Re: [PATCH v10 06/10] ACPI ERST: build the ACPI ERST table

[Eric DeVolder <eric.devolder@oracle.com>]

Michael,
Thanks for reviewing! Inline responses below.
eric

On 12/12/21 16:56, Michael S. Tsirkin wrote:
> On Thu, Dec 09, 2021 at 12:57:31PM -0500, Eric DeVolder wrote:
>> This builds the ACPI ERST table to inform OSPM how to communicate
>> with the acpi-erst device.
>>
>> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
>> ---
>>   hw/acpi/erst.c | 241 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 241 insertions(+)
>>
>> diff --git a/hw/acpi/erst.c b/hw/acpi/erst.c
>> index 81f5435..753425a 100644
>> --- a/hw/acpi/erst.c
>> +++ b/hw/acpi/erst.c
>> @@ -711,6 +711,247 @@ static const MemoryRegionOps erst_reg_ops = {
>>       .endianness = DEVICE_NATIVE_ENDIAN,
>>   };
>>   
>> +
>> +/*******************************************************************/
>> +/*******************************************************************/
>> +
>> +/* ACPI 4.0: Table 17-19 Serialization Instructions */
>> +#define INST_READ_REGISTER                 0x00
>> +#define INST_READ_REGISTER_VALUE           0x01
>> +#define INST_WRITE_REGISTER                0x02
>> +#define INST_WRITE_REGISTER_VALUE          0x03
>> +#define INST_NOOP                          0x04
>> +#define INST_LOAD_VAR1                     0x05
>> +#define INST_LOAD_VAR2                     0x06
>> +#define INST_STORE_VAR1                    0x07
>> +#define INST_ADD                           0x08
>> +#define INST_SUBTRACT                      0x09
>> +#define INST_ADD_VALUE                     0x0A
>> +#define INST_SUBTRACT_VALUE                0x0B
>> +#define INST_STALL                         0x0C
>> +#define INST_STALL_WHILE_TRUE              0x0D
>> +#define INST_SKIP_NEXT_INSTRUCTION_IF_TRUE 0x0E
>> +#define INST_GOTO                          0x0F
>> +#define INST_SET_SRC_ADDRESS_BASE          0x10
>> +#define INST_SET_DST_ADDRESS_BASE          0x11
>> +#define INST_MOVE_DATA                     0x12
>> +
> 
> I would create wrappers for the specific uses that we do have. Leave the
> rest alone.
> You just use 4 of these right? And a bunch of parameters are
> always the same. E.g. flags always 0, address always same.

If I understand correctly, I think you are suggesting making wrappers for the 4 in use (ie WRITE, 
WRITE_VALUE, READ, READ_VALUE). in an effort to simplify/hide the underlying call to 
build_serialization_instruction_entry(). OK, I'll do that.

> 
>> +/* ACPI 4.0: 17.4.1.2 Serialization Instruction Entries */
>> +static void build_serialization_instruction_entry(GArray *table_data,
>> +    uint8_t serialization_action,
>> +    uint8_t instruction,
>> +    uint8_t flags,
>> +    uint8_t register_bit_width,
> 
> maybe make it width in bytes, then you do not need a switch.

I can make it bytes, but the switch is still needed as the corresponding field is an encoding (ie 
1,2,3,4 vs 1, 2, 4, 8).

> 
>> +    uint64_t register_address,
>> +    uint64_t value,
>> +    uint64_t mask)
>> +{
>> +    /* ACPI 4.0: Table 17-18 Serialization Instruction Entry */
>> +    struct AcpiGenericAddress gas;
>> +
>> +    /* Serialization Action */
>> +    build_append_int_noprefix(table_data, serialization_action, 1);
>> +    /* Instruction */
>> +    build_append_int_noprefix(table_data, instruction         , 1);
>> +    /* Flags */
>> +    build_append_int_noprefix(table_data, flags               , 1);
>> +    /* Reserved */
>> +    build_append_int_noprefix(table_data, 0                   , 1);
>> +    /* Register Region */
>> +    gas.space_id = AML_SYSTEM_MEMORY;
>> +    gas.bit_width = register_bit_width;
>> +    gas.bit_offset = 0;
>> +    switch (register_bit_width) {
>> +    case 8:
>> +        gas.access_width = 1;
>> +        break;
>> +    case 16:
>> +        gas.access_width = 2;
>> +        break;
>> +    case 32:
>> +        gas.access_width = 3;
>> +        break;
>> +    case 64:
>> +        gas.access_width = 4;
>> +        break;
>> +    default:
>> +        gas.access_width = 0;
>> +        break;
> 
> does this default actually work?
I actually have no idea. But given that this is driven by code in this file, I'll set an assert 
there instead; this should never happen.

> 
>> +    }
>> +    gas.address = register_address;
>> +    build_append_gas_from_struct(table_data, &gas);
>> +    /* Value */
>> +    build_append_int_noprefix(table_data, value  , 8);
>> +    /* Mask */
>> +    build_append_int_noprefix(table_data, mask   , 8);
>> +}
>> +
>> +/* ACPI 4.0: 17.4.1 Serialization Action Table */
>> +void build_erst(GArray *table_data, BIOSLinker *linker, Object *erst_dev,
>> +    const char *oem_id, const char *oem_table_id)
>> +{
>> +    GArray *table_instruction_data;
>> +    unsigned action;
>> +    pcibus_t bar0, bar1;
>> +    AcpiTable table = { .sig = "ERST", .rev = 1, .oem_id = oem_id,
>> +                        .oem_table_id = oem_table_id };
>> +
>> +    bar0 = (pcibus_t)pci_get_bar_addr(PCI_DEVICE(erst_dev), 0);
>> +    trace_acpi_erst_pci_bar_0(bar0);
>> +    bar1 = (pcibus_t)pci_get_bar_addr(PCI_DEVICE(erst_dev), 1);
> 
> why do we need the cast here?
> Also assignment at declaration point will be cleaner, won't it?
Corrected; cast removed and assigned at declaration.
> 
>> +    trace_acpi_erst_pci_bar_1(bar1);
> 
> bar1 seems unused ... why do we bother with it just for trace?
Corrected; bar1 not needed.

> 
>> +
>> +#define MASK8  0x00000000000000FFUL
>> +#define MASK16 0x000000000000FFFFUL
>> +#define MASK32 0x00000000FFFFFFFFUL
>> +#define MASK64 0xFFFFFFFFFFFFFFFFUL
> 
> 
> can't we just pass # of bytes?
I could, but then I'd need a switch statement to convert to one of these masks. The full mask is 
embedded in the generic address structure.

Perhaps in the wrapper I can use width in bytes and the switch statement can producing the encoding 
and the mask...
> 
>> +
>> +    /*
>> +     * Serialization Action Table
>> +     * The serialization action table must be generated first
>> +     * so that its size can be known in order to populate the
>> +     * Instruction Entry Count field.
>> +     */
>> +    table_instruction_data = g_array_new(FALSE, FALSE, sizeof(char));
>> +
>> +    /* Serialization Instruction Entries */
>> +    action = ACTION_BEGIN_WRITE_OPERATION;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_BEGIN_READ_OPERATION;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_BEGIN_CLEAR_OPERATION;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_END_OPERATION;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_SET_RECORD_OFFSET;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER      , 0, 32,
>> +        bar0 + ERST_VALUE_OFFSET , 0, MASK32);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_EXECUTE_OPERATION;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_VALUE_OFFSET , ERST_EXECUTE_OPERATION_MAGIC, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_CHECK_BUSY_STATUS;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER_VALUE , 0, 32,
>> +        bar0 + ERST_VALUE_OFFSET, 0x01, MASK8);
>> +
>> +    action = ACTION_GET_COMMAND_STATUS;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER       , 0, 32,
>> +        bar0 + ERST_VALUE_OFFSET, 0, MASK8);
>> +
>> +    action = ACTION_GET_RECORD_IDENTIFIER;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER       , 0, 64,
>> +        bar0 + ERST_VALUE_OFFSET, 0, MASK64);
>> +
>> +    action = ACTION_SET_RECORD_IDENTIFIER;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER      , 0, 64,
>> +        bar0 + ERST_VALUE_OFFSET , 0, MASK64);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_GET_RECORD_COUNT;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER       , 0, 32,
>> +        bar0 + ERST_VALUE_OFFSET, 0, MASK32);
>> +
>> +    action = ACTION_BEGIN_DUMMY_WRITE_OPERATION;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +
>> +    action = ACTION_GET_ERROR_LOG_ADDRESS_RANGE;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER       , 0, 64,
>> +        bar0 + ERST_VALUE_OFFSET, 0, MASK64);
>> +
>> +    action = ACTION_GET_ERROR_LOG_ADDRESS_LENGTH;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER       , 0, 64,
>> +        bar0 + ERST_VALUE_OFFSET, 0, MASK32);
>> +
>> +    action = ACTION_GET_ERROR_LOG_ADDRESS_RANGE_ATTRIBUTES;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER       , 0, 32,
>> +        bar0 + ERST_VALUE_OFFSET, 0, MASK32);
>> +
>> +    action = ACTION_GET_EXECUTE_OPERATION_TIMINGS;
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_WRITE_REGISTER_VALUE, 0, 32,
>> +        bar0 + ERST_ACTION_OFFSET, action, MASK8);
>> +    build_serialization_instruction_entry(table_instruction_data,
>> +        action, INST_READ_REGISTER       , 0, 64,
>> +        bar0 + ERST_VALUE_OFFSET, 0, MASK64);
>> +
>> +    /* Serialization Header */
>> +    acpi_table_begin(&table, table_data);
>> +
>> +    /* Serialization Header Size */
>> +    build_append_int_noprefix(table_data, 48, 4);
>> +
>> +    /* Reserved */
>> +    build_append_int_noprefix(table_data,  0, 4);
>> +
>> +    /*
>> +     * Instruction Entry Count
>> +     * Each instruction entry is 32 bytes
>> +     */
> 
> assert that it's a multiple of 32 maybe
done!

> 
>> +    build_append_int_noprefix(table_data,
>> +        (table_instruction_data->len / 32), 4);
>> +
>> +    /* Serialization Instruction Entries */
>> +    g_array_append_vals(table_data, table_instruction_data->data,
>> +        table_instruction_data->len);
>> +    g_array_free(table_instruction_data, TRUE);
>> +
>> +    acpi_table_end(linker, &table);
>> +}
>> +
>>   /*******************************************************************/
>>   /*******************************************************************/
>>   static int erst_post_load(void *opaque, int version_id)
>> -- 
>> 1.8.3.1
>