| Message ID | 20200910143455.109293-12-boqun.feng@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Hyper-V: Support PAGE_SIZE larger than 4K | expand |
From: Boqun Feng <boqun.feng@gmail.com> Sent: Thursday, September 10, 2020 7:35 AM > > 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@gmail.com> > --- > drivers/scsi/storvsc_drv.c | 54 +++++++++++++++++++++++++++++++++----- > 1 file changed, 47 insertions(+), 7 deletions(-) > > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c > index 8f5f5dc863a4..119b76ca24a1 100644 > --- a/drivers/scsi/storvsc_drv.c > +++ b/drivers/scsi/storvsc_drv.c > @@ -1739,23 +1739,63 @@ 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 hvpg_offset = sgl->offset & ~HV_HYP_PAGE_MASK; This is a minor nit. The above expression uses sgl->offset. Code below uses sgl[0].offset. They're the same but the inconsistency sticks out a bit. > + unsigned int hvpg_count = HVPFN_UP(hvpg_offset + 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. > + */ > payload->range.len = length; > - payload->range.offset = sgl[0].offset; > + payload->range.offset = sgl[0].offset & ~HV_HYP_PAGE_MASK; Another nit. The right hand side of the above assignment is already calculated as hvpg_offset. Nits aside, Reviewed-by: Michael Kelley <mikelley@microsoft.com> > + hvpgoff = 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))); > - cur_sgl = sg_next(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; > } > } > > -- > 2.28.0
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 8f5f5dc863a4..119b76ca24a1 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -1739,23 +1739,63 @@ 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 hvpg_offset = sgl->offset & ~HV_HYP_PAGE_MASK; + unsigned int hvpg_count = HVPFN_UP(hvpg_offset + 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. + */ payload->range.len = length; - payload->range.offset = sgl[0].offset; + payload->range.offset = sgl[0].offset & ~HV_HYP_PAGE_MASK; + hvpgoff = 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))); - cur_sgl = sg_next(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; } }
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@gmail.com> --- drivers/scsi/storvsc_drv.c | 54 +++++++++++++++++++++++++++++++++----- 1 file changed, 47 insertions(+), 7 deletions(-)