On Wed, 6 Jan 2021 13:21:23 +0000
Jonathan Cameron <jonathan.came...@huawei.com> wrote:
> On Tue, 5 Jan 2021 08:52:58 -0800
> Ben Widawsky <ben.widaw...@intel.com> wrote:
>
> > This is the beginning of implementing mailbox support for CXL 2.0
> > devices.
> >
> > v2: Use register alignment helper (Ben)
> > Minor cleanups (Jonathan)
> > Rename error codes to match spec (Jonathan)
> > Update cap count from 1 to 2 (Jonathan)
> > Add infra to support CEL (Ben)
> > Add more of the actual mailbox handling from later patch (Ben)
> >
> > Signed-off-by: Ben Widawsky <ben.widaw...@intel.com>
>
> Hi Ben,
>
> I hacked support in for ARM64 to give this a spin and ran into an
> interesting problem around read sizes.
>
> The mailbox registers space allows 4 or 8 byte reads, but in the kernel
> driver (I think I have the right version from your github) you do
> the payload drain with
> memcpy_from_io()
>
> If the size of the payload is not a multiple of 8 bytes, on ARM64 that
> results in byte reads and an exception. This happens with some of the
> existing calls which happen to have non multiple of 8 payload sizes.
>
> I hacked below to allow 1 byte reads from that region but that's probably
> not the right fix. I found a statement in the CXL spec saying maximum read
> size from this register block was 8 bytes but couldn't immediately see a
> minimum.
> (I haven't looked that hard yet though!)
>
> Various approaches in kernel could also be used:
> 1) Change the payload drain to have specific handling for the end few bytes.
> 2) Pad the various structures to ensure payloads are always 8 byte multiples
> in length (nasty).
Bit more testing an another little thing below.
J
>
> > ---
> > hw/cxl/cxl-device-utils.c | 122 ++++++++++++++++++++++++-
> > hw/cxl/cxl-mailbox-utils.c | 173 ++++++++++++++++++++++++++++++++++++
> > hw/cxl/meson.build | 1 +
> > include/hw/cxl/cxl.h | 3 +
> > include/hw/cxl/cxl_device.h | 27 +++++-
> > 5 files changed, 322 insertions(+), 4 deletions(-)
> > create mode 100644 hw/cxl/cxl-mailbox-utils.c
> >
> > diff --git a/hw/cxl/cxl-device-utils.c b/hw/cxl/cxl-device-utils.c
> > index b86e5466bd..642e3c2617 100644
> > --- a/hw/cxl/cxl-device-utils.c
> > +++ b/hw/cxl/cxl-device-utils.c
> > @@ -44,6 +44,108 @@ static uint64_t dev_reg_read(void *opaque, hwaddr
> > offset, unsigned size)
> > return ldn_le_p(&retval, size);
> > }
> >
> > +static uint64_t mailbox_reg_read(void *opaque, hwaddr offset, unsigned
> > size)
> > +{
> > + CXLDeviceState *cxl_dstate = opaque;
> > +
> > + if (cxl_device_check_register_alignment(offset, size)) {
> > + qemu_log_mask(LOG_UNIMP, "Unaligned register read\n");
> > + return 0;
> > + }
> > +
> > + return ldn_le_p(cxl_dstate->mbox_reg_state + offset, size);
> > +}
> > +
> > +static void mailbox_mem_writel(uint32_t *reg_state, hwaddr offset,
> > + uint64_t value)
> > +{
> > + switch (offset) {
> > + case A_CXL_DEV_MAILBOX_CTRL:
> > + /* fallthrough */
> > + case A_CXL_DEV_MAILBOX_CAP:
> > + /* RO register */
> > + break;
> > + default:
> > + qemu_log_mask(LOG_UNIMP,
> > + "%s Unexpected 32-bit access to 0x%" PRIx64 "
> > (WI)\n",
> > + __func__, offset);
> > + break;
> > + }
> > +
> > + stl_le_p((uint8_t *)reg_state + offset, value);
> > +}
> > +
> > +static void mailbox_mem_writeq(uint8_t *reg_state, hwaddr offset,
> > + uint64_t value)
> > +{
> > + switch (offset) {
> > + case A_CXL_DEV_MAILBOX_CMD:
> > + break;
> > + case A_CXL_DEV_BG_CMD_STS:
> > + /* BG not supported */
> > + /* fallthrough */
> > + case A_CXL_DEV_MAILBOX_STS:
> > + /* Read only register, will get updated by the state machine */
> > + return;
> > + default:
> > + qemu_log_mask(LOG_UNIMP,
> > + "%s Unexpected 64-bit access to 0x%" PRIx64 "
> > (WI)\n",
> > + __func__, offset);
I've been debugging mail box issues and it seems we can hit this path if
a payload is written by the OS. Result is it never gets written into the memory
and hence isn't available when we try to read it below.
> > + return;
> > + }
> > +
> > + stq_le_p(reg_state + offset, value);
> > +}
> > +
> > +static void mailbox_reg_write(void *opaque, hwaddr offset, uint64_t value,
> > + unsigned size)
> > +{
> > + CXLDeviceState *cxl_dstate = opaque;
> > +
> > + /*
> > + * Lock is needed to prevent concurrent writes as well as to prevent
> > writes
> > + * coming in while the firmware is processing. Without background
> > commands
> > + * or the second mailbox implemented, this serves no purpose since the
> > + * memory access is synchronized at a higher level (per memory region).
> > + */
> > + RCU_READ_LOCK_GUARD();
> > +
> > + switch (size) {
> > + case 4:
> > + if (unlikely(offset & (sizeof(uint32_t) - 1))) {
> > + qemu_log_mask(LOG_UNIMP, "Unaligned register read\n");
> > + return;
> > + }
> > + mailbox_mem_writel(cxl_dstate->mbox_reg_state32, offset, value);
> > + break;
> > + case 8:
> > + if (unlikely(offset & (sizeof(uint64_t) - 1))) {
> > + qemu_log_mask(LOG_UNIMP, "Unaligned register read\n");
> > + return;
> > + }
> > + mailbox_mem_writeq(cxl_dstate->mbox_reg_state, offset, value);
> > + break;
> > + }
> > +
> > + if (ARRAY_FIELD_EX32(cxl_dstate->mbox_reg_state32,
> > CXL_DEV_MAILBOX_CTRL,
> > + DOORBELL))
> > + cxl_process_mailbox(cxl_dstate);
> > +}
> > +
> > +static const MemoryRegionOps mailbox_ops = {
> > + .read = mailbox_reg_read,
> > + .write = mailbox_reg_write,
> > + .endianness = DEVICE_LITTLE_ENDIAN,
> > + .valid = {
> > + .min_access_size = 4,
>
> Hack was to set this to 1 (and the impl below - no idea if both are needed).
>
> > + .max_access_size = 8,
> > + },
> > + .impl = {
> > + .min_access_size = 4,
> > + .max_access_size = 8,
> > + },
> > +};
> > +
> > static const MemoryRegionOps dev_ops = {
> > .read = dev_reg_read,
> > .write = NULL,
> > @@ -83,20 +185,33 @@ void cxl_device_register_block_init(Object *obj,
> > CXLDeviceState *cxl_dstate)
> > "cap-array", CXL_DEVICE_REGISTERS_OFFSET - 0);
> > memory_region_init_io(&cxl_dstate->device, obj, &dev_ops, cxl_dstate,
> > "device-status", CXL_DEVICE_REGISTERS_LENGTH);
> > + memory_region_init_io(&cxl_dstate->mailbox, obj, &mailbox_ops,
> > cxl_dstate,
> > + "mailbox", CXL_MAILBOX_REGISTERS_LENGTH);
> >
> > memory_region_add_subregion(&cxl_dstate->device_registers, 0,
> > &cxl_dstate->caps);
> > memory_region_add_subregion(&cxl_dstate->device_registers,
> > CXL_DEVICE_REGISTERS_OFFSET,
> > &cxl_dstate->device);
> > + memory_region_add_subregion(&cxl_dstate->device_registers,
> > + CXL_MAILBOX_REGISTERS_OFFSET,
> > + &cxl_dstate->mailbox);
> > }
> >
> > static void device_reg_init_common(CXLDeviceState *cxl_dstate) { }
> >
> > +static void mailbox_reg_init_common(CXLDeviceState *cxl_dstate)
> > +{
> > + /* 2048 payload size, with no interrupt or background support */
> > + ARRAY_FIELD_DP32(cxl_dstate->mbox_reg_state32, CXL_DEV_MAILBOX_CAP,
> > + PAYLOAD_SIZE, CXL_MAILBOX_PAYLOAD_SHIFT);
> > + cxl_dstate->payload_size = CXL_MAILBOX_MAX_PAYLOAD_SIZE;
> > +}
> > +
> > void cxl_device_register_init_common(CXLDeviceState *cxl_dstate)
> > {
> > uint32_t *cap_hdrs = cxl_dstate->caps_reg_state32;
> > - const int cap_count = 1;
> > + const int cap_count = 2;
> >
> > /* CXL Device Capabilities Array Register */
> > ARRAY_FIELD_DP32(cap_hdrs, CXL_DEV_CAP_ARRAY, CAP_ID, 0);
> > @@ -105,4 +220,9 @@ void cxl_device_register_init_common(CXLDeviceState
> > *cxl_dstate)
> >
> > cxl_device_cap_init(cxl_dstate, DEVICE, 1);
> > device_reg_init_common(cxl_dstate);
> > +
> > + cxl_device_cap_init(cxl_dstate, MAILBOX, 2);
> > + mailbox_reg_init_common(cxl_dstate);
> > +
> > + assert(cxl_initialize_mailbox(cxl_dstate) == 0);
> > }
> > diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> > new file mode 100644
> > index 0000000000..3a39c936de
> > --- /dev/null
> > +++ b/hw/cxl/cxl-mailbox-utils.c
> > @@ -0,0 +1,173 @@
> > +/*
> > + * CXL Utility library for mailbox interface
> > + *
> > + * Copyright(C) 2020 Intel Corporation.
> > + *
> > + * This work is licensed under the terms of the GNU GPL, version 2. See the
> > + * COPYING file in the top-level directory.
> > + */
> > +
> > +#include "qemu/osdep.h"
> > +#include "hw/cxl/cxl.h"
> > +#include "hw/pci/pci.h"
> > +#include "qemu/log.h"
> > +#include "qemu/uuid.h"
> > +
> > +/*
> > + * How to add a new command, example. The command set FOO, with cmd BAR.
> > + * 1. Add the command set and cmd to the enum.
> > + * FOO = 0x7f,
> > + * #define BAR 0
> > + * 2. Forward declare the handler.
> > + * declare_mailbox_handler(FOO_BAR);
> > + * 3. Add the command to the cxl_cmd_set[][]
> > + * CXL_CMD(FOO, BAR, 0, 0),
> > + * 4. Implement your handler
> > + * define_mailbox_handler(FOO_BAR) { ... return CXL_MBOX_SUCCESS; }
> > + *
> > + *
> > + * Writing the handler:
> > + * The handler will provide the &struct cxl_cmd, the &CXLDeviceState,
> > and the
> > + * in/out length of the payload. The handler is responsible for
> > consuming the
> > + * payload from cmd->payload and operating upon it as necessary. It
> > must then
> > + * fill the output data into cmd->payload (overwriting what was there),
> > + * setting the length, and returning a valid return code.
> > + *
> > + * XXX: The handler need not worry about endianess. The payload is read
> > out of
> > + * a register interface that already deals with it.
> > + */
> > +
> > +/* 8.2.8.4.5.1 Command Return Codes */
> > +typedef enum {
> > + CXL_MBOX_SUCCESS = 0x0,
> > + CXL_MBOX_BG_STARTED = 0x1,
> > + CXL_MBOX_INVALID_INPUT = 0x2,
> > + CXL_MBOX_UNSUPPORTED = 0x3,
> > + CXL_MBOX_INTERNAL_ERROR = 0x4,
> > + CXL_MBOX_RETRY_REQUIRED = 0x5,
> > + CXL_MBOX_BUSY = 0x6,
> > + CXL_MBOX_MEDIA_DISABLED = 0x7,
> > + CXL_MBOX_FW_XFER_IN_PROGRESS = 0x8,
> > + CXL_MBOX_FW_XFER_OUT_OF_ORDER = 0x9,
> > + CXL_MBOX_FW_AUTH_FAILED = 0xa,
> > + CXL_MBOX_FW_INVALID_SLOT = 0xb,
> > + CXL_MBOX_FW_ROLLEDBACK = 0xc,
> > + CXL_MBOX_FW_REST_REQD = 0xd,
> > + CXL_MBOX_INVALID_HANDLE = 0xe,
> > + CXL_MBOX_INVALID_PA = 0xf,
> > + CXL_MBOX_INJECT_POISON_LIMIT = 0x10,
> > + CXL_MBOX_PERMANENT_MEDIA_FAILURE = 0x11,
> > + CXL_MBOX_ABORTED = 0x12,
> > + CXL_MBOX_INVALID_SECURITY_STATE = 0x13,
> > + CXL_MBOX_INCORRECT_PASSPHRASE = 0x14,
> > + CXL_MBOX_UNSUPPORTED_MAILBOX = 0x15,
> > + CXL_MBOX_INVALID_PAYLOAD_LENGTH = 0x16,
> > + CXL_MBOX_MAX = 0x17
> > +} ret_code;
> > +
> > +struct cxl_cmd;
> > +typedef ret_code (*opcode_handler)(struct cxl_cmd *cmd,
> > + CXLDeviceState *cxl_dstate, uint16_t
> > *len);
> > +struct cxl_cmd {
> > + const char *name;
> > + opcode_handler handler;
> > + ssize_t in;
> > + uint16_t effect; /* Reported in CEL */
> > + uint8_t *payload;
> > +};
> > +
> > +#define define_mailbox_handler(name) \
> > + static ret_code cmd_##name(struct cxl_cmd *cmd, \
> > + CXLDeviceState *cxl_dstate, uint16_t *len)
> > +#define declare_mailbox_handler(name) define_mailbox_handler(name)
> > +
> > +#define CXL_CMD(s, c, in, cel_effect) \
> > + [s][c] = { stringify(s##_##c), cmd_##s##_##c, in, cel_effect }
> > +
> > +static struct cxl_cmd cxl_cmd_set[256][256] = {};
> > +
> > +#undef CXL_CMD
> > +
> > +QemuUUID cel_uuid;
> > +
> > +void cxl_process_mailbox(CXLDeviceState *cxl_dstate)
> > +{
> > + uint16_t ret = CXL_MBOX_SUCCESS;
> > + struct cxl_cmd *cxl_cmd;
> > + uint64_t status_reg;
> > + opcode_handler h;
> > +
> > + /*
> > + * current state of mailbox interface
> > + * mbox_cap_reg = cxl_dstate->reg_state32[R_CXL_DEV_MAILBOX_CAP];
> > + * mbox_ctrl_reg = cxl_dstate->reg_state32[R_CXL_DEV_MAILBOX_CTRL];
> > + * status_reg = *(uint64_t
> > *)&cxl_dstate->reg_state[A_CXL_DEV_MAILBOX_STS];
> > + */
> > + uint64_t command_reg =
> > + *(uint64_t *)&cxl_dstate->mbox_reg_state[A_CXL_DEV_MAILBOX_CMD];
> > +
> > + /* Check if we have to do anything */
> > + if (!ARRAY_FIELD_EX32(cxl_dstate->mbox_reg_state32,
> > CXL_DEV_MAILBOX_CTRL,
> > + DOORBELL)) {
> > + qemu_log_mask(LOG_UNIMP, "Corrupt internal state for firmware\n");
> > + return;
> > + }
> > +
> > + uint8_t set = FIELD_EX64(command_reg, CXL_DEV_MAILBOX_CMD,
> > COMMAND_SET);
> > + uint8_t cmd = FIELD_EX64(command_reg, CXL_DEV_MAILBOX_CMD, COMMAND);
> > + uint16_t len = FIELD_EX64(command_reg, CXL_DEV_MAILBOX_CMD, LENGTH);
> > + cxl_cmd = &cxl_cmd_set[set][cmd];
> > + h = cxl_cmd->handler;
> > + if (!h) {
> > + goto handled;
> > + }
> > +
> > + if (len != cxl_cmd->in) {
> > + ret = CXL_MBOX_INVALID_PAYLOAD_LENGTH;
> > + }
> > +
> > + cxl_cmd->payload = cxl_dstate->mbox_reg_state + A_CXL_DEV_CMD_PAYLOAD;
The return highlighted above on which registers are writable meant the payload
never has anything useful in it. Remove that and this seems to work and I
can query implemented commands + enable them.
> > + ret = (*h)(cxl_cmd, cxl_dstate, &len);
> > + assert(len <= cxl_dstate->payload_size);
> > +
> > +handled:
> > + /*
> > + * Set the return code
> > + * XXX: it's a 64b register, but we're not setting the vendor, so we
> > can get
> > + * away with this
> > + */
> > + status_reg = FIELD_DP64(0, CXL_DEV_MAILBOX_STS, ERRNO, ret);
> > +
> > + /*
> > + * Set the return length
> > + */
> > + command_reg = FIELD_DP64(command_reg, CXL_DEV_MAILBOX_CMD,
> > COMMAND_SET, 0);
> > + command_reg = FIELD_DP64(command_reg, CXL_DEV_MAILBOX_CMD, COMMAND, 0);
> > + command_reg = FIELD_DP64(command_reg, CXL_DEV_MAILBOX_CMD, LENGTH,
> > len);
> > +
> > + stq_le_p(cxl_dstate->mbox_reg_state + A_CXL_DEV_MAILBOX_CMD,
> > command_reg);
> > + stq_le_p(cxl_dstate->mbox_reg_state + A_CXL_DEV_MAILBOX_STS,
> > status_reg);
> > +
> > + /* Tell the host we're done */
> > + ARRAY_FIELD_DP32(cxl_dstate->mbox_reg_state32, CXL_DEV_MAILBOX_CTRL,
> > + DOORBELL, 0);
> > +}
> > +
> > +int cxl_initialize_mailbox(CXLDeviceState *cxl_dstate)
> > +{
> > + const char *cel_uuidstr = "0da9c0b5-bf41-4b78-8f79-96b1623b3f17";
> > +
> > + for (int i = 0; i < 256; i++) {
> > + for (int j = 0; j < 256; j++) {
> > + if (cxl_cmd_set[i][j].handler) {
> > + struct cxl_cmd *c = &cxl_cmd_set[i][j];
> > +
> > + cxl_dstate->cel_log[cxl_dstate->cel_size].opcode = (i <<
> > 8) | j;
> > + cxl_dstate->cel_log[cxl_dstate->cel_size].effect =
> > c->effect;
> > + cxl_dstate->cel_size++;
> > + }
> > + }
> > + }
> > +
> > + return qemu_uuid_parse(cel_uuidstr, &cel_uuid);
> > +}
> > diff --git a/hw/cxl/meson.build b/hw/cxl/meson.build
> > index 47154d6850..0eca715d10 100644
> > --- a/hw/cxl/meson.build
> > +++ b/hw/cxl/meson.build
> > @@ -1,4 +1,5 @@
> > softmmu_ss.add(when: 'CONFIG_CXL', if_true: files(
> > 'cxl-component-utils.c',
> > 'cxl-device-utils.c',
> > + 'cxl-mailbox-utils.c',
> > ))
> > diff --git a/include/hw/cxl/cxl.h b/include/hw/cxl/cxl.h
> > index 23f52c4cf9..362cda40de 100644
> > --- a/include/hw/cxl/cxl.h
> > +++ b/include/hw/cxl/cxl.h
> > @@ -14,5 +14,8 @@
> > #include "cxl_component.h"
> > #include "cxl_device.h"
> >
> > +#define COMPONENT_REG_BAR_IDX 0
> > +#define DEVICE_REG_BAR_IDX 2
> > +
> > #endif
> >
> > diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
> > index 3380fc9e7a..bdf990cec2 100644
> > --- a/include/hw/cxl/cxl_device.h
> > +++ b/include/hw/cxl/cxl_device.h
> > @@ -70,9 +70,10 @@
> > (CXL_MAILBOX_REGISTERS_SIZE + CXL_MAILBOX_MAX_PAYLOAD_SIZE)
> >
> > typedef struct cxl_device_state {
> > - /* Boss container and caps registers */
> > + /* Main register container */
> > MemoryRegion device_registers;
> >
> > + MemoryRegion device;
> > struct {
> > MemoryRegion caps;
> > union {
> > @@ -80,8 +81,19 @@ typedef struct cxl_device_state {
> > uint32_t caps_reg_state32[CXL_DEVICE_CAP_REG_SIZE >> 2];
> > };
> > };
> > - MemoryRegion device;
> > - MemoryRegion mailbox;
> > + struct {
> > + MemoryRegion mailbox;
> > + uint16_t payload_size;
> > + union {
> > + uint8_t mbox_reg_state[CXL_MAILBOX_REGISTERS_LENGTH];
> > + uint32_t mbox_reg_state32[CXL_MAILBOX_REGISTERS_LENGTH >> 2];
> > + };
> > + struct {
> > + uint16_t opcode;
> > + uint16_t effect;
> > + } cel_log[1 << 16];
> > + size_t cel_size;
> > + };
> >
> > MemoryRegion *pmem;
> > MemoryRegion *vmem;
> > @@ -122,6 +134,9 @@ CXL_DEVICE_CAPABILITY_HEADER_REGISTER(DEVICE,
> > CXL_DEVICE_CAP_HDR1_OFFSET)
> > CXL_DEVICE_CAPABILITY_HEADER_REGISTER(MAILBOX, CXL_DEVICE_CAP_HDR1_OFFSET
> > + \
> > CXL_DEVICE_CAP_REG_SIZE)
> >
> > +int cxl_initialize_mailbox(CXLDeviceState *cxl_dstate);
> > +void cxl_process_mailbox(CXLDeviceState *cxl_dstate);
> > +
> > #define cxl_device_cap_init(dstate, reg, cap_id)
> > \
> > do {
> > \
> > uint32_t *cap_hdrs = dstate->caps_reg_state32;
> > \
> > @@ -149,6 +164,12 @@ REG32(CXL_DEV_MAILBOX_CTRL, 4)
> > FIELD(CXL_DEV_MAILBOX_CTRL, INT_EN, 1, 1)
> > FIELD(CXL_DEV_MAILBOX_CTRL, BG_INT_EN, 2, 1)
> >
> > +/* XXX: actually a 64b register */
> > +REG32(CXL_DEV_MAILBOX_CMD, 8)
> > + FIELD(CXL_DEV_MAILBOX_CMD, COMMAND, 0, 8)
> > + FIELD(CXL_DEV_MAILBOX_CMD, COMMAND_SET, 8, 8)
> > + FIELD(CXL_DEV_MAILBOX_CMD, LENGTH, 16, 20)
> > +
> > /* XXX: actually a 64b register */
> > REG32(CXL_DEV_MAILBOX_STS, 0x10)
> > FIELD(CXL_DEV_MAILBOX_STS, BG_OP, 0, 1)
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