Messages in this thread | | | Date | Mon, 5 Dec 2022 23:50:49 +0800 | Subject | Re: [PATCH 1/1] scsi: storvsc: Fix swiotlb bounce buffer leak in confidential VM | From | Tianyu Lan <> |
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On 12/5/2022 3:52 AM, Michael Kelley wrote: > storvsc_queuecommand() maps the scatter/gather list using scsi_dma_map(), > which in a confidential VM allocates swiotlb bounce buffers. If the > I/O submission fails in storvsc_do_io(), the I/O is typically retried > by higher level code, but the bounce buffer memory is never freed. > The mostly like cause of I/O submission failure is a full VMBus > channel ring buffer, which is not uncommon under high I/O loads. > Eventually enough bounce buffer memory leaks that the confidential > VM can't do any I/O. The same problem can arise in a non-confidential > VM with kernel boot parameter swiotlb=force. > > Fix this by doing scsi_dma_unmap() in the case of an I/O submission > error, which frees the bounce buffer memory. > > Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver") > Signed-off-by: Michael Kelley<mikelley@microsoft.com> Nice catch! Thanks to fix this. Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
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