Commit 8f437105 authored by Boqun Feng's avatar Boqun Feng Committed by Wei Liu
Browse files

scsi: storvsc: Support PAGE_SIZE larger than 4K 



Hyper-V always use 4k page size (HV_HYP_PAGE_SIZE), so when
communicating with Hyper-V, a guest should always use HV_HYP_PAGE_SIZE
as the unit for page related data. For storvsc, the data is
vmbus_packet_mpb_array. And since in scsi_cmnd, sglist of pages (in unit
of PAGE_SIZE) is used, we need convert pages in the sglist of scsi_cmnd
into Hyper-V pages in vmbus_packet_mpb_array.

This patch does the conversion by dividing pages in sglist into Hyper-V
pages, offset and indexes in vmbus_packet_mpb_array are recalculated
accordingly.

Signed-off-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200916034817.30282-12-boqun.feng@gmail.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 061dc93e

drivers/scsi/storvsc_drv.c

+49 −7
Original line number Diff line number Diff line
@@ -1739,24 +1739,66 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) 
	payload_sz = sizeof(cmd_request->mpb);



	if (sg_count) {

		if (sg_count > MAX_PAGE_BUFFER_COUNT) {

		unsigned int hvpgoff = 0;

		unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK;

		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);

		u64 hvpfn;



			payload_sz = (sg_count * sizeof(u64) +

		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {



			payload_sz = (hvpg_count * sizeof(u64) +

				      sizeof(struct vmbus_packet_mpb_array));

			payload = kzalloc(payload_sz, GFP_ATOMIC);

			if (!payload)

				return SCSI_MLQUEUE_DEVICE_BUSY;

		}



		/*

		 * sgl is a list of PAGEs, and payload->range.pfn_array

		 * expects the page number in the unit of HV_HYP_PAGE_SIZE (the

		 * page size that Hyper-V uses, so here we need to divide PAGEs

		 * into HV_HYP_PAGE in case that PAGE_SIZE > HV_HYP_PAGE_SIZE.

		 * Besides, payload->range.offset should be the offset in one

		 * HV_HYP_PAGE.

		 */

		payload->range.len = length;

		payload->range.offset = sgl[0].offset;

		payload->range.offset = offset_in_hvpg;

		hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT;



		cur_sgl = sgl;

		for (i = 0; i < sg_count; i++) {

			payload->range.pfn_array[i] =

				page_to_pfn(sg_page((cur_sgl)));

		for (i = 0; i < hvpg_count; i++) {

			/*

			 * 'i' is the index of hv pages in the payload and

			 * 'hvpgoff' is the offset (in hv pages) of the first

			 * hv page in the the first page. The relationship

			 * between the sum of 'i' and 'hvpgoff' and the offset

			 * (in hv pages) in a payload page ('hvpgoff_in_page')

			 * is as follow:

			 *

			 * |------------------ PAGE -------------------|

			 * |   NR_HV_HYP_PAGES_IN_PAGE hvpgs in total  |

			 * |hvpg|hvpg| ...              |hvpg|... |hvpg|

			 * ^         ^                                 ^                 ^

			 * +-hvpgoff-+                                 +-hvpgoff_in_page-+

			 *           ^                                                   |

			 *           +--------------------- i ---------------------------+

			 */

			unsigned int hvpgoff_in_page =

				(i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE;



			/*

			 * Two cases that we need to fetch a page:

			 * 1) i == 0, the first step or

			 * 2) hvpgoff_in_page == 0, when we reach the boundary

			 *    of a page.

			 */

			if (hvpgoff_in_page == 0 || i == 0) {

				hvpfn = page_to_hvpfn(sg_page(cur_sgl));

				cur_sgl = sg_next(cur_sgl);

			}



			payload->range.pfn_array[i] = hvpfn + hvpgoff_in_page;

		}

	}



	cmd_request->payload = payload;

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