Re: SCSI driver for VMware's virtual HBA - V5.

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Forgot to copy the virtualization list..

On Wed, 2009-09-30 at 11:53 -0700, Alok Kataria wrote:
> Hi James,
> 
> Given that their are no more modification requests, I think this driver
> should be ready for prime time now. I have incorporated the remaining
> few outstanding comments while rebasing the patch for 32-rc1.
> 
> Please consider this for the SCSI tree. Also let me know if you have any
> feedback. Thanks.
> 
> VMware PVSCSI driver - v5.
> 
> Changelog (v5-v4)
> - use bool for pvscsi _disable_msi, _disable_msix, _use_msg
> - fix for 16 byte CDBs, max_cmd_len should be initialized to 16.
> - bump the driver version.
> - add <pv-drivers@xxxxxxxxxx> in the MAINTAINERS file.
> - rebase to 2.6.32-rc1.
> 
> Changelog (v4-v3) 
> - use size_t type for a loop iterator.
> - use IS_ALIGNED instead of ~PAGE_MASK, for alignment checks
> - use scsi_dma_ map/unmap API's
> - reduce the pvscsi_info buffer to 256 bytes
> - code cleanup in pvscsi_shutdown_intr
> 
> Changelog (v3-v2)
> - use kmalloc for allocating sg_lists. And pci_map it for device access.
> - re-use pdev->revision for setting up adapter->rev.
> 
> Changelog (v2-v1)
> - use PCI_VDEVICE instead of PCI_DEVICE.
> - use list_first_entry
> - use parenthesis for every sizeof usage
> - get rid of all #ifdef for CONFIG_PCI_MSI
> - use PVSCSI_MEM_SPACE_SIZE while checking for MMIO resource len.
> - use kcalloc instead of kmalloc.
> - replaced a couple of scmd_printk usage with dev_dbg
> - use dev_info and pr_info at couple of places.
> - add a comment to pvscsi_map_context
> - Add entry in MAINTAINERS.
> 
> Patch applies on top of 2.6.32-rc1.
> 
> --
> 
> SCSI driver for VMware's virtual HBA.
> 
> From: Alok N Kataria <akataria@xxxxxxxxxx>
> 
> This is a driver for VMware's paravirtualized SCSI device,
> which should improve disk performance for guests running
> under control of VMware hypervisors that support such devices.
> 
> Signed-off-by: Alok N Kataria <akataria@xxxxxxxxxx>
> ---
> 
>  MAINTAINERS           |    8 
>  drivers/scsi/Kconfig  |    8 
>  drivers/scsi/Makefile |    1 
>  drivers/scsi/pvscsi.c | 1393 +++++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/scsi/pvscsi.h |  397 ++++++++++++++
>  5 files changed, 1807 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/scsi/pvscsi.c
>  create mode 100644 drivers/scsi/pvscsi.h
> 
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c450f3a..45de4b3 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5608,6 +5608,14 @@ S:	Maintained
>  F:	drivers/vlynq/vlynq.c
>  F:	include/linux/vlynq.h
>  
> +VMware PVSCSI driver
> +M:	Alok Kataria <akataria@xxxxxxxxxx>
> +M:	VMware PV-Drivers <pv-drivers@xxxxxxxxxx>
> +L:	linux-scsi@xxxxxxxxxxxxxxx
> +S:	Maintained
> +F:	drivers/scsi/pvscsi.c
> +F:	drivers/scsi/pvscsi.h
> +
>  VOLTAGE AND CURRENT REGULATOR FRAMEWORK
>  M:	Liam Girdwood <lrg@xxxxxxxxxxxxxxx>
>  M:	Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
> index 82bb3b2..5a19ae0 100644
> --- a/drivers/scsi/Kconfig
> +++ b/drivers/scsi/Kconfig
> @@ -620,6 +620,14 @@ config SCSI_FLASHPOINT
>  	  substantial, so users of MultiMaster Host Adapters may not
>  	  wish to include it.
>  
> +config VMWARE_PVSCSI
> +	tristate "VMware PVSCSI driver support"
> +	depends on PCI && SCSI && X86
> +	help
> +	  This driver supports VMware's para virtualized SCSI HBA.
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called pvscsi.
> +
>  config LIBFC
>  	tristate "LibFC module"
>  	select SCSI_FC_ATTRS
> diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
> index 61a94af..8ddad00 100644
> --- a/drivers/scsi/Makefile
> +++ b/drivers/scsi/Makefile
> @@ -131,6 +131,7 @@ obj-$(CONFIG_PS3_ROM)		+= ps3rom.o
>  obj-$(CONFIG_SCSI_CXGB3_ISCSI)	+= libiscsi.o libiscsi_tcp.o cxgb3i/
>  obj-$(CONFIG_SCSI_BNX2_ISCSI)	+= libiscsi.o bnx2i/
>  obj-$(CONFIG_SCSI_PMCRAID)	+= pmcraid.o
> +obj-$(CONFIG_VMWARE_PVSCSI)	+= pvscsi.o
>  
>  obj-$(CONFIG_ARM)		+= arm/
>  
> diff --git a/drivers/scsi/pvscsi.c b/drivers/scsi/pvscsi.c
> new file mode 100644
> index 0000000..f0ba207
> --- /dev/null
> +++ b/drivers/scsi/pvscsi.c
> @@ -0,0 +1,1393 @@
> +/*
> + * Linux driver for VMware's para-virtualized SCSI HBA.
> + *
> + * Copyright (C) 2008-2009, VMware, Inc. All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; version 2 of the License and no later version.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
> + * NON INFRINGEMENT.  See the GNU General Public License for more
> + * details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
> + *
> + * Maintained by: Alok N Kataria <akataria@xxxxxxxxxx>
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/types.h>
> +#include <linux/interrupt.h>
> +#include <linux/workqueue.h>
> +#include <linux/pci.h>
> +
> +#include <scsi/scsi.h>
> +#include <scsi/scsi_host.h>
> +#include <scsi/scsi_cmnd.h>
> +#include <scsi/scsi_device.h>
> +
> +#include "pvscsi.h"
> +
> +#define PVSCSI_LINUX_DRIVER_DESC "VMware PVSCSI driver"
> +
> +MODULE_DESCRIPTION(PVSCSI_LINUX_DRIVER_DESC);
> +MODULE_AUTHOR("VMware, Inc.");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION(PVSCSI_DRIVER_VERSION_STRING);
> +
> +#define PVSCSI_DEFAULT_NUM_PAGES_PER_RING	8
> +#define PVSCSI_DEFAULT_NUM_PAGES_MSG_RING	1
> +#define PVSCSI_DEFAULT_QUEUE_DEPTH		64
> +#define SGL_SIZE				PAGE_SIZE
> +
> +#define pvscsi_dev(adapter) (&(adapter->dev->dev))
> +
> +struct pvscsi_sg_list {
> +	struct PVSCSISGElement sge[PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT];
> +};
> +
> +struct pvscsi_ctx {
> +	/*
> +	 * The index of the context in cmd_map serves as the context ID for a
> +	 * 1-to-1 mapping completions back to requests.
> +	 */
> +	struct scsi_cmnd	*cmd;
> +	struct pvscsi_sg_list	*sgl;
> +	struct list_head	list;
> +	dma_addr_t		dataPA;
> +	dma_addr_t		sensePA;
> +	dma_addr_t		sglPA;
> +};
> +
> +struct pvscsi_adapter {
> +	char				*mmioBase;
> +	unsigned int			irq;
> +	u8				rev;
> +	bool				use_msi;
> +	bool				use_msix;
> +	bool				use_msg;
> +
> +	spinlock_t			hw_lock;
> +
> +	struct workqueue_struct		*workqueue;
> +	struct work_struct		work;
> +
> +	struct PVSCSIRingReqDesc	*req_ring;
> +	unsigned			req_pages;
> +	unsigned			req_depth;
> +	dma_addr_t			reqRingPA;
> +
> +	struct PVSCSIRingCmpDesc	*cmp_ring;
> +	unsigned			cmp_pages;
> +	dma_addr_t			cmpRingPA;
> +
> +	struct PVSCSIRingMsgDesc	*msg_ring;
> +	unsigned			msg_pages;
> +	dma_addr_t			msgRingPA;
> +
> +	struct PVSCSIRingsState		*rings_state;
> +	dma_addr_t			ringStatePA;
> +
> +	struct pci_dev			*dev;
> +	struct Scsi_Host		*host;
> +
> +	struct list_head		cmd_pool;
> +	struct pvscsi_ctx		*cmd_map;
> +};
> +
> +
> +/* Command line parameters */
> +static int pvscsi_ring_pages     = PVSCSI_DEFAULT_NUM_PAGES_PER_RING;
> +static int pvscsi_msg_ring_pages = PVSCSI_DEFAULT_NUM_PAGES_MSG_RING;
> +static int pvscsi_cmd_per_lun    = PVSCSI_DEFAULT_QUEUE_DEPTH;
> +static bool pvscsi_disable_msi;
> +static bool pvscsi_disable_msix;
> +static bool pvscsi_use_msg       = true;
> +
> +#define PVSCSI_RW (S_IRUSR | S_IWUSR)
> +
> +module_param_named(ring_pages, pvscsi_ring_pages, int, PVSCSI_RW);
> +MODULE_PARM_DESC(ring_pages, "Number of pages per req/cmp ring - (default="
> +		 __stringify(PVSCSI_DEFAULT_NUM_PAGES_PER_RING) ")");
> +
> +module_param_named(msg_ring_pages, pvscsi_msg_ring_pages, int, PVSCSI_RW);
> +MODULE_PARM_DESC(msg_ring_pages, "Number of pages for the msg ring - (default="
> +		 __stringify(PVSCSI_DEFAULT_NUM_PAGES_MSG_RING) ")");
> +
> +module_param_named(cmd_per_lun, pvscsi_cmd_per_lun, int, PVSCSI_RW);
> +MODULE_PARM_DESC(cmd_per_lun, "Maximum commands per lun - (default="
> +		 __stringify(PVSCSI_MAX_REQ_QUEUE_DEPTH) ")");
> +
> +module_param_named(disable_msi, pvscsi_disable_msi, bool, PVSCSI_RW);
> +MODULE_PARM_DESC(disable_msi, "Disable MSI use in driver - (default=0)");
> +
> +module_param_named(disable_msix, pvscsi_disable_msix, bool, PVSCSI_RW);
> +MODULE_PARM_DESC(disable_msix, "Disable MSI-X use in driver - (default=0)");
> +
> +module_param_named(use_msg, pvscsi_use_msg, bool, PVSCSI_RW);
> +MODULE_PARM_DESC(use_msg, "Use msg ring when available - (default=1)");
> +
> +static const struct pci_device_id pvscsi_pci_tbl[] = {
> +	{ PCI_VDEVICE(VMWARE, PCI_DEVICE_ID_VMWARE_PVSCSI) },
> +	{ 0 }
> +};
> +
> +MODULE_DEVICE_TABLE(pci, pvscsi_pci_tbl);
> +
> +static struct pvscsi_ctx *
> +pvscsi_find_context(const struct pvscsi_adapter *adapter, struct scsi_cmnd *cmd)
> +{
> +	struct pvscsi_ctx *ctx, *end;
> +
> +	end = &adapter->cmd_map[adapter->req_depth];
> +	for (ctx = adapter->cmd_map; ctx < end; ctx++)
> +		if (ctx->cmd == cmd)
> +			return ctx;
> +
> +	return NULL;
> +}
> +
> +static struct pvscsi_ctx *
> +pvscsi_acquire_context(struct pvscsi_adapter *adapter, struct scsi_cmnd *cmd)
> +{
> +	struct pvscsi_ctx *ctx;
> +
> +	if (list_empty(&adapter->cmd_pool))
> +		return NULL;
> +
> +	ctx = list_first_entry(&adapter->cmd_pool, struct pvscsi_ctx, list);
> +	ctx->cmd = cmd;
> +	list_del(&ctx->list);
> +
> +	return ctx;
> +}
> +
> +static void pvscsi_release_context(struct pvscsi_adapter *adapter,
> +				   struct pvscsi_ctx *ctx)
> +{
> +	ctx->cmd = NULL;
> +	list_add(&ctx->list, &adapter->cmd_pool);
> +}
> +
> +/*
> + * Map a pvscsi_ctx struct to a context ID field value; we map to a simple
> + * non-zero integer. ctx always points to an entry in cmd_map array, hence
> + * the return value is always >=1.
> + */
> +static u64 pvscsi_map_context(const struct pvscsi_adapter *adapter,
> +			      const struct pvscsi_ctx *ctx)
> +{
> +	return ctx - adapter->cmd_map + 1;
> +}
> +
> +static struct pvscsi_ctx *
> +pvscsi_get_context(const struct pvscsi_adapter *adapter, u64 context)
> +{
> +	return &adapter->cmd_map[context - 1];
> +}
> +
> +static void pvscsi_reg_write(const struct pvscsi_adapter *adapter,
> +			     u32 offset, u32 val)
> +{
> +	writel(val, adapter->mmioBase + offset);
> +}
> +
> +static u32 pvscsi_reg_read(const struct pvscsi_adapter *adapter, u32 offset)
> +{
> +	return readl(adapter->mmioBase + offset);
> +}
> +
> +static u32 pvscsi_read_intr_status(const struct pvscsi_adapter *adapter)
> +{
> +	return pvscsi_reg_read(adapter, PVSCSI_REG_OFFSET_INTR_STATUS);
> +}
> +
> +static void pvscsi_write_intr_status(const struct pvscsi_adapter *adapter,
> +				     u32 val)
> +{
> +	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_STATUS, val);
> +}
> +
> +static void pvscsi_unmask_intr(const struct pvscsi_adapter *adapter)
> +{
> +	u32 intr_bits;
> +
> +	intr_bits = PVSCSI_INTR_CMPL_MASK;
> +	if (adapter->use_msg)
> +		intr_bits |= PVSCSI_INTR_MSG_MASK;
> +
> +	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_MASK, intr_bits);
> +}
> +
> +static void pvscsi_mask_intr(const struct pvscsi_adapter *adapter)
> +{
> +	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_MASK, 0);
> +}
> +
> +static void pvscsi_write_cmd_desc(const struct pvscsi_adapter *adapter,
> +				  u32 cmd, const void *desc, size_t len)
> +{
> +	const u32 *ptr = desc;
> +	size_t i;
> +
> +	len /= sizeof(*ptr);
> +	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_COMMAND, cmd);
> +	for (i = 0; i < len; i++)
> +		pvscsi_reg_write(adapter,
> +				 PVSCSI_REG_OFFSET_COMMAND_DATA, ptr[i]);
> +}
> +
> +static void pvscsi_abort_cmd(const struct pvscsi_adapter *adapter,
> +			     const struct pvscsi_ctx *ctx)
> +{
> +	struct PVSCSICmdDescAbortCmd cmd = { 0 };
> +
> +	cmd.target = ctx->cmd->device->id;
> +	cmd.context = pvscsi_map_context(adapter, ctx);
> +
> +	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_ABORT_CMD, &cmd, sizeof(cmd));
> +}
> +
> +static void pvscsi_kick_rw_io(const struct pvscsi_adapter *adapter)
> +{
> +	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_KICK_RW_IO, 0);
> +}
> +
> +static void pvscsi_process_request_ring(const struct pvscsi_adapter *adapter)
> +{
> +	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_KICK_NON_RW_IO, 0);
> +}
> +
> +static int scsi_is_rw(unsigned char op)
> +{
> +	return op == READ_6  || op == WRITE_6 ||
> +	       op == READ_10 || op == WRITE_10 ||
> +	       op == READ_12 || op == WRITE_12 ||
> +	       op == READ_16 || op == WRITE_16;
> +}
> +
> +static void pvscsi_kick_io(const struct pvscsi_adapter *adapter,
> +			   unsigned char op)
> +{
> +	if (scsi_is_rw(op))
> +		pvscsi_kick_rw_io(adapter);
> +	else
> +		pvscsi_process_request_ring(adapter);
> +}
> +
> +static void ll_adapter_reset(const struct pvscsi_adapter *adapter)
> +{
> +	dev_dbg(pvscsi_dev(adapter), "Adapter Reset on %p\n", adapter);
> +
> +	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_ADAPTER_RESET, NULL, 0);
> +}
> +
> +static void ll_bus_reset(const struct pvscsi_adapter *adapter)
> +{
> +	dev_dbg(pvscsi_dev(adapter), "Reseting bus on %p\n", adapter);
> +
> +	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_RESET_BUS, NULL, 0);
> +}
> +
> +static void ll_device_reset(const struct pvscsi_adapter *adapter, u32 target)
> +{
> +	struct PVSCSICmdDescResetDevice cmd = { 0 };
> +
> +	dev_dbg(pvscsi_dev(adapter), "Reseting device: target=%u\n", target);
> +
> +	cmd.target = target;
> +
> +	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_RESET_DEVICE,
> +			      &cmd, sizeof(cmd));
> +}
> +
> +static void pvscsi_create_sg(struct pvscsi_ctx *ctx,
> +			     struct scatterlist *sg, unsigned count)
> +{
> +	unsigned i;
> +	struct PVSCSISGElement *sge;
> +
> +	BUG_ON(count > PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT);
> +
> +	sge = &ctx->sgl->sge[0];
> +	for (i = 0; i < count; i++, sg++) {
> +		sge[i].addr   = sg_dma_address(sg);
> +		sge[i].length = sg_dma_len(sg);
> +		sge[i].flags  = 0;
> +	}
> +}
> +
> +/*
> + * Map all data buffers for a command into PCI space and
> + * setup the scatter/gather list if needed.
> + */
> +static void pvscsi_map_buffers(struct pvscsi_adapter *adapter,
> +			       struct pvscsi_ctx *ctx, struct scsi_cmnd *cmd,
> +			       struct PVSCSIRingReqDesc *e)
> +{
> +	unsigned count;
> +	unsigned bufflen = scsi_bufflen(cmd);
> +	struct scatterlist *sg;
> +
> +	e->dataLen = bufflen;
> +	e->dataAddr = 0;
> +	if (bufflen == 0)
> +		return;
> +
> +	sg = scsi_sglist(cmd);
> +	count = scsi_sg_count(cmd);
> +	if (count != 0) {
> +		int segs = scsi_dma_map(cmd);
> +		if (segs > 1) {
> +			pvscsi_create_sg(ctx, sg, segs);
> +
> +			e->flags |= PVSCSI_FLAG_CMD_WITH_SG_LIST;
> +			ctx->sglPA = pci_map_single(adapter->dev, ctx->sgl,
> +						    SGL_SIZE, PCI_DMA_TODEVICE);
> +			e->dataAddr = ctx->sglPA;
> +		} else
> +			e->dataAddr = sg_dma_address(sg);
> +	} else {
> +		/*
> +		 * In case there is no S/G list, scsi_sglist points
> +		 * directly to the buffer.
> +		 */
> +		ctx->dataPA = pci_map_single(adapter->dev, sg, bufflen,
> +					     cmd->sc_data_direction);
> +		e->dataAddr = ctx->dataPA;
> +	}
> +}
> +
> +static void pvscsi_unmap_buffers(const struct pvscsi_adapter *adapter,
> +				 struct pvscsi_ctx *ctx)
> +{
> +	struct scsi_cmnd *cmd;
> +	unsigned bufflen;
> +
> +	cmd = ctx->cmd;
> +	bufflen = scsi_bufflen(cmd);
> +
> +	if (bufflen != 0) {
> +		unsigned count = scsi_sg_count(cmd);
> +
> +		if (count != 0) {
> +			scsi_dma_unmap(cmd);
> +			if (ctx->sglPA) {
> +				pci_unmap_single(adapter->dev, ctx->sglPA,
> +						 SGL_SIZE, PCI_DMA_TODEVICE);
> +				ctx->sglPA = 0;
> +			}
> +		} else
> +			pci_unmap_single(adapter->dev, ctx->dataPA, bufflen,
> +					 cmd->sc_data_direction);
> +	}
> +	if (cmd->sense_buffer)
> +		pci_unmap_single(adapter->dev, ctx->sensePA,
> +				 SCSI_SENSE_BUFFERSIZE, PCI_DMA_FROMDEVICE);
> +}
> +
> +static int __devinit pvscsi_allocate_rings(struct pvscsi_adapter *adapter)
> +{
> +	adapter->rings_state = pci_alloc_consistent(adapter->dev, PAGE_SIZE,
> +						    &adapter->ringStatePA);
> +	if (!adapter->rings_state)
> +		return -ENOMEM;
> +
> +	adapter->req_pages = min(PVSCSI_MAX_NUM_PAGES_REQ_RING,
> +				 pvscsi_ring_pages);
> +	adapter->req_depth = adapter->req_pages
> +					* PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
> +	adapter->req_ring = pci_alloc_consistent(adapter->dev,
> +						 adapter->req_pages * PAGE_SIZE,
> +						 &adapter->reqRingPA);
> +	if (!adapter->req_ring)
> +		return -ENOMEM;
> +
> +	adapter->cmp_pages = min(PVSCSI_MAX_NUM_PAGES_CMP_RING,
> +				 pvscsi_ring_pages);
> +	adapter->cmp_ring = pci_alloc_consistent(adapter->dev,
> +						 adapter->cmp_pages * PAGE_SIZE,
> +						 &adapter->cmpRingPA);
> +	if (!adapter->cmp_ring)
> +		return -ENOMEM;
> +
> +	BUG_ON(!IS_ALIGNED(adapter->ringStatePA, PAGE_SIZE));
> +	BUG_ON(!IS_ALIGNED(adapter->reqRingPA, PAGE_SIZE));
> +	BUG_ON(!IS_ALIGNED(adapter->cmpRingPA, PAGE_SIZE));
> +
> +	if (!adapter->use_msg)
> +		return 0;
> +
> +	adapter->msg_pages = min(PVSCSI_MAX_NUM_PAGES_MSG_RING,
> +				 pvscsi_msg_ring_pages);
> +	adapter->msg_ring = pci_alloc_consistent(adapter->dev,
> +						 adapter->msg_pages * PAGE_SIZE,
> +						 &adapter->msgRingPA);
> +	if (!adapter->msg_ring)
> +		return -ENOMEM;
> +	BUG_ON(!IS_ALIGNED(adapter->msgRingPA, PAGE_SIZE));
> +
> +	return 0;
> +}
> +
> +static void pvscsi_setup_all_rings(const struct pvscsi_adapter *adapter)
> +{
> +	struct PVSCSICmdDescSetupRings cmd = { 0 };
> +	dma_addr_t base;
> +	unsigned i;
> +
> +	cmd.ringsStatePPN   = adapter->ringStatePA >> PAGE_SHIFT;
> +	cmd.reqRingNumPages = adapter->req_pages;
> +	cmd.cmpRingNumPages = adapter->cmp_pages;
> +
> +	base = adapter->reqRingPA;
> +	for (i = 0; i < adapter->req_pages; i++) {
> +		cmd.reqRingPPNs[i] = base >> PAGE_SHIFT;
> +		base += PAGE_SIZE;
> +	}
> +
> +	base = adapter->cmpRingPA;
> +	for (i = 0; i < adapter->cmp_pages; i++) {
> +		cmd.cmpRingPPNs[i] = base >> PAGE_SHIFT;
> +		base += PAGE_SIZE;
> +	}
> +
> +	memset(adapter->rings_state, 0, PAGE_SIZE);
> +	memset(adapter->req_ring, 0, adapter->req_pages * PAGE_SIZE);
> +	memset(adapter->cmp_ring, 0, adapter->cmp_pages * PAGE_SIZE);
> +
> +	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_SETUP_RINGS,
> +			      &cmd, sizeof(cmd));
> +
> +	if (adapter->use_msg) {
> +		struct PVSCSICmdDescSetupMsgRing cmd_msg = { 0 };
> +
> +		cmd_msg.numPages = adapter->msg_pages;
> +
> +		base = adapter->msgRingPA;
> +		for (i = 0; i < adapter->msg_pages; i++) {
> +			cmd_msg.ringPPNs[i] = base >> PAGE_SHIFT;
> +			base += PAGE_SIZE;
> +		}
> +		memset(adapter->msg_ring, 0, adapter->msg_pages * PAGE_SIZE);
> +
> +		pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_SETUP_MSG_RING,
> +				      &cmd_msg, sizeof(cmd_msg));
> +	}
> +}
> +
> +/*
> + * Pull a completion descriptor off and pass the completion back
> + * to the SCSI mid layer.
> + */
> +static void pvscsi_complete_request(struct pvscsi_adapter *adapter,
> +				    const struct PVSCSIRingCmpDesc *e)
> +{
> +	struct pvscsi_ctx *ctx;
> +	struct scsi_cmnd *cmd;
> +	u32 btstat = e->hostStatus;
> +	u32 sdstat = e->scsiStatus;
> +
> +	ctx = pvscsi_get_context(adapter, e->context);
> +	cmd = ctx->cmd;
> +	pvscsi_unmap_buffers(adapter, ctx);
> +	pvscsi_release_context(adapter, ctx);
> +	cmd->result = 0;
> +
> +	if (sdstat != SAM_STAT_GOOD &&
> +	    (btstat == BTSTAT_SUCCESS ||
> +	     btstat == BTSTAT_LINKED_COMMAND_COMPLETED ||
> +	     btstat == BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG)) {
> +		cmd->result = (DID_OK << 16) | sdstat;
> +		if (sdstat == SAM_STAT_CHECK_CONDITION && cmd->sense_buffer)
> +			cmd->result |= (DRIVER_SENSE << 24);
> +	} else
> +		switch (btstat) {
> +		case BTSTAT_SUCCESS:
> +		case BTSTAT_LINKED_COMMAND_COMPLETED:
> +		case BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG:
> +			/* If everything went fine, let's move on..  */
> +			cmd->result = (DID_OK << 16);
> +			break;
> +
> +		case BTSTAT_DATARUN:
> +		case BTSTAT_DATA_UNDERRUN:
> +			/* Report residual data in underruns */
> +			scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen);
> +			cmd->result = (DID_ERROR << 16);
> +			break;
> +
> +		case BTSTAT_SELTIMEO:
> +			/* Our emulation returns this for non-connected devs */
> +			cmd->result = (DID_BAD_TARGET << 16);
> +			break;
> +
> +		case BTSTAT_LUNMISMATCH:
> +		case BTSTAT_TAGREJECT:
> +		case BTSTAT_BADMSG:
> +			cmd->result = (DRIVER_INVALID << 24);
> +			/* fall through */
> +
> +		case BTSTAT_HAHARDWARE:
> +		case BTSTAT_INVPHASE:
> +		case BTSTAT_HATIMEOUT:
> +		case BTSTAT_NORESPONSE:
> +		case BTSTAT_DISCONNECT:
> +		case BTSTAT_HASOFTWARE:
> +		case BTSTAT_BUSFREE:
> +		case BTSTAT_SENSFAILED:
> +			cmd->result |= (DID_ERROR << 16);
> +			break;
> +
> +		case BTSTAT_SENTRST:
> +		case BTSTAT_RECVRST:
> +		case BTSTAT_BUSRESET:
> +			cmd->result = (DID_RESET << 16);
> +			break;
> +
> +		case BTSTAT_ABORTQUEUE:
> +			cmd->result = (DID_ABORT << 16);
> +			break;
> +
> +		case BTSTAT_SCSIPARITY:
> +			cmd->result = (DID_PARITY << 16);
> +			break;
> +
> +		default:
> +			cmd->result = (DID_ERROR << 16);
> +			scmd_printk(KERN_DEBUG, cmd,
> +				    "Unknown completion status: 0x%x\n",
> +				    btstat);
> +	}
> +
> +	dev_dbg(&cmd->device->sdev_gendev,
> +		"cmd=%p %x ctx=%p result=0x%x status=0x%x,%x\n",
> +		cmd, cmd->cmnd[0], ctx, cmd->result, btstat, sdstat);
> +
> +	cmd->scsi_done(cmd);
> +}
> +
> +/*
> + * barrier usage : Since the PVSCSI device is emulated, there could be cases
> + * where we may want to serialize some accesses between the driver and the
> + * emulation layer. We use compiler barriers instead of the more expensive
> + * memory barriers because PVSCSI is only supported on X86 which has strong
> + * memory access ordering.
> + */
> +static void pvscsi_process_completion_ring(struct pvscsi_adapter *adapter)
> +{
> +	struct PVSCSIRingsState *s = adapter->rings_state;
> +	struct PVSCSIRingCmpDesc *ring = adapter->cmp_ring;
> +	u32 cmp_entries = s->cmpNumEntriesLog2;
> +
> +	while (s->cmpConsIdx != s->cmpProdIdx) {
> +		struct PVSCSIRingCmpDesc *e = ring + (s->cmpConsIdx &
> +						      MASK(cmp_entries));
> +		/*
> +		 * This barrier() ensures that *e is not dereferenced while
> +		 * the device emulation still writes data into the slot.
> +		 * Since the device emulation advances s->cmpProdIdx only after
> +		 * updating the slot we want to check it first.
> +		 */
> +		barrier();
> +		pvscsi_complete_request(adapter, e);
> +		/*
> +		 * This barrier() ensures that compiler doesn't reorder write
> +		 * to s->cmpConsIdx before the read of (*e) inside
> +		 * pvscsi_complete_request. Otherwise, device emulation may
> +		 * overwrite *e before we had a chance to read it.
> +		 */
> +		barrier();
> +		s->cmpConsIdx++;
> +	}
> +}
> +
> +/*
> + * Translate a Linux SCSI request into a request ring entry.
> + */
> +static int pvscsi_queue_ring(struct pvscsi_adapter *adapter,
> +			     struct pvscsi_ctx *ctx, struct scsi_cmnd *cmd)
> +{
> +	struct PVSCSIRingsState *s;
> +	struct PVSCSIRingReqDesc *e;
> +	struct scsi_device *sdev;
> +	u32 req_entries;
> +
> +	s = adapter->rings_state;
> +	sdev = cmd->device;
> +	req_entries = s->reqNumEntriesLog2;
> +
> +	/*
> +	 * If this condition holds, we might have room on the request ring, but
> +	 * we might not have room on the completion ring for the response.
> +	 * However, we have already ruled out this possibility - we would not
> +	 * have successfully allocated a context if it were true, since we only
> +	 * have one context per request entry.  Check for it anyway, since it
> +	 * would be a serious bug.
> +	 */
> +	if (s->reqProdIdx - s->cmpConsIdx >= 1 << req_entries) {
> +		scmd_printk(KERN_ERR, cmd,
> +			    "pvscsi: ring full: reqProdIdx=%d cmpConsIdx=%d\n",
> +			    s->reqProdIdx, s->cmpConsIdx);
> +		return -1;
> +	}
> +
> +	e = adapter->req_ring + (s->reqProdIdx & MASK(req_entries));
> +
> +	e->bus    = sdev->channel;
> +	e->target = sdev->id;
> +	memset(e->lun, 0, sizeof(e->lun));
> +	e->lun[1] = sdev->lun;
> +
> +	if (cmd->sense_buffer) {
> +		ctx->sensePA = pci_map_single(adapter->dev, cmd->sense_buffer,
> +					      SCSI_SENSE_BUFFERSIZE,
> +					      PCI_DMA_FROMDEVICE);
> +		e->senseAddr = ctx->sensePA;
> +		e->senseLen = SCSI_SENSE_BUFFERSIZE;
> +	} else {
> +		e->senseLen  = 0;
> +		e->senseAddr = 0;
> +	}
> +	e->cdbLen   = cmd->cmd_len;
> +	e->vcpuHint = smp_processor_id();
> +	memcpy(e->cdb, cmd->cmnd, e->cdbLen);
> +
> +	e->tag = SIMPLE_QUEUE_TAG;
> +	if (sdev->tagged_supported &&
> +	    (cmd->tag == HEAD_OF_QUEUE_TAG ||
> +	     cmd->tag == ORDERED_QUEUE_TAG))
> +		e->tag = cmd->tag;
> +
> +	if (cmd->sc_data_direction == DMA_FROM_DEVICE)
> +		e->flags = PVSCSI_FLAG_CMD_DIR_TOHOST;
> +	else if (cmd->sc_data_direction == DMA_TO_DEVICE)
> +		e->flags = PVSCSI_FLAG_CMD_DIR_TODEVICE;
> +	else if (cmd->sc_data_direction == DMA_NONE)
> +		e->flags = PVSCSI_FLAG_CMD_DIR_NONE;
> +	else
> +		e->flags = 0;
> +
> +	pvscsi_map_buffers(adapter, ctx, cmd, e);
> +
> +	e->context = pvscsi_map_context(adapter, ctx);
> +
> +	barrier();
> +
> +	s->reqProdIdx++;
> +
> +	return 0;
> +}
> +
> +static int pvscsi_queue(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
> +{
> +	struct Scsi_Host *host = cmd->device->host;
> +	struct pvscsi_adapter *adapter = shost_priv(host);
> +	struct pvscsi_ctx *ctx;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&adapter->hw_lock, flags);
> +
> +	ctx = pvscsi_acquire_context(adapter, cmd);
> +	if (!ctx || pvscsi_queue_ring(adapter, ctx, cmd) != 0) {
> +		if (ctx)
> +			pvscsi_release_context(adapter, ctx);
> +		spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +		return SCSI_MLQUEUE_HOST_BUSY;
> +	}
> +
> +	cmd->scsi_done = done;
> +
> +	dev_dbg(&cmd->device->sdev_gendev,
> +		"queued cmd %p, ctx %p, op=%x\n", cmd, ctx, cmd->cmnd[0]);
> +
> +	spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +
> +	pvscsi_kick_io(adapter, cmd->cmnd[0]);
> +
> +	return 0;
> +}
> +
> +static int pvscsi_abort(struct scsi_cmnd *cmd)
> +{
> +	struct pvscsi_adapter *adapter = shost_priv(cmd->device->host);
> +	struct pvscsi_ctx *ctx;
> +	unsigned long flags;
> +
> +	scmd_printk(KERN_DEBUG, cmd, "task abort on host %u, %p\n",
> +		    adapter->host->host_no, cmd);
> +
> +	spin_lock_irqsave(&adapter->hw_lock, flags);
> +
> +	/*
> +	 * Poll the completion ring first - we might be trying to abort
> +	 * a command that is waiting to be dispatched in the completion ring.
> +	 */
> +	pvscsi_process_completion_ring(adapter);
> +
> +	/*
> +	 * If there is no context for the command, it either already succeeded
> +	 * or else was never properly issued.  Not our problem.
> +	 */
> +	ctx = pvscsi_find_context(adapter, cmd);
> +	if (!ctx) {
> +		scmd_printk(KERN_DEBUG, cmd, "Failed to abort cmd %p\n", cmd);
> +		goto out;
> +	}
> +
> +	pvscsi_abort_cmd(adapter, ctx);
> +
> +	pvscsi_process_completion_ring(adapter);
> +
> +out:
> +	spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +	return SUCCESS;
> +}
> +
> +/*
> + * Abort all outstanding requests.  This is only safe to use if the completion
> + * ring will never be walked again or the device has been reset, because it
> + * destroys the 1-1 mapping between context field passed to emulation and our
> + * request structure.
> + */
> +static void pvscsi_reset_all(struct pvscsi_adapter *adapter)
> +{
> +	unsigned i;
> +
> +	for (i = 0; i < adapter->req_depth; i++) {
> +		struct pvscsi_ctx *ctx = &adapter->cmd_map[i];
> +		struct scsi_cmnd *cmd = ctx->cmd;
> +		if (cmd) {
> +			scmd_printk(KERN_ERR, cmd,
> +				    "Forced reset on cmd %p\n", cmd);
> +			pvscsi_unmap_buffers(adapter, ctx);
> +			pvscsi_release_context(adapter, ctx);
> +			cmd->result = (DID_RESET << 16);
> +			cmd->scsi_done(cmd);
> +		}
> +	}
> +}
> +
> +static int pvscsi_host_reset(struct scsi_cmnd *cmd)
> +{
> +	struct Scsi_Host *host = cmd->device->host;
> +	struct pvscsi_adapter *adapter = shost_priv(host);
> +	unsigned long flags;
> +	bool use_msg;
> +
> +	scmd_printk(KERN_INFO, cmd, "SCSI Host reset\n");
> +
> +	spin_lock_irqsave(&adapter->hw_lock, flags);
> +
> +	use_msg = adapter->use_msg;
> +
> +	if (use_msg) {
> +		adapter->use_msg = 0;
> +		spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +
> +		/*
> +		 * Now that we know that the ISR won't add more work on the
> +		 * workqueue we can safely flush any outstanding work.
> +		 */
> +		flush_workqueue(adapter->workqueue);
> +		spin_lock_irqsave(&adapter->hw_lock, flags);
> +	}
> +
> +	/*
> +	 * We're going to tear down the entire ring structure and set it back
> +	 * up, so stalling new requests until all completions are flushed and
> +	 * the rings are back in place.
> +	 */
> +
> +	pvscsi_process_request_ring(adapter);
> +
> +	ll_adapter_reset(adapter);
> +
> +	/*
> +	 * Now process any completions.  Note we do this AFTER adapter reset,
> +	 * which is strange, but stops races where completions get posted
> +	 * between processing the ring and issuing the reset.  The backend will
> +	 * not touch the ring memory after reset, so the immediately pre-reset
> +	 * completion ring state is still valid.
> +	 */
> +	pvscsi_process_completion_ring(adapter);
> +
> +	pvscsi_reset_all(adapter);
> +	adapter->use_msg = use_msg;
> +	pvscsi_setup_all_rings(adapter);
> +	pvscsi_unmask_intr(adapter);
> +
> +	spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +
> +	return SUCCESS;
> +}
> +
> +static int pvscsi_bus_reset(struct scsi_cmnd *cmd)
> +{
> +	struct Scsi_Host *host = cmd->device->host;
> +	struct pvscsi_adapter *adapter = shost_priv(host);
> +	unsigned long flags;
> +
> +	scmd_printk(KERN_INFO, cmd, "SCSI Bus reset\n");
> +
> +	/*
> +	 * We don't want to queue new requests for this bus after
> +	 * flushing all pending requests to emulation, since new
> +	 * requests could then sneak in during this bus reset phase,
> +	 * so take the lock now.
> +	 */
> +	spin_lock_irqsave(&adapter->hw_lock, flags);
> +
> +	pvscsi_process_request_ring(adapter);
> +	ll_bus_reset(adapter);
> +	pvscsi_process_completion_ring(adapter);
> +
> +	spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +
> +	return SUCCESS;
> +}
> +
> +static int pvscsi_device_reset(struct scsi_cmnd *cmd)
> +{
> +	struct Scsi_Host *host = cmd->device->host;
> +	struct pvscsi_adapter *adapter = shost_priv(host);
> +	unsigned long flags;
> +
> +	scmd_printk(KERN_INFO, cmd, "SCSI device reset on scsi%u:%u\n",
> +		    host->host_no, cmd->device->id);
> +
> +	/*
> +	 * We don't want to queue new requests for this device after flushing
> +	 * all pending requests to emulation, since new requests could then
> +	 * sneak in during this device reset phase, so take the lock now.
> +	 */
> +	spin_lock_irqsave(&adapter->hw_lock, flags);
> +
> +	pvscsi_process_request_ring(adapter);
> +	ll_device_reset(adapter, cmd->device->id);
> +	pvscsi_process_completion_ring(adapter);
> +
> +	spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +
> +	return SUCCESS;
> +}
> +
> +static struct scsi_host_template pvscsi_template;
> +
> +static const char *pvscsi_info(struct Scsi_Host *host)
> +{
> +	struct pvscsi_adapter *adapter = shost_priv(host);
> +	static char buf[256];
> +
> +	sprintf(buf, "VMware PVSCSI storage adapter rev %d, req/cmp/msg rings: "
> +		"%u/%u/%u pages, cmd_per_lun=%u", adapter->rev,
> +		adapter->req_pages, adapter->cmp_pages, adapter->msg_pages,
> +		pvscsi_template.cmd_per_lun);
> +
> +	return buf;
> +}
> +
> +static struct scsi_host_template pvscsi_template = {
> +	.module				= THIS_MODULE,
> +	.name				= "VMware PVSCSI Host Adapter",
> +	.proc_name			= "pvscsi",
> +	.info				= pvscsi_info,
> +	.queuecommand			= pvscsi_queue,
> +	.this_id			= -1,
> +	.sg_tablesize			= PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT,
> +	.dma_boundary			= UINT_MAX,
> +	.max_sectors			= 0xffff,
> +	.use_clustering			= ENABLE_CLUSTERING,
> +	.eh_abort_handler		= pvscsi_abort,
> +	.eh_device_reset_handler	= pvscsi_device_reset,
> +	.eh_bus_reset_handler		= pvscsi_bus_reset,
> +	.eh_host_reset_handler		= pvscsi_host_reset,
> +};
> +
> +static void pvscsi_process_msg(const struct pvscsi_adapter *adapter,
> +			       const struct PVSCSIRingMsgDesc *e)
> +{
> +	struct PVSCSIRingsState *s = adapter->rings_state;
> +	struct Scsi_Host *host = adapter->host;
> +	struct scsi_device *sdev;
> +
> +	printk(KERN_INFO "pvscsi: msg type: 0x%x - MSG RING: %u/%u (%u) \n",
> +	       e->type, s->msgProdIdx, s->msgConsIdx, s->msgNumEntriesLog2);
> +
> +	BUILD_BUG_ON(PVSCSI_MSG_LAST != 2);
> +
> +	if (e->type == PVSCSI_MSG_DEV_ADDED) {
> +		struct PVSCSIMsgDescDevStatusChanged *desc;
> +		desc = (struct PVSCSIMsgDescDevStatusChanged *)e;
> +
> +		printk(KERN_INFO "pvscsi: msg: device added at scsi%u:%u:%u\n",
> +		       desc->bus, desc->target, desc->lun[1]);
> +
> +		if (!scsi_host_get(host))
> +			return;
> +
> +		sdev = scsi_device_lookup(host, desc->bus, desc->target,
> +					  desc->lun[1]);
> +		if (sdev) {
> +			printk(KERN_INFO "pvscsi: device already exists\n");
> +			scsi_device_put(sdev);
> +		} else
> +			scsi_add_device(adapter->host, desc->bus,
> +					desc->target, desc->lun[1]);
> +
> +		scsi_host_put(host);
> +	} else if (e->type == PVSCSI_MSG_DEV_REMOVED) {
> +		struct PVSCSIMsgDescDevStatusChanged *desc;
> +		desc = (struct PVSCSIMsgDescDevStatusChanged *)e;
> +
> +		printk(KERN_INFO "pvscsi: msg: device removed at scsi%u:%u:%u\n",
> +		       desc->bus, desc->target, desc->lun[1]);
> +
> +		if (!scsi_host_get(host))
> +			return;
> +
> +		sdev = scsi_device_lookup(host, desc->bus, desc->target,
> +					  desc->lun[1]);
> +		if (sdev) {
> +			scsi_remove_device(sdev);
> +			scsi_device_put(sdev);
> +		} else
> +			printk(KERN_INFO "pvscsi: failed to lookup scsi%u:%u:%u\n",
> +			       desc->bus, desc->target, desc->lun[1]);
> +
> +		scsi_host_put(host);
> +	}
> +}
> +
> +static int pvscsi_msg_pending(const struct pvscsi_adapter *adapter)
> +{
> +	struct PVSCSIRingsState *s = adapter->rings_state;
> +
> +	return s->msgProdIdx != s->msgConsIdx;
> +}
> +
> +static void pvscsi_process_msg_ring(const struct pvscsi_adapter *adapter)
> +{
> +	struct PVSCSIRingsState *s = adapter->rings_state;
> +	struct PVSCSIRingMsgDesc *ring = adapter->msg_ring;
> +	u32 msg_entries = s->msgNumEntriesLog2;
> +
> +	while (pvscsi_msg_pending(adapter)) {
> +		struct PVSCSIRingMsgDesc *e = ring + (s->msgConsIdx &
> +						      MASK(msg_entries));
> +
> +		barrier();
> +		pvscsi_process_msg(adapter, e);
> +		barrier();
> +		s->msgConsIdx++;
> +	}
> +}
> +
> +static void pvscsi_msg_workqueue_handler(struct work_struct *data)
> +{
> +	struct pvscsi_adapter *adapter;
> +
> +	adapter = container_of(data, struct pvscsi_adapter, work);
> +
> +	pvscsi_process_msg_ring(adapter);
> +}
> +
> +static int pvscsi_setup_msg_workqueue(struct pvscsi_adapter *adapter)
> +{
> +	char name[32];
> +
> +	if (!pvscsi_use_msg)
> +		return 0;
> +
> +	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_COMMAND,
> +			 PVSCSI_CMD_SETUP_MSG_RING);
> +
> +	if (pvscsi_reg_read(adapter, PVSCSI_REG_OFFSET_COMMAND_STATUS) == -1)
> +		return 0;
> +
> +	snprintf(name, sizeof(name), "pvscsi_wq_%u", adapter->host->host_no);
> +
> +	adapter->workqueue = create_singlethread_workqueue(name);
> +	if (!adapter->workqueue) {
> +		printk(KERN_ERR "pvscsi: failed to create work queue\n");
> +		return 0;
> +	}
> +	INIT_WORK(&adapter->work, pvscsi_msg_workqueue_handler);
> +
> +	return 1;
> +}
> +
> +static irqreturn_t pvscsi_isr(int irq, void *devp)
> +{
> +	struct pvscsi_adapter *adapter = devp;
> +	int handled;
> +
> +	if (adapter->use_msi || adapter->use_msix)
> +		handled = true;
> +	else {
> +		u32 val = pvscsi_read_intr_status(adapter);
> +		handled = (val & PVSCSI_INTR_ALL_SUPPORTED) != 0;
> +		if (handled)
> +			pvscsi_write_intr_status(devp, val);
> +	}
> +
> +	if (handled) {
> +		unsigned long flags;
> +
> +		spin_lock_irqsave(&adapter->hw_lock, flags);
> +
> +		pvscsi_process_completion_ring(adapter);
> +		if (adapter->use_msg && pvscsi_msg_pending(adapter))
> +			queue_work(adapter->workqueue, &adapter->work);
> +
> +		spin_unlock_irqrestore(&adapter->hw_lock, flags);
> +	}
> +
> +	return IRQ_RETVAL(handled);
> +}
> +
> +static void pvscsi_free_sgls(const struct pvscsi_adapter *adapter)
> +{
> +	struct pvscsi_ctx *ctx = adapter->cmd_map;
> +	unsigned i;
> +
> +	for (i = 0; i < adapter->req_depth; ++i, ++ctx)
> +		kfree(ctx->sgl);
> +}
> +
> +static int pvscsi_setup_msix(const struct pvscsi_adapter *adapter, int *irq)
> +{
> +	struct msix_entry entry = { 0, PVSCSI_VECTOR_COMPLETION };
> +	int ret;
> +
> +	ret = pci_enable_msix(adapter->dev, &entry, 1);
> +	if (ret)
> +		return ret;
> +
> +	*irq = entry.vector;
> +
> +	return 0;
> +}
> +
> +static void pvscsi_shutdown_intr(struct pvscsi_adapter *adapter)
> +{
> +	if (adapter->irq) {
> +		free_irq(adapter->irq, adapter);
> +		adapter->irq = 0;
> +	}
> +	if (adapter->use_msi) {
> +		pci_disable_msi(adapter->dev);
> +		adapter->use_msi = 0;
> +	} else if (adapter->use_msix) {
> +		pci_disable_msix(adapter->dev);
> +		adapter->use_msix = 0;
> +	}
> +}
> +
> +static void pvscsi_release_resources(struct pvscsi_adapter *adapter)
> +{
> +	pvscsi_shutdown_intr(adapter);
> +
> +	if (adapter->workqueue)
> +		destroy_workqueue(adapter->workqueue);
> +
> +	if (adapter->mmioBase)
> +		pci_iounmap(adapter->dev, adapter->mmioBase);
> +
> +	pci_release_regions(adapter->dev);
> +
> +	if (adapter->cmd_map) {
> +		pvscsi_free_sgls(adapter);
> +		kfree(adapter->cmd_map);
> +	}
> +
> +	if (adapter->rings_state)
> +		pci_free_consistent(adapter->dev, PAGE_SIZE,
> +				    adapter->rings_state, adapter->ringStatePA);
> +
> +	if (adapter->req_ring)
> +		pci_free_consistent(adapter->dev,
> +				    adapter->req_pages * PAGE_SIZE,
> +				    adapter->req_ring, adapter->reqRingPA);
> +
> +	if (adapter->cmp_ring)
> +		pci_free_consistent(adapter->dev,
> +				    adapter->cmp_pages * PAGE_SIZE,
> +				    adapter->cmp_ring, adapter->cmpRingPA);
> +
> +	if (adapter->msg_ring)
> +		pci_free_consistent(adapter->dev,
> +				    adapter->msg_pages * PAGE_SIZE,
> +				    adapter->msg_ring, adapter->msgRingPA);
> +}
> +
> +/*
> + * Allocate scatter gather lists.
> + *
> + * These are statically allocated.  Trying to be clever was not worth it.
> + *
> + * Dynamic allocation can fail, and we can't go deeep into the memory
> + * allocator, since we're a SCSI driver, and trying too hard to allocate
> + * memory might generate disk I/O.  We also don't want to fail disk I/O
> + * in that case because we can't get an allocation - the I/O could be
> + * trying to swap out data to free memory.  Since that is pathological,
> + * just use a statically allocated scatter list.
> + *
> + */
> +static int __devinit pvscsi_allocate_sg(struct pvscsi_adapter *adapter)
> +{
> +	struct pvscsi_ctx *ctx;
> +	int i;
> +
> +	ctx = adapter->cmd_map;
> +	BUILD_BUG_ON(sizeof(struct pvscsi_sg_list) > SGL_SIZE);
> +
> +	for (i = 0; i < adapter->req_depth; ++i, ++ctx) {
> +		ctx->sgl = kmalloc(SGL_SIZE, GFP_KERNEL);
> +		ctx->sglPA = 0;
> +		BUG_ON(!IS_ALIGNED(((unsigned long)ctx->sgl), PAGE_SIZE));
> +		if (!ctx->sgl) {
> +			for (; i >= 0; --i, --ctx) {
> +				kfree(ctx->sgl);
> +				ctx->sgl = NULL;
> +			}
> +			return -ENOMEM;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int __devinit pvscsi_probe(struct pci_dev *pdev,
> +				  const struct pci_device_id *id)
> +{
> +	struct pvscsi_adapter *adapter;
> +	struct Scsi_Host *host;
> +	unsigned int i;
> +	int error;
> +
> +	error = -ENODEV;
> +
> +	if (pci_enable_device(pdev))
> +		return error;
> +
> +	if (pci_set_dma_mask(pdev, DMA_BIT_MASK(64)) == 0 &&
> +	    pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64)) == 0) {
> +		printk(KERN_INFO "pvscsi: using 64bit dma\n");
> +	} else if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32)) == 0 &&
> +		   pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32)) == 0) {
> +		printk(KERN_INFO "pvscsi: using 32bit dma\n");
> +	} else {
> +		printk(KERN_ERR "pvscsi: failed to set DMA mask\n");
> +		goto out_disable_device;
> +	}
> +
> +	pvscsi_template.can_queue =
> +		min(PVSCSI_MAX_NUM_PAGES_REQ_RING, pvscsi_ring_pages) *
> +		PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
> +	pvscsi_template.cmd_per_lun =
> +		min(pvscsi_template.can_queue, pvscsi_cmd_per_lun);
> +	host = scsi_host_alloc(&pvscsi_template, sizeof(struct pvscsi_adapter));
> +	if (!host) {
> +		printk(KERN_ERR "pvscsi: failed to allocate host\n");
> +		goto out_disable_device;
> +	}
> +
> +	adapter = shost_priv(host);
> +	memset(adapter, 0, sizeof(*adapter));
> +	adapter->dev  = pdev;
> +	adapter->host = host;
> +
> +	spin_lock_init(&adapter->hw_lock);
> +
> +	host->max_channel = 0;
> +	host->max_id      = 16;
> +	host->max_lun     = 1;
> +	host->max_cmd_len = 16;
> +
> +	adapter->rev = pdev->revision;
> +
> +	if (pci_request_regions(pdev, "pvscsi")) {
> +		printk(KERN_ERR "pvscsi: pci memory selection failed\n");
> +		goto out_free_host;
> +	}
> +
> +	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
> +		if ((pci_resource_flags(pdev, i) & PCI_BASE_ADDRESS_SPACE_IO))
> +			continue;
> +
> +		if (pci_resource_len(pdev, i) < PVSCSI_MEM_SPACE_SIZE)
> +			continue;
> +
> +		break;
> +	}
> +
> +	if (i == DEVICE_COUNT_RESOURCE) {
> +		printk(KERN_ERR "pvscsi: adapter has no suitable MMIO region\n");
> +		goto out_release_resources;
> +	}
> +
> +	adapter->mmioBase = pci_iomap(pdev, i, PVSCSI_MEM_SPACE_SIZE);
> +
> +	if (!adapter->mmioBase) {
> +		printk(KERN_ERR "pvscsi: can't iomap for BAR %d memsize %lu\n",
> +		       i, PVSCSI_MEM_SPACE_SIZE);
> +		goto out_release_resources;
> +	}
> +
> +	pci_set_master(pdev);
> +	pci_set_drvdata(pdev, host);
> +
> +	ll_adapter_reset(adapter);
> +
> +	adapter->use_msg = pvscsi_setup_msg_workqueue(adapter);
> +
> +	error = pvscsi_allocate_rings(adapter);
> +	if (error) {
> +		printk(KERN_ERR "pvscsi: unable to allocate ring memory\n");
> +		goto out_release_resources;
> +	}
> +
> +	/*
> +	 * From this point on we should reset the adapter if anything goes
> +	 * wrong.
> +	 */
> +	pvscsi_setup_all_rings(adapter);
> +
> +	adapter->cmd_map = kcalloc(adapter->req_depth,
> +				   sizeof(struct pvscsi_ctx), GFP_KERNEL);
> +	if (!adapter->cmd_map) {
> +		printk(KERN_ERR "pvscsi: failed to allocate memory.\n");
> +		error = -ENOMEM;
> +		goto out_reset_adapter;
> +	}
> +
> +	INIT_LIST_HEAD(&adapter->cmd_pool);
> +	for (i = 0; i < adapter->req_depth; i++) {
> +		struct pvscsi_ctx *ctx = adapter->cmd_map + i;
> +		list_add(&ctx->list, &adapter->cmd_pool);
> +	}
> +
> +	error = pvscsi_allocate_sg(adapter);
> +	if (error) {
> +		printk(KERN_ERR "pvscsi: unable to allocate s/g table\n");
> +		goto out_reset_adapter;
> +	}
> +
> +	if (!pvscsi_disable_msix &&
> +	    pvscsi_setup_msix(adapter, &adapter->irq) == 0) {
> +		printk(KERN_INFO "pvscsi: using MSI-X\n");
> +		adapter->use_msix = 1;
> +	} else if (!pvscsi_disable_msi && pci_enable_msi(pdev) == 0) {
> +		printk(KERN_INFO "pvscsi: using MSI\n");
> +		adapter->use_msi = 1;
> +		adapter->irq = pdev->irq;
> +	} else {
> +		printk(KERN_INFO "pvscsi: using INTx\n");
> +		adapter->irq = pdev->irq;
> +	}
> +
> +	error = request_irq(adapter->irq, pvscsi_isr, IRQF_SHARED,
> +			    "pvscsi", adapter);
> +	if (error) {
> +		printk(KERN_ERR "pvscsi: unable to request IRQ: %d\n", error);
> +		adapter->irq = 0;
> +		goto out_reset_adapter;
> +	}
> +
> +	error = scsi_add_host(host, &pdev->dev);
> +	if (error) {
> +		printk(KERN_ERR "pvscsi: scsi_add_host failed: %d\n", error);
> +		goto out_reset_adapter;
> +	}
> +
> +	dev_info(&pdev->dev, "VMware PVSCSI rev %d host #%u\n",
> +		 adapter->rev, host->host_no);
> +
> +	pvscsi_unmask_intr(adapter);
> +
> +	scsi_scan_host(host);
> +
> +	return 0;
> +
> +out_reset_adapter:
> +	ll_adapter_reset(adapter);
> +out_release_resources:
> +	pvscsi_release_resources(adapter);
> +out_free_host:
> +	scsi_host_put(host);
> +out_disable_device:
> +	pci_set_drvdata(pdev, NULL);
> +	pci_disable_device(pdev);
> +
> +	return error;
> +}
> +
> +static void __pvscsi_shutdown(struct pvscsi_adapter *adapter)
> +{
> +	pvscsi_mask_intr(adapter);
> +
> +	if (adapter->workqueue)
> +		flush_workqueue(adapter->workqueue);
> +
> +	pvscsi_shutdown_intr(adapter);
> +
> +	pvscsi_process_request_ring(adapter);
> +	pvscsi_process_completion_ring(adapter);
> +	ll_adapter_reset(adapter);
> +}
> +
> +static void pvscsi_shutdown(struct pci_dev *dev)
> +{
> +	struct Scsi_Host *host = pci_get_drvdata(dev);
> +	struct pvscsi_adapter *adapter = shost_priv(host);
> +
> +	__pvscsi_shutdown(adapter);
> +}
> +
> +static void pvscsi_remove(struct pci_dev *pdev)
> +{
> +	struct Scsi_Host *host = pci_get_drvdata(pdev);
> +	struct pvscsi_adapter *adapter = shost_priv(host);
> +
> +	scsi_remove_host(host);
> +
> +	__pvscsi_shutdown(adapter);
> +	pvscsi_release_resources(adapter);
> +
> +	scsi_host_put(host);
> +
> +	pci_set_drvdata(pdev, NULL);
> +	pci_disable_device(pdev);
> +}
> +
> +static struct pci_driver pvscsi_pci_driver = {
> +	.name		= "pvscsi",
> +	.id_table	= pvscsi_pci_tbl,
> +	.probe		= pvscsi_probe,
> +	.remove		= __devexit_p(pvscsi_remove),
> +	.shutdown       = pvscsi_shutdown,
> +};
> +
> +static int __init pvscsi_init(void)
> +{
> +	pr_info("%s - version %s\n",
> +		PVSCSI_LINUX_DRIVER_DESC, PVSCSI_DRIVER_VERSION_STRING);
> +	return pci_register_driver(&pvscsi_pci_driver);
> +}
> +
> +static void __exit pvscsi_exit(void)
> +{
> +	pci_unregister_driver(&pvscsi_pci_driver);
> +}
> +
> +module_init(pvscsi_init);
> +module_exit(pvscsi_exit);
> diff --git a/drivers/scsi/pvscsi.h b/drivers/scsi/pvscsi.h
> new file mode 100644
> index 0000000..9753eee
> --- /dev/null
> +++ b/drivers/scsi/pvscsi.h
> @@ -0,0 +1,397 @@
> +/*
> + * VMware PVSCSI header file
> + *
> + * Copyright (C) 2008-2009, VMware, Inc. All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; version 2 of the License and no later version.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
> + * NON INFRINGEMENT.  See the GNU General Public License for more
> + * details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
> + *
> + * Maintained by: Alok N Kataria <akataria@xxxxxxxxxx>
> + *
> + */
> +
> +#ifndef _PVSCSI_H_
> +#define _PVSCSI_H_
> +
> +#include <linux/types.h>
> +
> +#define PVSCSI_DRIVER_VERSION_STRING   "1.0.1.0-k"
> +
> +#define PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT 128
> +
> +#define MASK(n)        ((1 << (n)) - 1)        /* make an n-bit mask */
> +
> +#define PCI_VENDOR_ID_VMWARE		0x15AD
> +#define PCI_DEVICE_ID_VMWARE_PVSCSI	0x07C0
> +
> +/*
> + * host adapter status/error codes
> + */
> +enum HostBusAdapterStatus {
> +   BTSTAT_SUCCESS       = 0x00,  /* CCB complete normally with no errors */
> +   BTSTAT_LINKED_COMMAND_COMPLETED           = 0x0a,
> +   BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG = 0x0b,
> +   BTSTAT_DATA_UNDERRUN = 0x0c,
> +   BTSTAT_SELTIMEO      = 0x11,  /* SCSI selection timeout */
> +   BTSTAT_DATARUN       = 0x12,  /* data overrun/underrun */
> +   BTSTAT_BUSFREE       = 0x13,  /* unexpected bus free */
> +   BTSTAT_INVPHASE      = 0x14,  /* invalid bus phase or sequence requested by target */
> +   BTSTAT_LUNMISMATCH   = 0x17,  /* linked CCB has different LUN from first CCB */
> +   BTSTAT_SENSFAILED    = 0x1b,  /* auto request sense failed */
> +   BTSTAT_TAGREJECT     = 0x1c,  /* SCSI II tagged queueing message rejected by target */
> +   BTSTAT_BADMSG        = 0x1d,  /* unsupported message received by the host adapter */
> +   BTSTAT_HAHARDWARE    = 0x20,  /* host adapter hardware failed */
> +   BTSTAT_NORESPONSE    = 0x21,  /* target did not respond to SCSI ATN, sent a SCSI RST */
> +   BTSTAT_SENTRST       = 0x22,  /* host adapter asserted a SCSI RST */
> +   BTSTAT_RECVRST       = 0x23,  /* other SCSI devices asserted a SCSI RST */
> +   BTSTAT_DISCONNECT    = 0x24,  /* target device reconnected improperly (w/o tag) */
> +   BTSTAT_BUSRESET      = 0x25,  /* host adapter issued BUS device reset */
> +   BTSTAT_ABORTQUEUE    = 0x26,  /* abort queue generated */
> +   BTSTAT_HASOFTWARE    = 0x27,  /* host adapter software error */
> +   BTSTAT_HATIMEOUT     = 0x30,  /* host adapter hardware timeout error */
> +   BTSTAT_SCSIPARITY    = 0x34,  /* SCSI parity error detected */
> +};
> +
> +/*
> + * Register offsets.
> + *
> + * These registers are accessible both via i/o space and mm i/o.
> + */
> +
> +enum PVSCSIRegOffset {
> +	PVSCSI_REG_OFFSET_COMMAND        =    0x0,
> +	PVSCSI_REG_OFFSET_COMMAND_DATA   =    0x4,
> +	PVSCSI_REG_OFFSET_COMMAND_STATUS =    0x8,
> +	PVSCSI_REG_OFFSET_LAST_STS_0     =  0x100,
> +	PVSCSI_REG_OFFSET_LAST_STS_1     =  0x104,
> +	PVSCSI_REG_OFFSET_LAST_STS_2     =  0x108,
> +	PVSCSI_REG_OFFSET_LAST_STS_3     =  0x10c,
> +	PVSCSI_REG_OFFSET_INTR_STATUS    = 0x100c,
> +	PVSCSI_REG_OFFSET_INTR_MASK      = 0x2010,
> +	PVSCSI_REG_OFFSET_KICK_NON_RW_IO = 0x3014,
> +	PVSCSI_REG_OFFSET_DEBUG          = 0x3018,
> +	PVSCSI_REG_OFFSET_KICK_RW_IO     = 0x4018,
> +};
> +
> +/*
> + * Virtual h/w commands.
> + */
> +
> +enum PVSCSICommands {
> +	PVSCSI_CMD_FIRST             = 0, /* has to be first */
> +
> +	PVSCSI_CMD_ADAPTER_RESET     = 1,
> +	PVSCSI_CMD_ISSUE_SCSI        = 2,
> +	PVSCSI_CMD_SETUP_RINGS       = 3,
> +	PVSCSI_CMD_RESET_BUS         = 4,
> +	PVSCSI_CMD_RESET_DEVICE      = 5,
> +	PVSCSI_CMD_ABORT_CMD         = 6,
> +	PVSCSI_CMD_CONFIG            = 7,
> +	PVSCSI_CMD_SETUP_MSG_RING    = 8,
> +	PVSCSI_CMD_DEVICE_UNPLUG     = 9,
> +
> +	PVSCSI_CMD_LAST              = 10  /* has to be last */
> +};
> +
> +/*
> + * Command descriptor for PVSCSI_CMD_RESET_DEVICE --
> + */
> +
> +struct PVSCSICmdDescResetDevice {
> +	u32	target;
> +	u8	lun[8];
> +} __packed;
> +
> +/*
> + * Command descriptor for PVSCSI_CMD_ABORT_CMD --
> + *
> + * - currently does not support specifying the LUN.
> + * - _pad should be 0.
> + */
> +
> +struct PVSCSICmdDescAbortCmd {
> +	u64	context;
> +	u32	target;
> +	u32	_pad;
> +} __packed;
> +
> +/*
> + * Command descriptor for PVSCSI_CMD_SETUP_RINGS --
> + *
> + * Notes:
> + * - reqRingNumPages and cmpRingNumPages need to be power of two.
> + * - reqRingNumPages and cmpRingNumPages need to be different from 0,
> + * - reqRingNumPages and cmpRingNumPages need to be inferior to
> + *   PVSCSI_SETUP_RINGS_MAX_NUM_PAGES.
> + */
> +
> +#define PVSCSI_SETUP_RINGS_MAX_NUM_PAGES        32
> +struct PVSCSICmdDescSetupRings {
> +	u32	reqRingNumPages;
> +	u32	cmpRingNumPages;
> +	u64	ringsStatePPN;
> +	u64	reqRingPPNs[PVSCSI_SETUP_RINGS_MAX_NUM_PAGES];
> +	u64	cmpRingPPNs[PVSCSI_SETUP_RINGS_MAX_NUM_PAGES];
> +} __packed;
> +
> +/*
> + * Command descriptor for PVSCSI_CMD_SETUP_MSG_RING --
> + *
> + * Notes:
> + * - this command was not supported in the initial revision of the h/w
> + *   interface. Before using it, you need to check that it is supported by
> + *   writing PVSCSI_CMD_SETUP_MSG_RING to the 'command' register, then
> + *   immediately after read the 'command status' register:
> + *       * a value of -1 means that the cmd is NOT supported,
> + *       * a value != -1 means that the cmd IS supported.
> + *   If it's supported the 'command status' register should return:
> + *      sizeof(PVSCSICmdDescSetupMsgRing) / sizeof(u32).
> + * - this command should be issued _after_ the usual SETUP_RINGS so that the
> + *   RingsState page is already setup. If not, the command is a nop.
> + * - numPages needs to be a power of two,
> + * - numPages needs to be different from 0,
> + * - _pad should be zero.
> + */
> +
> +#define PVSCSI_SETUP_MSG_RING_MAX_NUM_PAGES  16
> +
> +struct PVSCSICmdDescSetupMsgRing {
> +	u32	numPages;
> +	u32	_pad;
> +	u64	ringPPNs[PVSCSI_SETUP_MSG_RING_MAX_NUM_PAGES];
> +} __packed;
> +
> +enum PVSCSIMsgType {
> +	PVSCSI_MSG_DEV_ADDED          = 0,
> +	PVSCSI_MSG_DEV_REMOVED        = 1,
> +	PVSCSI_MSG_LAST               = 2,
> +};
> +
> +/*
> + * Msg descriptor.
> + *
> + * sizeof(struct PVSCSIRingMsgDesc) == 128.
> + *
> + * - type is of type enum PVSCSIMsgType.
> + * - the content of args depend on the type of event being delivered.
> + */
> +
> +struct PVSCSIRingMsgDesc {
> +	u32	type;
> +	u32	args[31];
> +} __packed;
> +
> +struct PVSCSIMsgDescDevStatusChanged {
> +	u32	type;  /* PVSCSI_MSG_DEV _ADDED / _REMOVED */
> +	u32	bus;
> +	u32	target;
> +	u8	lun[8];
> +	u32	pad[27];
> +} __packed;
> +
> +/*
> + * Rings state.
> + *
> + * - the fields:
> + *    . msgProdIdx,
> + *    . msgConsIdx,
> + *    . msgNumEntriesLog2,
> + *   .. are only used once the SETUP_MSG_RING cmd has been issued.
> + * - '_pad' helps to ensure that the msg related fields are on their own
> + *   cache-line.
> + */
> +
> +struct PVSCSIRingsState {
> +	u32	reqProdIdx;
> +	u32	reqConsIdx;
> +	u32	reqNumEntriesLog2;
> +
> +	u32	cmpProdIdx;
> +	u32	cmpConsIdx;
> +	u32	cmpNumEntriesLog2;
> +
> +	u8	_pad[104];
> +
> +	u32	msgProdIdx;
> +	u32	msgConsIdx;
> +	u32	msgNumEntriesLog2;
> +} __packed;
> +
> +/*
> + * Request descriptor.
> + *
> + * sizeof(RingReqDesc) = 128
> + *
> + * - context: is a unique identifier of a command. It could normally be any
> + *   64bit value, however we currently store it in the serialNumber variable
> + *   of struct SCSI_Command, so we have the following restrictions due to the
> + *   way this field is handled in the vmkernel storage stack:
> + *    * this value can't be 0,
> + *    * the upper 32bit need to be 0 since serialNumber is as a u32.
> + *   Currently tracked as PR 292060.
> + * - dataLen: contains the total number of bytes that need to be transferred.
> + * - dataAddr:
> + *   * if PVSCSI_FLAG_CMD_WITH_SG_LIST is set: dataAddr is the PA of the first
> + *     s/g table segment, each s/g segment is entirely contained on a single
> + *     page of physical memory,
> + *   * if PVSCSI_FLAG_CMD_WITH_SG_LIST is NOT set, then dataAddr is the PA of
> + *     the buffer used for the DMA transfer,
> + * - flags:
> + *   * PVSCSI_FLAG_CMD_WITH_SG_LIST: see dataAddr above,
> + *   * PVSCSI_FLAG_CMD_DIR_NONE: no DMA involved,
> + *   * PVSCSI_FLAG_CMD_DIR_TOHOST: transfer from device to main memory,
> + *   * PVSCSI_FLAG_CMD_DIR_TODEVICE: transfer from main memory to device,
> + *   * PVSCSI_FLAG_CMD_OUT_OF_BAND_CDB: reserved to handle CDBs larger than
> + *     16bytes. To be specified.
> + * - vcpuHint: vcpuId of the processor that will be most likely waiting for the
> + *   completion of the i/o. For guest OSes that use lowest priority message
> + *   delivery mode (such as windows), we use this "hint" to deliver the
> + *   completion action to the proper vcpu. For now, we can use the vcpuId of
> + *   the processor that initiated the i/o as a likely candidate for the vcpu
> + *   that will be waiting for the completion..
> + * - bus should be 0: we currently only support bus 0 for now.
> + * - unused should be zero'd.
> + */
> +
> +#define PVSCSI_FLAG_CMD_WITH_SG_LIST        (1 << 0)
> +#define PVSCSI_FLAG_CMD_OUT_OF_BAND_CDB     (1 << 1)
> +#define PVSCSI_FLAG_CMD_DIR_NONE            (1 << 2)
> +#define PVSCSI_FLAG_CMD_DIR_TOHOST          (1 << 3)
> +#define PVSCSI_FLAG_CMD_DIR_TODEVICE        (1 << 4)
> +
> +struct PVSCSIRingReqDesc {
> +	u64	context;
> +	u64	dataAddr;
> +	u64	dataLen;
> +	u64	senseAddr;
> +	u32	senseLen;
> +	u32	flags;
> +	u8	cdb[16];
> +	u8	cdbLen;
> +	u8	lun[8];
> +	u8	tag;
> +	u8	bus;
> +	u8	target;
> +	u8	vcpuHint;
> +	u8	unused[59];
> +} __packed;
> +
> +/*
> + * Scatter-gather list management.
> + *
> + * As described above, when PVSCSI_FLAG_CMD_WITH_SG_LIST is set in the
> + * RingReqDesc.flags, then RingReqDesc.dataAddr is the PA of the first s/g
> + * table segment.
> + *
> + * - each segment of the s/g table contain a succession of struct
> + *   PVSCSISGElement.
> + * - each segment is entirely contained on a single physical page of memory.
> + * - a "chain" s/g element has the flag PVSCSI_SGE_FLAG_CHAIN_ELEMENT set in
> + *   PVSCSISGElement.flags and in this case:
> + *     * addr is the PA of the next s/g segment,
> + *     * length is undefined, assumed to be 0.
> + */
> +
> +struct PVSCSISGElement {
> +	u64	addr;
> +	u32	length;
> +	u32	flags;
> +} __packed;
> +
> +/*
> + * Completion descriptor.
> + *
> + * sizeof(RingCmpDesc) = 32
> + *
> + * - context: identifier of the command. The same thing that was specified
> + *   under "context" as part of struct RingReqDesc at initiation time,
> + * - dataLen: number of bytes transferred for the actual i/o operation,
> + * - senseLen: number of bytes written into the sense buffer,
> + * - hostStatus: adapter status,
> + * - scsiStatus: device status,
> + * - _pad should be zero.
> + */
> +
> +struct PVSCSIRingCmpDesc {
> +	u64	context;
> +	u64	dataLen;
> +	u32	senseLen;
> +	u16	hostStatus;
> +	u16	scsiStatus;
> +	u32	_pad[2];
> +} __packed;
> +
> +/*
> + * Interrupt status / IRQ bits.
> + */
> +
> +#define PVSCSI_INTR_CMPL_0                 (1 << 0)
> +#define PVSCSI_INTR_CMPL_1                 (1 << 1)
> +#define PVSCSI_INTR_CMPL_MASK              MASK(2)
> +
> +#define PVSCSI_INTR_MSG_0                  (1 << 2)
> +#define PVSCSI_INTR_MSG_1                  (1 << 3)
> +#define PVSCSI_INTR_MSG_MASK               (MASK(2) << 2)
> +
> +#define PVSCSI_INTR_ALL_SUPPORTED          MASK(4)
> +
> +/*
> + * Number of MSI-X vectors supported.
> + */
> +#define PVSCSI_MAX_INTRS        24
> +
> +/*
> + * Enumeration of supported MSI-X vectors
> + */
> +#define PVSCSI_VECTOR_COMPLETION   0
> +
> +/*
> + * Misc constants for the rings.
> + */
> +
> +#define PVSCSI_MAX_NUM_PAGES_REQ_RING   PVSCSI_SETUP_RINGS_MAX_NUM_PAGES
> +#define PVSCSI_MAX_NUM_PAGES_CMP_RING   PVSCSI_SETUP_RINGS_MAX_NUM_PAGES
> +#define PVSCSI_MAX_NUM_PAGES_MSG_RING   PVSCSI_SETUP_MSG_RING_MAX_NUM_PAGES
> +
> +#define PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE \
> +				(PAGE_SIZE / sizeof(struct PVSCSIRingReqDesc))
> +
> +#define PVSCSI_MAX_REQ_QUEUE_DEPTH \
> +	(PVSCSI_MAX_NUM_PAGES_REQ_RING * PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE)
> +
> +#define PVSCSI_MEM_SPACE_COMMAND_NUM_PAGES     1
> +#define PVSCSI_MEM_SPACE_INTR_STATUS_NUM_PAGES 1
> +#define PVSCSI_MEM_SPACE_MISC_NUM_PAGES        2
> +#define PVSCSI_MEM_SPACE_KICK_IO_NUM_PAGES     2
> +#define PVSCSI_MEM_SPACE_MSIX_NUM_PAGES        2
> +
> +enum PVSCSIMemSpace {
> +	PVSCSI_MEM_SPACE_COMMAND_PAGE		= 0,
> +	PVSCSI_MEM_SPACE_INTR_STATUS_PAGE	= 1,
> +	PVSCSI_MEM_SPACE_MISC_PAGE		= 2,
> +	PVSCSI_MEM_SPACE_KICK_IO_PAGE		= 4,
> +	PVSCSI_MEM_SPACE_MSIX_TABLE_PAGE	= 6,
> +	PVSCSI_MEM_SPACE_MSIX_PBA_PAGE		= 7,
> +};
> +
> +#define PVSCSI_MEM_SPACE_NUM_PAGES \
> +	(PVSCSI_MEM_SPACE_COMMAND_NUM_PAGES +       \
> +	 PVSCSI_MEM_SPACE_INTR_STATUS_NUM_PAGES +   \
> +	 PVSCSI_MEM_SPACE_MISC_NUM_PAGES +          \
> +	 PVSCSI_MEM_SPACE_KICK_IO_NUM_PAGES +       \
> +	 PVSCSI_MEM_SPACE_MSIX_NUM_PAGES)
> +
> +#define PVSCSI_MEM_SPACE_SIZE        (PVSCSI_MEM_SPACE_NUM_PAGES * PAGE_SIZE)
> +
> +#endif /* _PVSCSI_H_ */
> 

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