[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [BUG] repeated live migration for VM failed


On 22/05/17 12:11, Andrew Cooper wrote:
From 3d4ce135ea3b396bb63752c39e6234366d590c16 Mon Sep 17 00:00:00 2001
From: George Dunlap <george.dunlap@xxxxxxxxxx>
Date: Mon, 22 May 2017 11:38:31 +0100
Subject: [PATCH] Restore HVM_OP hypercall continuation (partial revert of

Commit ae20ccf removed the hypercall continuation logic from the end
of do_hvm_op(), claiming:

"This patch removes the need for handling HVMOP restarts, so that
infrastructure is removed."

That turns out to be false.  The removal of HVMOP_set_mem_type removed
the need to store a start iteration value in the hypercall
continuation, but a grep through hvm.c for ERESTART turns up at least
two places where do_hvm_op() may still need a hypercall continuation:

 * HVMOP_set_hvm_param can return -ERESTART when setting
HVM_PARAM_IDENT_PT in the event that it fails to acquire the domctl

 * HVMOP_flush_tlbs can return -ERESTART if several vcpus call it at
   the same time

In both cases, a simple restart (with no stored iteration information)
is necessary.

Add a check for -ERESTART again, along with a comment at the top of
the function regarding the lack of decoding any information from the
op value.

Reported-by: Xudong Hao <xudong.hao@xxxxxxxxx>
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Paul Durrant <paul.durrant@xxxxxxxxxx>

Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> (with the final
hunk removed)

Release-acked-by: Julien Grall <julien.grall@xxxxxxx>


Julien Grall

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.