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Re: [Qemu-devel] [PATCH v2] exec: fix access to ram_list.dirty_memory wh
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v2] exec: fix access to ram_list.dirty_memory when sync dirty bitmap |
Date: |
Wed, 28 Jun 2017 11:04:28 +0100 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
On Wed, Jun 28, 2017 at 04:37:04PM +0800, Haozhong Zhang wrote:
> In cpu_physical_memory_sync_dirty_bitmap(rb, start, ...), the 2nd
> argument 'start' is relative to the start of the ramblock 'rb'. When
> it's used to access the dirty memory bitmap of ram_list (i.e.
> ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION]->blocks[]), an offset to
> the start of all RAM (i.e. rb->offset) should be added to it, which has
> however been missed since c/s 6b6712efcc. For a ramblock of host memory
> backend whose offset is not zero, cpu_physical_memory_sync_dirty_bitmap()
> synchronizes the incorrect part of the dirty memory bitmap of ram_list
> to the per ramblock dirty bitmap. As a result, a guest with host
> memory backend may crash after migration.
>
> Fix it by adding the offset of ramblock when accessing the dirty memory
> bitmap of ram_list in cpu_physical_memory_sync_dirty_bitmap().
>
> Reported-by: Stefan Hajnoczi <address@hidden>
> Signed-off-by: Haozhong Zhang <address@hidden>
> ---
> Changes in v2:
> * Avoid shadowing variable 'offset'. (Paolo)
> ---
> include/exec/ram_addr.h | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
Tested-by: Stefan Hajnoczi <address@hidden>
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