linux-kernel - Re: [PATCH 2/4 V3] Allocate pages for kdump without encryption when SME is enabled

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Message-ID: <e74e94b6-97dc-23d9-6262-44a7ae8d63bd@redhat.com>
Date:   Thu, 21 Jun 2018 13:06:05 +0800
From:   lijiang <lijiang@...hat.com>
To:     Baoquan He <bhe@...hat.com>
Cc:     linux-kernel@...r.kernel.org, thomas.lendacky@....com,
        iommu@...ts.linux-foundation.org, dyoung@...hat.com,
        kexec@...ts.infradead.org
Subject: Re: [PATCH 2/4 V3] Allocate pages for kdump without encryption when
 SME is enabled

在 2018年06月21日 09:53, Baoquan He 写道:
> On 06/16/18 at 04:27pm, Lianbo Jiang wrote:
>> When SME is enabled in the first kernel, we will allocate pages
>> for kdump without encryption in order to be able to boot the
>> second kernel in the same manner as kexec, which helps to keep
>> the same code style.
>>
>> Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
>> ---
>>  kernel/kexec_core.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
>> index 20fef1a..3c22a9b 100644
>> --- a/kernel/kexec_core.c
>> +++ b/kernel/kexec_core.c
>> @@ -471,6 +471,16 @@ static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
>>  		}
>>  	}
>>  
>> +	if (pages) {
>> +		unsigned int count, i;
>> +
>> +		pages->mapping = NULL;
>> +		set_page_private(pages, order);
>> +		count = 1 << order;
>> +		for (i = 0; i < count; i++)
>> +			SetPageReserved(pages + i);
> 
> I guess you might imitate the kexec case, however kexec get pages from
> buddy. Crash pages are reserved in memblock, these codes might make no sense.
> 
Thanks for your comments.
We have changed the attribute of pages, so the original attribute of pages will be
restored when they free.

Thanks.
Lianbo
>> +		arch_kexec_post_alloc_pages(page_address(pages), 1 << order, 0);
>> +	}
>>  	return pages;
>>  }
>>  
>> @@ -865,6 +875,7 @@ static int kimage_load_crash_segment(struct kimage *image,
>>  			result  = -ENOMEM;
>>  			goto out;
>>  		}
>> +		arch_kexec_post_alloc_pages(page_address(page), 1, 0);
>>  		ptr = kmap(page);
>>  		ptr += maddr & ~PAGE_MASK;
>>  		mchunk = min_t(size_t, mbytes,
>> @@ -882,6 +893,7 @@ static int kimage_load_crash_segment(struct kimage *image,
>>  			result = copy_from_user(ptr, buf, uchunk);
>>  		kexec_flush_icache_page(page);
>>  		kunmap(page);
>> +		arch_kexec_pre_free_pages(page_address(page), 1);
>>  		if (result) {
>>  			result = -EFAULT;
>>  			goto out;
>> -- 
>> 2.9.5
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec

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