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From: Stefan Berger <stefanb@linux.ibm.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Joelle van Dyne <j@getutm.app>,
	qemu-devel@nongnu.org, Stefan Berger <stefanb@linux.vnet.ibm.com>
Subject: Re: [PATCH 04/11] tpm_crb: use a single read-as-mem/write-as-mmio mapping
Date: Thu, 13 Jul 2023 11:28:22 -0400	[thread overview]
Message-ID: <ab339186-1af7-171c-eb11-fe124f12b4a2@linux.ibm.com> (raw)
In-Reply-To: <CAFEAcA-r_VOc18-jm99asYQQk4TJMBW_7oJMzFQofEHqVdF50A@mail.gmail.com>



On 7/13/23 10:50, Peter Maydell wrote:
> On Thu, 13 Jul 2023 at 15:18, Stefan Berger <stefanb@linux.ibm.com> wrote:
>>
>>
>>
>> On 7/12/23 23:51, Joelle van Dyne wrote:
>>> On Apple Silicon, when Windows performs a LDP on the CRB MMIO space,
>>> the exception is not decoded by hardware and we cannot trap the MMIO
>>> read. This led to the idea from @agraf to use the same mapping type as
>>> ROM devices: namely that reads should be seen as memory type and
>>> writes should trap as MMIO.

>>> +++ b/hw/tpm/tpm_crb.c
>>> @@ -68,7 +68,6 @@ static const VMStateDescription vmstate_tpm_crb_none = {
>>>        .name = "tpm-crb",
>>>        .pre_save = tpm_crb_none_pre_save,
>>>        .fields = (VMStateField[]) {
>>> -        VMSTATE_UINT32_ARRAY(state.regs, CRBState, TPM_CRB_R_MAX),
>>
>> This has to stay here otherwise we cannot restart VMs from saved state once QEMU is upgraded.
>>
>> 2023-07-13T14:15:43.997718Z qemu-system-x86_64: Unknown ramblock "tpm-crb-cmd", cannot accept migration
>> 2023-07-13T14:15:43.997813Z qemu-system-x86_64: error while loading state for instance 0x0 of device 'ram'
>> 2023-07-13T14:15:43.997841Z qemu-system-x86_64: load of migration failed: Invalid argument
> 
> More generally, for migration compatibility in the other
> direction you need to use memory_region_init_rom_device_nomigrate()
> and make sure you keep migrating the data via this, not
> via the MemoryRegion.
> 
> I'm not a super-fan of hacking around the fact that LDP
> to hardware registers isn't supported in specific device
> models, though...

What does this mean for this effort here?

    Stefan

> 
> thanks
> -- PMM


  reply	other threads:[~2023-07-13 15:29 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-13  3:51 [PATCH 00/11] tpm: introduce TPM CRB SysBus device Joelle van Dyne
2023-07-13  3:51 ` [PATCH 01/11] tpm_crb: refactor common code Joelle van Dyne
2023-07-13 13:22   ` Stefan Berger
2023-07-13  3:51 ` [PATCH 02/11] tpm_crb: CTRL_RSP_ADDR is 64-bits wide Joelle van Dyne
2023-07-13 15:31   ` Stefan Berger
2023-07-13  3:51 ` [PATCH 03/11] tpm_ppi: refactor memory space initialization Joelle van Dyne
2023-07-13 16:00   ` Stefan Berger
2023-07-13  3:51 ` [PATCH 04/11] tpm_crb: use a single read-as-mem/write-as-mmio mapping Joelle van Dyne
2023-07-13 14:17   ` Stefan Berger
2023-07-13 14:50     ` Peter Maydell
2023-07-13 15:28       ` Stefan Berger [this message]
2023-07-13 15:34         ` Peter Maydell
2023-07-13 15:46           ` Stefan Berger
2023-07-13 15:55             ` Peter Maydell
2023-07-13 16:53               ` Stefan Berger
2023-07-13 17:07                 ` Peter Maydell
2023-07-13 17:16                   ` Stefan Berger
2023-07-13 17:18                     ` Peter Maydell
2023-07-13 18:43                       ` Stefan Berger
2023-07-14 10:05                         ` Peter Maydell
2023-07-14 11:56                           ` Stefan Berger
2023-07-14 17:38                             ` Joelle van Dyne
2023-07-13  3:51 ` [PATCH 05/11] tpm_crb: use the ISA bus Joelle van Dyne
2023-07-13 18:35   ` Stefan Berger
2023-07-13  3:51 ` [PATCH 06/11] tpm_crb: move ACPI table building to device interface Joelle van Dyne
2023-07-13 16:08   ` Stefan Berger
2023-07-13 18:10     ` Joelle van Dyne
2023-07-13 18:30       ` Stefan Berger
2023-07-13  3:51 ` [PATCH 07/11] hw/arm/virt: add plug handler for TPM on SysBus Joelle van Dyne
2023-07-13 13:13   ` Stefan Berger
2023-07-13 15:31   ` Peter Maydell
2023-07-13 18:07     ` Joelle van Dyne
2023-07-13  3:51 ` [PATCH 08/11] hw/loongarch/virt: " Joelle van Dyne
2023-07-13  3:51 ` [PATCH 09/11] tpm_tis_sysbus: fix crash when PPI is enabled Joelle van Dyne
2023-07-13 16:49   ` Stefan Berger
2023-07-13 18:15     ` Joelle van Dyne
2023-07-13 18:31       ` Stefan Berger
2023-07-13  3:51 ` [PATCH 10/11] tpm_tis_sysbus: move DSDT AML generation to device Joelle van Dyne
2023-07-13  3:51 ` [PATCH 11/11] tpm_crb_sysbus: introduce TPM CRB SysBus device Joelle van Dyne
2023-07-13 13:07 ` [PATCH 00/11] tpm: " Stefan Berger
2023-07-13 17:35   ` Joelle van Dyne

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