Re: Lost partition tables on ide-hd + ahci drive

[Fiona Ebner <f.ebner@proxmox.com>]

Am 23.08.23 um 10:47 schrieb Fiona Ebner:
> Am 17.02.23 um 22:22 schrieb Mike Maslenkin:
>> I can not tell anything about dma-reentracy issues, but yes, i would
>> start to look at check_cmd() function call sequence.
>> The most interesting is why Sector Count = 1. I thought about race
>> with IDE reset where registers initialized with
>> value SATA_SIGNATURE_DISK = 0x00000101, but this means LBA=1 as well...
>>
> 
> You got it! Since we got another report (after half a year of nothing)
> and also because of Simon's mail, I gave it another shot too and was
> finally able to reproduce the issue (with our patched QEMU 8.0, but
> patches shouldn't affect IDE code). See below for the traces that
> confirm your theory. The reason the write goes to sector 0 and not 1 is
> because ide_dma_cb() uses sector_num = ide_get_sector(s); and that will
> evaluate to 0 after a reset.
> 
> So the issue is indeed that ide_dma_cb can get called with an IDEState
> just after that state was reset. Can we somehow wait for pending
> requests before proceeding with the reset, or can we force an error
> return for callbacks that are still pending during reset?
> 

I noticed that ide_bus_reset() does the reset first and then cancels the
aiocb. Maybe it's already enough to switch those around?

Best Regards,
Fiona