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SubjectRe: [PATCH v15 5/6] x86/boot: Parse SRAT address from RSDP and store immovable memory
On Wed, Jan 16, 2019 at 03:28:52PM +0800, Kairui Song wrote:
>On Mon, Jan 7, 2019 at 11:24 AM Chao Fan <fanc.fnst@cn.fujitsu.com> wrote:
>>
>> +
>> +/* Determine RSDP, based on acpi_os_get_root_pointer(). */
>> +static acpi_physical_address get_rsdp_addr(void)
>> +{
>> + acpi_physical_address pa;
>> +
>> + pa = get_acpi_rsdp();
>> +
>> + if (!pa)
>> + pa = efi_get_rsdp_addr();
>> +
>> + if (!pa)
>> + pa = bios_get_rsdp_addr();
>> +
>> + return pa;
>> +}
>
>acpi_rsdp might be provided by boot_params.acpi_rsdp_addr too,
>it's introduced in ae7e1238e68f2a for Xen PVH guest and later move to
>boot_params in e6e094e053af,
>kexec could use it to pass RSDP to second kernel as well. Please check
>it as well make sure it always works.
>

Hi Kairui,

I saw the parsing code has been added to kernel, but I didn't see
where to fill in the 'acpi_rsdp_addr'. If only you(KEXEC) use it,
I can add "#ifdef CONFIG_KEXEC", but you said Xen will use it also,
so I didn't add ifdef to control it. I was trying to do as below:

static inline acpi_physical_address get_boot_params_rsdp(void)
{
return boot_params->acpi_rsdp_addr;
}

static acpi_physical_address get_rsdp_addr(void)
{
bool boot_params_rsdp_exist;
acpi_physical_address pa;

pa = get_acpi_rsdp();

if (!pa)
pa = get_boot_params_rsdp();

if (!pa) {
pa = efi_get_rsdp_addr();
boot_params_rsdp_exist = false;
}
else
boot_params_rsdp_exist = true;

if (!pa)
pa = bios_get_rsdp_addr();

if (pa && !boot_params_rsdp_exist)
boot_params.acpi_rsdp_addr = pa;

return pa;
}

At the same time, I notice kernel only parses it when
"#ifdef CONFIG_ACPI", we should keep sync with kernel, but I think
we are parsing SRAT, CONFIG_ACPI is needed sure, so I am going to
update the define of EARLY_SRAT_PARSE:

config EARLY_SRAT_PARSE
bool "EARLY SRAT parsing"
def_bool y
depends on RANDOMIZE_BASE && MEMORY_HOTREMOVE && ACPI

Boris, how do you think the update for the new acpi_rsdp_addr?
If I misunderstand something, please let me know.

Thanks,
Chao Fan

>> +
>> +/* Compute SRAT address from RSDP. */
>> +static struct acpi_table_header *get_acpi_srat_table(void)
>> +{
>> + acpi_physical_address acpi_table;
>> + acpi_physical_address root_table;
>> + struct acpi_table_header *header;
>> + struct acpi_table_rsdp *rsdp;
>> + u32 num_entries;
>> + char arg[10];
>> + u8 *entry;
>> + u32 size;
>> + u32 len;
>> +
>> + rsdp = (struct acpi_table_rsdp *)(long)get_rsdp_addr();
>> + if (!rsdp)
>> + return NULL;
>> +
>> + /* Get RSDT or XSDT from RSDP. */
>> + if (!(cmdline_find_option("acpi", arg, sizeof(arg)) == 4 &&
>> + !strncmp(arg, "rsdt", 4)) &&
>> + rsdp->xsdt_physical_address &&
>> + rsdp->revision > 1) {
>> + root_table = rsdp->xsdt_physical_address;
>> + size = ACPI_XSDT_ENTRY_SIZE;
>> + } else {
>> + root_table = rsdp->rsdt_physical_address;
>> + size = ACPI_RSDT_ENTRY_SIZE;
>> + }
>> +
>> + /* Get ACPI root table from RSDT or XSDT.*/
>> + if (!root_table)
>> + return NULL;
>> + header = (struct acpi_table_header *)(long)root_table;
>> +
>> + len = header->length;
>> + if (len < sizeof(struct acpi_table_header) + size)
>> + return NULL;
>> +
>> + num_entries = (u32)((len - sizeof(struct acpi_table_header)) / size);
>> + entry = ACPI_ADD_PTR(u8, header, sizeof(struct acpi_table_header));
>> +
>> + while (num_entries--) {
>> + u64 address64;
>> +
>> + if (size == ACPI_RSDT_ENTRY_SIZE)
>> + acpi_table = *ACPI_CAST_PTR(u32, entry);
>> + else {
>> + address64 = *(u64 *)entry;
>> + acpi_table = address64;
>> + }
>> +
>> + if (acpi_table) {
>> + header = (struct acpi_table_header *)(long)acpi_table;
>> +
>> + if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_SRAT))
>> + return header;
>> + }
>> + entry += size;
>> + }
>> + return NULL;
>> +}
>> +
>> +/*
>> + * According to ACPI table, filter the immovable memory regions
>> + * and store them in immovable_mem[].
>> + */
>> +void get_immovable_mem(void)
>> +{
>> + struct acpi_table_header *table_header;
>> + struct acpi_subtable_header *table;
>> + struct acpi_srat_mem_affinity *ma;
>> + char arg[MAX_ACPI_ARG_LENGTH];
>> + unsigned long table_end;
>> + int i = 0;
>> +
>> + if (cmdline_find_option("acpi", arg, sizeof(arg)) == 3 &&
>> + !strncmp(arg, "off", 3))
>> + return;
>> +
>> + table_header = get_acpi_srat_table();
>> + if (!table_header)
>> + return;
>> +
>> + table_end = (unsigned long)table_header + table_header->length;
>> + table = (struct acpi_subtable_header *)
>> + ((unsigned long)table_header + sizeof(struct acpi_table_srat));
>> +
>> + while (((unsigned long)table) +
>> + sizeof(struct acpi_subtable_header) < table_end) {
>> + if (table->type == ACPI_SRAT_TYPE_MEMORY_AFFINITY) {
>> + ma = (struct acpi_srat_mem_affinity *)table;
>> + if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE)) {
>> + immovable_mem[i].start = ma->base_address;
>> + immovable_mem[i].size = ma->length;
>> + i++;
>> + }
>> +
>> + if (i >= MAX_NUMNODES*2) {
>> + debug_putstr("Too many immovable memory regions, aborting.\n");
>> + return;
>> + }
>> + }
>> + table = (struct acpi_subtable_header *)
>> + ((unsigned long)table + table->length);
>> + }
>> + num_immovable_mem = i;
>> +}
>> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
>> index 9ed9709d9947..b251572e77af 100644
>> --- a/arch/x86/boot/compressed/kaslr.c
>> +++ b/arch/x86/boot/compressed/kaslr.c
>> @@ -87,10 +87,6 @@ static unsigned long get_boot_seed(void)
>> #define KASLR_COMPRESSED_BOOT
>> #include "../../lib/kaslr.c"
>>
>> -struct mem_vector {
>> - unsigned long long start;
>> - unsigned long long size;
>> -};
>>
>> /* Only supporting at most 4 unusable memmap regions with kaslr */
>> #define MAX_MEMMAP_REGIONS 4
>> diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
>> index a1d5918765f3..b49748366a5b 100644
>> --- a/arch/x86/boot/compressed/misc.h
>> +++ b/arch/x86/boot/compressed/misc.h
>> @@ -77,6 +77,11 @@ void choose_random_location(unsigned long input,
>> unsigned long *output,
>> unsigned long output_size,
>> unsigned long *virt_addr);
>> +struct mem_vector {
>> + unsigned long long start;
>> + unsigned long long size;
>> +};
>> +
>> /* cpuflags.c */
>> bool has_cpuflag(int flag);
>> #else
>> @@ -116,3 +121,17 @@ static inline void console_init(void)
>> void set_sev_encryption_mask(void);
>>
>> #endif
>> +
>> +/* acpi.c */
>> +#ifdef CONFIG_RANDOMIZE_BASE
>> +/* Amount of immovable memory regions */
>> +int num_immovable_mem;
>> +#endif
>> +
>> +#ifdef CONFIG_EARLY_SRAT_PARSE
>> +void get_immovable_mem(void);
>> +#else
>> +static void get_immovable_mem(void)
>> +{
>> +}
>> +#endif
>> --
>> 2.20.1
>>
>>
>>
>
>
>--
>Best Regards,
>Kairui Song
>
>


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