Re: [PATCH v2 3/7] ACPI ERST: support for ACPI ERST feature

On Mon, 8 Feb 2021 15:57:55 -0500
Eric DeVolder <eric.devolder@oracle.com> wrote:

> This change implements the support for the ACPI ERST feature[1,2].
>
> The size of the ACPI ERST storage is declared via the QEMU
> global parameter acpi-erst.size. The size can range from 64KiB
> to to 64MiB. The default is 64KiB.
>
> The location of the ACPI ERST storage backing file is delared
> via the QEMU global parameter acpi-erst.filename. The default
> is acpi-erst.backing.
>
> [1] "Advanced Configuration and Power Interface Specification",
>     version 6.2, May 2017.
>     https://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdf
>
> [2] "Unified Extensible Firmware Interface Specification",
>     version 2.8, March 2019.
>     https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf
>
> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>

items 2/4/5 from v1 review still need to be addressed.

>
> 2. patch is too big to review, please split it up in smaller chunks.
>
> EJD: Done.

(separating a header and a makefile rule doesn't make much sense)

it should be split at least on part that implements device model and ACPI parts

EJD: I'll rebase this patch set on qemu-6 and accommodate your suggestions with how to split/organize the patch set.

[...]
>
> 4. Maybe instead of SYSBUS device, implement it as a PCI device and
>    use its BAR/control registers for pstore storage and control interface.
>    It could save you headache of picking address where to map it +
>    it would take care of migration part automatically, as firmware
>    would do it for you and then QEMU could pickup firmware programmed
>    address and put it into ERST table.
> EJD: Thanks for the idea. For now I've left it as a SYSBUS device; we can revisit as needed.

I would really prefer to see a PCI version (current way is just a hack)

EJD: I understand, I don't like the base address problem either. Is there an example PCI device that gets its base address assigned during ACPI setup that I could reference and pattern this work after? I've been using SYSBUS as that most closely mimics the real hardware implementations I've studied in order to produce this code.

EJD: I thought my inexperience with authoring QEMU devices was the primary problem in establishing a solution for the base address. Otherwise, this thing only needs a single 4KiB page (for the 2 registers + exchange buffer) exposed.

> 5. instead of dealing with file for storage directly, reuse hostmem backend
> to provide it to for your device. ex: pc-dimm. i.e. split device
> on frontend and backend
>
> EJD: I had looked into that prior to posting v1. The entire ERST storage is not memory mapped, just an exchange buffer. So the hostmem backend is not suitable for this purpose.

Is there a compelling reason why it can't be memory mapped?

EJD: Well, this ERST device I've coded pretty much follows the ACPI ERST spec verbatim. As it stands today, the spec doesn't provide a way to report the total size of the persistent storage behind the interface; you know when storage is full only when you receive an Out Of Storage error code upon write. In a sense, that allows the size of the storage to vary greatly and be implemented in any way needed (ie actual hardware, this has tended to be in the 64KiB range when it is carved out of system parallel flash memory, but some hardware uses serial flash as well). In virtual environments, it can be of any size, and we at Oracle have intentions of heavily utilizing ACPI ERST to stuff all kinds of diagnostic information into it, thus wanting the storage to be very large. By not actually exposing/memory-mapping the storage, the issue of where to drop it in the memory map goes away (yes a PCI BAR could solve this).

EJD: But at the end of the day, could this storage be memory mapped? I suppose it could be, but then that rather circumvents the entire need for the ACPI ERST interface to start with. Linux and Windows both already know how to utilize ACPI ERST.

> ---
> hw/acpi/erst.c | 952 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 952 insertions(+)
> create mode 100644 hw/acpi/erst.c
>
> diff --git a/hw/acpi/erst.c b/hw/acpi/erst.c
> new file mode 100644
> index 0000000..3a342f9
> --- /dev/null
> +++ b/hw/acpi/erst.c
> @@ -0,0 +1,952 @@
> +/*
> + * ACPI Error Record Serialization Table, ERST, Implementation
> + *
> + * Copyright (c) 2020 Oracle and/or its affiliates.
> + *
> + * See ACPI specification,
> + * "ACPI Platform Error Interfaces" : "Error Serialization"
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation;
> + * version 2 of the License.
> + *
> + * This library 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. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see <http://www.gnu.org/licenses/>
> + */
> +
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <unistd.h>
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "hw/sysbus.h"
> +#include "qom/object_interfaces.h"
> +#include "qemu/error-report.h"
> +#include "migration/vmstate.h"
> +#include "hw/qdev-properties.h"
> +#include "hw/acpi/acpi.h"
> +#include "hw/acpi/acpi-defs.h"
> +#include "hw/acpi/aml-build.h"
> +#include "hw/acpi/bios-linker-loader.h"
> +#include "exec/address-spaces.h"
> +#include "hw/acpi/erst.h"
> +
> +#ifdef _ERST_DEBUG
> +#define erst_debug(fmt, ...) \
> +    do { fprintf(stderr, fmt, ## __VA_ARGS__); fflush(stderr); } while (0)
> +#else
> +#define erst_debug(fmt, ...) do { } while (0)
> +#endif
> +
> +/* See UEFI spec, Appendix N Common Platform Error Record */
> +/* UEFI CPER allows for an OSPM book keeping area in the record */
> +#define UEFI_CPER_RECORD_MIN_SIZE 128U
> +#define UEFI_CPER_SIZE_OFFSET 20U
> +#define UEFI_CPER_RECORD_ID_OFFSET 96U
> +#define IS_UEFI_CPER_RECORD(ptr) \
> +    (((ptr)[0] == 'C') && \
> +     ((ptr)[1] == 'P') && \
> +     ((ptr)[2] == 'E') && \
> +     ((ptr)[3] == 'R'))
> +#define THE_UEFI_CPER_RECORD_ID(ptr) \
> +    (*(uint64_t *)(&(ptr)[UEFI_CPER_RECORD_ID_OFFSET]))
> +
> +#define ERST_INVALID_RECORD_ID (~0UL)
> +#define ERST_EXECUTE_OPERATION_MAGIC 0x9CUL
> +#define ERST_CSR_ACTION (0UL << 3) /* action (cmd) */
> +#define ERST_CSR_VALUE (1UL << 3) /* argument/value (data) */
> +
> +/*
> + * As ERST_IOMEM_SIZE is used to map the ERST into the guest,
> + * it should/must be an integer multiple of PAGE_SIZE.
> + * NOTE that any change to this value will make any pre-
> + * existing backing files, not of the same ERST_IOMEM_SIZE,
> + * unusable to the guest.
> + */
> +#define ERST_IOMEM_SIZE (2UL * 4096)
> +
> +/*
> + * This implementation is an ACTION (cmd) and VALUE (data)
> + * interface consisting of just two 64-bit registers.
> + */
> +#define ERST_REG_LEN (2UL * sizeof(uint64_t))
> +
> +/*
> + * The space not utilized by the register interface is the
> + * buffer for exchanging ERST record contents.
> + */
> +#define ERST_RECORD_SIZE (ERST_IOMEM_SIZE - ERST_REG_LEN)
> +
> +/*
> + * Mode to be used for backing file
> + */
> +#define ERST_BACKING_FILE_MODE 0644 /* S_IRWXU|S_IRWXG */
> +
> +#define ACPIERST(obj) \
> +    OBJECT_CHECK(ERSTDeviceState, (obj), TYPE_ACPI_ERST)
> +#define ACPIERST_CLASS(oc) \
> +    OBJECT_CLASS_CHECK(ERSTDeviceStateClass, (oc), TYPE_ACPI_ERST)
> +#define ACPIERST_GET_CLASS(obj) \
> +    OBJECT_GET_CLASS(ERSTDeviceStateClass, (obj), TYPE_ACPI_ERST)
> +
> +static hwaddr erst_base;
> +
> +typedef struct {
> +    SysBusDevice parent_obj;
> +
> +    MemoryRegion iomem;
> +    uint32_t prop_size;
> +    char *prop_filename;
> +    hwaddr base;
> +
> +    uint8_t operation;
> +    uint8_t busy_status;
> +    uint8_t command_status;
> +    uint32_t record_offset;
> +    uint32_t record_count;
> +    uint64_t reg_action;
> +    uint64_t reg_value;
> +    uint64_t record_identifier;
> +
> +    unsigned next_record_index;
> +    uint8_t record[ERST_RECORD_SIZE]; /* read/written directly by guest */
> +    uint8_t tmp_record[ERST_RECORD_SIZE]; /* intermediate manipulation buffer */
> +    uint8_t *nvram; /* persistent storage, of length prop_size */
> +
> +} ERSTDeviceState;
> +
> +static void update_erst_backing_file(ERSTDeviceState *s,
> +    off_t offset, const uint8_t *data, size_t length)
> +{
> +    int fd;
> +
> +    /* Bounds check */
> +    if ((offset + length) > s->prop_size) {
> +        error_report("update: off 0x%lx len 0x%lx > size 0x%lx out of range",
> +            (long)offset, (long)length, (long)s->prop_size);
> +        return;
> +    }
> +
> +    fd = open(s->prop_filename, O_WRONLY | O_CREAT, ERST_BACKING_FILE_MODE);
> +    if (fd > 0) {
> +        off_t src;
> +        size_t wrc = 0;
> +        src = "" offset, SEEK_SET);
> +        if (offset == src) {
> +            wrc = write(fd, data, length);
> +        }
> +        if ((offset != src) || (length != wrc)) {
> +            error_report("ERST write failed: %d %d", (int)wrc, (int)length);
> +        }
> +        close(fd);
> +    } else {
> +        error_report("open failed: %s : %d", s->prop_filename, fd);
> +    }
> +}
> +
> +static unsigned copy_from_nvram_by_index(ERSTDeviceState *s, unsigned index)
> +{
> +    /* Read a nvram[] entry into tmp_record */
> +    unsigned rc = ACPI_ERST_STATUS_FAILED;
> +    off_t offset = (index * ERST_RECORD_SIZE);
> +
> +    if ((offset + ERST_RECORD_SIZE) <= s->prop_size) {
> +        memcpy(s->tmp_record, &s->nvram[offset], ERST_RECORD_SIZE);
> +        rc = ACPI_ERST_STATUS_SUCCESS;
> +    }
> +    return rc;
> +}
> +
> +static unsigned copy_to_nvram_by_index(ERSTDeviceState *s, unsigned index)
> +{
> +    /* Write entry in tmp_record into nvram[], and backing file */
> +    unsigned rc = ACPI_ERST_STATUS_FAILED;
> +    off_t offset = (index * ERST_RECORD_SIZE);
> +
> +    if ((offset + ERST_RECORD_SIZE) <= s->prop_size) {
> +        memcpy(&s->nvram[offset], s->tmp_record, ERST_RECORD_SIZE);
> +        update_erst_backing_file(s, offset, s->tmp_record, ERST_RECORD_SIZE);
> +        rc = ACPI_ERST_STATUS_SUCCESS;
> +    }
> +    return rc;
> +}
> +
> +static int lookup_erst_record_by_identifier(ERSTDeviceState *s,
> +    uint64_t record_identifier, bool *record_found, bool alloc_for_write)
> +{
> +    int rc = -1;
> +    int empty_index = -1;
> +    int index = 0;
> +    unsigned rrc;
> +
> +    *record_found = 0;
> +
> +    do {
> +        rrc = copy_from_nvram_by_index(s, (unsigned)index);
> +        if (rrc == ACPI_ERST_STATUS_SUCCESS) {
> +            uint64_t this_identifier;
> +            this_identifier = THE_UEFI_CPER_RECORD_ID(s->tmp_record);
> +            if (IS_UEFI_CPER_RECORD(s->tmp_record) &&
> +                (this_identifier == record_identifier)) {
> +                rc = index;
> +                *record_found = 1;
> +                break;
> +            }
> +            if ((this_identifier == ERST_INVALID_RECORD_ID) &&
> +                (empty_index < 0)) {
> +                empty_index = index; /* first available for write */
> +            }
> +        }
> +        ++index;
> +    } while (rrc == ACPI_ERST_STATUS_SUCCESS);
> +
> +    /* Record not found, allocate for writing */
> +    if ((rc < 0) && alloc_for_write) {
> +        rc = empty_index;
> +    }
> +
> +    return rc;
> +}
> +
> +static unsigned clear_erst_record(ERSTDeviceState *s)
> +{
> +    unsigned rc = ACPI_ERST_STATUS_RECORD_NOT_FOUND;
> +    bool record_found;
> +    int index;
> +
> +    index = lookup_erst_record_by_identifier(s,
> +        s->record_identifier, &record_found, 0);
> +    if (record_found) {
> +        memset(s->tmp_record, 0xFF, ERST_RECORD_SIZE);
> +        rc = copy_to_nvram_by_index(s, (unsigned)index);
> +        if (rc == ACPI_ERST_STATUS_SUCCESS) {
> +            s->record_count -= 1;
> +        }
> +    }
> +
> +    return rc;
> +}
> +
> +static unsigned write_erst_record(ERSTDeviceState *s)
> +{
> +    unsigned rc = ACPI_ERST_STATUS_FAILED;
> +
> +    if (s->record_offset < (ERST_RECORD_SIZE - UEFI_CPER_RECORD_MIN_SIZE)) {
> +        uint64_t record_identifier;
> +        uint8_t *record = &s->record[s->record_offset];
> +        bool record_found;
> +        int index;
> +
> +        record_identifier = (s->record_identifier == ERST_INVALID_RECORD_ID)
> +            ? THE_UEFI_CPER_RECORD_ID(record) : s->record_identifier;
> +
> +        index = lookup_erst_record_by_identifier(s,
> +            record_identifier, &record_found, 1);
> +        if (index < 0) {
> +            rc = ACPI_ERST_STATUS_NOT_ENOUGH_SPACE;
> +        } else {
> +            if (0 != s->record_offset) {
> +                memset(&s->tmp_record[ERST_RECORD_SIZE - s->record_offset],
> +                    0xFF, s->record_offset);
> +            }
> +            memcpy(s->tmp_record, record, ERST_RECORD_SIZE - s->record_offset);
> +            rc = copy_to_nvram_by_index(s, (unsigned)index);
> +            if (rc == ACPI_ERST_STATUS_SUCCESS) {
> +                if (!record_found) { /* not overwriting existing record */
> +                    s->record_count += 1; /* writing new record */
> +                }
> +            }
> +        }
> +    }
> +
> +    return rc;
> +}
> +
> +static unsigned next_erst_record(ERSTDeviceState *s,
> +    uint64_t *record_identifier)
> +{
> +    unsigned rc = ACPI_ERST_STATUS_RECORD_NOT_FOUND;
> +    unsigned index;
> +    unsigned rrc;
> +
> +    *record_identifier = ERST_INVALID_RECORD_ID;
> +
> +    index = s->next_record_index;
> +    do {
> +        rrc = copy_from_nvram_by_index(s, (unsigned)index);
> +        if (rrc == ACPI_ERST_STATUS_SUCCESS) {
> +            if (IS_UEFI_CPER_RECORD(s->tmp_record)) {
> +                s->next_record_index = index + 1; /* where to start next time */
> +                *record_identifier = THE_UEFI_CPER_RECORD_ID(s->tmp_record);
> +                rc = ACPI_ERST_STATUS_SUCCESS;
> +                break;
> +            }
> +            ++index;
> +        } else {
> +            if (s->next_record_index == 0) {
> +                rc = ACPI_ERST_STATUS_RECORD_STORE_EMPTY;
> +            }
> +            s->next_record_index = 0; /* at end, reset */
> +        }
> +    } while (rrc == ACPI_ERST_STATUS_SUCCESS);
> +
> +    return rc;
> +}
> +
> +static unsigned read_erst_record(ERSTDeviceState *s)
> +{
> +    unsigned rc = ACPI_ERST_STATUS_RECORD_NOT_FOUND;
> +    bool record_found;
> +    int index;
> +
> +    index = lookup_erst_record_by_identifier(s,
> +        s->record_identifier, &record_found, 0);
> +    if (record_found) {
> +        rc = copy_from_nvram_by_index(s, (unsigned)index);
> +        if (rc == ACPI_ERST_STATUS_SUCCESS) {
> +            if (s->record_offset < ERST_RECORD_SIZE) {
> +                memcpy(&s->record[s->record_offset], s->tmp_record,
> +                    ERST_RECORD_SIZE - s->record_offset);
> +            }
> +        }
> +    }
> +
> +    return rc;
> +}
> +
> +static unsigned get_erst_record_count(ERSTDeviceState *s)
> +{
> +    /* Compute record_count */
> +    off_t offset;
> +
> +    s->record_count = 0;
> +    offset = 0;
> +    do {
> +        uint8_t *ptr = &s->nvram[offset];
> +        uint64_t record_identifier = THE_UEFI_CPER_RECORD_ID(ptr);
> +        if (IS_UEFI_CPER_RECORD(ptr) &&
> +            (ERST_INVALID_RECORD_ID != record_identifier)) {
> +            s->record_count += 1;
> +        }
> +        offset += ERST_RECORD_SIZE;
> +    } while (offset < (off_t)s->prop_size);
> +
> +    return s->record_count;
> +}
> +
> +static void load_erst_backing_file(ERSTDeviceState *s)
> +{
> +    int fd;
> +    struct stat statbuf;
> +
> +    erst_debug("+load_erst_backing_file()\n");
> +
> +    /* Allocate and initialize nvram[] */
> +    s->nvram = g_malloc(s->prop_size);
> +    memset(s->nvram, 0xFF, s->prop_size);
> +
> +    /* Ensure backing file at least same as prop_size */
> +    if (stat(s->prop_filename, &statbuf) == 0) {
> +        /* ensure prop_size at least matches file size */
> +        if (statbuf.st_size < s->prop_size) {
> +            /* Ensure records are ERST_INVALID_RECORD_ID */
> +            memset(s->nvram, 0xFF, s->prop_size - statbuf.st_size);
> +            update_erst_backing_file(s,
> +                statbuf.st_size, s->nvram, s->prop_size - statbuf.st_size);
> +        }
> +    }
> +
> +    /* Pre-load nvram[] from backing file, if present */
> +    fd = open(s->prop_filename, O_RDONLY, ERST_BACKING_FILE_MODE);
> +    if (fd > 0) {
> +        size_t rrc = read(fd, s->nvram, s->prop_size);
> +        (void)rrc;
> +        close(fd);
> +        /*
> +         * If existing file is smaller than prop_size, it will be resized
> +         * accordingly upon subsequent record writes. If the file
> +         * is larger than prop_size, only prop_size bytes are utilized,
> +         * the extra bytes are untouched (though will be lost after
> +         * a migration when the backing file is re-written as length
> +         * of prop_size bytes).
> +         */
> +    } else {
> +        /* Create empty backing file */
> +        update_erst_backing_file(s, 0, s->nvram, s->prop_size);
> +    }
> +
> +    /* Initialize record_count */
> +    get_erst_record_count(s);
> +
> +    erst_debug("-load_erst_backing_file() %d\n", s->record_count);
> +}
> +
> +static uint64_t erst_rd_reg64(hwaddr addr,
> +    uint64_t reg, unsigned size)
> +{
> +    uint64_t rdval;
> +    uint64_t mask;
> +    unsigned shift;
> +
> +    if (size == sizeof(uint64_t)) {
> +        /* 64b access */
> +        mask = 0xFFFFFFFFFFFFFFFFUL;
> +        shift = 0;
> +    } else {
> +        /* 32b access */
> +        mask = 0x00000000FFFFFFFFUL;
> +        shift = ((addr & 0x4) == 0x4) ? 32 : 0;
> +    }
> +
> +    rdval = reg;
> +    rdval >>= shift;
> +    rdval &= mask;
> +
> +    return rdval;
> +}
> +
> +static uint64_t erst_wr_reg64(hwaddr addr,
> +    uint64_t reg, uint64_t val, unsigned size)
> +{
> +    uint64_t wrval;
> +    uint64_t mask;
> +    unsigned shift;
> +
> +    if (size == sizeof(uint64_t)) {
> +        /* 64b access */
> +        mask = 0xFFFFFFFFFFFFFFFFUL;
> +        shift = 0;
> +    } else {
> +        /* 32b access */
> +        mask = 0x00000000FFFFFFFFUL;
> +        shift = ((addr & 0x4) == 0x4) ? 32 : 0;
> +    }
> +
> +    val &= mask;
> +    val <<= shift;
> +    mask <<= shift;
> +    wrval = reg;
> +    wrval &= ~mask;
> +    wrval |= val;
> +
> +    return wrval;
> +}
> +
> +static void erst_write(void *opaque, hwaddr addr,
> +    uint64_t val, unsigned size)
> +{
> +    ERSTDeviceState *s = (ERSTDeviceState *)opaque;
> +
> +    if (addr < ERST_REG_LEN) {
> +        /*
> +         * NOTE: All actions/operations/side effects happen on the WRITE,
> +         * by design. The READs simply return the reg_value contents.
> +         */
> +        erst_debug("ERST write %016lx %10s val %016lx sz %u",
> +            addr, erst_reg(addr), val, size);
> +        /* The REGISTER region */
> +        switch (addr) {
> +        case ERST_CSR_VALUE + 0:
> +        case ERST_CSR_VALUE + 4:
> +            s->reg_value = erst_wr_reg64(addr, s->reg_value, val, size);
> +            break;
> +        case ERST_CSR_ACTION + 0:
> +/*      case ERST_CSR_ACTION+4: as coded, not really a 64b register */
> +            switch (val) {
> +            case ACPI_ERST_ACTION_BEGIN_WRITE_OPERATION:
> +            case ACPI_ERST_ACTION_BEGIN_READ_OPERATION:
> +            case ACPI_ERST_ACTION_BEGIN_CLEAR_OPERATION:
> +            case ACPI_ERST_ACTION_BEGIN_DUMMY_WRITE_OPERATION:
> +            case ACPI_ERST_ACTION_END_OPERATION:
> +                s->operation = val;
> +                break;
> +            case ACPI_ERST_ACTION_SET_RECORD_OFFSET:
> +                s->record_offset = s->reg_value;
> +                break;
> +            case ACPI_ERST_ACTION_EXECUTE_OPERATION:
> +                if ((uint8_t)s->reg_value == ERST_EXECUTE_OPERATION_MAGIC) {
> +                    s->busy_status = 1;
> +                    switch (s->operation) {
> +                    case ACPI_ERST_ACTION_BEGIN_WRITE_OPERATION:
> +                        s->command_status = write_erst_record(s);
> +                        break;
> +                    case ACPI_ERST_ACTION_BEGIN_READ_OPERATION:
> +                        s->command_status = read_erst_record(s);
> +                        break;
> +                    case ACPI_ERST_ACTION_BEGIN_CLEAR_OPERATION:
> +                        s->command_status = clear_erst_record(s);
> +                        break;
> +                    case ACPI_ERST_ACTION_BEGIN_DUMMY_WRITE_OPERATION:
> +                        s->command_status = ACPI_ERST_STATUS_SUCCESS;
> +                        break;
> +                    case ACPI_ERST_ACTION_END_OPERATION:
> +                        s->command_status = ACPI_ERST_STATUS_SUCCESS;
> +                        break;
> +                    default:
> +                        s->command_status = ACPI_ERST_STATUS_FAILED;
> +                        break;
> +                    }
> +                    s->record_identifier = ERST_INVALID_RECORD_ID;
> +                    s->busy_status = 0;
> +                }
> +                break;
> +            case ACPI_ERST_ACTION_CHECK_BUSY_STATUS:
> +                s->reg_value = s->busy_status;
> +                break;
> +            case ACPI_ERST_ACTION_GET_COMMAND_STATUS:
> +                s->reg_value = s->command_status;
> +                break;
> +            case ACPI_ERST_ACTION_GET_RECORD_IDENTIFIER:
> +                s->command_status = next_erst_record(s, &s->reg_value);
> +                break;
> +            case ACPI_ERST_ACTION_SET_RECORD_IDENTIFIER:
> +                s->record_identifier = s->reg_value;
> +                break;
> +            case ACPI_ERST_ACTION_GET_RECORD_COUNT:
> +                s->reg_value = s->record_count;
> +                break;
> +            case ACPI_ERST_ACTION_GET_ERROR_LOG_ADDRESS_RANGE:
> +                s->reg_value = s->base + ERST_REG_LEN;
> +                break;
> +            case ACPI_ERST_ACTION_GET_ERROR_LOG_ADDRESS_LENGTH:
> +                s->reg_value = ERST_RECORD_SIZE;
> +                break;
> +            case ACPI_ERST_ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES:
> +                s->reg_value = 0; /* correct/intended value */
> +                break;
> +            case ACPI_ERST_ACTION_GET_EXECUTE_OPERATION_TIMINGS:
> +                /*
> +                 * 100UL is max, 10UL is nominal
> +                 */
> +                s->reg_value = ((100UL << 32) | (10UL << 0));
> +                break;
> +            case ACPI_ERST_ACTION_RESERVED:
> +            default:
> +                /*
> +                 * NOP
> +                 */
> +                break;
> +            }
> +            break;
> +        default:
> +            /*
> +             * All other register writes are NO-OPs
> +             */
> +            break;
> +        }
> +    } else {
> +        /* The RECORD region */
> +        unsigned offset = addr - ERST_REG_LEN;
> +        uint8_t *ptr = &s->record[offset];
> +        switch (size) {
> +        default:
> +        case sizeof(uint8_t):
> +            *(uint8_t *)ptr = (uint8_t)val;
> +            break;
> +        case sizeof(uint16_t):
> +            *(uint16_t *)ptr = (uint16_t)val;
> +            break;
> +        case sizeof(uint32_t):
> +            *(uint32_t *)ptr = (uint32_t)val;
> +            break;
> +        case sizeof(uint64_t):
> +            *(uint64_t *)ptr = (uint64_t)val;
> +            break;
> +        }
> +    }
> +}
> +
> +static uint64_t erst_read(void *opaque, hwaddr addr,
> +                                unsigned size)
> +{
> +    ERSTDeviceState *s = (ERSTDeviceState *)opaque;
> +    uint64_t val = 0;
> +
> +    if (addr < ERST_REG_LEN) {
> +        switch (addr) {
> +        case ERST_CSR_ACTION + 0:
> +        case ERST_CSR_ACTION + 4:
> +            val = erst_rd_reg64(addr, s->reg_action, size);
> +            break;
> +        case ERST_CSR_VALUE + 0:
> +        case ERST_CSR_VALUE + 4:
> +            val = erst_rd_reg64(addr, s->reg_value, size);
> +            break;
> +        default:
> +            break;
> +        }
> +    erst_debug("ERST read %016lx %10s val %016lx sz %u\n",
> +        addr, erst_reg(addr), val, size);
> +    } else {
> +        /*
> +         * The RECORD region
> +         */
> +        uint8_t *ptr = &s->record[addr - ERST_REG_LEN];
> +        switch (size) {
> +        default:
> +        case sizeof(uint8_t):
> +            val = *(uint8_t *)ptr;
> +            break;
> +        case sizeof(uint16_t):
> +            val = *(uint16_t *)ptr;
> +            break;
> +        case sizeof(uint32_t):
> +            val = *(uint32_t *)ptr;
> +            break;
> +        case sizeof(uint64_t):
> +            val = *(uint64_t *)ptr;
> +            break;
> +        }
> +    }
> +    erst_debug("ERST read %016lx %10s val %016lx sz %u\n",
> +        addr, erst_reg(addr), val, size);
> +    return val;
> +}
> +
> +static size_t build_erst_action(GArray *table_data,
> +    uint8_t serialization_action,
> +    uint8_t instruction,
> +    uint8_t flags,
> +    uint8_t width,
> +    uint64_t address,
> +    uint64_t value,
> +    uint64_t mask)
> +{
> +    /* See ACPI spec, Error Serialization */
> +    uint8_t access_width = 0;
> +    build_append_int_noprefix(table_data, serialization_action, 1);
> +    build_append_int_noprefix(table_data, instruction         , 1);
> +    build_append_int_noprefix(table_data, flags               , 1);
> +    build_append_int_noprefix(table_data, 0                   , 1);
> +    /* GAS space_id */
> +    build_append_int_noprefix(table_data, AML_SYSTEM_MEMORY   , 1);
> +    /* GAS bit_width */
> +    build_append_int_noprefix(table_data, width               , 1);
> +    /* GAS bit_offset */
> +    build_append_int_noprefix(table_data, 0                   , 1);
> +    /* GAS access_width */
> +    switch (width) {
> +    case 8:
> +        access_width = 1;
> +        break;
> +    case 16:
> +        access_width = 2;
> +        break;
> +    case 32:
> +        access_width = 3;
> +        break;
> +    case 64:
> +        access_width = 4;
> +        break;
> +    default:
> +        access_width = 0;
> +        break;
> +    }
> +    build_append_int_noprefix(table_data, access_width        , 1);
> +    /* GAS address */
> +    build_append_int_noprefix(table_data, address, 8);
> +    /* value */
> +    build_append_int_noprefix(table_data, value , 8);
> +    /* mask */
> +    build_append_int_noprefix(table_data, mask   , 8);
> +
> +    return 1;
> +}
> +
> +static const MemoryRegionOps erst_rw_ops = {
> +    .read = erst_read,
> +    .write = erst_write,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +void build_erst(GArray *table_data, BIOSLinker *linker, hwaddr base)
> +{
> +    unsigned action, insns = 0;
> +    unsigned erst_start = table_data->len;
> +    unsigned iec_offset = 0;
> +
> +    /* See ACPI spec, Error Serialization */
> +    acpi_data_push(table_data, sizeof(AcpiTableHeader));
> +    /* serialization_header_length */
> +    build_append_int_noprefix(table_data, 48, 4);
> +    /* reserved */
> +    build_append_int_noprefix(table_data, 0, 4);
> +    iec_offset = table_data->len;
> +    /* instruction_entry_count (placeholder) */
> +    build_append_int_noprefix(table_data, 0, 4);
> +
> +#define BEA(I, F, W, ADDR, VAL, MASK) \
> +    build_erst_action(table_data, action, \
> +        ACPI_ERST_INST_##I, F, W, base + ADDR, VAL, MASK)
> +#define MASK8 0x00000000000000FFUL
> +#define MASK16 0x000000000000FFFFUL
> +#define MASK32 0x00000000FFFFFFFFUL
> +#define MASK64 0xFFFFFFFFFFFFFFFFUL
> +
> +    for (action = "" action < ACPI_ERST_MAX_ACTIONS; ++action) {
> +        switch (action) {
> +        case ACPI_ERST_ACTION_BEGIN_WRITE_OPERATION:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_BEGIN_READ_OPERATION:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_BEGIN_CLEAR_OPERATION:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_END_OPERATION:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_SET_RECORD_OFFSET:
> +            insns += BEA(WRITE_REGISTER      , 0, 32,
> +                ERST_CSR_VALUE , 0, MASK32);
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_EXECUTE_OPERATION:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_VALUE , ERST_EXECUTE_OPERATION_MAGIC, MASK8);
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_CHECK_BUSY_STATUS:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER_VALUE , 0, 32,
> +                ERST_CSR_VALUE, 0x01, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_GET_COMMAND_STATUS:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER       , 0, 32,
> +                ERST_CSR_VALUE, 0, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_GET_RECORD_IDENTIFIER:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER       , 0, 64,
> +                ERST_CSR_VALUE, 0, MASK64);
> +            break;
> +        case ACPI_ERST_ACTION_SET_RECORD_IDENTIFIER:
> +            insns += BEA(WRITE_REGISTER      , 0, 64,
> +                ERST_CSR_VALUE , 0, MASK64);
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_GET_RECORD_COUNT:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER       , 0, 32,
> +                ERST_CSR_VALUE, 0, MASK32);
> +            break;
> +        case ACPI_ERST_ACTION_BEGIN_DUMMY_WRITE_OPERATION:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_RESERVED:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            break;
> +        case ACPI_ERST_ACTION_GET_ERROR_LOG_ADDRESS_RANGE:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER       , 0, 64,
> +                ERST_CSR_VALUE, 0, MASK64);
> +            break;
> +        case ACPI_ERST_ACTION_GET_ERROR_LOG_ADDRESS_LENGTH:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER       , 0, 64,
> +                ERST_CSR_VALUE, 0, MASK32);
> +            break;
> +        case ACPI_ERST_ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER       , 0, 32,
> +                ERST_CSR_VALUE, 0, MASK32);
> +            break;
> +        case ACPI_ERST_ACTION_GET_EXECUTE_OPERATION_TIMINGS:
> +            insns += BEA(WRITE_REGISTER_VALUE, 0, 32,
> +                ERST_CSR_ACTION, action, MASK8);
> +            insns += BEA(READ_REGISTER       , 0, 64,
> +                ERST_CSR_VALUE, 0, MASK64);
> +        default:
> +            insns += BEA(NOOP, 0, 0, 0, action, 0);
> +            break;
> +        }
> +    }
> +
> +    /* acpi_data_push() within BEA() can result in new GArray pointer */
> +    *(uint32_t *)(table_data->data + iec_offset) = cpu_to_le32(insns);
> +
> +    build_header(linker, table_data,
> +                 (void *)(table_data->data + erst_start),
> +                 "ERST", table_data->len - erst_start,
> +                 1, NULL, NULL);
> +
> +    if (erst_base == 0) {
> +        /*
> +         * This ACPI routine is invoked twice, but this code
> +         * snippet needs to happen just once.
> +         * And this code in erst_class_init() is too early.
> +         */
> +        DeviceState *dev;
> +        SysBusDevice *s;
> +
> +        dev = qdev_new(TYPE_ACPI_ERST);
> +        erst_debug("qdev_create dev %p\n", dev);
> +        s = SYS_BUS_DEVICE(dev);
> +        sysbus_realize_and_unref(s, &error_fatal);
> +
> +        ACPIERST(dev)->base = base;
> +        sysbus_mmio_map(s, 0, base);
> +        erst_base = base;
> +        erst_debug("erst_base %lx\n", base);
> +    }
> +}
> +
> +/*******************************************************************/
> +/*******************************************************************/
> +static int erst_post_load(void *opaque, int version_id)
> +{
> +    ERSTDeviceState *s = opaque;
> +    erst_debug("+erst_post_load(%d)\n", version_id);
> +    /* Ensure nvram[] persists into backing file */
> +    update_erst_backing_file(s, 0, s->nvram, s->prop_size);
> +    erst_debug("-erst_post_load()\n");
> +    return 0;
> +}
> +
> +static const VMStateDescription erst_vmstate = {
> +    .name = "acpi-erst",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .post_load = erst_post_load,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT8(operation, ERSTDeviceState),
> +        VMSTATE_UINT8(busy_status, ERSTDeviceState),
> +        VMSTATE_UINT8(command_status, ERSTDeviceState),
> +        VMSTATE_UINT32(record_offset, ERSTDeviceState),
> +        VMSTATE_UINT32(record_count, ERSTDeviceState),
> +        VMSTATE_UINT64(reg_action, ERSTDeviceState),
> +        VMSTATE_UINT64(reg_value, ERSTDeviceState),
> +        VMSTATE_UINT64(record_identifier, ERSTDeviceState),
> +        VMSTATE_UINT8_ARRAY(record, ERSTDeviceState, ERST_RECORD_SIZE),
> +        VMSTATE_UINT8_ARRAY(tmp_record, ERSTDeviceState, ERST_RECORD_SIZE),
> +        VMSTATE_VARRAY_UINT32(nvram, ERSTDeviceState, prop_size, 0,
> +            vmstate_info_uint8, uint8_t),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static void erst_realizefn(DeviceState *dev, Error **errp)
> +{
> +    SysBusDevice *d = SYS_BUS_DEVICE(dev);
> +    ERSTDeviceState *s = ACPIERST(dev);
> +
> +    erst_debug("+erst_realizefn()\n");
> +    if (!s->prop_filename) {
> +        s->prop_filename = (char *)(TYPE_ACPI_ERST ".backing");
> +    }
> +
> +    if (!s->prop_filename) {
> +        error_setg(errp, "'filename' property is not set");
> +        return;
> +    }
> +
> +    if (!(s->prop_size > ERST_RECORD_SIZE) &&
> +        (s->prop_size <= 0x04000000)) {
> +        error_setg(errp, "'size' property %d is not set properly",
> +            s->prop_size);
> +        return;
> +    }
> +
> +    /* Convert prop_size to integer multiple of ERST_RECORD_SIZE */
> +    s->prop_size -= (s->prop_size % ERST_RECORD_SIZE);
> +
> +    load_erst_backing_file(s);
> +
> +    erst_debug("filename %s\n", s->prop_filename);
> +    erst_debug("size %x\n", s->prop_size);
> +
> +    memory_region_init_io(&s->iomem, OBJECT(s), &erst_rw_ops, s,
> +                          TYPE_ACPI_ERST, ERST_IOMEM_SIZE);
> +    sysbus_init_mmio(d, &s->iomem);
> +    erst_debug("-erst_realizefn()\n");
> +}
> +
> +static void erst_unrealizefn(DeviceState *dev)
> +{
> +    ERSTDeviceState *s = ACPIERST(dev);
> +
> +    erst_debug("+erst_unrealizefn()\n");
> +    if (s->nvram) {
> +        /* Ensure nvram[] persists into backing file */
> +        update_erst_backing_file(s, 0, s->nvram, s->prop_size);
> +        g_free(s->nvram);
> +        s->nvram = NULL;
> +    }
> +    erst_debug("-erst_unrealizefn()\n");
> +}
> +
> +static void erst_reset(DeviceState *dev)
> +{
> +    ERSTDeviceState *s = ACPIERST(dev);
> +
> +    erst_debug("+erst_reset(%p) %d\n", s, s->record_count);
> +    s->operation = 0;
> +    s->busy_status = 0;
> +    s->command_status = ACPI_ERST_STATUS_SUCCESS;
> +    /* indicate empty/no-more until further notice */
> +    s->record_identifier = ERST_INVALID_RECORD_ID;
> +    s->record_offset = 0;
> +    s->next_record_index = 0;
> +    /* NOTE: record_count and nvram[] are initialized elsewhere */
> +    erst_debug("-erst_reset()\n");
> +}
> +
> +static Property erst_properties[] = {
> +    DEFINE_PROP_UINT32("size", ERSTDeviceState, prop_size, 0x00010000),
> +    DEFINE_PROP_STRING("filename", ERSTDeviceState, prop_filename),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void erst_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    erst_debug("+erst_class_init()\n");
> +    dc->realize = erst_realizefn;
> +    dc->unrealize = erst_unrealizefn;
> +    dc->reset = erst_reset;
> +    dc->vmsd = &erst_vmstate;
> +    device_class_set_props(dc, erst_properties);
> +    dc->desc = "ACPI Error Record Serialization Table (ERST) device";
> +    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    erst_debug("-erst_class_init()\n");
> +}
> +
> +static const TypeInfo erst_type_info = {
> +    .name          = TYPE_ACPI_ERST,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .class_init    = erst_class_init,
> +    .instance_size = sizeof(ERSTDeviceState),
> +};
> +
> +static void erst_register_types(void)
> +{
> +    type_register_static(&erst_type_info);
> +}
> +
> +type_init(erst_register_types)

From:	Eric DeVolder
Subject:	Re: [PATCH v2 3/7] ACPI ERST: support for ACPI ERST feature
Date:	Fri, 9 Apr 2021 15:54:47 +0000