Re: [kvm-unit-tests PATCH v5 14/29] arm64: Add support for cpu initialization through ACPI

[Shaoqin Huang <shahuang@redhat.com>]

On 4/28/23 20:03, Nikos Nikoleris wrote:
> In systems with ACPI support and when a DT is not provided, we can use
> the MADTs to discover the number of CPUs and their corresponding MIDR.
> This change implements this but retains the default behavior; we check
> if a valid DT is provided, if not, we try to discover the cores in the
> system using ACPI.
> 
> Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
> Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> ---
>   lib/acpi.h      | 63 +++++++++++++++++++++++++++++++++++++++++++++++++
>   lib/acpi.c      | 20 ++++++++++++++++
>   lib/arm/setup.c | 42 ++++++++++++++++++++++++++++++---
>   3 files changed, 122 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/acpi.h b/lib/acpi.h
> index 04e4d1c3..4a59f543 100644
> --- a/lib/acpi.h
> +++ b/lib/acpi.h
> @@ -17,6 +17,7 @@
>   #define XSDT_SIGNATURE ACPI_SIGNATURE('X','S','D','T')
>   #define FACP_SIGNATURE ACPI_SIGNATURE('F','A','C','P')
>   #define FACS_SIGNATURE ACPI_SIGNATURE('F','A','C','S')
> +#define MADT_SIGNATURE ACPI_SIGNATURE('A','P','I','C')
>   #define SPCR_SIGNATURE ACPI_SIGNATURE('S','P','C','R')
>   #define GTDT_SIGNATURE ACPI_SIGNATURE('G','T','D','T')
>   
> @@ -147,6 +148,67 @@ struct acpi_table_facs_rev1 {
>   	u8 reserved3[40];	/* Reserved - must be zero */
>   };
>   
> +struct acpi_table_madt {
> +	ACPI_TABLE_HEADER_DEF	/* ACPI common table header */
> +	u32 address;		/* Physical address of local APIC */
> +	u32 flags;
> +};
> +
> +struct acpi_subtable_header {
> +	u8 type;
> +	u8 length;
> +};
> +
> +typedef int (*acpi_table_handler)(struct acpi_subtable_header *header);
> +
> +/* 11: Generic interrupt - GICC (ACPI 5.0 + ACPI 6.0 + ACPI 6.3 changes) */
> +
> +struct acpi_madt_generic_interrupt {
> +	u8 type;
> +	u8 length;
> +	u16 reserved;		/* reserved - must be zero */
> +	u32 cpu_interface_number;
> +	u32 uid;
> +	u32 flags;
> +	u32 parking_version;
> +	u32 performance_interrupt;
> +	u64 parked_address;
> +	u64 base_address;
> +	u64 gicv_base_address;
> +	u64 gich_base_address;
> +	u32 vgic_interrupt;
> +	u64 gicr_base_address;
> +	u64 arm_mpidr;
> +	u8 efficiency_class;
> +	u8 reserved2[1];
> +	u16 spe_interrupt;	/* ACPI 6.3 */
> +};
> +
> +/* Values for MADT subtable type in struct acpi_subtable_header */
> +
> +enum acpi_madt_type {
> +	ACPI_MADT_TYPE_LOCAL_APIC = 0,
> +	ACPI_MADT_TYPE_IO_APIC = 1,
> +	ACPI_MADT_TYPE_INTERRUPT_OVERRIDE = 2,
> +	ACPI_MADT_TYPE_NMI_SOURCE = 3,
> +	ACPI_MADT_TYPE_LOCAL_APIC_NMI = 4,
> +	ACPI_MADT_TYPE_LOCAL_APIC_OVERRIDE = 5,
> +	ACPI_MADT_TYPE_IO_SAPIC = 6,
> +	ACPI_MADT_TYPE_LOCAL_SAPIC = 7,
> +	ACPI_MADT_TYPE_INTERRUPT_SOURCE = 8,
> +	ACPI_MADT_TYPE_LOCAL_X2APIC = 9,
> +	ACPI_MADT_TYPE_LOCAL_X2APIC_NMI = 10,
> +	ACPI_MADT_TYPE_GENERIC_INTERRUPT = 11,
> +	ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR = 12,
> +	ACPI_MADT_TYPE_GENERIC_MSI_FRAME = 13,
> +	ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR = 14,
> +	ACPI_MADT_TYPE_GENERIC_TRANSLATOR = 15,
> +	ACPI_MADT_TYPE_RESERVED = 16	/* 16 and greater are reserved */
> +};
> +
> +/* MADT Local APIC flags */
> +#define ACPI_MADT_ENABLED		(1)	/* 00: Processor is usable if set */
> +
>   struct spcr_descriptor {
>   	ACPI_TABLE_HEADER_DEF	/* ACPI common table header */
>   	u8 interface_type;	/* 0=full 16550, 1=subset of 16550 */
> @@ -192,5 +254,6 @@ struct acpi_table_gtdt {
>   
>   void set_efi_rsdp(struct acpi_table_rsdp *rsdp);
>   void *find_acpi_table_addr(u32 sig);
> +void acpi_table_parse_madt(enum acpi_madt_type mtype, acpi_table_handler handler);
>   
>   #endif
> diff --git a/lib/acpi.c b/lib/acpi.c
> index a197f3dd..bbe33d08 100644
> --- a/lib/acpi.c
> +++ b/lib/acpi.c
> @@ -102,3 +102,23 @@ void *find_acpi_table_addr(u32 sig)
>   
>   	return NULL;
>   }
> +
> +void acpi_table_parse_madt(enum acpi_madt_type mtype, acpi_table_handler handler)
> +{
> +	struct acpi_table_madt *madt;
> +	struct acpi_subtable_header *header;
> +	void *end;
> +
> +	madt = find_acpi_table_addr(MADT_SIGNATURE);
> +	assert(madt);
> +
> +	header = (void *)(ulong) madt + sizeof(struct acpi_table_madt);
> +	end = (void *)((ulong) madt + madt->length);
> +
> +	while ((void *)header < end) {
> +		if (header->type == mtype)
> +			handler(header);
> +
> +		header = (void *)(ulong) header + header->length;
> +	}
> +}
> diff --git a/lib/arm/setup.c b/lib/arm/setup.c
> index 1572c64e..59b0aedd 100644
> --- a/lib/arm/setup.c
> +++ b/lib/arm/setup.c
> @@ -55,7 +55,7 @@ int mpidr_to_cpu(uint64_t mpidr)
>   	return -1;
>   }
>   
> -static void cpu_set(int fdtnode __unused, u64 regval, void *info __unused)
> +static void cpu_set_fdt(int fdtnode __unused, u64 regval, void *info __unused)
>   {
>   	int cpu = nr_cpus++;
>   
> @@ -65,13 +65,49 @@ static void cpu_set(int fdtnode __unused, u64 regval, void *info __unused)
>   	set_cpu_present(cpu, true);
>   }
>   
> +#ifdef CONFIG_EFI
> +
> +#include <acpi.h>
> +
> +static int cpu_set_acpi(struct acpi_subtable_header *header)
> +{
> +	int cpu = nr_cpus++;
> +	struct acpi_madt_generic_interrupt *gicc = (void *)header;
> +
> +	assert_msg(cpu < NR_CPUS, "Number cpus exceeds maximum supported (%d).", NR_CPUS);
> +
> +	cpus[cpu] = gicc->arm_mpidr;
> +	set_cpu_present(cpu, true);
> +
> +	return 0;
> +}
> +
> +static void cpu_init_acpi(void)
> +{
> +	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT, cpu_set_acpi);
> +}
> +
> +#else
> +
> +static void cpu_init_acpi(void)
> +{
> +	assert_msg(false, "ACPI not available");
> +}
> +
> +#endif
> +
>   static void cpu_init(void)
>   {
>   	int ret;
>   
>   	nr_cpus = 0;
> -	ret = dt_for_each_cpu_node(cpu_set, NULL);
> -	assert(ret == 0);
> +	if (dt_available()) {
> +		ret = dt_for_each_cpu_node(cpu_set_fdt, NULL);
> +		assert(ret == 0);
> +	} else {
> +		cpu_init_acpi();
> +	}
> +
>   	set_cpu_online(0, true);
>   }
>   

-- 
Shaoqin