Re: [Qemu-devel] [Qemu-block] [PATCH v2 1/5] block/nvme: don't flip CQ phase bits

[John Snow <jsnow@redhat.com>]

On 4/17/19 3:53 PM, Maxim Levitsky wrote:
> Phase bits are only set by the hardware to indicate new completions
> and not by the device driver.
> 
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>  block/nvme.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/block/nvme.c b/block/nvme.c
> index 0684bbd077..2d208000df 100644
> --- a/block/nvme.c
> +++ b/block/nvme.c
> @@ -340,8 +340,6 @@ static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q)
>          qemu_mutex_lock(&q->lock);
>          c->cid = cpu_to_le16(0);
>          q->inflight--;
> -        /* Flip Phase Tag bit. */
> -        c->status = cpu_to_le16(le16_to_cpu(c->status) ^ 0x1);
>          progress = true;
>      }
>      if (progress) {
> 

Since you've not got much traction on this and you've pinged a v2, can
you point me to a spec or a reproducer that illustrates the problem?

(Or wait for more NVME knowledgeable people to give you a review...!)