Re: [PATCH v2 09/11] tpm_tis_sysbus: move DSDT AML generation to device

[Joelle van Dyne]

On Fri, Jul 14, 2023 at 9:19 AM Stefan Berger <stefanb@linux.ibm.com> wrote:
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> I don't know whether we would want multiple devices. tpm_find() usage is 
> certainly not prepared for multiple devices.
Sorry, "multiple TPM interfaces" here does not mean "at the same
time". Will clarify the description.

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> Good for the consolidation.
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> Does moving the TIS to a different address help on aarch64?
That was the first thing we tried and no it doesn't help.
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> Can the size really be an option? I don't see it useful and if one gave the 
> wrong size it may break things.
It was added for consistency (otherwise we have to determine the size
by looking at the interface everywhere). Also, it is possible for the
size to be larger than the constant. For example, Apple Silicon uses
16KiB page sizes and we may decide to force the device to be 16KiB
aligned (not sure if this is needed yet while we still track down why
the dual mapping was not working). In that case, we would need to
inform the OS of the true region size to prevent any overlap issues.
Both baseaddr and size should be provided only by the plug handler in
the virt machine, otherwise things may break even if we get rid of
size and have just an incorrect baseaddr.

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