Re: [PATCH v3 8/8] hw/ide/ahci: fix broken SError handling

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 9/6/23 16:08, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@wdc.com>
> 
> When encountering an NCQ error, you should not write the NCQ tag to the
> SError register. This is completely wrong.
> 
> The SError register has a clear definition, where each bit represents a
> different error, see PxSERR definition in AHCI 1.3.1.
> 
> If we write a random value (like the NCQ tag) in SError, e.g. Linux will
> read SError, and will trigger arbitrary error handling depending on the
> NCQ tag that happened to be executing.
> 
> In case of success, ncq_cb() will call ncq_finish().
> In case of error, ncq_cb() will call ncq_err() (which will clear
> ncq_tfs->used), and then call ncq_finish(), thus using ncq_tfs->used is
> sufficient to tell if finished should get set or not.
> 

Cc: qemu-stable@nongnu.org
Fixes: f6ad2e32f8 ("ahci: add ahci emulation")
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   hw/ide/ahci.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)