On Wed, May 27, 2026 at 1:54 AM Philippe Mathieu-Daudé
<[email protected]> wrote:
>
> On 26/5/26 22:16, Philippe Mathieu-Daudé wrote:
> > +Paolo/Peter
> >
> > On 26/5/26 21:45, Philippe Mathieu-Daudé wrote:
> >> +Richard/Pierrick
> >>
> >> On 26/5/26 20:07, Mohammadfaiz Bawa wrote:
> >>> On Tue, May 26, 2026 at 11:13 PM Peter Maydell
> >>> <[email protected]> wrote:
> >>>>
> >>>> On Tue, 26 May 2026 at 17:49, Mohammadfaiz Bawa <[email protected]>
> >>>> wrote:
> >>>>>
> >>>>> memory_region_init_ram_device_ptr() requires the target page
> >>>>> size to be finalized, which has not happened during
> >>>>> instance_init. Calling it from tpm_tis_sysbus_initfn() causes
> >>>>> an assertion failure when the device is introspected without
> >>>>> being realized, for example:
> >>>>>
> >>>>>    $ qemu-system-aarch64 -device tpm-tis-device,help
> >>>>>    qemu-system-aarch64: ../system/physmem.c:2524:
> >>>>>    qemu_ram_alloc_internal:
> >>>>>    Assertion 'target_page.decided' failed.
> >>>>>    Aborted (core dumped)
> >
> > I can not reproduce this error, however en macOS this command triggers:
> >
> > (lldb) bt
> > * thread #1, queue = 'com.apple.main-thread', stop reason = hit program
> > assert
> >      frame #0: 0x000000019c642388 libsystem_kernel.dylib`__pthread_kill + 8
> >      frame #1: 0x000000019c67b848 libsystem_pthread.dylib`pthread_kill +
> > 296
> >      frame #2: 0x000000019c584b50 libsystem_c.dylib`abort + 124
> >      frame #3: 0x000000019c583d84 libsystem_c.dylib`__assert_rtn + 284
> >    * frame #4: 0x0000000100a3870c qemu-system-
> > aarch64`qemu_mutex_lock_impl.cold.1 at qemu-thread-posix.c:107:5
> >      frame #5: 0x0000000100981e78 qemu-system-
> > aarch64`qemu_mutex_lock_impl(mutex=<unavailable>, file=<unavailable>,
> > line=<unavailable>) at qemu-thread-posix.c:107:5
> >      frame #6: 0x0000000100345d08 qemu-system-
> > aarch64`qemu_mutex_lock_ramlist at physmem.c:1454:5
> >      frame #7: 0x0000000100345ce4 qemu-system-
> > aarch64`ram_block_add(new_block=0x0000000133104f10,
> > errp=0x000000016fdfe650) at physmem.c:2161:5
> >      frame #8: 0x0000000100346c34 qemu-system-
> > aarch64`qemu_ram_alloc_internal(size=16384, max_size=16384,
> > resized=0x0000000000000000, host=0x000000013380c000, ram_flags=1,
> > mr=0x000000013380a910, errp=0x0000000101c37c20) at physmem.c:2540:5
> >      frame #9: 0x00000001003469c8 qemu-system-
> > aarch64`qemu_ram_alloc_from_ptr(size=<unavailable>, host=<unavailable>,
> > mr=<unavailable>, errp=<unavailable>) at physmem.c:2552:12 [artificial]
> >      frame #10: 0x000000010033b56c qemu-system-
> > aarch64`memory_region_set_ram_ptr(mr=0x000000013380a910, size=1024,
> > ptr=0x000000013380c000) at memory.c:1664:20 [inlined]
> >      frame #11: 0x000000010033b550 qemu-system-
> > aarch64`memory_region_init_ram_device_ptr(mr=0x000000013380a910,
> > owner=<unavailable>, name=<unavailable>, size=1024,
> > ptr=0x000000013380c000) at memory.c:1684:5
> >      frame #12: 0x00000001002ca594 qemu-system-
> > aarch64`tpm_tis_sysbus_initfn(obj=0x0000000133809400) at
> > tpm_tis_sysbus.c:114:5
> >      frame #13: 0x00000001007e8e58 qemu-system-
> > aarch64`object_initialize_with_type(obj=0x0000000133809400, size=5680,
> > type=0x0000000131f4e250) at object.c:504:5
> >      frame #14: 0x00000001007e964c qemu-system-
> > aarch64`object_new_with_type(type=0x0000000131f4e250) at object.c:707:5
> >      frame #15: 0x00000001007e95fc qemu-system-
> > aarch64`object_new_with_class(klass=<unavailable>) at object.c:716:12
> > [artificial]
> >      frame #16: 0x00000001008ca264 qemu-system-
> > aarch64`qmp_device_list_properties(typename="tpm-tis-device",
> > errp=0x000000016fdfe8a0) at qom-qmp-cmds.c:206:11
> >      frame #17: 0x000000010034c7a0 qemu-system-
> > aarch64`qdev_device_help(opts=<unavailable>) at qdev-monitor.c:315:17
> >      frame #18: 0x000000010033179c qemu-system-
> > aarch64`device_help_func(opaque=<unavailable>, opts=<unavailable>,
> > errp=<unavailable>) at vl.c:1209:12 [artificial]
> >      frame #19: 0x000000010098aa10 qemu-system-
> > aarch64`qemu_opts_foreach(list=<unavailable>, func=(qemu-system-
> > aarch64`device_help_func at vl.c:1208), opaque=0x0000000000000000,
> > errp=0x0000000000000000) at qemu-option.c:1148:14
> >      frame #20: 0x000000010032d45c qemu-system-
> > aarch64`qemu_process_help_options at vl.c:2642:9 [inlined]
> >      frame #21: 0x000000010032d408 qemu-system-
> > aarch64`qemu_init(argc=<unavailable>, argv=0x000000016fdff148) at
> > vl.c:3738:5
> >      frame #22: 0x00000001008dcef8 qemu-system-
> > aarch64`main(argc=<unavailable>, argv=<unavailable>) at main.c:71:5
> >      frame #23: 0x000000019c2dab98 dyld`start + 6076
> >
Hi Philippe,

I looked into this, the target_page.decided assertion only
shows up with CONFIG_DEBUG_TCG enabled, which is I guess how I hit it.

I rebuilt with --disable-debug-tcg and got the same crash as
your macOS backtrace, mutex assert in ram_block_add().

> >>>>>
> >>>>> Property introspection only calls instance_init, never
> >>>>> realizefn, so moving the memory region setup to realizefn
> >>>>> avoids the crash while keeping the device fully functional
> >>>>> when actually used in a VM.
> >>>>>
> >>>>> Move the PPI buffer allocation, memory_region_init_ram_device_ptr()
> >>>>> and the corresponding sysbus_init_mmio() from
> >>>>> tpm_tis_sysbus_initfn() to tpm_tis_sysbus_realizefn(), placing
> >>>>> them just before the existing vmstate_register_ram() call.
> >>>>>
> >>>>> Signed-off-by: Mohammadfaiz Bawa <[email protected]>
> >>>>> ---
> >>>>>   hw/tpm/tpm_tis_sysbus.c | 13 ++++++-------
> >>>>>   1 file changed, 6 insertions(+), 7 deletions(-)
> >>>>>
> >>>>> diff --git a/hw/tpm/tpm_tis_sysbus.c b/hw/tpm/tpm_tis_sysbus.c
> >>>>> index 6bec30c36f..33fe9e332c 100644
> >>>>> --- a/hw/tpm/tpm_tis_sysbus.c
> >>>>> +++ b/hw/tpm/tpm_tis_sysbus.c
> >>>>> @@ -100,7 +100,6 @@ static void tpm_tis_sysbus_initfn(Object *obj)
> >>>>>   {
> >>>>>       TPMStateSysBus *sbdev = TPM_TIS_SYSBUS(obj);
> >>>>>       TPMState *s = &sbdev->state;
> >>>>> -    size_t host_page_size = qemu_real_host_page_size();
> >>>>
> >>>> This is asking about the host page size, so why does it wind up
> >>>> asserting about the target page size not being fixed ?
> >>>>
> >>>> thanks
> >>>> -- PMM
> >>>
> >>> The host_page_size line itself doesn't cause the crash -
> >>> qemu_real_host_page_size() is safe to call anywhere. It was
> >>> moved simply because it has no other consumers in initfn.
> >>>
> >>> The actual crash comes from memory_region_init_ram_device_ptr()
> >>> - which calls qemu_ram_alloc_internal(). In there, line 2522
> >>> evaluates TARGET_PAGE_SIZE: align = MAX(align, TARGET_PAGE_SIZE);
> >>>
> >>> With CONFIG_DEBUG_TCG, TARGET_PAGE_SIZE expands through
> >>> TARGET_PAGE_MASK which contains: assert(target_page.decided)
> >>>
> >>> That's where it blows up: the target page size hasn't been
> >>> finalized yet during instance_init.
>
> When a realize() can fail, deferring resources allocation to it
> (after checking any failure) is indeed preferred pattern (but it
> should come with these resources being released in a unrealize
> handler, which this file lacks -- pre-existing).
>
> With that in mind I'd also move tpm-tis-mmio allocation:

Makes sense, will do in v2.

> -- >8 --
> diff --git a/hw/tpm/tpm_tis_sysbus.c b/hw/tpm/tpm_tis_sysbus.c
> index 6bec30c36fc..aae9ffd8392 100644
> --- a/hw/tpm/tpm_tis_sysbus.c
> +++ b/hw/tpm/tpm_tis_sysbus.c
> @@ -102,7 +102,2 @@ static void tpm_tis_sysbus_initfn(Object *obj)
>       TPMState *s = &sbdev->state;
> -    size_t host_page_size = qemu_real_host_page_size();
> -
> -    memory_region_init_io(&s->mmio, obj, &tpm_tis_memory_ops,
> -                          s, "tpm-tis-mmio",
> -                          TPM_TIS_NUM_LOCALITIES <<
> TPM_TIS_LOCALITY_SHIFT);
>
> @@ -111,6 +106,2 @@ static void tpm_tis_sysbus_initfn(Object *obj)
>
> -    s->ppi.buf = qemu_memalign(host_page_size,
> -                                ROUND_UP(TPM_PPI_ADDR_SIZE,
> host_page_size));
> -    memory_region_init_ram_device_ptr(&s->ppi.ram, obj, "tpm-ppi",
> -                                      TPM_PPI_ADDR_SIZE, s->ppi.buf);
>       sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->ppi.ram);
> @@ -122,2 +113,3 @@ static void tpm_tis_sysbus_realizefn(DeviceState
> *dev, Error **errp)
>       TPMState *s = &sbdev->state;
> +    const size_t host_page_size = qemu_real_host_page_size();
>
> @@ -133,2 +125,10 @@ static void tpm_tis_sysbus_realizefn(DeviceState
> *dev, Error **errp)
>
> +    s->ppi.buf = qemu_memalign(host_page_size,
> +                               ROUND_UP(TPM_PPI_ADDR_SIZE,
> host_page_size));
> +    memory_region_init_io(&s->mmio, OBJECT(dev), &tpm_tis_memory_ops,
> +                          s, "tpm-tis-mmio",
> +                          TPM_TIS_NUM_LOCALITIES <<
> TPM_TIS_LOCALITY_SHIFT);
> +
> +    memory_region_init_ram_device_ptr(&s->ppi.ram, OBJECT(dev), "tpm-ppi",
> +                                      TPM_PPI_ADDR_SIZE, s->ppi.buf);
>       vmstate_register_ram(&s->ppi.ram, dev);
> ---
>
> At any rate the commit description has to be reworded.
>
Will update thank you for the review.

Thanks
--Faiz


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