Re: [Qemu-devel] [PATCH repost] ahci: fix win7 hang on boot

[Kevin Wolf]

Am 28.10.2013 um 20:01 hat Michael S. Tsirkin geschrieben:
> From: Alexander Graf <address@hidden>
> 
> When AHCI executes an asynchronous IDE command, it checked DRDY without
> checking either DRQ or BSY.  This sometimes caused interrupt to be sent
> before command is actually completed.
> 
> This resulted in a race condition: if guest then managed to access the
> device before command has completed, it would hang waiting for an
> interrupt.
> This was observed with windows 7 guests.
> 
> To fix, check for DRQ or BSY in additiona to DRDY, if set,
> the command is asynchronous so delay the interrupt until
> asynchronous done callback is invoked.
> 
> Reported-by: Michael S. Tsirkin <address@hidden>
> Reviewed-by: Michael S. Tsirkin <address@hidden>
> Tested-by: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Michael S. Tsirkin <address@hidden>

Thanks, applied to the block branch.

Kevin