linux-kernel - Re: [PATCH 2/2] x86/kexec_file: add reserved e820 ranges to 2nd kernel e820 table

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Date:   Tue, 18 Sep 2018 18:20:26 +0800
From:   lijiang <lijiang@...hat.com>
To:     Dave Young <dyoung@...hat.com>
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
        hpa@...or.com, x86@...nel.org, akpm@...ux-foundation.org
Subject: Re: [PATCH 2/2] x86/kexec_file: add reserved e820 ranges to 2nd
 kernel e820 table

在 2018年09月18日 11:20, Dave Young 写道:
> On 09/18/18 at 10:48am, Lianbo Jiang wrote:
>> e820 reserved ranges is useful in kdump kernel, we have added this in
>> kexec-tools code.
>>
>> One reason is PCI mmconf (extended mode) requires reserved region
>> otherwise it falls back to legacy mode.
>>
>> When AMD SME kdump support, it needs to map dmi table area as unencrypted.
>> For normal boot these ranges sit in e820 reserved ranges thus the early
>> ioremap code naturally map them as unencrypted. So if we have same e820
>> reserve setup in kdump kernel then it will just work like normal kernel.
>>
>> Signed-off-by: Dave Young <dyoung@...hat.com>
>> Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
>> ---
>>  arch/x86/kernel/crash.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
>> index 3c113e6545a3..db453e9c117b 100644
>> --- a/arch/x86/kernel/crash.c
>> +++ b/arch/x86/kernel/crash.c
>> @@ -384,6 +384,12 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
>>  	walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
>>  			memmap_entry_callback);
>>  
>> +	/* Add all reserved ranges */
>> +	cmd.type = E820_TYPE_RESERVED;
>> +	flags = IORESOURCE_MEM;
> 
> Lianbo, rethink about this, we will miss other io resource types if only
> match IORESOURCE_MEM here, can you redo the patch with just using "0"
> for the passing flags?
> 

This patches align on kexec-tools for e820 reserved ranges, if so, the kexec-tools also need to
be improved for the other type, such as IORESOURCE_IO/BUS/DMA(...), right?

I will improve these patches and post v2 tomorrow.

Thanks.

>> +	walk_iomem_res_desc(IORES_DESC_NONE, flags, 0, -1, &cmd,
>> +			memmap_entry_callback);
>> +
>>  	/* Add crashk_low_res region */
>>  	if (crashk_low_res.end) {
>>  		ei.addr = crashk_low_res.start;
>> -- 
>> 2.17.1
>>