lkml.org 
[lkml]   [2018]   [Jan]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 3/5] x86/mm: Centralize PMD flags in sme_encrypt_kernel()
From
Date
On 1/7/2018 10:28 AM, Borislav Petkov wrote:
> On Thu, Dec 21, 2017 at 04:03:12PM -0600, Tom Lendacky wrote:
>> In preparation for encrypting more than just the kernel during early
>> boot processing, centralize the use of the PMD flag settings based
>> on the type of mapping desired. When 4KB aligned encryption is added,
>> this will allow either PTE flags or large page PMD flags to be used
>> without requiring the caller to adjust.
>>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>> arch/x86/mm/mem_encrypt.c | 131 ++++++++++++++++++++++++++-------------------
>> 1 file changed, 77 insertions(+), 54 deletions(-)
>>
>> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
>> index 5a20696..9b180f8 100644
>> --- a/arch/x86/mm/mem_encrypt.c
>> +++ b/arch/x86/mm/mem_encrypt.c
>> @@ -468,31 +468,40 @@ struct sme_populate_pgd_data {
>> void *pgtable_area;
>> pgd_t *pgd;
>>
>> - pmdval_t pmd_val;
>> + pmdval_t pmd_flags;
>> + unsigned long paddr;
>> +
>> unsigned long vaddr;
>> + unsigned long vaddr_end;
>> };
>>
>> -static void __init sme_clear_pgd(pgd_t *pgd_base, unsigned long start,
>> - unsigned long end)
>> +static void __init sme_clear_pgd(struct sme_populate_pgd_data *ppd)
>> {
>> unsigned long pgd_start, pgd_end, pgd_size;
>> pgd_t *pgd_p;
>>
>> - pgd_start = start & PGDIR_MASK;
>> - pgd_end = end & PGDIR_MASK;
>> + pgd_start = ppd->vaddr & PGDIR_MASK;
>> + pgd_end = ppd->vaddr_end & PGDIR_MASK;
>>
>> pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1);
>> pgd_size *= sizeof(pgd_t);
>
> This is a strange way of writing this. I'd expect:
>
> pgd_size = (((pgd_end - pgd_start) / PGDIR_SIZE) + 1) * sizeof(pgd_t);

Yup, clearer as one line. I can fix that up.

>
>>
>> - pgd_p = pgd_base + pgd_index(start);
>> + pgd_p = ppd->pgd + pgd_index(ppd->vaddr);
>>
>> memset(pgd_p, 0, pgd_size);
>> }
>>
>> -#define PGD_FLAGS _KERNPG_TABLE_NOENC
>> -#define P4D_FLAGS _KERNPG_TABLE_NOENC
>> -#define PUD_FLAGS _KERNPG_TABLE_NOENC
>> -#define PMD_FLAGS (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
>> +#define PGD_FLAGS _KERNPG_TABLE_NOENC
>> +#define P4D_FLAGS _KERNPG_TABLE_NOENC
>> +#define PUD_FLAGS _KERNPG_TABLE_NOENC
>> +
>> +#define PMD_FLAGS_LARGE (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)
>> +
>> +#define PMD_FLAGS_DEC PMD_FLAGS_LARGE
>> +#define PMD_FLAGS_DEC_WP ((PMD_FLAGS_DEC & ~_PAGE_CACHE_MASK) | \
>> + (_PAGE_PAT | _PAGE_PWT))
>> +
>> +#define PMD_FLAGS_ENC (PMD_FLAGS_LARGE | _PAGE_ENC)
>>
>> static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd)
>> {
>> @@ -561,7 +570,36 @@ static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd)
>>
>> pmd_p += pmd_index(ppd->vaddr);
>> if (!native_pmd_val(*pmd_p) || !(native_pmd_val(*pmd_p) & _PAGE_PSE))
>> - native_set_pmd(pmd_p, native_make_pmd(ppd->pmd_val));
>> + native_set_pmd(pmd_p,
>> + native_make_pmd(ppd->paddr | ppd->pmd_flags));
>
> Never do those ugly line breaks. Just let it stick out.

Will do.

Thanks,
Tom

>
> Otherwise, sme_encrypt_kernel() is starting to look quite readable :)
>

\
 
 \ /
  Last update: 2018-01-14 23:18    [W:0.074 / U:2.480 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site