On Tue, Aug 10, 2021 at 12:25:07PM +0200, Eric Auger wrote: > Hello Ard, > On 8/10/21 11:36 AM, Ard Biesheuvel wrote: > > On Tue, 10 Aug 2021 at 10:31, Eric Auger <eric.au...@redhat.com> wrote: > >> ARM SBBR specification mandates DBG2 table (Debug Port Table 2). > >> this latter allows to describe one or more debug ports. > >> > >> Generate an DBG2 table featuring a single debug port, the PL011. > >> > >> The DBG2 specification can be found at: > >> https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/acpi-debug-port-table?redirectedfrom=MSDN > >> > > Have the legal issues around this table been resolved in the mean > > time? > I don't know exactly what they are. Adding Al and Jon in the loop they > have more information about this. > How did you resolve the issue for EDK2 > (DynamicTablesPkg/Library/Acpi/Arm/AcpiDbg2LibArm/Dbg2Generator.c)? > > Also, any clue why this table is mandatory to begin with? The > > SBBR has been very trigger happy lately with making things mandatory > > that aren't truly required from a functional perspective. > It seems there are kernel FW test suites that check all mandated tables > are available and they currently fail for ARM virt. > Indeed from a function pov, I don't know much about its usage on ARM.
There's also a bug with getting console output on tty0 with graphical VMs https://bugzilla.redhat.com/show_bug.cgi?id=1661288 Discussion that includes DBG2 as a possible solution starts around comment 47. I just skimmed the BZ again though and there doesn't appear to be a clear consensus that DBG2 is the solution. Thanks, drew > > Maybe the SBBR spec should not flag the DBG2 as mandatory and test > suites shall be updated. I think this should be clarified at ARM then, > all the more so if there are legal issues as its spec is owned by Microsoft? > > Thanks > > Eric > > > > > >> Signed-off-by: Eric Auger <eric.au...@redhat.com> > >> > >> --- > >> > >> Tested by comparing the content with the table generated > >> by EDK2 along with the SBSA-REF machine (code generated by > >> DynamicTablesPkg/Library/Acpi/Arm/AcpiDbg2LibArm/Dbg2Generator.c). > >> > >> I reused the Generic Address Structure filled by QEMU in the SPCR, ie. > >> bit_width = 8 and byte access. While EDK2 sets bit_width = 32 and > >> dword access. Also the name exposed by acpica tools is different: > >> 'COM0' in my case where '\_SB.COM0' in SBSA-REF case? > >> --- > >> hw/arm/virt-acpi-build.c | 77 ++++++++++++++++++++++++++++++++++++- > >> include/hw/acpi/acpi-defs.h | 50 ++++++++++++++++++++++++ > >> 2 files changed, 126 insertions(+), 1 deletion(-) > >> > >> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c > >> index 037cc1fd82..35f27b41df 100644 > >> --- a/hw/arm/virt-acpi-build.c > >> +++ b/hw/arm/virt-acpi-build.c > >> @@ -563,6 +563,78 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, > >> VirtMachineState *vms) > >> vms->oem_table_id); > >> } > >> > >> +#define ACPI_DBG2_PL011_UART_LENGTH 0x1000 > >> + > >> +/* DBG2 */ > >> +static void > >> +build_dbg2(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms) > >> +{ > >> + int addr_offset, addrsize_offset, namespace_offset, namespace_length; > >> + const MemMapEntry *uart_memmap = &vms->memmap[VIRT_UART]; > >> + struct AcpiGenericAddress *base_address; > >> + int dbg2_start = table_data->len; > >> + AcpiDbg2Device *dbg2dev; > >> + char name[] = "COM0"; > >> + AcpiDbg2Table *dbg2; > >> + uint32_t *addr_size; > >> + uint8_t *namespace; > >> + > >> + dbg2 = acpi_data_push(table_data, sizeof *dbg2); > >> + dbg2->info_offset = sizeof *dbg2; > >> + dbg2->info_count = 1; > >> + > >> + /* debug device info structure */ > >> + > >> + dbg2dev = acpi_data_push(table_data, sizeof(AcpiDbg2Device)); > >> + > >> + dbg2dev->revision = 0; > >> + namespace_length = sizeof name; > >> + dbg2dev->length = sizeof *dbg2dev + sizeof(struct AcpiGenericAddress) > >> + > >> + 4 + namespace_length; > >> + dbg2dev->register_count = 1; > >> + > >> + addr_offset = sizeof *dbg2dev; > >> + addrsize_offset = addr_offset + sizeof(struct AcpiGenericAddress); > >> + namespace_offset = addrsize_offset + 4; > >> + > >> + dbg2dev->namepath_length = cpu_to_le16(namespace_length); > >> + dbg2dev->namepath_offset = cpu_to_le16(namespace_offset); > >> + dbg2dev->oem_data_length = cpu_to_le16(0); > >> + dbg2dev->oem_data_offset = cpu_to_le16(0); /* No OEM data is present > >> */ > >> + dbg2dev->port_type = cpu_to_le16(ACPI_DBG2_SERIAL_PORT); > >> + dbg2dev->port_subtype = cpu_to_le16(ACPI_DBG2_ARM_PL011); > >> + > >> + dbg2dev->base_address_offset = cpu_to_le16(addr_offset); > >> + dbg2dev->address_size_offset = cpu_to_le16(addrsize_offset); > >> + > >> + /* > >> + * variable length content: > >> + * BaseAddressRegister[1] > >> + * AddressSize[1] > >> + * NamespaceString[1] > >> + */ > >> + > >> + base_address = acpi_data_push(table_data, > >> + sizeof(struct AcpiGenericAddress)); > >> + > >> + base_address->space_id = AML_SYSTEM_MEMORY; > >> + base_address->bit_width = 8; > >> + base_address->bit_offset = 0; > >> + base_address->access_width = 1; > >> + base_address->address = cpu_to_le64(uart_memmap->base); > >> + > >> + addr_size = acpi_data_push(table_data, sizeof *addr_size); > >> + *addr_size = cpu_to_le32(ACPI_DBG2_PL011_UART_LENGTH); > >> + > >> + namespace = acpi_data_push(table_data, namespace_length); > >> + memcpy(namespace, name, namespace_length); > >> + > >> + build_header(linker, table_data, > >> + (void *)(table_data->data + dbg2_start), "DBG2", > >> + table_data->len - dbg2_start, 3, vms->oem_id, > >> + vms->oem_table_id); > >> +} > >> + > >> /* MADT */ > >> static void > >> build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms) > >> @@ -790,7 +862,7 @@ void virt_acpi_build(VirtMachineState *vms, > >> AcpiBuildTables *tables) > >> dsdt = tables_blob->len; > >> build_dsdt(tables_blob, tables->linker, vms); > >> > >> - /* FADT MADT GTDT MCFG SPCR pointed to by RSDT */ > >> + /* FADT MADT GTDT MCFG SPCR DBG2 pointed to by RSDT */ > >> acpi_add_table(table_offsets, tables_blob); > >> build_fadt_rev5(tables_blob, tables->linker, vms, dsdt); > >> > >> @@ -813,6 +885,9 @@ void virt_acpi_build(VirtMachineState *vms, > >> AcpiBuildTables *tables) > >> acpi_add_table(table_offsets, tables_blob); > >> build_spcr(tables_blob, tables->linker, vms); > >> > >> + acpi_add_table(table_offsets, tables_blob); > >> + build_dbg2(tables_blob, tables->linker, vms); > >> + > >> if (vms->ras) { > >> build_ghes_error_table(tables->hardware_errors, tables->linker); > >> acpi_add_table(table_offsets, tables_blob); > >> diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h > >> index cf9f44299c..bdb2ebed2c 100644 > >> --- a/include/hw/acpi/acpi-defs.h > >> +++ b/include/hw/acpi/acpi-defs.h > >> @@ -618,4 +618,54 @@ struct AcpiIortRC { > >> } QEMU_PACKED; > >> typedef struct AcpiIortRC AcpiIortRC; > >> > >> +/* DBG2 */ > >> + > >> +/* Types for port_type field above */ > >> + > >> +#define ACPI_DBG2_SERIAL_PORT 0x8000 > >> +#define ACPI_DBG2_1394_PORT 0x8001 > >> +#define ACPI_DBG2_USB_PORT 0x8002 > >> +#define ACPI_DBG2_NET_PORT 0x8003 > >> + > >> +/* Subtypes for port_subtype field above */ > >> + > >> +#define ACPI_DBG2_16550_COMPATIBLE 0x0000 > >> +#define ACPI_DBG2_16550_SUBSET 0x0001 > >> +#define ACPI_DBG2_ARM_PL011 0x0003 > >> +#define ACPI_DBG2_ARM_SBSA_32BIT 0x000D > >> +#define ACPI_DBG2_ARM_SBSA_GENERIC 0x000E > >> +#define ACPI_DBG2_ARM_DCC 0x000F > >> +#define ACPI_DBG2_BCM2835 0x0010 > >> + > >> +#define ACPI_DBG2_1394_STANDARD 0x0000 > >> + > >> +#define ACPI_DBG2_USB_XHCI 0x0000 > >> +#define ACPI_DBG2_USB_EHCI 0x0001 > >> + > >> +/* Debug Device Information Subtable */ > >> + > >> +struct AcpiDbg2Device { > >> + uint8_t revision; > >> + uint16_t length; > >> + uint8_t register_count; /* Number of base_address registers */ > >> + uint16_t namepath_length; > >> + uint16_t namepath_offset; > >> + uint16_t oem_data_length; > >> + uint16_t oem_data_offset; > >> + uint16_t port_type; > >> + uint16_t port_subtype; > >> + uint8_t reserved[2]; > >> + uint16_t base_address_offset; > >> + uint16_t address_size_offset; > >> +} QEMU_PACKED; > >> +typedef struct AcpiDbg2Device AcpiDbg2Device; > >> + > >> +struct AcpiDbg2Table { > >> + ACPI_TABLE_HEADER_DEF /* ACPI common table header */ > >> + uint32_t info_offset; /* offset to the first debug struct */ > >> + uint32_t info_count; /* number of debug device info struct entries */ > >> + uint8_t dbg2_device_info[]; > >> +} QEMU_PACKED; > >> +typedef struct AcpiDbg2Table AcpiDbg2Table; > >> + > >> #endif > >> -- > >> 2.26.3 > >> >