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Date: Fri, 30 Nov 2018 11:37:03 +0800
From: Dave Young <dyoung@...hat.com>
To: Lianbo Jiang <lijiang@...hat.com>
Cc: linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
x86@...nel.org, linux-ia64@...r.kernel.org,
linux-efi@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
bp@...en8.de, akpm@...ux-foundation.org,
dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
ard.biesheuvel@...aro.org, tony.luck@...el.com,
fenghua.yu@...el.com, bhe@...hat.com,
Tom Lendacky <thomas.lendacky@....com>,
Toshi Kani <toshi.kani@...com>,
Dan Williams <dan.j.williams@...el.com>
Subject: Re: [PATCH 1/2 v8] resource: add the new I/O resource descriptor
'IORES_DESC_RESERVED'
+ more people
On 11/29/18 at 04:09pm, Lianbo Jiang wrote:
> When doing kexec_file_load, the first kernel needs to pass the e820
> reserved ranges to the second kernel. But kernel can not exactly
> match the e820 reserved ranges when walking through the iomem resources
> with the descriptor 'IORES_DESC_NONE', because several e820 types(
> e.g. E820_TYPE_RESERVED_KERN/E820_TYPE_RAM/E820_TYPE_UNUSABLE/E820
> _TYPE_RESERVED) are converted to the descriptor 'IORES_DESC_NONE'. It
> may pass these four types to the kdump kernel, that is not desired result.
>
> So, this patch adds 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' is introduced,
> these code originally related to the descriptor 'IORES_DESC_NONE' need to
> be updated. Otherwise, it will be easily confused and also cause some
> errors. Because the 'E820_TYPE_RESERVED' type is converted to the new
> descriptor 'IORES_DESC_RESERVED' instead of 'IORES_DESC_NONE', it has been
> changed.
>
> Suggested-by: Dave Young <dyoung@...hat.com>
> Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
> ---
> arch/ia64/kernel/efi.c | 4 ++++
> arch/x86/kernel/e820.c | 2 +-
> arch/x86/mm/ioremap.c | 13 ++++++++++++-
> include/linux/ioport.h | 1 +
> kernel/resource.c | 6 +++---
> 5 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
> index 8f106638913c..1841e9b4db30 100644
> --- a/arch/ia64/kernel/efi.c
> +++ b/arch/ia64/kernel/efi.c
> @@ -1231,6 +1231,10 @@ efi_initialize_iomem_resources(struct resource *code_resource,
> break;
>
> case EFI_RESERVED_TYPE:
> + name = "reserved";
Ingo updated X86 code to use "Reserved", I think it would be good to do
same for this case as well
> + desc = IORES_DESC_RESERVED;
> + break;
> +
> case EFI_RUNTIME_SERVICES_CODE:
> case EFI_RUNTIME_SERVICES_DATA:
> case EFI_ACPI_RECLAIM_MEMORY:
Originally, above 3 are all "reserved", so probably they all should be
IORES_DESC_RESERVED.
Can any IA64 people to review this?
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 50895c2f937d..57fafdafb860 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -1048,10 +1048,10 @@ 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 5378d10f1d31..fea2ef99415d 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -83,7 +83,18 @@ static bool __ioremap_check_ram(struct resource *res)
>
> static int __ioremap_check_desc_other(struct resource *res)
> {
> - return (res->desc != IORES_DESC_NONE);
> + /*
> + * But now, the 'E820_TYPE_RESERVED' type is converted to the new
> + * descriptor 'IORES_DESC_RESERVED' instead of 'IORES_DESC_NONE',
> + * it has been changed. And the value of 'mem_flags.desc_other'
> + * is equal to 'true' if we don't strengthen the condition in this
> + * function, that is wrong. Because originally it is equal to
> + * 'false' for the same reserved type.
> + *
> + * So, that would be nice to keep it the same as before.
> + */
> + return ((res->desc != IORES_DESC_NONE) &&
> + (res->desc != IORES_DESC_RESERVED));
> }
Added Tom since he added the check function. Is it possible to only
check explict valid desc types instead of exclude IORES_DESC_NONE?
>
> static int __ioremap_res_check(struct resource *res, void *arg)
> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
> index da0ebaec25f0..6ed59de48bd5 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -133,6 +133,7 @@ enum {
> IORES_DESC_PERSISTENT_MEMORY_LEGACY = 5,
> IORES_DESC_DEVICE_PRIVATE_MEMORY = 6,
> IORES_DESC_DEVICE_PUBLIC_MEMORY = 7,
> + IORES_DESC_RESERVED = 8,
> };
>
> /* helpers to define resources */
> diff --git a/kernel/resource.c b/kernel/resource.c
> index b0fbf685c77a..f34a632c4169 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -994,7 +994,7 @@ __reserve_region_with_split(struct resource *root, resource_size_t start,
> res->start = start;
> res->end = end;
> res->flags = type | IORESOURCE_BUSY;
> - res->desc = IORES_DESC_NONE;
> + res->desc = IORES_DESC_RESERVED;
>
> while (1) {
>
> @@ -1029,7 +1029,7 @@ __reserve_region_with_split(struct resource *root, resource_size_t start,
> next_res->start = conflict->end + 1;
> next_res->end = end;
> next_res->flags = type | IORESOURCE_BUSY;
> - next_res->desc = IORES_DESC_NONE;
> + next_res->desc = IORES_DESC_RESERVED;
> }
> } else {
> res->start = conflict->end + 1;
> @@ -1477,7 +1477,7 @@ static int __init reserve_setup(char *str)
> res->start = io_start;
> res->end = io_start + io_num - 1;
> res->flags |= IORESOURCE_BUSY;
> - res->desc = IORES_DESC_NONE;
> + res->desc = IORES_DESC_RESERVED;
> res->child = NULL;
> if (request_resource(parent, res) == 0)
> reserved = x+1;
> --
> 2.17.1
>
There are a lot of places call region_intersects which use DESC_NONE,
I'm not sure if needed changes accordingly. Cced Dan and Toshi.
Thanks
Dave
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