diff --git a/MAINTAINERS b/MAINTAINERS index 018ed62560..73ec940bea 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2350,6 +2350,7 @@ S: Maintained F: hw/net/vmxnet* F: hw/scsi/vmw_pvscsi* F: tests/qtest/vmxnet3-test.c +F: docs/specs/vwm_pvscsi-spec.rst Rocker M: Jiri Pirko diff --git a/docs/specs/index.rst b/docs/specs/index.rst index e58be38c41..d23efbe248 100644 --- a/docs/specs/index.rst +++ b/docs/specs/index.rst @@ -24,3 +24,4 @@ guest hardware that is specific to QEMU. acpi_erst sev-guest-firmware fw_cfg + vmw_pvscsi-spec diff --git a/docs/specs/vmw_pvscsi-spec.rst b/docs/specs/vmw_pvscsi-spec.rst new file mode 100644 index 0000000000..b6f434a418 --- /dev/null +++ b/docs/specs/vmw_pvscsi-spec.rst @@ -0,0 +1,115 @@ +============================== +VMWare PVSCSI Device Interface +============================== + +.. + Created by Dmitry Fleytman (dmitry@daynix.com), Daynix Computing LTD. + +This document describes the VMWare PVSCSI device interface specification, +based on the source code of the PVSCSI Linux driver from kernel 3.0.4. + +Overview +======== + +The interface is based on a memory area shared between hypervisor and VM. +The memory area is obtained by driver as a device IO memory resource of +``PVSCSI_MEM_SPACE_SIZE`` length. +The shared memory consists of a registers area and a 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 commands (with optional short data), +issue device interrupts, and control interrupt masking. + +PVSCSI Device Rings +=================== + +There are three rings in shared memory: + +Request ring (``struct PVSCSIRingReqDesc *req_ring``) + ring for OS to device requests + +Completion ring (``struct PVSCSIRingCmpDesc *cmp_ring``) + ring for device request completions + +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 +================================ + +The following interrupt types are supported by the PVSCSI device: + +Completion interrupts (completion ring notifications): + +- ``PVSCSI_INTR_CMPL_0`` +- ``PVSCSI_INTR_CMPL_1`` + +Message interrupts (message ring notifications): + +- ``PVSCSI_INTR_MSG_0`` +- ``PVSCSI_INTR_MSG_1`` + +Interrupts are controlled via the ``PVSCSI_REG_OFFSET_INTR_MASK`` +register. If a bit is set it means the interrupt is enabled, and if +it is clear then the interrupt is disabled. + +The interrupt modes supported are legacy, MSI and MSI-X. +In the case of legacy interrupts, the ``PVSCSI_REG_OFFSET_INTR_STATUS`` +register 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 +================================= + +Startup sequence +---------------- + +a. Issue ``PVSCSI_CMD_ADAPTER_RESET`` command +b. Windows driver reads interrupt status register here +c. 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) +d. Issue ``PVSCSI_CMD_SETUP_RINGS`` command, provide rings configuration + as ``struct PVSCSICmdDescSetupRings`` +e. Issue ``PVSCSI_CMD_SETUP_MSG_RING`` command again, provide + rings configuration as ``struct PVSCSICmdDescSetupMsgRing`` +f. Unmask completion and message (if device messages enabled) interrupts + +Shutdown sequence +----------------- + +a. Mask interrupts +b. Flush request ring using ``PVSCSI_REG_OFFSET_KICK_NON_RW_IO`` +c. Issue ``PVSCSI_CMD_ADAPTER_RESET`` command + +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 + +Abort command +------------- + +a. Issue ``PVSCSI_CMD_ABORT_CMD`` command + +Request completion processing +----------------------------- + +a. Upon completion interrupt arrival process completion + and message (if enabled) rings diff --git a/docs/specs/vmw_pvscsi-spec.txt b/docs/specs/vmw_pvscsi-spec.txt deleted file mode 100644 index 49affb2a42..0000000000 --- a/docs/specs/vmw_pvscsi-spec.txt +++ /dev/null @@ -1,92 +0,0 @@ -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.