On 7/14/23 13:04, Joelle van Dyne wrote:
On Fri, Jul 14, 2023 at 7:51 AM Stefan Berger <stef...@linux.ibm.com> wrote:
On 7/14/23 10:05, Stefan Berger wrote:
On 7/14/23 03:09, Joelle van Dyne wrote:
When we moved to a single mapping and modified TPM CRB's VMState, it
broke restoring of VMs that were saved on an older version. This
change allows those VMs to gracefully migrate to the new memory
mapping.
Thanks. This has to be in 4/11 though.
After applying the whole series and trying to resume state taken with current
git
master I cannot restore it but it leads to this error here. I would just leave
it
completely untouched in 4/11.
2023-07-14T14:46:34.547550Z qemu-system-x86_64: Unknown ramblock "tpm-crb-cmd",
cannot accept migration
2023-07-14T14:46:34.547799Z qemu-system-x86_64: error while loading state for
instance 0x0 of device 'ram'
2023-07-14T14:46:34.547835Z qemu-system-x86_64: load of migration failed:
Invalid argument
Stefan
To be clear, you are asking to back out of 4/11? That patch changes
how the registers are mapped so it's impossible to support the old
style register mapping. This patch attempts to fix that with a
Why can we not keep the old style register mapping as 'secondary mapping'?
The expectation is that old VM state / CRB state can be used by the new QEMU and
also new QEMU CRB state should be readable by old QEMU. So in a way the old
'secondary'
mmaping has to hold the true value of the registers so that the latter works.
migration path but I realized that I missed the "tpm-crb-cmd"
ramblock. It can be added to v3 for this patch. Similar to the logic
to have `legacy_regs` we will add a `legacy_cmdmem` memory region that
is not registered with the system bus but only exists to migrate the
data. Would that work? Also open to better ideas on migrating legacy
saved state.
If we back out of 4/11 (the split mapping), then the proposed way for
working on Apple Silicon would not be available and we would have to
go down the path of emulating AArch64 instruction in HVF backend (or
decide not to support Apple Silicon).
