[SeaBIOS] Re: [UNVERIFIED SENDER] [PATCH 1/3] nvme: Record maximum allowed request size

[Sironi, Filippo]

________________________________________
From: Alexander Graf 
Sent: Tuesday, September 29, 2020 20:36
To: [e-mail]
Subject: [UNVERIFIED SENDER] [SeaBIOS] [PATCH 1/3] nvme: Record maximum allowed request size

NVMe has a limit on how many sectors it can handle at most within a single
request. Remember that number, so that in a follow-up patch, we can verify
that we don't exceed it.

Signed-off-by: Alexander Graf 
---
 src/hw/nvme-int.h |  8 +++++++-
 src/hw/nvme.c     | 13 +++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/hw/nvme-int.h b/src/hw/nvme-int.h
index 9f95dd8..674008a 100644
--- a/src/hw/nvme-int.h
+++ b/src/hw/nvme-int.h
@@ -117,6 +117,7 @@ struct nvme_namespace {

u32 block_size;
     u32 metadata_size;
+    u32 max_req_size;

/* Page aligned buffer of size NVME_PAGE_SIZE. */
     char *dma_buffer;
@@ -131,7 +132,12 @@ struct nvme_identify_ctrl {
     char mn[40];
     char fr[8];

-    char _boring[516 - 72];
+    u8 rab;
+    u8 ieee[3];
+    u8 cmic;
+    u8 mdts;
+
+    char _boring[516 - 78];

u32 nn;                     /* number of namespaces */
 };
diff --git a/src/hw/nvme.c b/src/hw/nvme.c
index 6a01204..2cde6a7 100644
--- a/src/hw/nvme.c
+++ b/src/hw/nvme.c
@@ -238,7 +238,8 @@ nvme_admin_identify_ns(struct nvme_ctrl *ctrl, u32 ns_id)
 }

static void
-nvme_probe_ns(struct nvme_ctrl *ctrl, struct nvme_namespace *ns, u32 ns_id)
+nvme_probe_ns(struct nvme_ctrl *ctrl, struct nvme_namespace *ns, u32 ns_id,
+              u8 mdts)
 {
     ns->ctrl  = ctrl;
     ns->ns_id = ns_id;
@@ -281,6 +282,14 @@ nvme_probe_ns(struct nvme_ctrl *ctrl, struct nvme_namespace *ns, u32 ns_id)
     ns->drive.blksize   = ns->block_size;
     ns->drive.sectors   = ns->lba_count;

+    if (mdts) {
+        ns->max_req_size = 1U << mdts;
+        dprintf(3, "NVME NS %u max request size: %d sectors\n",
+                ns->max_req_size);

The use of dprintf is incorrect, you're only providing one variable to print instead of two. You're missing the number of sectors.

+    } else {
+        ns->max_req_size = -1U;
+    }
+
     ns->dma_buffer = zalloc_page_aligned(&ZoneHigh, NVME_PAGE_SIZE);

char *desc = znprintf(MAXDESCSIZE, "NVMe NS %u: %llu MiB (%llu %u-byte "
@@ -567,7 +576,7 @@ nvme_controller_enable(struct nvme_ctrl *ctrl)
     /* Populate namespace IDs */
     int ns_idx;
     for (ns_idx = 0; ns_idx < ctrl->ns_count; ns_idx++) {
-        nvme_probe_ns(ctrl, &ctrl->ns[ns_idx], ns_idx + 1);
+        nvme_probe_ns(ctrl, &ctrl->ns[ns_idx], ns_idx + 1, identify->mdts);
     }

dprintf(3, "NVMe initialization complete!\n");
--
2.16.4

Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879

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Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879