linux-kernel - Re: [PATCH v15 5/6] x86/boot: Parse SRAT address from RSDP and store immovable memory

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Date:   Fri, 18 Jan 2019 09:14:45 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     Borislav Petkov <bp@...en8.de>
CC:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <hpa@...or.com>,
        <keescook@...omium.org>, <bhe@...hat.com>, <msys.mizuma@...il.com>,
        <indou.takao@...fujitsu.com>, <caoj.fnst@...fujitsu.com>
Subject: Re: [PATCH v15 5/6] x86/boot: Parse SRAT address from RSDP and store
 immovable memory

On Thu, Jan 17, 2019 at 04:27:51PM +0100, Borislav Petkov wrote:
>On Thu, Jan 17, 2019 at 11:20:27AM +0800, Chao Fan wrote:
>> I have changed as you suggested, looks clear without type cast, and
>> we need some variable as long to calculate the address, and at same
>> time as the struct pointer to find it's length, so I change as below,
>> and get_acpi_srat_table() return an unsigned long.
>> How do you think of that.
>> 
>> int get_immovable_mem_num(void)
>
>I'd call that
>
>int count_immovable_mem_regions(void)
>
>or
>
>int enumerate_immovable_regions(void)
>
>or so and put a comment above it explaining what it does and what it
>returns.
>
>"mem_num" is not clear what it is.
>

Sounds good, I will rename it.

>> {
>>         unsigned long table_addr, table_end, table;
>>         struct acpi_table_header *table_header;
>>         struct acpi_subtable_header *sub_table;
>>         char arg[MAX_ACPI_ARG_LENGTH];
>>         int num = 0;
>> 
>>         if (cmdline_find_option("acpi", arg, sizeof(arg)) == 3 &&
>>             !strncmp(arg, "off", 3))
>>                 return;
>> 
>>         table_addr = get_acpi_srat_table();
>>         if (!table_addr)
>>                 return;
>> 
>>         table_header = (struct acpi_table_header *)table_addr;
>>         table_end = table_addr + table_header->length;
>>         table = table_addr + sizeof(struct acpi_table_srat);
>> 
>>         while (table + sizeof(struct acpi_subtable_header) < table_end) {
>>                 sub_table = (struct acpi_subtable_header *)table;
>>                 if (sub_table->type == ACPI_SRAT_TYPE_MEMORY_AFFINITY) {
>>                         struct acpi_srat_mem_affinity *ma;
>> 
>>                         ma = (struct acpi_srat_mem_affinity *)table;
>>                         if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE)) {
>>                                 immovable_mem[num].start = ma->base_address;
>>                                 immovable_mem[num].size = ma->length;
>>                                 num++;
>>                         }
>> 
>>                         if (num >= MAX_NUMNODES*2) {
>>                                 debug_putstr("Too many immovable memory regions, aborting.\n");
>>                                 return 0;
>>                         }
>>                 }
>>                 table += sub_table->length;
>>         }
>>         return num;
>> }
>
>That looks clean.

Then I will change based on that.

Thanks,
Chao Fan

>
>Thx.
>
>-- 
>Regards/Gruss,
>    Boris.
>
>Good mailing practices for 400: avoid top-posting and trim the reply.
>
>