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: Boqun Feng <boqun.feng@xxxxxxxxx>
---
drivers/scsi/storvsc_drv.c | 60 ++++++++++++++++++++++++++++++++++----
1 file changed, 54 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 8f5f5dc863a4..3f6610717d4e 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1739,23 +1739,71 @@ 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 hvpg_idx = 0;
+ unsigned int j = 0;
+ unsigned long hvpg_offset = sgl->offset & ~HV_HYP_PAGE_MASK;
+ unsigned int hvpg_count = HVPFN_UP(hvpg_offset + length);
- 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.
+ */
payload->range.len = length;
- payload->range.offset = sgl[0].offset;
+ payload->range.offset = sgl[0].offset & ~HV_HYP_PAGE_MASK;
+ hvpg_idx = sgl[0].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, j = 0; i < sg_count; i++) {
+ /*
+ * "PAGE_SIZE / HV_HYP_PAGE_SIZE - hvpg_idx" is the #
+ * of HV_HYP_PAGEs in the current PAGE.
+ *
+ * "hvpg_count - j" is the # of unhandled HV_HYP_PAGEs.
+ *
+ * As shown in the following, the minimal of both is
+ * the # of HV_HYP_PAGEs, we need to handle in this
+ * PAGE.
+ *
+ * |------------------ PAGE ----------------------|
+ * | PAGE_SIZE / HV_HYP_PAGE_SIZE in total |
+ * |hvpg|hvpg| ... |hvpg|... |hvpg|
+ * ^ ^
+ * hvpg_idx |
+ * ^ |
+ * +---(hvpg_count - j)--+
+ *
+ * or
+ *
+ * |------------------ PAGE ----------------------|
+ * | PAGE_SIZE / HV_HYP_PAGE_SIZE in total |
+ * |hvpg|hvpg| ... |hvpg|... |hvpg|
+ * ^ ^
+ * hvpg_idx |
+ * ^ |
+ * +---(hvpg_count - j)------------------------+
+ */
+ unsigned int nr_hvpg = min((unsigned int)(PAGE_SIZE / HV_HYP_PAGE_SIZE) - hvpg_idx,
+ hvpg_count - j);
+ unsigned int k;
+
+ for (k = 0; k < nr_hvpg; k++) {
+ payload->range.pfn_array[j] =
+ page_to_hvpfn(sg_page((cur_sgl))) + hvpg_idx + k;
+ j++;
+ }
cur_sgl = sg_next(cur_sgl);
+ hvpg_idx = 0;
}
}
--
2.28.0
