From e3d52209b0158a2753463b98245fe3dc0cdf25ce Mon Sep 17 00:00:00 2001 From: Olaf Hering Date: Thu, 9 Feb 2012 18:47:53 +0000 Subject: [PATCH] xenpaging: deal with MEM_EVENT_FLAG_EVICT_FAIL request in tools/xenpaging If a page is nominated but not evicted,then dom0 accesses the page,it will change the page's p2mt to be p2m_ram_paging_in,and the req.flags is MEM_EVENT_FLAG_EVICT_FAIL;so it will fail in p2m_mem_paging_evict() because of the p2mt;and paging->num_paged_out will not increase in this case;After the paging process is terminated, the p2mt p2m_ram_paging_in still remains in p2m table.Once domU accesses the nominated page,it will result in BSOD or vm'stuck. The patch adds the dealing of this request to resume the page before xenpaging is ended. [ This can happen if p2m_mem_paging_populate() was called by a foreign domain. In this case MEM_EVENT_FLAG_VCPU_PAUSED is not set and xenpaging will not sent a response. And in this case the ring is in an inconsistent state anyway, new requests cant be added, I think. - Olaf ] Signed-off-by: hongkaixing Signed-off-by: shizhen Acked-by: Olaf Hering Committed-by: Ian Jackson --- tools/xenpaging/xenpaging.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/xenpaging/xenpaging.c b/tools/xenpaging/xenpaging.c index 101c4e286..2e8c10d14 100644 --- a/tools/xenpaging/xenpaging.c +++ b/tools/xenpaging/xenpaging.c @@ -911,7 +911,7 @@ int main(int argc, char *argv[]) !!(req.flags & MEM_EVENT_FLAG_EVICT_FAIL) ); /* Tell Xen to resume the vcpu */ - if ( req.flags & MEM_EVENT_FLAG_VCPU_PAUSED ) + if (( req.flags & MEM_EVENT_FLAG_VCPU_PAUSED ) || ( req.flags & MEM_EVENT_FLAG_EVICT_FAIL )) { /* Prepare the response */ rsp.gfn = req.gfn; -- 2.39.5