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From: lijiang <lijiang@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
	tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org,
	x86@kernel.org, hpa@zytor.com, dyoung@redhat.com, bhe@redhat.com,
	Thomas.Lendacky@amd.com, brijesh.singh@amd.com
Subject: Re: [PATCH 2/3 v3] x86/kexec: Set the C-bit in the identity map page table when SEV is active
Date: Thu, 16 May 2019 09:12:26 +0800	[thread overview]
Message-ID: <4707fb2d-b7d3-34e3-a488-8aa9bdca05f1@redhat.com> (raw)
In-Reply-To: <20190515133006.GG24212@zn.tnic>

在 2019年05月15日 21:30, Borislav Petkov 写道:
> On Tue, Apr 30, 2019 at 03:44:20PM +0800, Lianbo Jiang wrote:
>> When SEV is active, the second kernel image is loaded into the
>> encrypted memory. Lets make sure that when kexec builds the
>> identity mapping page table it adds the memory encryption mask(C-bit).
>>
>> Co-developed-by: Brijesh Singh <brijesh.singh@amd.com>
>> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
>> Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
>> ---
>>  arch/x86/kernel/machine_kexec_64.c | 12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
>> index f60611531d17..11fe352f7344 100644
>> --- a/arch/x86/kernel/machine_kexec_64.c
>> +++ b/arch/x86/kernel/machine_kexec_64.c
>> @@ -56,6 +56,7 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
>>  	pte_t *pte;
>>  	unsigned long vaddr, paddr;
>>  	int result = -ENOMEM;
>> +	pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
>>  
>>  	vaddr = (unsigned long)relocate_kernel;
>>  	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
>> @@ -92,7 +93,11 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
>>  		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
>>  	}
>>  	pte = pte_offset_kernel(pmd, vaddr);
>> -	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC_NOENC));
>> +
>> +	if (sev_active())
>> +		prot = PAGE_KERNEL_EXEC;
>> +
>> +	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
>>  	return 0;
>>  err:
>>  	return result;
>> @@ -129,6 +134,11 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
>>  	level4p = (pgd_t *)__va(start_pgtable);
>>  	clear_page(level4p);
>>  
>> +	if (sev_active()) {
>> +		info.page_flag |= _PAGE_ENC;
>> +		info.kernpg_flag = _KERNPG_TABLE;
> 
> kernpg_flag above is initialized to _KERNPG_TABLE_NOENC so you can do here
> 
> 		info.kernpg_flag |= _PAGE_ENC;
> 
> too, to make it even more clear what this does, right?
> 
OK, i will modify it according to your suggestion and post again.

Thanks.
Lianbo

> IOW:
> 
> diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
> index 783ce5184405..16c37fe489bc 100644
> --- a/arch/x86/kernel/machine_kexec_64.c
> +++ b/arch/x86/kernel/machine_kexec_64.c
> @@ -135,8 +135,8 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
>         clear_page(level4p);
>  
>         if (sev_active()) {
> -               info.page_flag |= _PAGE_ENC;
> -               info.kernpg_flag = _KERNPG_TABLE;
> +               info.page_flag   |= _PAGE_ENC;
> +               info.kernpg_flag |= _PAGE_ENC;
>         }
>  
>         if (direct_gbpages)
> 
> 

  reply	other threads:[~2019-05-16  1:47 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-30  7:44 [PATCH 0/3 v3] Add kdump support for the SEV enabled guest Lianbo Jiang
2019-04-30  7:44 ` [PATCH 1/3 v3] x86/kexec: Do not map the kexec area as decrypted when SEV is active Lianbo Jiang
2019-06-20 10:01   ` [tip:x86/kdump] x86/kexec: Do not map " tip-bot for Lianbo Jiang
2019-04-30  7:44 ` [PATCH 2/3 v3] x86/kexec: Set the C-bit in the identity map page table " Lianbo Jiang
2019-05-15 13:30   ` Borislav Petkov
2019-05-16  1:12     ` lijiang [this message]
2019-05-16  8:15       ` Boris Petkov
2019-05-16 11:35         ` lijiang
2019-06-12  1:34         ` lijiang
2019-06-20 10:02   ` [tip:x86/kdump] " tip-bot for Lianbo Jiang
2019-04-30  7:44 ` [PATCH 3/3 v3] kdump,proc/vmcore: Enable dumping encrypted memory when SEV was active Lianbo Jiang
2019-06-20 10:03   ` [tip:x86/kdump] fs/proc/vmcore: Enable dumping of " tip-bot for Lianbo Jiang

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