[PATCH v5 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format

[PATCH v5 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format

[Sia Jee Heng]

Update the SPCR table to accommodate the SPCR Table revision 4 [1].
The SPCR table has been modified to adhere to the revision 4 format [2].

Meanwhile, the virt SPCR golden reference file for RISC-V have been updated to
accommodate the SPCR Table revision 4.

[1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
[2]: https://github.com/acpica/acpica/pull/931

Changes in v5:
- Reverted the SPCR table revision history for the ARM architecture.
- Corrected the output of the SPCR Table diff.

Changes in v4:
- Remove the SPCR table revision 4 update for the ARM architecture.

Changes in v3:
- Rebased on the latest QEMU.
- Added Acked-by: Alistair Francis <alistair.francis@wdc.com>

Changes in v2:
- Utilizes a three-patch approach to modify the ACPI pre-built binary
  files required by the Bios-Table-Test.
- Rebases and incorporates changes to support both ARM and RISC-V ACPI
  pre-built binary files.

Sia Jee Heng (3):
  qtest: allow SPCR acpi table changes
  hw/acpi: Upgrade ACPI SPCR table to support SPCR table revision 4
    format
  tests/qtest/bios-tables-test: Update virt SPCR golden reference for
    RISC-V

 hw/acpi/aml-build.c               |  20 ++++++++++++++++----
 hw/arm/virt-acpi-build.c          |   8 ++++++--
 hw/riscv/virt-acpi-build.c        |  12 +++++++++---
 include/hw/acpi/acpi-defs.h       |   7 +++++--
 include/hw/acpi/aml-build.h       |   2 +-
 tests/data/acpi/riscv64/virt/SPCR | Bin 80 -> 90 bytes
 6 files changed, 37 insertions(+), 12 deletions(-)


base-commit: cec99171931ea79215c79661d33423ac84e63b6e
-- 
2.34.1

[PATCH v5 1/3] qtest: allow SPCR acpi table changes

[Sia Jee Heng]

Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
---
 tests/qtest/bios-tables-test-allowed-diff.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/qtest/bios-tables-test-allowed-diff.h b/tests/qtest/bios-tables-test-allowed-diff.h
index dfb8523c8b..aae973048a 100644
--- a/tests/qtest/bios-tables-test-allowed-diff.h
+++ b/tests/qtest/bios-tables-test-allowed-diff.h
@@ -1 +1,2 @@
 /* List of comma-separated changed AML files to ignore */
+"tests/data/acpi/riscv64/virt/SPCR",
-- 
2.34.1

[PATCH v5 2/3] hw/acpi: Upgrade ACPI SPCR table to support SPCR table revision 4 format

[Sia Jee Heng]

Update the SPCR table to accommodate the SPCR Table revision 4 [1].
The SPCR table has been modified to adhere to the revision 4 format [2].

[1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
[2]: https://github.com/acpica/acpica/pull/931

Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
---
 hw/acpi/aml-build.c         | 20 ++++++++++++++++----
 hw/arm/virt-acpi-build.c    |  8 ++++++--
 hw/riscv/virt-acpi-build.c  | 12 +++++++++---
 include/hw/acpi/acpi-defs.h |  7 +++++--
 include/hw/acpi/aml-build.h |  2 +-
 5 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 6d4517cfbe..99a1b403e2 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -1996,7 +1996,7 @@ static void build_processor_hierarchy_node(GArray *tbl, uint32_t flags,
 
 void build_spcr(GArray *table_data, BIOSLinker *linker,
                 const AcpiSpcrData *f, const uint8_t rev,
-                const char *oem_id, const char *oem_table_id)
+                const char *oem_id, const char *oem_table_id, const char *name)
 {
     AcpiTable table = { .sig = "SPCR", .rev = rev, .oem_id = oem_id,
                         .oem_table_id = oem_table_id };
@@ -2042,9 +2042,21 @@ void build_spcr(GArray *table_data, BIOSLinker *linker,
     build_append_int_noprefix(table_data, f->pci_flags, 4);
     /* PCI Segment */
     build_append_int_noprefix(table_data, f->pci_segment, 1);
-    /* Reserved */
-    build_append_int_noprefix(table_data, 0, 4);
-
+    if (rev < 4) {
+        /* Reserved */
+        build_append_int_noprefix(table_data, 0, 4);
+    } else {
+        /* UartClkFreq */
+        build_append_int_noprefix(table_data, f->uart_clk_freq, 4);
+        /* PreciseBaudrate */
+        build_append_int_noprefix(table_data, f->precise_baudrate, 4);
+        /* NameSpaceStringLength */
+        build_append_int_noprefix(table_data, f->namespace_string_length, 2);
+        /* NameSpaceStringOffset */
+        build_append_int_noprefix(table_data, f->namespace_string_offset, 2);
+        /* NamespaceString[] */
+        g_array_append_vals(table_data, name, f->namespace_string_length);
+    }
     acpi_table_end(linker, &table);
 }
 /*
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index f76fb117ad..0b6f5f8d8d 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -464,8 +464,12 @@ spcr_setup(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
         .pci_flags = 0,
         .pci_segment = 0,
     };
-
-    build_spcr(table_data, linker, &serial, 2, vms->oem_id, vms->oem_table_id);
+    /*
+     * Passing NULL as the SPCR Table for Revision 2 doesn't support
+     * NameSpaceString.
+     */
+    build_spcr(table_data, linker, &serial, 2, vms->oem_id, vms->oem_table_id,
+               NULL);
 }
 
 /*
diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
index 36d6a3a412..68ef15acac 100644
--- a/hw/riscv/virt-acpi-build.c
+++ b/hw/riscv/virt-acpi-build.c
@@ -200,14 +200,15 @@ acpi_dsdt_add_uart(Aml *scope, const MemMapEntry *uart_memmap,
 
 /*
  * Serial Port Console Redirection Table (SPCR)
- * Rev: 1.07
+ * Rev: 1.10
  */
 
 static void
 spcr_setup(GArray *table_data, BIOSLinker *linker, RISCVVirtState *s)
 {
+    const char name[] = ".";
     AcpiSpcrData serial = {
-        .interface_type = 0,       /* 16550 compatible */
+        .interface_type = 0x12,       /* 16550 compatible */
         .base_addr.id = AML_AS_SYSTEM_MEMORY,
         .base_addr.width = 32,
         .base_addr.offset = 0,
@@ -229,9 +230,14 @@ spcr_setup(GArray *table_data, BIOSLinker *linker, RISCVVirtState *s)
         .pci_function = 0,
         .pci_flags = 0,
         .pci_segment = 0,
+        .uart_clk_freq = 0,
+        .precise_baudrate = 0,
+        .namespace_string_length = sizeof(name),
+        .namespace_string_offset = 88,
     };
 
-    build_spcr(table_data, linker, &serial, 2, s->oem_id, s->oem_table_id);
+    build_spcr(table_data, linker, &serial, 4, s->oem_id, s->oem_table_id,
+               name);
 }
 
 /* RHCT Node[N] starts at offset 56 */
diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
index 0e6e82b339..2e6e341998 100644
--- a/include/hw/acpi/acpi-defs.h
+++ b/include/hw/acpi/acpi-defs.h
@@ -112,7 +112,6 @@ typedef struct AcpiSpcrData {
     uint8_t flow_control;
     uint8_t terminal_type;
     uint8_t language;
-    uint8_t reserved1;
     uint16_t pci_device_id;    /* Must be 0xffff if not PCI device */
     uint16_t pci_vendor_id;    /* Must be 0xffff if not PCI device */
     uint8_t pci_bus;
@@ -120,7 +119,11 @@ typedef struct AcpiSpcrData {
     uint8_t pci_function;
     uint32_t pci_flags;
     uint8_t pci_segment;
-    uint32_t reserved2;
+    uint32_t uart_clk_freq;
+    uint32_t precise_baudrate;
+    uint32_t namespace_string_length;
+    uint32_t namespace_string_offset;
+    char namespace_string[];
 } AcpiSpcrData;
 
 #define ACPI_FADT_ARM_PSCI_COMPLIANT  (1 << 0)
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index a3784155cb..68c0f2dbee 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -500,5 +500,5 @@ void build_tpm2(GArray *table_data, BIOSLinker *linker, GArray *tcpalog,
 
 void build_spcr(GArray *table_data, BIOSLinker *linker,
                 const AcpiSpcrData *f, const uint8_t rev,
-                const char *oem_id, const char *oem_table_id);
+                const char *oem_id, const char *oem_table_id, const char *name);
 #endif
-- 
2.34.1

[PATCH v5 3/3] tests/qtest/bios-tables-test: Update virt SPCR golden reference for RISC-V

[Sia Jee Heng]

Update the virt SPCR golden reference file for RISC-V to accommodate the
SPCR Table revision 4 [1], utilizing the iasl binary compiled from the
latest ACPICA repository. The SPCR table has been modified to
adhere to the revision 4 format [2].

[1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
[2]: https://github.com/acpica/acpica/pull/931

Diffs from iasl:
/*
  * Intel ACPI Component Architecture
  * AML/ASL+ Disassembler version 20200925 (64-bit version)
  * Copyright (c) 2000 - 2020 Intel Corporation
  *
- * Disassembly of tests/data/acpi/riscv64/virt/SPCR, Wed Aug 28 18:28:19 2024
+ * Disassembly of /tmp/aml-MN0NS2, Wed Aug 28 18:28:19 2024
  *
  * ACPI Data Table [SPCR]
  *
  * Format: [HexOffset DecimalOffset ByteLength]  FieldName : FieldValue
  */

 [000h 0000   4]                    Signature : "SPCR"    [Serial Port Console Redirection table]
-[004h 0004   4]                 Table Length : 00000050
-[008h 0008   1]                     Revision : 02
-[009h 0009   1]                     Checksum : B9
+[004h 0004   4]                 Table Length : 0000005A
+[008h 0008   1]                     Revision : 04
+[009h 0009   1]                     Checksum : 13
 [00Ah 0010   6]                       Oem ID : "BOCHS "
 [010h 0016   8]                 Oem Table ID : "BXPC    "
 [018h 0024   4]                 Oem Revision : 00000001
 [01Ch 0028   4]              Asl Compiler ID : "BXPC"
 [020h 0032   4]        Asl Compiler Revision : 00000001

-[024h 0036   1]               Interface Type : 00
+[024h 0036   1]               Interface Type : 12
 [025h 0037   3]                     Reserved : 000000

 [028h 0040  12]         Serial Port Register : [Generic Address Structure]
 [028h 0040   1]                     Space ID : 00 [SystemMemory]
 [029h 0041   1]                    Bit Width : 20
 [02Ah 0042   1]                   Bit Offset : 00
 [02Bh 0043   1]         Encoded Access Width : 01 [Byte Access:8]
 [02Ch 0044   8]                      Address : 0000000010000000

 [034h 0052   1]               Interrupt Type : 10
 [035h 0053   1]          PCAT-compatible IRQ : 00
 [036h 0054   4]                    Interrupt : 0000000A
 [03Ah 0058   1]                    Baud Rate : 07
 [03Bh 0059   1]                       Parity : 00
 [03Ch 0060   1]                    Stop Bits : 01
 [03Dh 0061   1]                 Flow Control : 00
 [03Eh 0062   1]                Terminal Type : 00
 [04Ch 0076   1]                     Reserved : 00
 [040h 0064   2]                PCI Device ID : FFFF
 [042h 0066   2]                PCI Vendor ID : FFFF
 [044h 0068   1]                      PCI Bus : 00
 [045h 0069   1]                   PCI Device : 00
 [046h 0070   1]                 PCI Function : 00
 [047h 0071   4]                    PCI Flags : 00000000
 [04Bh 0075   1]                  PCI Segment : 00
-[04Ch 0076   4]                     Reserved : 00000000
+[04Ch 0076 004h]             Uart Clock Freq : 00000000
+[050h 0080 004h]           Precise Baud rate : 00000000
+[054h 0084 002h]       NameSpaceStringLength : 0002
+[056h 0086 002h]       NameSpaceStringOffset : 0058
+[058h 0088 002h]             NamespaceString : "."

-Raw Table Data: Length 80 (0x50)
+Raw Table Data: Length 90 (0x5A)

-    0000: 53 50 43 52 50 00 00 00 02 B9 42 4F 43 48 53 20  // SPCRP.....BOCHS
+    0000: 53 50 43 52 5A 00 00 00 04 13 42 4F 43 48 53 20  // SPCRZ.....BOCHS
     0010: 42 58 50 43 20 20 20 20 01 00 00 00 42 58 50 43  // BXPC    ....BXPC
-    0020: 01 00 00 00 00 00 00 00 00 20 00 01 00 00 00 10  // ......... ......
+    0020: 01 00 00 00 12 00 00 00 00 20 00 01 00 00 00 10  // ......... ......
     0030: 00 00 00 00 10 00 0A 00 00 00 07 00 01 00 00 03  // ................
     0040: FF FF FF FF 00 00 00 00 00 00 00 00 00 00 00 00  // ................
+    0050: 00 00 00 00 02 00 58 00 2E 00                    // ......X...

Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
---
 tests/data/acpi/riscv64/virt/SPCR           | Bin 80 -> 90 bytes
 tests/qtest/bios-tables-test-allowed-diff.h |   1 -
 2 files changed, 1 deletion(-)

diff --git a/tests/data/acpi/riscv64/virt/SPCR b/tests/data/acpi/riscv64/virt/SPCR
index 4da9daf65f71a13ac2b488d4e9728f194b569a43..09617f8793a6f7b1f08172f735b58aa748671540 100644
GIT binary patch
delta 32
mcmWHD;tCFM4vJ!6U|<oR$R))nG*MNX3&>+&Vu)bSV*mhNumqU^

delta 21
ccmazF;0g|K4hmpkU|`xgkxPn^VWO%w05v59j{pDw

diff --git a/tests/qtest/bios-tables-test-allowed-diff.h b/tests/qtest/bios-tables-test-allowed-diff.h
index aae973048a..dfb8523c8b 100644
--- a/tests/qtest/bios-tables-test-allowed-diff.h
+++ b/tests/qtest/bios-tables-test-allowed-diff.h
@@ -1,2 +1 @@
 /* List of comma-separated changed AML files to ignore */
-"tests/data/acpi/riscv64/virt/SPCR",
-- 
2.34.1

Re: [PATCH v5 3/3] tests/qtest/bios-tables-test: Update virt SPCR golden reference for RISC-V

[Sunil V L]

On Wed, Aug 28, 2024 at 06:59:20PM -0700, Sia Jee Heng wrote:
> Update the virt SPCR golden reference file for RISC-V to accommodate the
> SPCR Table revision 4 [1], utilizing the iasl binary compiled from the
> latest ACPICA repository. The SPCR table has been modified to
> adhere to the revision 4 format [2].
> 
> [1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
> [2]: https://github.com/acpica/acpica/pull/931
> 
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>

Thanks!

Re: [PATCH v5 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format

[Michael S. Tsirkin]

On Wed, Aug 28, 2024 at 06:59:17PM -0700, Sia Jee Heng wrote:
> Update the SPCR table to accommodate the SPCR Table revision 4 [1].
> The SPCR table has been modified to adhere to the revision 4 format [2].
> 
> Meanwhile, the virt SPCR golden reference file for RISC-V have been updated to
> accommodate the SPCR Table revision 4.
> 
> [1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
> [2]: https://github.com/acpica/acpica/pull/931

Seems most appropriate on riscv5 tree.
The code looks ok.

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>


> Changes in v5:
> - Reverted the SPCR table revision history for the ARM architecture.
> - Corrected the output of the SPCR Table diff.
> 
> Changes in v4:
> - Remove the SPCR table revision 4 update for the ARM architecture.
> 
> Changes in v3:
> - Rebased on the latest QEMU.
> - Added Acked-by: Alistair Francis <alistair.francis@wdc.com>
> 
> Changes in v2:
> - Utilizes a three-patch approach to modify the ACPI pre-built binary
>   files required by the Bios-Table-Test.
> - Rebases and incorporates changes to support both ARM and RISC-V ACPI
>   pre-built binary files.
> 
> Sia Jee Heng (3):
>   qtest: allow SPCR acpi table changes
>   hw/acpi: Upgrade ACPI SPCR table to support SPCR table revision 4
>     format
>   tests/qtest/bios-tables-test: Update virt SPCR golden reference for
>     RISC-V
> 
>  hw/acpi/aml-build.c               |  20 ++++++++++++++++----
>  hw/arm/virt-acpi-build.c          |   8 ++++++--
>  hw/riscv/virt-acpi-build.c        |  12 +++++++++---
>  include/hw/acpi/acpi-defs.h       |   7 +++++--
>  include/hw/acpi/aml-build.h       |   2 +-
>  tests/data/acpi/riscv64/virt/SPCR | Bin 80 -> 90 bytes
>  6 files changed, 37 insertions(+), 12 deletions(-)
> 
> 
> base-commit: cec99171931ea79215c79661d33423ac84e63b6e
> -- 
> 2.34.1

RE: [PATCH v5 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format

[JeeHeng Sia]

> -----Original Message-----
> From: JeeHeng Sia <jeeheng.sia@starfivetech.com>
> Sent: Thursday, 29 August, 2024 9:59 AM
> To: qemu-arm@nongnu.org; qemu-devel@nongnu.org; qemu-riscv@nongnu.org
> Cc: mst@redhat.com; imammedo@redhat.com; anisinha@redhat.com; peter.maydell@linaro.org; JeeHeng Sia
> <jeeheng.sia@starfivetech.com>; shannon.zhaosl@gmail.com; sunilvl@ventanamicro.com; palmer@dabbelt.com;
> alistair.francis@wdc.com; bin.meng@windriver.com; liwei1518@gmail.com; dbarboza@ventanamicro.com;
> zhiwei_liu@linux.alibaba.com
> Subject: [PATCH v5 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format
> 
> Update the SPCR table to accommodate the SPCR Table revision 4 [1].
> The SPCR table has been modified to adhere to the revision 4 format [2].
> 
> Meanwhile, the virt SPCR golden reference file for RISC-V have been updated to
> accommodate the SPCR Table revision 4.
> 
> [1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
> [2]: https://github.com/acpica/acpica/pull/931
> 
> Changes in v5:
> - Reverted the SPCR table revision history for the ARM architecture.
> - Corrected the output of the SPCR Table diff.
> 
> Changes in v4:
> - Remove the SPCR table revision 4 update for the ARM architecture.
> 
> Changes in v3:
> - Rebased on the latest QEMU.
> - Added Acked-by: Alistair Francis <alistair.francis@wdc.com>
> 
> Changes in v2:
> - Utilizes a three-patch approach to modify the ACPI pre-built binary
>   files required by the Bios-Table-Test.
> - Rebases and incorporates changes to support both ARM and RISC-V ACPI
>   pre-built binary files.
> 
> Sia Jee Heng (3):
>   qtest: allow SPCR acpi table changes
>   hw/acpi: Upgrade ACPI SPCR table to support SPCR table revision 4
>     format
>   tests/qtest/bios-tables-test: Update virt SPCR golden reference for
>     RISC-V
> 
>  hw/acpi/aml-build.c               |  20 ++++++++++++++++----
>  hw/arm/virt-acpi-build.c          |   8 ++++++--
>  hw/riscv/virt-acpi-build.c        |  12 +++++++++---
>  include/hw/acpi/acpi-defs.h       |   7 +++++--
>  include/hw/acpi/aml-build.h       |   2 +-
>  tests/data/acpi/riscv64/virt/SPCR | Bin 80 -> 90 bytes
>  6 files changed, 37 insertions(+), 12 deletions(-)
> 
> 
> base-commit: cec99171931ea79215c79661d33423ac84e63b6e
> --
> 2.34.1
Hi, are there any more comments? This patch has been open for more than 6 weeks and has not been merged yet.

Re: [PATCH v5 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format

[Michael S. Tsirkin]

On Wed, Aug 28, 2024 at 06:59:17PM -0700, Sia Jee Heng wrote:
> Update the SPCR table to accommodate the SPCR Table revision 4 [1].
> The SPCR table has been modified to adhere to the revision 4 format [2].

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Pls take through the arm tree.


> Meanwhile, the virt SPCR golden reference file for RISC-V have been updated to
> accommodate the SPCR Table revision 4.
> 
> [1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
> [2]: https://github.com/acpica/acpica/pull/931
> 
> Changes in v5:
> - Reverted the SPCR table revision history for the ARM architecture.
> - Corrected the output of the SPCR Table diff.
> 
> Changes in v4:
> - Remove the SPCR table revision 4 update for the ARM architecture.
> 
> Changes in v3:
> - Rebased on the latest QEMU.
> - Added Acked-by: Alistair Francis <alistair.francis@wdc.com>
> 
> Changes in v2:
> - Utilizes a three-patch approach to modify the ACPI pre-built binary
>   files required by the Bios-Table-Test.
> - Rebases and incorporates changes to support both ARM and RISC-V ACPI
>   pre-built binary files.
> 
> Sia Jee Heng (3):
>   qtest: allow SPCR acpi table changes
>   hw/acpi: Upgrade ACPI SPCR table to support SPCR table revision 4
>     format
>   tests/qtest/bios-tables-test: Update virt SPCR golden reference for
>     RISC-V
> 
>  hw/acpi/aml-build.c               |  20 ++++++++++++++++----
>  hw/arm/virt-acpi-build.c          |   8 ++++++--
>  hw/riscv/virt-acpi-build.c        |  12 +++++++++---
>  include/hw/acpi/acpi-defs.h       |   7 +++++--
>  include/hw/acpi/aml-build.h       |   2 +-
>  tests/data/acpi/riscv64/virt/SPCR | Bin 80 -> 90 bytes
>  6 files changed, 37 insertions(+), 12 deletions(-)
> 
> 
> base-commit: cec99171931ea79215c79661d33423ac84e63b6e
> -- 
> 2.34.1

Re: [PATCH v5 2/3] hw/acpi: Upgrade ACPI SPCR table to support SPCR table revision 4 format

[maobibo]

On 2024/8/29 上午9:59, Sia Jee Heng wrote:
> Update the SPCR table to accommodate the SPCR Table revision 4 [1].
> The SPCR table has been modified to adhere to the revision 4 format [2].
> 
> [1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
> [2]: https://github.com/acpica/acpica/pull/931
> 
> Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
> Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
> Acked-by: Alistair Francis <alistair.francis@wdc.com>
> ---
>   hw/acpi/aml-build.c         | 20 ++++++++++++++++----
>   hw/arm/virt-acpi-build.c    |  8 ++++++--
>   hw/riscv/virt-acpi-build.c  | 12 +++++++++---
>   include/hw/acpi/acpi-defs.h |  7 +++++--
>   include/hw/acpi/aml-build.h |  2 +-
>   5 files changed, 37 insertions(+), 12 deletions(-)
> 
> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> index 6d4517cfbe..99a1b403e2 100644
> --- a/hw/acpi/aml-build.c
> +++ b/hw/acpi/aml-build.c
> @@ -1996,7 +1996,7 @@ static void build_processor_hierarchy_node(GArray *tbl, uint32_t flags,
>   
>   void build_spcr(GArray *table_data, BIOSLinker *linker,
>                   const AcpiSpcrData *f, const uint8_t rev,
> -                const char *oem_id, const char *oem_table_id)
> +                const char *oem_id, const char *oem_table_id, const char *name)

Sorry for late response. LoongArch virt-machine uses function 
build_spcr() also. Maybe there need small modification on it.

Regards
Bibo Mao
>   {
>       AcpiTable table = { .sig = "SPCR", .rev = rev, .oem_id = oem_id,
>                           .oem_table_id = oem_table_id };
> @@ -2042,9 +2042,21 @@ void build_spcr(GArray *table_data, BIOSLinker *linker,
>       build_append_int_noprefix(table_data, f->pci_flags, 4);
>       /* PCI Segment */
>       build_append_int_noprefix(table_data, f->pci_segment, 1);
> -    /* Reserved */
> -    build_append_int_noprefix(table_data, 0, 4);
> -
> +    if (rev < 4) {
> +        /* Reserved */
> +        build_append_int_noprefix(table_data, 0, 4);
> +    } else {
> +        /* UartClkFreq */
> +        build_append_int_noprefix(table_data, f->uart_clk_freq, 4);
> +        /* PreciseBaudrate */
> +        build_append_int_noprefix(table_data, f->precise_baudrate, 4);
> +        /* NameSpaceStringLength */
> +        build_append_int_noprefix(table_data, f->namespace_string_length, 2);
> +        /* NameSpaceStringOffset */
> +        build_append_int_noprefix(table_data, f->namespace_string_offset, 2);
> +        /* NamespaceString[] */
> +        g_array_append_vals(table_data, name, f->namespace_string_length);
> +    }
>       acpi_table_end(linker, &table);
>   }
>   /*
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index f76fb117ad..0b6f5f8d8d 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -464,8 +464,12 @@ spcr_setup(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>           .pci_flags = 0,
>           .pci_segment = 0,
>       };
> -
> -    build_spcr(table_data, linker, &serial, 2, vms->oem_id, vms->oem_table_id);
> +    /*
> +     * Passing NULL as the SPCR Table for Revision 2 doesn't support
> +     * NameSpaceString.
> +     */
> +    build_spcr(table_data, linker, &serial, 2, vms->oem_id, vms->oem_table_id,
> +               NULL);
>   }
>   
>   /*
> diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
> index 36d6a3a412..68ef15acac 100644
> --- a/hw/riscv/virt-acpi-build.c
> +++ b/hw/riscv/virt-acpi-build.c
> @@ -200,14 +200,15 @@ acpi_dsdt_add_uart(Aml *scope, const MemMapEntry *uart_memmap,
>   
>   /*
>    * Serial Port Console Redirection Table (SPCR)
> - * Rev: 1.07
> + * Rev: 1.10
>    */
>   
>   static void
>   spcr_setup(GArray *table_data, BIOSLinker *linker, RISCVVirtState *s)
>   {
> +    const char name[] = ".";
>       AcpiSpcrData serial = {
> -        .interface_type = 0,       /* 16550 compatible */
> +        .interface_type = 0x12,       /* 16550 compatible */
>           .base_addr.id = AML_AS_SYSTEM_MEMORY,
>           .base_addr.width = 32,
>           .base_addr.offset = 0,
> @@ -229,9 +230,14 @@ spcr_setup(GArray *table_data, BIOSLinker *linker, RISCVVirtState *s)
>           .pci_function = 0,
>           .pci_flags = 0,
>           .pci_segment = 0,
> +        .uart_clk_freq = 0,
> +        .precise_baudrate = 0,
> +        .namespace_string_length = sizeof(name),
> +        .namespace_string_offset = 88,
>       };
>   
> -    build_spcr(table_data, linker, &serial, 2, s->oem_id, s->oem_table_id);
> +    build_spcr(table_data, linker, &serial, 4, s->oem_id, s->oem_table_id,
> +               name);
>   }
>   
>   /* RHCT Node[N] starts at offset 56 */
> diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> index 0e6e82b339..2e6e341998 100644
> --- a/include/hw/acpi/acpi-defs.h
> +++ b/include/hw/acpi/acpi-defs.h
> @@ -112,7 +112,6 @@ typedef struct AcpiSpcrData {
>       uint8_t flow_control;
>       uint8_t terminal_type;
>       uint8_t language;
> -    uint8_t reserved1;
>       uint16_t pci_device_id;    /* Must be 0xffff if not PCI device */
>       uint16_t pci_vendor_id;    /* Must be 0xffff if not PCI device */
>       uint8_t pci_bus;
> @@ -120,7 +119,11 @@ typedef struct AcpiSpcrData {
>       uint8_t pci_function;
>       uint32_t pci_flags;
>       uint8_t pci_segment;
> -    uint32_t reserved2;
> +    uint32_t uart_clk_freq;
> +    uint32_t precise_baudrate;
> +    uint32_t namespace_string_length;
> +    uint32_t namespace_string_offset;
> +    char namespace_string[];
>   } AcpiSpcrData;
>   
>   #define ACPI_FADT_ARM_PSCI_COMPLIANT  (1 << 0)
> diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
> index a3784155cb..68c0f2dbee 100644
> --- a/include/hw/acpi/aml-build.h
> +++ b/include/hw/acpi/aml-build.h
> @@ -500,5 +500,5 @@ void build_tpm2(GArray *table_data, BIOSLinker *linker, GArray *tcpalog,
>   
>   void build_spcr(GArray *table_data, BIOSLinker *linker,
>                   const AcpiSpcrData *f, const uint8_t rev,
> -                const char *oem_id, const char *oem_table_id);
> +                const char *oem_id, const char *oem_table_id, const char *name);
>   #endif
>