microvm_machine_reset(MachineState *machine, ShutdownCause reason)
+static void microvm_machine_reset(MachineState *machine, ResetType type)
 {
     MicrovmMachineState *mms = MICROVM_MACHINE(machine);
     CPUState *cs;
@@ -475,7 +475,7 @@ static void microvm_machine_reset(MachineState *machine, ShutdownCause reason)
         mms->kernel_cmdline_fixed = true;
     }
 
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
 
     CPU_FOREACH(cs) {
         cpu = X86_CPU(cs);
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 8d84c22458..79a626a3eb 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1712,12 +1712,12 @@ static void pc_machine_initfn(Object *obj)
     qemu_add_machine_init_done_notifier(&pcms->machine_done);
 }
 
-static void pc_machine_reset(MachineState *machine, ShutdownCause reason)
+static void pc_machine_reset(MachineState *machine, ResetType type)
 {
     CPUState *cs;
     X86CPU *cpu;
 
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
 
     /* Reset APIC after devices have been reset to cancel
      * any changes that qemu_devices_reset() might have done.
@@ -1732,7 +1732,7 @@ static void pc_machine_reset(MachineState *machine, ShutdownCause reason)
 static void pc_machine_wakeup(MachineState *machine)
 {
     cpu_synchronize_all_states();
-    pc_machine_reset(machine, SHUTDOWN_CAUSE_NONE);
+    pc_machine_reset(machine, RESET_TYPE_COLD);
     cpu_synchronize_all_post_reset();
 }
 
diff --git a/hw/ppc/pegasos2.c b/hw/ppc/pegasos2.c
index 9b0a6b70ab..8ff4a00c34 100644
--- a/hw/ppc/pegasos2.c
+++ b/hw/ppc/pegasos2.c
@@ -291,14 +291,14 @@ static void pegasos2_superio_write(uint8_t addr, uint8_t val)
     cpu_physical_memory_write(PCI1_IO_BASE + 0x3f1, &val, 1);
 }
 
-static void pegasos2_machine_reset(MachineState *machine, ShutdownCause reason)
+static void pegasos2_machine_reset(MachineState *machine, ResetType type)
 {
     Pegasos2MachineState *pm = PEGASOS2_MACHINE(machine);
     void *fdt;
     uint64_t d[2];
     int sz;
 
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
     if (!pm->vof) {
         return; /* Firmware should set up machine so nothing to do */
     }
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 3526852685..988fd55d88 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -709,13 +709,13 @@ static void pnv_powerdown_notify(Notifier *n, void *opaque)
     }
 }
 
-static void pnv_reset(MachineState *machine, ShutdownCause reason)
+static void pnv_reset(MachineState *machine, ResetType type)
 {
     PnvMachineState *pnv = PNV_MACHINE(machine);
     IPMIBmc *bmc;
     void *fdt;
 
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
 
     /*
      * The machine should provide by default an internal BMC simulator.
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 8aa3ce7449..2c10a70a48 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1725,7 +1725,7 @@ void spapr_check_mmu_mode(bool guest_radix)
     }
 }
 
-static void spapr_machine_reset(MachineState *machine, ShutdownCause reason)
+static void spapr_machine_reset(MachineState *machine, ResetType type)
 {
     SpaprMachineState *spapr = SPAPR_MACHINE(machine);
     PowerPCCPU *first_ppc_cpu;
@@ -1733,7 +1733,7 @@ static void spapr_machine_reset(MachineState *machine, ShutdownCause reason)
     void *fdt;
     int rc;
 
-    if (reason != SHUTDOWN_CAUSE_SNAPSHOT_LOAD) {
+    if (type != RESET_TYPE_SNAPSHOT_LOAD) {
         /*
          * Record-replay snapshot load must not consume random, this was
          * already replayed from initial machine reset.
@@ -1762,7 +1762,7 @@ static void spapr_machine_reset(MachineState *machine, ShutdownCause reason)
         spapr_setup_hpt(spapr);
     }
 
-    qemu_devices_reset(reason);
+    qemu_devices_reset(type);
 
     spapr_ovec_cleanup(spapr->ov5_cas);
     spapr->ov5_cas = spapr_ovec_new();
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 18240a0fd8..5aa8d207a3 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -440,7 +440,7 @@ static void s390_pv_prepare_reset(S390CcwMachineState *ms)
     s390_pv_prep_reset();
 }
 
-static void s390_machine_reset(MachineState *machine, ShutdownCause reason)
+static void s390_machine_reset(MachineState *machine, ResetType type)
 {
     S390CcwMachineState *ms = S390_CCW_MACHINE(machine);
     enum s390_reset reset_type;
@@ -472,7 +472,7 @@ static void s390_machine_reset(MachineState *machine, ShutdownCause reason)
          * Device reset includes CPU clear resets so this has to be
          * done AFTER the unprotect call above.
          */
-        qemu_devices_reset(reason);
+        qemu_devices_reset(type);
         s390_crypto_reset();
 
         /* configure and start the ipl CPU only */
diff --git a/include/hw/boards.h b/include/hw/boards.h
index ff25c53671..5966069baa 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -10,6 +10,7 @@
 #include "qemu/module.h"
 #include "qom/object.h"
 #include "hw/core/cpu.h"
+#include "hw/resettable.h"
 
 #define TYPE_MACHINE_SUFFIX "-machine"
 
@@ -257,7 +258,7 @@ struct MachineClass {
     const char *deprecation_reason;
 
     void (*init)(MachineState *state);
-    void (*reset)(MachineState *state, ShutdownCause reason);
+    void (*reset)(MachineState *state, ResetType type);
     void (*wakeup)(MachineState *state);
     int (*kvm_type)(MachineState *machine, const char *arg);
     int (*hvf_get_physical_address_range)(MachineState *machine);
diff --git a/include/sysemu/reset.h b/include/sysemu/reset.h
index ae436044a9..0e297c0e02 100644
--- a/include/sysemu/reset.h
+++ b/include/sysemu/reset.h
@@ -27,6 +27,7 @@
 #ifndef QEMU_SYSEMU_RESET_H
 #define QEMU_SYSEMU_RESET_H
 
+#include "hw/resettable.h"
 #include "qapi/qapi-events-run-state.h"
 
 typedef void QEMUResetHandler(void *opaque);
@@ -110,7 +111,7 @@ void qemu_unregister_reset(QEMUResetHandler *func, void *opaque);
 
 /**
  * qemu_devices_reset: Perform a complete system reset
- * @reason: reason for the reset
+ * @reason: type of the reset
  *
  * This function performs the low-level work needed to do a complete reset
  * of the system (calling all the callbacks registered with
@@ -121,6 +122,6 @@ void qemu_unregister_reset(QEMUResetHandler *func, void *opaque);
  * If you want to trigger a system reset from, for instance, a device
  * model, don't use this function. Use qemu_system_reset_request().
  */
-void qemu_devices_reset(ShutdownCause reason);
+void qemu_devices_reset(ResetType type);
 
 #endif
diff --git a/system/runstate.c b/system/runstate.c
index a0e2a5fd22..c2c9afa905 100644
--- a/system/runstate.c
+++ b/system/runstate.c
@@ -32,6 +32,7 @@
 #include "exec/cpu-common.h"
 #include "gdbstub/syscalls.h"
 #include "hw/boards.h"
+#include "hw/resettable.h"
 #include "migration/misc.h"
 #include "migration/postcopy-ram.h"
 #include "monitor/monitor.h"
@@ -507,15 +508,23 @@ static int qemu_debug_requested(void)
 void qemu_system_reset(ShutdownCause reason)
 {
     MachineClass *mc;
+    ResetType type;
 
     mc = current_machine ? MACHINE_GET_CLASS(current_machine) : NULL;
 
     cpu_synchronize_all_states();
 
+    switch (reason) {
+    case SHUTDOWN_CAUSE_SNAPSHOT_LOAD:
+        type = RESET_TYPE_SNAPSHOT_LOAD;
+        break;
+    default:
+        type = RESET_TYPE_COLD;
+    }
     if (mc && mc->reset) {
-        mc->reset(current_machine, reason);
+        mc->reset(current_machine, type);
     } else {
-        qemu_devices_reset(reason);
+        qemu_devices_reset(type);
     }
     switch (reason) {
     case SHUTDOWN_CAUSE_NONE:
-- 
2.46.1

[PULL 3/6] reset: Add RESET_TYPE_WAKEUP

[David Hildenbrand]

From: Juraj Marcin <jmarcin@redhat.com>

Some devices need to distinguish cold start reset from waking up from a
suspended state. This patch adds new value to the enum, and updates the
i386 wakeup method to use this new reset type.

Message-ID: <20240904103722.946194-3-jmarcin@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 docs/devel/reset.rst    | 12 +++++++++++-
 hw/i386/pc.c            |  2 +-
 include/hw/resettable.h |  2 ++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/docs/devel/reset.rst b/docs/devel/reset.rst
index ed41e09f16..74c7c0171a 100644
--- a/docs/devel/reset.rst
+++ b/docs/devel/reset.rst
@@ -44,6 +44,17 @@ The Resettable interface handles reset types with an enum ``ResetType``:
   value on each cold reset, such as RNG seed information, and which they
   must not reinitialize on a snapshot-load reset.
 
+``RESET_TYPE_WAKEUP``
+  If the machine supports waking up from a suspended state and needs to reset
+  its devices during wake-up (from the ``MachineClass::wakeup()`` method), this
+  reset type should be used for such a request. Devices can utilize this reset
+  type to differentiate the reset requested during machine wake-up from other
+  reset requests. For example, RAM content must not be lost during wake-up, and
+  memory devices like virtio-mem that provide additional RAM must not reset
+  such state during wake-ups, but might do so during cold resets. However, this
+  reset type should not be used for wake-up detection, as not every machine
+  type issues a device reset request during wake-up.
+
 ``RESET_TYPE_S390_CPU_NORMAL``
   This is only used for S390 CPU objects; it clears interrupts, stops
   processing, and clears the TLB, but does not touch register contents.
@@ -53,7 +64,6 @@ The Resettable interface handles reset types with an enum ``ResetType``:
   ``RESET_TYPE_S390_CPU_NORMAL`` does and also clears the PSW, prefix,
   FPC, timer and control registers. It does not touch gprs, fprs or acrs.
 
-
 Devices which implement reset methods must treat any unknown ``ResetType``
 as equivalent to ``RESET_TYPE_COLD``; this will reduce the amount of
 existing code we need to change if we add more types in future.
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 79a626a3eb..80a65d965f 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1732,7 +1732,7 @@ static void pc_machine_reset(MachineState *machine, ResetType type)
 static void pc_machine_wakeup(MachineState *machine)
 {
     cpu_synchronize_all_states();
-    pc_machine_reset(machine, RESET_TYPE_COLD);
+    pc_machine_reset(machine, RESET_TYPE_WAKEUP);
     cpu_synchronize_all_post_reset();
 }
 
diff --git a/include/hw/resettable.h b/include/hw/resettable.h
index 94f6f22e3c..fd862f1e9f 100644
--- a/include/hw/resettable.h
+++ b/include/hw/resettable.h
@@ -29,6 +29,7 @@ typedef struct ResettableState ResettableState;
  * Types of reset.
  *
  * + Cold: reset resulting from a power cycle of the object.
+ * + Wakeup: reset resulting from a wake-up from a suspended state.
  *
  * TODO: Support has to be added to handle more types. In particular,
  * ResettableState structure needs to be expanded.
@@ -36,6 +37,7 @@ typedef struct ResettableState ResettableState;
 typedef enum ResetType {
     RESET_TYPE_COLD,
     RESET_TYPE_SNAPSHOT_LOAD,
+    RESET_TYPE_WAKEUP,
     RESET_TYPE_S390_CPU_INITIAL,
     RESET_TYPE_S390_CPU_NORMAL,
 } ResetType;
-- 
2.46.1

[PULL 4/6] virtio-mem: Use new Resettable framework instead of LegacyReset

[David Hildenbrand]

From: Juraj Marcin <jmarcin@redhat.com>

LegacyReset does not pass ResetType to the reset callback method, which
the new Resettable framework uses. Due to this, virtio-mem cannot use
the new RESET_TYPE_WAKEUP to skip the reset during wake-up from a
suspended state.

This patch adds overrides Resettable interface methods in VirtIOMEMClass
to use the new Resettable framework and replaces
qemu_[un]register_reset() calls with qemu_[un]register_resettable().

Message-ID: <20240904103722.946194-4-jmarcin@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/virtio/virtio-mem.c         | 38 +++++++++++++++++++++-------------
 include/hw/virtio/virtio-mem.h |  4 ++++
 2 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index 4075f3d4ce..484d3a5a54 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -902,18 +902,6 @@ static int virtio_mem_validate_features(VirtIODevice *vdev)
     return 0;
 }
 
-static void virtio_mem_system_reset(void *opaque)
-{
-    VirtIOMEM *vmem = VIRTIO_MEM(opaque);
-
-    /*
-     * During usual resets, we will unplug all memory and shrink the usable
-     * region size. This is, however, not possible in all scenarios. Then,
-     * the guest has to deal with this manually (VIRTIO_MEM_REQ_UNPLUG_ALL).
-     */
-    virtio_mem_unplug_all(vmem);
-}
-
 static void virtio_mem_prepare_mr(VirtIOMEM *vmem)
 {
     const uint64_t region_size = memory_region_size(&vmem->memdev->mr);
@@ -1130,7 +1118,7 @@ static void virtio_mem_device_realize(DeviceState *dev, Error **errp)
         vmstate_register_any(VMSTATE_IF(vmem),
                              &vmstate_virtio_mem_device_early, vmem);
     }
-    qemu_register_reset(virtio_mem_system_reset, vmem);
+    qemu_register_resettable(OBJECT(vmem));
 
     /*
      * Set ourselves as RamDiscardManager before the plug handler maps the
@@ -1150,7 +1138,7 @@ static void virtio_mem_device_unrealize(DeviceState *dev)
      * found via an address space anymore. Unset ourselves.
      */
     memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL);
-    qemu_unregister_reset(virtio_mem_system_reset, vmem);
+    qemu_unregister_resettable(OBJECT(vmem));
     if (vmem->early_migration) {
         vmstate_unregister(VMSTATE_IF(vmem), &vmstate_virtio_mem_device_early,
                            vmem);
@@ -1850,12 +1838,31 @@ static void virtio_mem_unplug_request_check(VirtIOMEM *vmem, Error **errp)
     }
 }
 
+static ResettableState *virtio_mem_get_reset_state(Object *obj)
+{
+    VirtIOMEM *vmem = VIRTIO_MEM(obj);
+    return &vmem->reset_state;
+}
+
+static void virtio_mem_system_reset_hold(Object *obj, ResetType type)
+{
+    VirtIOMEM *vmem = VIRTIO_MEM(obj);
+
+    /*
+     * During usual resets, we will unplug all memory and shrink the usable
+     * region size. This is, however, not possible in all scenarios. Then,
+     * the guest has to deal with this manually (VIRTIO_MEM_REQ_UNPLUG_ALL).
+     */
+    virtio_mem_unplug_all(vmem);
+}
+
 static void virtio_mem_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
     VirtIOMEMClass *vmc = VIRTIO_MEM_CLASS(klass);
     RamDiscardManagerClass *rdmc = RAM_DISCARD_MANAGER_CLASS(klass);
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
 
     device_class_set_props(dc, virtio_mem_properties);
     dc->vmsd = &vmstate_virtio_mem;
@@ -1882,6 +1889,9 @@ static void virtio_mem_class_init(ObjectClass *klass, void *data)
     rdmc->replay_discarded = virtio_mem_rdm_replay_discarded;
     rdmc->register_listener = virtio_mem_rdm_register_listener;
     rdmc->unregister_listener = virtio_mem_rdm_unregister_listener;
+
+    rc->get_state = virtio_mem_get_reset_state;
+    rc->phases.hold = virtio_mem_system_reset_hold;
 }
 
 static const TypeInfo virtio_mem_info = {
diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h
index 5f5b02b8f9..a1af144c28 100644
--- a/include/hw/virtio/virtio-mem.h
+++ b/include/hw/virtio/virtio-mem.h
@@ -14,6 +14,7 @@
 #define HW_VIRTIO_MEM_H
 
 #include "standard-headers/linux/virtio_mem.h"
+#include "hw/resettable.h"
 #include "hw/virtio/virtio.h"
 #include "qapi/qapi-types-misc.h"
 #include "sysemu/hostmem.h"
@@ -115,6 +116,9 @@ struct VirtIOMEM {
 
     /* listeners to notify on plug/unplug activity. */
     QLIST_HEAD(, RamDiscardListener) rdl_list;
+
+    /* State of the resettable container */
+    ResettableState reset_state;
 };
 
 struct VirtIOMEMClass {
-- 
2.46.1

[PULL 5/6] virtio-mem: Add support for suspend+wake-up with plugged memory

[David Hildenbrand]

From: Juraj Marcin <jmarcin@redhat.com>

Before, the virtio-mem device would unplug all the memory with any reset
of the device, including during the wake-up of the guest from a
suspended state. Due to this, the virtio-mem driver in the Linux kernel
disallowed suspend-to-ram requests in the guest when the
VIRTIO_MEM_F_PERSISTENT_SUSPEND feature is not exposed by QEMU.

This patch adds the code to skip the reset on wake-up and exposes
theVIRTIO_MEM_F_PERSISTENT_SUSPEND feature to the guest kernel driver
when suspending is possible in QEMU (currently only x86).

Message-ID: <20240904103722.946194-5-jmarcin@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juraj Marcin <jmarcin@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/virtio/virtio-mem.c | 10 ++++++++++
 hw/virtio/virtio-qmp.c |  3 +++
 2 files changed, 13 insertions(+)

diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index 484d3a5a54..ae1e81d7ba 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -890,6 +890,9 @@ static uint64_t virtio_mem_get_features(VirtIODevice *vdev, uint64_t features,
     if (vmem->unplugged_inaccessible == ON_OFF_AUTO_ON) {
         virtio_add_feature(&features, VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE);
     }
+    if (qemu_wakeup_suspend_enabled()) {
+        virtio_add_feature(&features, VIRTIO_MEM_F_PERSISTENT_SUSPEND);
+    }
     return features;
 }
 
@@ -1848,6 +1851,13 @@ static void virtio_mem_system_reset_hold(Object *obj, ResetType type)
 {
     VirtIOMEM *vmem = VIRTIO_MEM(obj);
 
+    /*
+     * When waking up from standby/suspend-to-ram, do not unplug any memory.
+     */
+    if (type == RESET_TYPE_WAKEUP) {
+        return;
+    }
+
     /*
      * During usual resets, we will unplug all memory and shrink the usable
      * region size. This is, however, not possible in all scenarios. Then,
diff --git a/hw/virtio/virtio-qmp.c b/hw/virtio/virtio-qmp.c
index 1dd96ed20f..cccc6fe761 100644
--- a/hw/virtio/virtio-qmp.c
+++ b/hw/virtio/virtio-qmp.c
@@ -450,6 +450,9 @@ static const qmp_virtio_feature_map_t virtio_mem_feature_map[] = {
     FEATURE_ENTRY(VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE, \
             "VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE: Unplugged memory cannot be "
             "accessed"),
+    FEATURE_ENTRY(VIRTIO_MEM_F_PERSISTENT_SUSPEND, \
+            "VIRTIO_MEM_F_PERSISTENT_SUSPND: Plugged memory will remain "
+            "plugged when suspending+resuming"),
     { -1, "" }
 };
 #endif
-- 
2.46.1

[PULL 6/6] hostmem: Apply merge property after the memory region is initialized

[David Hildenbrand]

From: Gavin Shan <gshan@redhat.com>

The semantic change has been introduced by commit 5becdc0ab0 ("hostmem:
simplify the code for merge and dump properties") even it clarifies that
no senmatic change has been introduced. After the commit, the merge
property can be applied even the corresponding memory region isn't
initialized yet. This leads to crash dump by the following command
lines.

  # /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64  \
    -accel kvm  -machine virt -cpu host                      \
    -object memory-backend-ram,id=mem-memN0,size=4096M,merge=off
    :
    qemu-system-aarch64: ../system/memory.c:2419: memory_region_get_ram_ptr: \
    Assertion `mr->ram_block' failed.

Fix it by applying the merge property only when the memory region is
initialized.

Message-ID: <20240915233117.478169-1-gshan@redhat.com>
Fixes: 5becdc0ab083 ("hostmem: simplify the code for merge and dump properties")
Reported-by: Zhenyu Zhang <zhenyzha@redhat.com>
Tested-by: Zhenyu Zhang <zhenyzha@redhat.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 backends/hostmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/backends/hostmem.c b/backends/hostmem.c
index 4e5576a4ad..181446626a 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -178,7 +178,7 @@ static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
         return;
     }
 
-    if (!host_memory_backend_mr_inited(backend) &&
+    if (host_memory_backend_mr_inited(backend) &&
         value != backend->merge) {
         void *ptr = memory_region_get_ram_ptr(&backend->mr);
         uint64_t sz = memory_region_size(&backend->mr);
-- 
2.46.1

Re: [PULL 0/6] Host Memory Backends and Memory devices queue 2024-09-24

[Peter Maydell]

On Tue, 24 Sept 2024 at 11:03, David Hildenbrand <david@redhat.com> wrote:
>
> Hi,
>
> due to reset changes this contains a bit of churn that touches various
> architectures, but it's all fairly minimal and straight-forward.
>
> The following changes since commit 01dc65a3bc262ab1bec8fe89775e9bbfa627becb:
>
>   Merge tag 'pull-target-arm-20240919' of https://git.linaro.org/people/pmaydell/qemu-arm into staging (2024-09-19 14:15:15 +0100)
>
> are available in the Git repository at:
>
>   https://github.com/davidhildenbrand/qemu.git tags/mem-2024-09-24
>
> for you to fetch changes up to 78c8f780d3f0d6d17aa93d6f99ff72960080fdd7:
>
>   hostmem: Apply merge property after the memory region is initialized (2024-09-24 11:33:35 +0200)
>
> ----------------------------------------------------------------
> Hi,
>
> "Host Memory Backends" and "Memory devices" queue ("mem"):
> - Kconfig fix for virtio-based memory devices
> - virtio-mem support for suspend+wake-up with plugged memory
> - hostmem fix when specifying "merge=off"
>



Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/9.2
for any user-visible changes.

-- PMM