| Message ID | 20190508144422.13171-10-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Intel MKTME enabling | expand |
On Wed, May 08, 2019 at 05:43:29PM +0300, Kirill A. Shutemov wrote: > + * Cast PAGE_MASK to a signed type so that it is sign-extended if > + * virtual addresses are 32-bits but physical addresses are larger > + * (ie, 32-bit PAE). On 32bit, 'long' is still 32bit, did you want to cast to 'long long' instead? Ideally we'd use pteval_t here, but I see that is unsigned. > */ > -#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ > +#define PTE_PFN_MASK_MAX \ > + (((signed long)PAGE_MASK) & ((1ULL << __PHYSICAL_MASK_SHIFT) - 1)) > +#define _PAGE_CHG_MASK (PTE_PFN_MASK_MAX | _PAGE_PCD | _PAGE_PWT | \ > _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \ > _PAGE_SOFT_DIRTY | _PAGE_DEVMAP) > #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
On Fri, Jun 14, 2019 at 11:15:14AM +0200, Peter Zijlstra wrote: > On Wed, May 08, 2019 at 05:43:29PM +0300, Kirill A. Shutemov wrote: > > + * Cast PAGE_MASK to a signed type so that it is sign-extended if > > + * virtual addresses are 32-bits but physical addresses are larger > > + * (ie, 32-bit PAE). > > On 32bit, 'long' is still 32bit, did you want to cast to 'long long' > instead? Ideally we'd use pteval_t here, but I see that is unsigned. It will be cased implecitly to unsigned long long by '& ((1ULL << __PHYSICAL_MASK_SHIFT) - 1)' and due to sign-extension it will get it right for PAE. Just to be on safe side, I've re-checked that nothing changed for PAE by the patch using the test below. PTE_PFN_MASK and PTE_PFN_MASK_MAX are identical when compiled with -m32. > > */ > > -#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ > > +#define PTE_PFN_MASK_MAX \ > > + (((signed long)PAGE_MASK) & ((1ULL << __PHYSICAL_MASK_SHIFT) - 1)) > > +#define _PAGE_CHG_MASK (PTE_PFN_MASK_MAX | _PAGE_PCD | _PAGE_PWT | \ > > _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \ > > _PAGE_SOFT_DIRTY | _PAGE_DEVMAP) > > #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE) > #include <stdio.h> typedef unsigned long long u64; typedef u64 pteval_t; typedef u64 phys_addr_t; #define PAGE_SHIFT 12 #define PAGE_SIZE (1UL << PAGE_SHIFT) #define PAGE_MASK (~(PAGE_SIZE-1)) #define __PHYSICAL_MASK_SHIFT 52 #define __PHYSICAL_MASK ((phys_addr_t)((1ULL << __PHYSICAL_MASK_SHIFT) - 1)) #define PHYSICAL_PAGE_MASK (((signed long)PAGE_MASK) & __PHYSICAL_MASK) #define PTE_PFN_MASK ((pteval_t)PHYSICAL_PAGE_MASK) #define PTE_PFN_MASK_MAX (((signed long)PAGE_MASK) & ((1ULL << __PHYSICAL_MASK_SHIFT) - 1)) int main(void) { printf("PTE_PFN_MASK: %#llx\n", PTE_PFN_MASK); printf("PTE_PFN_MASK_MAX: %#llx\n", PTE_PFN_MASK_MAX); return 0; }
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index d6ff0bbdb394..7d6f68431538 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -117,12 +117,25 @@ _PAGE_ACCESSED | _PAGE_DIRTY) /* - * Set of bits not changed in pte_modify. The pte's - * protection key is treated like _PAGE_RW, for - * instance, and is *not* included in this mask since - * pte_modify() does modify it. + * Set of bits not changed in pte_modify. + * + * The pte's protection key is treated like _PAGE_RW, for instance, and is + * *not* included in this mask since pte_modify() does modify it. + * + * They include the physical address and the memory encryption keyID. + * The paddr and the keyID never occupy the same bits at the same time. + * But, a given bit might be used for the keyID on one system and used for + * the physical address on another. As an optimization, we manage them in + * one unit here since their combination always occupies the same hardware + * bits. PTE_PFN_MASK_MAX stores combined mask. + * + * Cast PAGE_MASK to a signed type so that it is sign-extended if + * virtual addresses are 32-bits but physical addresses are larger + * (ie, 32-bit PAE). */ -#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ +#define PTE_PFN_MASK_MAX \ + (((signed long)PAGE_MASK) & ((1ULL << __PHYSICAL_MASK_SHIFT) - 1)) +#define _PAGE_CHG_MASK (PTE_PFN_MASK_MAX | _PAGE_PCD | _PAGE_PWT | \ _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \ _PAGE_SOFT_DIRTY | _PAGE_DEVMAP) #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
An encrypted VMA will have KeyID stored in vma->vm_page_prot. This way we don't need to do anything special to setup encrypted page table entries and don't need to reserve space for KeyID in a VMA. This patch changes _PAGE_CHG_MASK to include KeyID bits. Otherwise they are going to be stripped from vm_page_prot on the first pgprot_modify(). Define PTE_PFN_MASK_MAX similar to PTE_PFN_MASK but based on __PHYSICAL_MASK_SHIFT. This way we include whole range of bits architecturally available for PFN without referencing physical_mask and mktme_keyid_mask variables. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- arch/x86/include/asm/pgtable_types.h | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)