Date: Sat, 09 Apr 2022 15:50:46 -0700 From: Ravi Pokala <rpokala@freebsd.org> To: Warner Losh <imp@FreeBSD.org>, <src-committers@FreeBSD.org>, <dev-commits-src-all@FreeBSD.org>, <dev-commits-src-main@FreeBSD.org> Subject: Re: 214df80a9cb3 - main - nvme: new define for size of host memory buffer sizes Message-ID: <3BC728DB-39BB-43BC-BECE-720FECB5B20D@panasas.com> In-Reply-To: <202204090506.239567Ag038413@gitrepo.freebsd.org> References: <202204090506.239567Ag038413@gitrepo.freebsd.org>
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-----Original Message-----
From: <owner-src-committers@freebsd.org> on behalf of Warner Losh <imp@Free=
BSD.org>
Date: 2022-04-08, Friday at 22:06
To: <src-committers@FreeBSD.org>, <dev-commits-src-all@FreeBSD.org>, <dev-c=
ommits-src-main@FreeBSD.org>
Subject: git: 214df80a9cb3 - main - nvme: new define for size of host memor=
y buffer sizes
The branch main has been updated by imp:
URL: https://cgit.FreeBSD.org/src/commit/?id=3D214df80a9cb3e95a140b13af7d=
19deec2bbfae76
commit 214df80a9cb3e95a140b13af7d19deec2bbfae76
Author: Warner Losh <imp@FreeBSD.org>
AuthorDate: 2022-04-09 05:01:06 +0000
Commit: Warner Losh <imp@FreeBSD.org>
CommitDate: 2022-04-09 05:05:25 +0000
nvme: new define for size of host memory buffer sizes
The nvme spec defines the various fields that specify sizes for hos=
t
memory buffers in terms of 4096 chunks. So, rather than use a bare =
4096
here, use NVME_HMB_UNITS. This is explicitly not the host page size=
of
4096, nor the default memory page size (mps) of the NVMe drive, but=
its
own thing and needs its own define.
Hi Warner,
Are you sure about that?=20
NVMe-1.4, Figure 297: Host Memory Buffer =E2=80=93 Host Memory Buffer Descriptor =
Entry
| Buffer Size (BSIZE): Indicates the number of contiguous
| memory page size (CC.MPS) units for this descriptor.
|=20
| Buffer Address (BADD): Indicates the host memory address for
| this descriptor aligned to the memory page size (CC.MPS).=20
| The lower bits (n:0) of this field indicate the offset
| within the memory page is 0h (e.g., if the memory page size
| is 4 KiB, then bits 11:00 shall be 0h; if the memory page
| size is 8 KiB, then bits 12:00 shall be 0h).
They both reference mps, not 4096 bytes.
-Ravi (rpokala@)
No functional change is intended, only the logical spelling of 4k.
Sponsored by: Netflix
---
sys/dev/nvme/nvme.h | 3 +++
sys/dev/nvme/nvme_ctrlr.c | 8 ++++----
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/sys/dev/nvme/nvme.h b/sys/dev/nvme/nvme.h
index f2ef2467c9b1..55e94c40dd2c 100644
--- a/sys/dev/nvme/nvme.h
+++ b/sys/dev/nvme/nvme.h
@@ -62,6 +62,9 @@
/* Cap transfers by the maximum addressable by page-sized PRP (4KB -> =
2MB). */
#define NVME_MAX_XFER_SIZE MIN(maxphys, (PAGE_SIZE/8*PAGE_SIZE))
+/* Host memory buffer sizes are always in 4096 byte chunks */
+#define NVME_HMB_UNITS 4096
+
/* Register field definitions */
#define NVME_CAP_LO_REG_MQES_SHIFT (0)
#define NVME_CAP_LO_REG_MQES_MASK (0xFFFF)
diff --git a/sys/dev/nvme/nvme_ctrlr.c b/sys/dev/nvme/nvme_ctrlr.c
index 95a2b5c4285d..6996b3151b0d 100644
--- a/sys/dev/nvme/nvme_ctrlr.c
+++ b/sys/dev/nvme/nvme_ctrlr.c
@@ -936,11 +936,11 @@ nvme_ctrlr_hmb_alloc(struct nvme_controller *ctrl=
r)
max =3D (uint64_t)physmem * PAGE_SIZE / 20;
TUNABLE_UINT64_FETCH("hw.nvme.hmb_max", &max);
- min =3D (long long unsigned)ctrlr->cdata.hmmin * 4096;
+ min =3D (long long unsigned)ctrlr->cdata.hmmin * NVME_HMB_UNITS;
if (max =3D=3D 0 || max < min)
return;
- pref =3D MIN((long long unsigned)ctrlr->cdata.hmpre * 4096, max);
- minc =3D MAX(ctrlr->cdata.hmminds * 4096, PAGE_SIZE);
+ pref =3D MIN((long long unsigned)ctrlr->cdata.hmpre * NVME_HMB_UNITS, m=
ax);
+ minc =3D MAX(ctrlr->cdata.hmminds * NVME_HMB_UNITS, PAGE_SIZE);
if (min > 0 && ctrlr->cdata.hmmaxd > 0)
minc =3D MAX(minc, min / ctrlr->cdata.hmmaxd);
ctrlr->hmb_chunk =3D pref;
@@ -1023,7 +1023,7 @@ again:
for (i =3D 0; i < ctrlr->hmb_nchunks; i++) {
ctrlr->hmb_desc_vaddr[i].addr =3D
htole64(ctrlr->hmb_chunks[i].hmbc_paddr);
- ctrlr->hmb_desc_vaddr[i].size =3D htole32(ctrlr->hmb_chunk / 4096);
+ ctrlr->hmb_desc_vaddr[i].size =3D htole32(ctrlr->hmb_chunk / NVME_HMB_=
UNITS);
}
bus_dmamap_sync(ctrlr->hmb_desc_tag, ctrlr->hmb_desc_map,
BUS_DMASYNC_PREWRITE);
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