From da8de3e9a8a8ed94857fd00a66afde0d67eba3f2 Mon Sep 17 00:00:00 2001
From: Chuck Tuffli <chuck@FreeBSD.org>
Date: Fri, 27 Mar 2020 15:28:00 +0000
Subject: [PATCH] bhyve: refactor NVMe PRP memcpy

Add a "copy direction" parameter to nvme_prp_memcpy such that data can
be copied to the memory specified by the PRP entries (current behavior)
or copied from the PRP entries (new behavior). The upcoming deallocate
functionality will use the copy from capability.

Reviewed by:	jhb, araujo
Approved by:	jhb (maintainer)
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D21837
---
 usr.sbin/bhyve/pci_nvme.c | 46 ++++++++++++++++++++++++++-------------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/usr.sbin/bhyve/pci_nvme.c b/usr.sbin/bhyve/pci_nvme.c
index 72ae4c81750..3dba1ff2c47 100644
--- a/usr.sbin/bhyve/pci_nvme.c
+++ b/usr.sbin/bhyve/pci_nvme.c
@@ -140,6 +140,11 @@ enum nvme_cmd_cdw11 {
 	NVME_CMD_CDW11_IV  = 0xFFFF0000,
 };
 
+enum nvme_copy_dir {
+	NVME_COPY_TO_PRP,
+	NVME_COPY_FROM_PRP,
+};
+
 #define	NVME_CQ_INTEN	0x01
 #define	NVME_CQ_INTCOAL	0x02
 
@@ -545,10 +550,10 @@ pci_nvme_init_controller(struct vmctx *ctx, struct pci_nvme_softc *sc)
 }
 
 static int
-nvme_prp_memcpy(struct vmctx *ctx, uint64_t prp1, uint64_t prp2, uint8_t *src,
-	size_t len)
+nvme_prp_memcpy(struct vmctx *ctx, uint64_t prp1, uint64_t prp2, uint8_t *b,
+	size_t len, enum nvme_copy_dir dir)
 {
-	uint8_t *dst;
+	uint8_t *p;
 	size_t bytes;
 
 	if (len > (8 * 1024)) {
@@ -559,14 +564,17 @@ nvme_prp_memcpy(struct vmctx *ctx, uint64_t prp1, uint64_t prp2, uint8_t *src,
 	bytes = PAGE_SIZE - (prp1 & PAGE_MASK);
 	bytes = MIN(bytes, len);
 
-	dst = vm_map_gpa(ctx, prp1, bytes);
-	if (dst == NULL) {
+	p = vm_map_gpa(ctx, prp1, bytes);
+	if (p == NULL) {
 		return (-1);
 	}
 
-	memcpy(dst, src, bytes);
+	if (dir == NVME_COPY_TO_PRP)
+		memcpy(p, b, bytes);
+	else
+		memcpy(b, p, bytes);
 
-	src += bytes;
+	b += bytes;
 
 	len -= bytes;
 	if (len == 0) {
@@ -575,12 +583,15 @@ nvme_prp_memcpy(struct vmctx *ctx, uint64_t prp1, uint64_t prp2, uint8_t *src,
 
 	len = MIN(len, PAGE_SIZE);
 
-	dst = vm_map_gpa(ctx, prp2, len);
-	if (dst == NULL) {
+	p = vm_map_gpa(ctx, prp2, len);
+	if (p == NULL) {
 		return (-1);
 	}
 
-	memcpy(dst, src, len);
+	if (dir == NVME_COPY_TO_PRP)
+		memcpy(p, b, len);
+	else
+		memcpy(b, p, len);
 
 	return (0);
 }
@@ -726,16 +737,19 @@ nvme_opc_get_log_page(struct pci_nvme_softc* sc, struct nvme_command* command,
 	switch (logpage) {
 	case NVME_LOG_ERROR:
 		nvme_prp_memcpy(sc->nsc_pi->pi_vmctx, command->prp1,
-		    command->prp2, (uint8_t *)&sc->err_log, logsize);
+		    command->prp2, (uint8_t *)&sc->err_log, logsize,
+		    NVME_COPY_TO_PRP);
 		break;
 	case NVME_LOG_HEALTH_INFORMATION:
 		/* TODO: present some smart info */
 		nvme_prp_memcpy(sc->nsc_pi->pi_vmctx, command->prp1,
-		    command->prp2, (uint8_t *)&sc->health_log, logsize);
+		    command->prp2, (uint8_t *)&sc->health_log, logsize,
+		    NVME_COPY_TO_PRP);
 		break;
 	case NVME_LOG_FIRMWARE_SLOT:
 		nvme_prp_memcpy(sc->nsc_pi->pi_vmctx, command->prp1,
-		    command->prp2, (uint8_t *)&sc->fw_log, logsize);
+		    command->prp2, (uint8_t *)&sc->fw_log, logsize,
+		    NVME_COPY_TO_PRP);
 		break;
 	default:
 		WPRINTF(("%s get log page %x command not supported",
@@ -760,12 +774,14 @@ nvme_opc_identify(struct pci_nvme_softc* sc, struct nvme_command* command,
 	switch (command->cdw10 & 0xFF) {
 	case 0x00: /* return Identify Namespace data structure */
 		nvme_prp_memcpy(sc->nsc_pi->pi_vmctx, command->prp1,
-		    command->prp2, (uint8_t *)&sc->nsdata, sizeof(sc->nsdata));
+		    command->prp2, (uint8_t *)&sc->nsdata, sizeof(sc->nsdata),
+		    NVME_COPY_TO_PRP);
 		break;
 	case 0x01: /* return Identify Controller data structure */
 		nvme_prp_memcpy(sc->nsc_pi->pi_vmctx, command->prp1,
 		    command->prp2, (uint8_t *)&sc->ctrldata,
-		    sizeof(sc->ctrldata));
+		    sizeof(sc->ctrldata),
+		    NVME_COPY_TO_PRP);
 		break;
 	case 0x02: /* list of 1024 active NSIDs > CDW1.NSID */
 		dest = vm_map_gpa(sc->nsc_pi->pi_vmctx, command->prp1,