mirror of
https://github.com/qemu/qemu.git
synced 2024-11-26 04:13:39 +08:00
881d588a98
Signed-off-by: Dmitry Fleytman <dmitry@daynix.com> Signed-off-by: Yan Vugenfirer <yan@daynix.com> [ Rename files to vmw_pvscsi, fix setting of hostStatus in pvscsi_request_cancelled - Paolo ] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
93 lines
3.6 KiB
Plaintext
93 lines
3.6 KiB
Plaintext
General Description
|
|
===================
|
|
|
|
This document describes VMWare PVSCSI device interface specification.
|
|
Created by Dmitry Fleytman (dmitry@daynix.com), Daynix Computing LTD.
|
|
Based on source code of PVSCSI Linux driver from kernel 3.0.4
|
|
|
|
PVSCSI Device Interface Overview
|
|
================================
|
|
|
|
The interface is based on memory area shared between hypervisor and VM.
|
|
Memory area is obtained by driver as device IO memory resource of
|
|
PVSCSI_MEM_SPACE_SIZE length.
|
|
The shared memory consists of registers area and rings area.
|
|
The registers area is used to raise hypervisor interrupts and issue device
|
|
commands. The rings area is used to transfer data descriptors and SCSI
|
|
commands from VM to hypervisor and to transfer messages produced by
|
|
hypervisor to VM. Data itself is transferred via virtual scatter-gather DMA.
|
|
|
|
PVSCSI Device Registers
|
|
=======================
|
|
|
|
The length of the registers area is 1 page (PVSCSI_MEM_SPACE_COMMAND_NUM_PAGES).
|
|
The structure of the registers area is described by the PVSCSIRegOffset enum.
|
|
There are registers to issue device command (with optional short data),
|
|
issue device interrupt, control interrupts masking.
|
|
|
|
PVSCSI Device Rings
|
|
===================
|
|
|
|
There are three rings in shared memory:
|
|
|
|
1. Request ring (struct PVSCSIRingReqDesc *req_ring)
|
|
- ring for OS to device requests
|
|
2. Completion ring (struct PVSCSIRingCmpDesc *cmp_ring)
|
|
- ring for device request completions
|
|
3. Message ring (struct PVSCSIRingMsgDesc *msg_ring)
|
|
- ring for messages from device.
|
|
This ring is optional and the guest might not configure it.
|
|
There is a control area (struct PVSCSIRingsState *rings_state) used to control
|
|
rings operation.
|
|
|
|
PVSCSI Device to Host Interrupts
|
|
================================
|
|
There are following interrupt types supported by PVSCSI device:
|
|
1. Completion interrupts (completion ring notifications):
|
|
PVSCSI_INTR_CMPL_0
|
|
PVSCSI_INTR_CMPL_1
|
|
2. Message interrupts (message ring notifications):
|
|
PVSCSI_INTR_MSG_0
|
|
PVSCSI_INTR_MSG_1
|
|
|
|
Interrupts are controlled via PVSCSI_REG_OFFSET_INTR_MASK register
|
|
Bit set means interrupt enabled, bit cleared - disabled
|
|
|
|
Interrupt modes supported are legacy, MSI and MSI-X
|
|
In case of legacy interrupts, register PVSCSI_REG_OFFSET_INTR_STATUS
|
|
is used to check which interrupt has arrived. Interrupts are
|
|
acknowledged when the corresponding bit is written to the interrupt
|
|
status register.
|
|
|
|
PVSCSI Device Operation Sequences
|
|
=================================
|
|
|
|
1. Startup sequence:
|
|
a. Issue PVSCSI_CMD_ADAPTER_RESET command;
|
|
aa. Windows driver reads interrupt status register here;
|
|
b. Issue PVSCSI_CMD_SETUP_MSG_RING command with no additional data,
|
|
check status and disable device messages if error returned;
|
|
(Omitted if device messages disabled by driver configuration)
|
|
c. Issue PVSCSI_CMD_SETUP_RINGS command, provide rings configuration
|
|
as struct PVSCSICmdDescSetupRings;
|
|
d. Issue PVSCSI_CMD_SETUP_MSG_RING command again, provide
|
|
rings configuration as struct PVSCSICmdDescSetupMsgRing;
|
|
e. Unmask completion and message (if device messages enabled) interrupts.
|
|
|
|
2. Shutdown sequences
|
|
a. Mask interrupts;
|
|
b. Flush request ring using PVSCSI_REG_OFFSET_KICK_NON_RW_IO;
|
|
c. Issue PVSCSI_CMD_ADAPTER_RESET command.
|
|
|
|
3. Send request
|
|
a. Fill next free request ring descriptor;
|
|
b. Issue PVSCSI_REG_OFFSET_KICK_RW_IO for R/W operations;
|
|
or PVSCSI_REG_OFFSET_KICK_NON_RW_IO for other operations.
|
|
|
|
4. Abort command
|
|
a. Issue PVSCSI_CMD_ABORT_CMD command;
|
|
|
|
5. Request completion processing
|
|
a. Upon completion interrupt arrival process completion
|
|
and message (if enabled) rings.
|