https://github.com/torvalds/linux
Revision cc5e710759470bc7f3c61d11fd54586f15fdbdf4 authored by Jason Wang on 16 January 2019, 08:54:42 UTC, committed by David S. Miller on 18 January 2019, 05:43:24 UTC
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>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent f655f8b
History
Tip revision: cc5e710759470bc7f3c61d11fd54586f15fdbdf4 authored by Jason Wang on 16 January 2019, 08:54:42 UTC
vhost: log dirty page correctly
Tip revision: cc5e710
File Mode Size
Documentation
LICENSES
arch
block
certs
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.clang-format -rw-r--r-- 12.7 KB
.cocciconfig -rw-r--r-- 59 bytes
.get_maintainer.ignore -rw-r--r-- 31 bytes
.gitattributes -rw-r--r-- 30 bytes
.gitignore -rw-r--r-- 1.5 KB
.mailmap -rw-r--r-- 10.7 KB
COPYING -rw-r--r-- 423 bytes
CREDITS -rw-r--r-- 96.9 KB
Kbuild -rw-r--r-- 1.7 KB
Kconfig -rw-r--r-- 563 bytes
MAINTAINERS -rw-r--r-- 481.0 KB
Makefile -rw-r--r-- 59.1 KB
README -rw-r--r-- 727 bytes

README

back to top