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: <20190329103958.GC21152@zn.tnic>
Date:   Fri, 29 Mar 2019 11:39:58 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Lianbo Jiang <lijiang@...hat.com>
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'

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?

-- 
Regards/Gruss,
    Boris.

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