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From: David Miller <davem@davemloft.net>
To: jasowang@redhat.com
Cc: kvm@vger.kernel.org, mst@redhat.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	jintack@cs.columbia.edu
Subject: Re: [PATCH net V4] vhost: log dirty page correctly
Date: Thu, 17 Jan 2019 11:58:55 -0800 (PST)	[thread overview]
Message-ID: <20190117.115855.725358558291814993.davem__21229.1419077248$1547755256$gmane$org@davemloft.net> (raw)
In-Reply-To: <20190116085442.3836-1-jasowang@redhat.com>

From: Jason Wang <jasowang@redhat.com>
Date: Wed, 16 Jan 2019 16:54:42 +0800

> Vhost dirty page logging API is designed to sync through GPA. But we
> try to log GIOVA when device IOTLB is enabled. This is wrong and may
> lead to missing data after migration.
> 
> To solve this issue, when logging with device IOTLB enabled, we will:
> 
> 1) reuse the device IOTLB translation result of GIOVA->HVA mapping to
>    get HVA, for writable descriptor, get HVA through iovec. For used
>    ring update, translate its GIOVA to HVA
> 2) traverse the GPA->HVA mapping to get the possible GPA and log
>    through GPA. Pay attention this reverse mapping is not guaranteed
>    to be unique, so we should log each possible GPA in this case.
> 
> This fix the failure of scp to guest during migration. In -next, we
> will probably support passing GIOVA->GPA instead of GIOVA->HVA.
> 
> Fixes: 6b1e6cc7855b ("vhost: new device IOTLB API")
> Reported-by: Jintack Lim <jintack@cs.columbia.edu>
> Cc: Jintack Lim <jintack@cs.columbia.edu>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Michaell, can I get a review for this please?

Thank you.

  reply	other threads:[~2019-01-17 19:58 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-16  8:54 [PATCH net V4] vhost: log dirty page correctly Jason Wang
2019-01-17 19:58 ` David Miller [this message]
2019-01-17 19:58 ` David Miller
2019-01-17 20:42 ` Michael S. Tsirkin
2019-01-17 20:42 ` Michael S. Tsirkin
2019-01-18  5:47 ` David Miller
2019-01-18  5:47 ` David Miller
  -- strict thread matches above, loose matches on Subject: below --
2019-01-16  8:54 Jason Wang

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