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Message-ID: <9d5826a4-fce4-fcfe-c821-7bb5e019a59a@redhat.com>
Date: Fri, 25 Jan 2019 19:55:43 +0800
From: lijiang <lijiang@...hat.com>
To: "Lendacky, Thomas" <Thomas.Lendacky@....com>
Cc: Dave Young <dyoung@...hat.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"kexec@...ts.infradead.org" <kexec@...ts.infradead.org>,
"x86@...nel.org" <x86@...nel.org>,
"linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>,
"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
"tglx@...utronix.de" <tglx@...utronix.de>,
"mingo@...hat.com" <mingo@...hat.com>,
"bp@...en8.de" <bp@...en8.de>,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
"luto@...nel.org" <luto@...nel.org>,
"peterz@...radead.org" <peterz@...radead.org>,
"ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>,
"tony.luck@...el.com" <tony.luck@...el.com>,
"fenghua.yu@...el.com" <fenghua.yu@...el.com>,
"bhe@...hat.com" <bhe@...hat.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'
在 2018年12月05日 05:33, Lendacky, Thomas 写道:
> On 11/29/2018 09:37 PM, Dave Young wrote:
>> + 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?
>
> Sorry for the delay...
>
> The original intent of the check was to map most memory as encrypted under
> SEV if it was marked with a specific descriptor, since it was likely to
> not be MMIO. I tried converting most things that mapped memory to memremap
> vs ioremap, but ACPI was one area that I left alone and this check catches
> the mapping of the ACPI tables. I suppose it's possible to change this to
> check just for IORES_DESC_ACPI_* values, but I would have to do some
> testing.
>
If you have any updates, would you mind sharing the test results about this
issue?
Thank you, Tom.
Lianbo
> Thanks,
> Tom
>
>>
>>>
>>> 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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