linux-kernel - Re: [PATCH 1/2 v10] x86/mm, resource: add a new I/O resource descriptor 'IORES_DESC

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Message-ID: <16545118-2658-43b5-d43c-cb029c85d2b9@redhat.com>
Date:   Fri, 29 Mar 2019 19:41:00 +0800
From:   lijiang <lijiang@...hat.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
        tglx@...utronix.de, mingo@...hat.com, akpm@...ux-foundation.org,
        dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        x86@...nel.org, hpa@...or.com, dyoung@...hat.com, bhe@...hat.com,
        Thomas.Lendacky@....com
Subject: Re: [PATCH 1/2 v10] x86/mm, resource: add a new I/O resource
 descriptor 'IORES_DESC_RESERVED'

在 2019年03月29日 18:39, Borislav Petkov 写道:
> On Fri, Mar 29, 2019 at 02:56:48PM +0800, Lianbo Jiang wrote:
>> When doing kexec_file_load(), the first kernel needs to pass the e820
>> reserved ranges to the second kernel, because some devices may use it
>> in kdump kernel, such as PCI devices.
>>
>> But, the kernel can not exactly match the e820 reserved ranges when
>> walking through the iomem resources via the 'IORES_DESC_NONE', because
>> there are several types of e820 that are described as the 'IORES_DESC_NONE'
>> type. Please refer to the e820_type_to_iores_desc().
>>
>> Therefore, add a new I/O resource descriptor 'IORES_DESC_RESERVED' for
>> the iomem resources search interfaces. It is helpful to exactly match
>> the reserved resource ranges when walking through iomem resources.
>>
>> In addition, since the new descriptor 'IORES_DESC_RESERVED' has been
>> created for the reserved areas, the code originally related to the
>> descriptor 'IORES_DESC_NONE' also need to be updated.
>>
>> Suggested-by: Borislav Petkov <bp@...e.de>
>> Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
>> ---
>>  arch/x86/kernel/e820.c |  2 +-
>>  arch/x86/mm/ioremap.c  | 16 ++++++++++++++--
>>  include/linux/ioport.h |  1 +
>>  3 files changed, 16 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
>> index 2879e234e193..16fcde196243 100644
>> --- a/arch/x86/kernel/e820.c
>> +++ b/arch/x86/kernel/e820.c
>> @@ -1050,10 +1050,10 @@ static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry)
>>  	case E820_TYPE_NVS:		return IORES_DESC_ACPI_NV_STORAGE;
>>  	case E820_TYPE_PMEM:		return IORES_DESC_PERSISTENT_MEMORY;
>>  	case E820_TYPE_PRAM:		return IORES_DESC_PERSISTENT_MEMORY_LEGACY;
>> +	case E820_TYPE_RESERVED:	return IORES_DESC_RESERVED;
>>  	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */
>>  	case E820_TYPE_RAM:		/* Fall-through: */
>>  	case E820_TYPE_UNUSABLE:	/* Fall-through: */
>> -	case E820_TYPE_RESERVED:	/* Fall-through: */
>>  	default:			return IORES_DESC_NONE;
>>  	}
>>  }
>> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
>> index 0029604af8a4..5671ec24df49 100644
>> --- a/arch/x86/mm/ioremap.c
>> +++ b/arch/x86/mm/ioremap.c
>> @@ -81,9 +81,21 @@ static bool __ioremap_check_ram(struct resource *res)
>>  	return false;
>>  }
>>  
>> -static int __ioremap_check_desc_other(struct resource *res)
> 
> I can see this patch doesn't build even without applying and building
> it.
> 
> How about you build-test your stuff before submitting?
> 
Oh, my God. I made a mistake when i copied the code from another machine.
I will correct this issue and resend the patch v10.

Thanks.
Lianbo