From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Michael Kelley <mikelley@microsoft.com>
Cc: kys@microsoft.com, martin.petersen@oracle.com,
longli@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
jejb@linux.ibm.com, linux-hyperv@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: [PATCH 1/1] scsi: storvsc: Fix swiotlb bounce buffer leak in confidential VM
Date: Tue, 13 Dec 2022 21:55:13 -0500 [thread overview]
Message-ID: <yq1r0x2eltj.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <1670183564-76254-1-git-send-email-mikelley@microsoft.com> (Michael Kelley's message of "Sun, 4 Dec 2022 11:52:44 -0800")
Michael,
> 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.
Applied to 6.2/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2022-12-14 2:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-04 19:52 [PATCH 1/1] scsi: storvsc: Fix swiotlb bounce buffer leak in confidential VM Michael Kelley
2022-12-04 21:17 ` Dexuan Cui
2022-12-05 15:50 ` Tianyu Lan
2022-12-14 2:55 ` Martin K. Petersen [this message]
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