[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Problem about dump-core
On Tue, 2014-09-16 at 15:23 +0800, Wen Congyang wrote: > On 09/16/2014 10:35 AM, Wen Congyang wrote: > > Hi, everyone: > > > > The command 'xl dump-core' will fail after migration. The guest is HVM > > guest(without pv driver). > > I use the newest staging branch to test. Both source and dest dom0 use the > > same kernel. > > The kernel version is 3.2, and it only supports IOCTL_PRIVCMD_MMAPBATCH. > > After more investigation, the reason is that the mfn is ~0UL, and > xc_map_foreign_range() > doesn't return NULL on dest host. > > This patch can fix this problem: > > From: Wen Congyang <wency@xxxxxxxxxxxxxx> > Date: Tue, 16 Sep 2014 14:56:03 +0800 > Subject: [PATCH] check if mfn is valid before checking if > PRIVCMD_MMAPBATCH_MFN_ERROR is set > > If mfn is invalid, ioctl(fd, IOCTL_PRIVCMD_MMAPBATCH, ..) also returns 0, > and we set mfn to mfn | PRIVCMD_MMAPBATCH_MFN_ERROR. But if mfn is ~0UL, > pfn[i] ^ arr[i] returns 0, and we cannot find this error. So we should > check if mfn is valid first before testing pfn[i] ^ arr[i]. I don't think we can reliably distinguish between a large MFN and an error with this approach, can we? I suspect it would be better to perform a check before making the hypercall that the 4 (?) error bits are not set in the input. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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