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Date:      Mon, 29 Jun 2020 00:31:27 +0000 (UTC)
From:      Chuck Tuffli <chuck@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r362749 - head/usr.sbin/bhyve
Message-ID:  <202006290031.05T0VRCv047109@repo.freebsd.org>
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Author: chuck
Date: Mon Jun 29 00:31:27 2020
New Revision: 362749
URL: https://svnweb.freebsd.org/changeset/base/362749

Log:
  bhyve: Consolidate NVMe CQ update
  
  Consolidate the code which writes Completion Queue entries and updates
  the CQ doorbell value. While in the neighborhood, convert the "toggle CQ
  phase bit" code to use an XOR operation instead of an "if/else" branch.
  
  Tested by:	Jason Tubnor
  MFC after:	2 weeks
  Differential Revision: https://reviews.freebsd.org/D24882

Modified:
  head/usr.sbin/bhyve/pci_nvme.c

Modified: head/usr.sbin/bhyve/pci_nvme.c
==============================================================================
--- head/usr.sbin/bhyve/pci_nvme.c	Mon Jun 29 00:31:24 2020	(r362748)
+++ head/usr.sbin/bhyve/pci_nvme.c	Mon Jun 29 00:31:27 2020	(r362749)
@@ -329,16 +329,6 @@ pci_nvme_status_genc(uint16_t *status, uint16_t code)
 	pci_nvme_status_tc(status, NVME_SCT_GENERIC, code);
 }
 
-static __inline void
-pci_nvme_toggle_phase(uint16_t *status, int prev)
-{
-
-	if (prev)
-		*status &= ~NVME_STATUS_P;
-	else
-		*status |= NVME_STATUS_P;
-}
-
 /*
  * Initialize the requested number or IO Submission and Completion Queues.
  * Admin queues are allocated implicitly.
@@ -617,6 +607,7 @@ pci_nvme_init_controller(struct vmctx *ctx, struct pci
 	sc->compl_queues[0].size = acqs;
 	sc->compl_queues[0].qbase = vm_map_gpa(ctx, sc->regs.acq,
 	         sizeof(struct nvme_completion) * acqs);
+
 	DPRINTF("%s mapping Admin-CQ guest 0x%lx, host: %p",
 	        __func__, sc->regs.acq, sc->compl_queues[0].qbase);
 }
@@ -668,6 +659,45 @@ nvme_prp_memcpy(struct vmctx *ctx, uint64_t prp1, uint
 	return (0);
 }
 
+/*
+ * Write a Completion Queue Entry update
+ *
+ * Write the completion and update the doorbell value
+ */
+static void
+pci_nvme_cq_update(struct pci_nvme_softc *sc,
+		struct nvme_completion_queue *cq,
+		uint32_t cdw0,
+		uint16_t cid,
+		uint16_t sqid,
+		uint16_t status)
+{
+	struct nvme_submission_queue *sq = &sc->submit_queues[sqid];
+	struct nvme_completion *cqe;
+
+	assert(cq->qbase != NULL);
+
+	pthread_mutex_lock(&cq->mtx);
+
+	cqe = &cq->qbase[cq->tail];
+
+	/* Flip the phase bit */
+	status |= (cqe->status ^ NVME_STATUS_P) & NVME_STATUS_P_MASK;
+
+	cqe->cdw0 = cdw0;
+	cqe->sqhd = sq->head;
+	cqe->sqid = sqid;
+	cqe->cid = cid;
+	cqe->status = status;
+
+	cq->tail++;
+	if (cq->tail >= cq->size) {
+		cq->tail = 0;
+	}
+
+	pthread_mutex_unlock(&cq->mtx);
+}
+
 static int
 nvme_opc_delete_io_sq(struct pci_nvme_softc* sc, struct nvme_command* command,
 	struct nvme_completion* compl)
@@ -757,6 +787,7 @@ static int
 nvme_opc_create_io_cq(struct pci_nvme_softc* sc, struct nvme_command* command,
 	struct nvme_completion* compl)
 {
+
 	if (command->cdw11 & NVME_CMD_CDW11_PC) {
 		uint16_t qid = command->cdw10 & 0xffff;
 		struct nvme_completion_queue *ncq;
@@ -1191,24 +1222,11 @@ pci_nvme_handle_admin_cmd(struct pci_nvme_softc* sc, u
 		sqhead = (sqhead + 1) % sq->size;
 
 		if (NVME_COMPLETION_VALID(compl)) {
-			struct nvme_completion *cp;
-			int phase;
-
-			pthread_mutex_lock(&cq->mtx);
-
-			cp = &(cq->qbase)[cq->tail];
-			cp->cdw0 = compl.cdw0;
-			cp->sqid = 0;
-			cp->sqhd = sqhead;
-			cp->cid = cmd->cid;
-
-			phase = NVME_STATUS_GET_P(cp->status);
-			cp->status = compl.status;
-			pci_nvme_toggle_phase(&cp->status, phase);
-
-			cq->tail = (cq->tail + 1) % cq->size;
-
-			pthread_mutex_unlock(&cq->mtx);
+			pci_nvme_cq_update(sc, &sc->compl_queues[0],
+			    compl.cdw0,
+			    cmd->cid,
+			    0,		/* SQID */
+			    compl.status);
 		}
 	}
 
@@ -1311,32 +1329,16 @@ pci_nvme_set_completion(struct pci_nvme_softc *sc,
 	uint32_t cdw0, uint16_t status)
 {
 	struct nvme_completion_queue *cq = &sc->compl_queues[sq->cqid];
-	struct nvme_completion *compl;
-	int phase;
 
 	DPRINTF("%s sqid %d cqid %u cid %u status: 0x%x 0x%x",
 		 __func__, sqid, sq->cqid, cid, NVME_STATUS_GET_SCT(status),
 		 NVME_STATUS_GET_SC(status));
 
-	pthread_mutex_lock(&cq->mtx);
-
-	assert(cq->qbase != NULL);
-
-	compl = &cq->qbase[cq->tail];
-
-	compl->cdw0 = cdw0;
-	compl->sqid = sqid;
-	compl->sqhd = sq->head;
-	compl->cid = cid;
-
-	// toggle phase
-	phase = NVME_STATUS_GET_P(compl->status);
-	compl->status = status;
-	pci_nvme_toggle_phase(&compl->status, phase);
-
-	cq->tail = (cq->tail + 1) % cq->size;
-
-	pthread_mutex_unlock(&cq->mtx);
+	pci_nvme_cq_update(sc, cq,
+	    0,		/* CDW0 */
+	    cid,
+	    sqid,
+	    status);
 
 	if (cq->head != cq->tail) {
 		if (cq->intr_en & NVME_CQ_INTEN) {

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