[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Problem about dump-core
On 09/17/2014 12:38 AM, Ian Campbell wrote: > 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. Yes, we can check it more earlier. If the 4 error bits are set, is it a valid mfn? Thanks Wen Congyang > > Ian. > > . > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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