On Sep 19 17:07, Alan Adamson wrote:
Adds support for the controller atomic parameters: AWUN and AWUPF. Atomic
Compare and Write Unit (ACWU) is not currently supported.
Writes that adhere to the ACWU and AWUPF parameters are guaranteed to be atomic.
New NVMe QEMU Parameters (See NVMe Specification for details):
atomic.dn (default off) - Set the value of Disable Normal.
atomic.awun=UINT16 (default: 0)
atomic.awupf=UINT16 (default: 0)
By default (Disable Normal set to zero), the maximum atomic write size is
set to the AWUN value. If Disable Normal is set, the maximum atomic write
size is set to AWUPF.
Signed-off-by: Alan Adamson <alan.adam...@oracle.com>
Reviewed-by: Klaus Jensen <k.jen...@samsung.com>
---
hw/nvme/ctrl.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++-
hw/nvme/nvme.h | 12 ++++
2 files changed, 175 insertions(+), 1 deletion(-)
diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 9e94a2405407..0af46c57ee86 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -40,6 +40,9 @@
* sriov_vi_flexible=<N[optional]> \
* sriov_max_vi_per_vf=<N[optional]> \
* sriov_max_vq_per_vf=<N[optional]> \
+ * atomic.dn=<on|off[optional]>, \
+ * atomic.awun<N[optional]>, \
+ * atomic.awupf<N[optional]>, \
* subsys=<subsys_id>
* -device nvme-ns,drive=<drive_id>,bus=<bus_name>,nsid=<nsid>,\
* zoned=<true|false[optional]>, \
@@ -254,6 +257,7 @@ static const uint32_t nvme_feature_cap[NVME_FID_MAX] = {
[NVME_ERROR_RECOVERY] = NVME_FEAT_CAP_CHANGE | NVME_FEAT_CAP_NS,
[NVME_VOLATILE_WRITE_CACHE] = NVME_FEAT_CAP_CHANGE,
[NVME_NUMBER_OF_QUEUES] = NVME_FEAT_CAP_CHANGE,
+ [NVME_WRITE_ATOMICITY] = NVME_FEAT_CAP_CHANGE,
[NVME_ASYNCHRONOUS_EVENT_CONF] = NVME_FEAT_CAP_CHANGE,
[NVME_TIMESTAMP] = NVME_FEAT_CAP_CHANGE,
[NVME_HOST_BEHAVIOR_SUPPORT] = NVME_FEAT_CAP_CHANGE,
@@ -6293,8 +6297,10 @@ defaults:
if (ret) {
return ret;
}
- goto out;
+ break;
+ case NVME_WRITE_ATOMICITY:
+ result = n->dn;
break;
default:
result = nvme_feature_default[fid];
@@ -6378,6 +6384,8 @@ static uint16_t nvme_set_feature(NvmeCtrl *n, NvmeRequest
*req)
uint8_t save = NVME_SETFEAT_SAVE(dw10);
uint16_t status;
int i;
+ NvmeIdCtrl *id = &n->id_ctrl;
+ NvmeAtomic *atomic = &n->atomic;
trace_pci_nvme_setfeat(nvme_cid(req), nsid, fid, save, dw11);
@@ -6530,6 +6538,22 @@ static uint16_t nvme_set_feature(NvmeCtrl *n, NvmeRequest *req)
return NVME_CMD_SEQ_ERROR | NVME_DNR;
case NVME_FDP_EVENTS:
return nvme_set_feature_fdp_events(n, ns, req);
+ case NVME_WRITE_ATOMICITY:
+
+ n->dn = 0x1 & dw11;
+
+ if (n->dn) {
+ atomic->atomic_max_write_size = id->awupf + 1;
+ } else {
+ atomic->atomic_max_write_size = id->awun + 1;
+ }
le16_to_cpu()'s needed here.
+
+ if (atomic->atomic_max_write_size == 1) {
+ atomic->atomic_writes = 0;
+ } else {
+ atomic->atomic_writes = 1;
+ }
+ break;
default:
return NVME_FEAT_NOT_CHANGEABLE | NVME_DNR;
}
@@ -7227,6 +7251,80 @@ static void nvme_update_sq_tail(NvmeSQueue *sq)
trace_pci_nvme_update_sq_tail(sq->sqid, sq->tail);
}
+#define NVME_ATOMIC_NO_START 0
+#define NVME_ATOMIC_START_ATOMIC 1
+#define NVME_ATOMIC_START_NONATOMIC 2
+
+static int nvme_atomic_write_check(NvmeCtrl *n, NvmeCmd *cmd,
+ NvmeAtomic *atomic)
+{
+ NvmeRwCmd *rw = (NvmeRwCmd *)cmd;
+ uint64_t slba = le64_to_cpu(rw->slba);
+ uint32_t nlb = (uint32_t)le16_to_cpu(rw->nlb);
+ uint64_t elba = slba + nlb;
+ bool cmd_atomic_wr = true;
+ int i;
+
+ if ((cmd->opcode == NVME_CMD_READ) || ((cmd->opcode == NVME_CMD_WRITE) &&
+ ((rw->nlb + 1) > atomic->atomic_max_write_size))) {
+ cmd_atomic_wr = false;
+ }
+
+ /*
+ * Walk the queues to see if there are any atomic conflicts.
+ */
+ for (i = 1; i < n->params.max_ioqpairs + 1; i++) {
+ NvmeSQueue *sq;
+ NvmeRequest *req;
+ NvmeRwCmd *req_rw;
+ uint64_t req_slba;
+ uint32_t req_nlb;
+ uint64_t req_elba;
+
+ sq = n->sq[i];
+ if (!sq) {
+ break;
This needs to be a `continue`.
+ }
+
+ /*
+ * Walk all the requests on a given queue.
+ */
+ QTAILQ_FOREACH(req, &sq->out_req_list, entry) {
+ req_rw = (NvmeRwCmd *)&req->cmd;
+
+ if (((req_rw->opcode == NVME_CMD_WRITE) || (req_rw->opcode ==
NVME_CMD_READ)) &&
+ (cmd->nsid == req->ns->params.nsid)) {
+ req_slba = le64_to_cpu(req_rw->slba);
+ req_nlb = (uint32_t)le16_to_cpu(req_rw->nlb);
+ req_elba = req_slba + req_nlb;
+
+ if (cmd_atomic_wr) {
+ if ((elba >= req_slba) && (slba <= req_elba)) {
+ return NVME_ATOMIC_NO_START;
+ }
+ } else {
+ if (req->atomic_write && ((elba >= req_slba) &&
+ (slba <= req_elba))) {
+ return NVME_ATOMIC_NO_START;
+ }
+ }
+ }
+ }
+ }
+ if (cmd_atomic_wr) {
+ return NVME_ATOMIC_START_ATOMIC;
+ }
+ return NVME_ATOMIC_START_NONATOMIC;
+}
+
+static NvmeAtomic *nvme_get_atomic(NvmeCtrl *n, NvmeCmd *cmd)
+{
+ if (n->atomic.atomic_writes) {
+ return &n->atomic;
+ }
+ return NULL;
+}
+
static void nvme_process_sq(void *opaque)
{
NvmeSQueue *sq = opaque;
@@ -7243,6 +7341,9 @@ static void nvme_process_sq(void *opaque)
}
while (!(nvme_sq_empty(sq) || QTAILQ_EMPTY(&sq->req_list))) {
+ NvmeAtomic *atomic;
+ bool cmd_is_atomic;
+
addr = sq->dma_addr + (sq->head << NVME_SQES);
if (nvme_addr_read(n, addr, (void *)&cmd, sizeof(cmd))) {
trace_pci_nvme_err_addr_read(addr);
@@ -7250,6 +7351,28 @@ static void nvme_process_sq(void *opaque)
stl_le_p(&n->bar.csts, NVME_CSTS_FAILED);
break;
}
+
+ atomic = nvme_get_atomic(n, &cmd);
+
+ cmd_is_atomic = false;
+ if (sq->sqid && atomic) {
+ int ret;
+
+ qemu_mutex_lock(&atomic->atomic_lock);
I don't think this needs to be protected by a lock. The nvme emulation
is running in the main loop, so a Set Feature cannot be processed at the
same time as this. I think that is what we are expecting to guard
against?
If I/O queues were processed from an iothread, this would be needed, but
then we also need to take the lock when processing the feature and a
bunch of other stuff might become more complicated.
For now, I think it can just be dropped since if we enable the user to
attach an iothread, my intention is to reduce such complexity by
disabling all the "faked" features of the device.
