Re: [RFC PATCH v9 08/27] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW

From: Kees Cook
Date: Tue Feb 25 2020 - 15:12:24 EST

On Wed, Feb 05, 2020 at 10:19:16AM -0800, Yu-cheng Yu wrote:
> Before introducing _PAGE_DIRTY_SW for non-hardware memory management
> purposes in the next patch, rename _PAGE_DIRTY to _PAGE_DIRTY_HW and
> _PAGE_BIT_DIRTY to _PAGE_BIT_DIRTY_HW to make these PTE dirty bits
> more clear. There are no functional changes from this patch.
>
> v9:
> - At some places _PAGE_DIRTY were not changed to _PAGE_DIRTY_HW, because
> they will be changed again in the next patch to _PAGE_DIRTY_BITS.
> However, this causes compile issues if the next patch is not yet applied.
> Fix it by changing all _PAGE_DIRTY to _PAGE_DRITY_HW.
>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

> ---
> arch/x86/include/asm/pgtable.h | 18 +++++++++---------
> arch/x86/include/asm/pgtable_types.h | 17 +++++++++--------
> arch/x86/kernel/relocate_kernel_64.S | 2 +-
> arch/x86/kvm/vmx/vmx.c | 2 +-
> 4 files changed, 20 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index ad97dc155195..ab50d25f9afc 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -122,7 +122,7 @@ extern pmdval_t early_pmd_flags;
> */
> static inline int pte_dirty(pte_t pte)
> {
> - return pte_flags(pte) & _PAGE_DIRTY;
> + return pte_flags(pte) & _PAGE_DIRTY_HW;
> }
>
>
> @@ -161,7 +161,7 @@ static inline int pte_young(pte_t pte)
>
> static inline int pmd_dirty(pmd_t pmd)
> {
> - return pmd_flags(pmd) & _PAGE_DIRTY;
> + return pmd_flags(pmd) & _PAGE_DIRTY_HW;
> }
>
> static inline int pmd_young(pmd_t pmd)
> @@ -171,7 +171,7 @@ static inline int pmd_young(pmd_t pmd)
>
> static inline int pud_dirty(pud_t pud)
> {
> - return pud_flags(pud) & _PAGE_DIRTY;
> + return pud_flags(pud) & _PAGE_DIRTY_HW;
> }
>
> static inline int pud_young(pud_t pud)
> @@ -312,7 +312,7 @@ static inline pte_t pte_clear_flags(pte_t pte, pteval_t clear)
>
> static inline pte_t pte_mkclean(pte_t pte)
> {
> - return pte_clear_flags(pte, _PAGE_DIRTY);
> + return pte_clear_flags(pte, _PAGE_DIRTY_HW);
> }
>
> static inline pte_t pte_mkold(pte_t pte)
> @@ -332,7 +332,7 @@ static inline pte_t pte_mkexec(pte_t pte)
>
> static inline pte_t pte_mkdirty(pte_t pte)
> {
> - return pte_set_flags(pte, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
> + return pte_set_flags(pte, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
> }
>
> static inline pte_t pte_mkyoung(pte_t pte)
> @@ -396,7 +396,7 @@ static inline pmd_t pmd_mkold(pmd_t pmd)
>
> static inline pmd_t pmd_mkclean(pmd_t pmd)
> {
> - return pmd_clear_flags(pmd, _PAGE_DIRTY);
> + return pmd_clear_flags(pmd, _PAGE_DIRTY_HW);
> }
>
> static inline pmd_t pmd_wrprotect(pmd_t pmd)
> @@ -406,7 +406,7 @@ static inline pmd_t pmd_wrprotect(pmd_t pmd)
>
> static inline pmd_t pmd_mkdirty(pmd_t pmd)
> {
> - return pmd_set_flags(pmd, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
> + return pmd_set_flags(pmd, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
> }
>
> static inline pmd_t pmd_mkdevmap(pmd_t pmd)
> @@ -450,7 +450,7 @@ static inline pud_t pud_mkold(pud_t pud)
>
> static inline pud_t pud_mkclean(pud_t pud)
> {
> - return pud_clear_flags(pud, _PAGE_DIRTY);
> + return pud_clear_flags(pud, _PAGE_DIRTY_HW);
> }
>
> static inline pud_t pud_wrprotect(pud_t pud)
> @@ -460,7 +460,7 @@ static inline pud_t pud_wrprotect(pud_t pud)
>
> static inline pud_t pud_mkdirty(pud_t pud)
> {
> - return pud_set_flags(pud, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
> + return pud_set_flags(pud, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
> }
>
> static inline pud_t pud_mkdevmap(pud_t pud)
> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
> index b5e49e6bac63..e647e3c75578 100644
> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -15,7 +15,7 @@
> #define _PAGE_BIT_PWT 3 /* page write through */
> #define _PAGE_BIT_PCD 4 /* page cache disabled */
> #define _PAGE_BIT_ACCESSED 5 /* was accessed (raised by CPU) */
> -#define _PAGE_BIT_DIRTY 6 /* was written to (raised by CPU) */
> +#define _PAGE_BIT_DIRTY_HW 6 /* was written to (raised by CPU) */
> #define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page */
> #define _PAGE_BIT_PAT 7 /* on 4KB pages */
> #define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
> @@ -45,7 +45,7 @@
> #define _PAGE_PWT (_AT(pteval_t, 1) << _PAGE_BIT_PWT)
> #define _PAGE_PCD (_AT(pteval_t, 1) << _PAGE_BIT_PCD)
> #define _PAGE_ACCESSED (_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED)
> -#define _PAGE_DIRTY (_AT(pteval_t, 1) << _PAGE_BIT_DIRTY)
> +#define _PAGE_DIRTY_HW (_AT(pteval_t, 1) << _PAGE_BIT_DIRTY_HW)
> #define _PAGE_PSE (_AT(pteval_t, 1) << _PAGE_BIT_PSE)
> #define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
> #define _PAGE_SOFTW1 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW1)
> @@ -73,7 +73,7 @@
> _PAGE_PKEY_BIT3)
>
> #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
> -#define _PAGE_KNL_ERRATUM_MASK (_PAGE_DIRTY | _PAGE_ACCESSED)
> +#define _PAGE_KNL_ERRATUM_MASK (_PAGE_DIRTY_HW | _PAGE_ACCESSED)
> #else
> #define _PAGE_KNL_ERRATUM_MASK 0
> #endif
> @@ -111,9 +111,9 @@
> #define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
>
> #define _PAGE_TABLE_NOENC (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |\
> - _PAGE_ACCESSED | _PAGE_DIRTY)
> + _PAGE_ACCESSED | _PAGE_DIRTY_HW)
> #define _KERNPG_TABLE_NOENC (_PAGE_PRESENT | _PAGE_RW | \
> - _PAGE_ACCESSED | _PAGE_DIRTY)
> + _PAGE_ACCESSED | _PAGE_DIRTY_HW)
>
> /*
> * Set of bits not changed in pte_modify. The pte's
> @@ -122,7 +122,7 @@
> * pte_modify() does modify it.
> */
> #define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
> - _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \
> + _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY_HW | \
> _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
> #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
>
> @@ -167,7 +167,8 @@ enum page_cache_mode {
> _PAGE_ACCESSED)
>
> #define __PAGE_KERNEL_EXEC \
> - (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
> + (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY_HW | _PAGE_ACCESSED | \
> + _PAGE_GLOBAL)
> #define __PAGE_KERNEL (__PAGE_KERNEL_EXEC | _PAGE_NX)
>
> #define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
> @@ -186,7 +187,7 @@ enum page_cache_mode {
> #define _PAGE_ENC (_AT(pteval_t, sme_me_mask))
>
> #define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | \
> - _PAGE_DIRTY | _PAGE_ENC)
> + _PAGE_DIRTY_HW | _PAGE_ENC)
> #define _PAGE_TABLE (_KERNPG_TABLE | _PAGE_USER)
>
> #define __PAGE_KERNEL_ENC (__PAGE_KERNEL | _PAGE_ENC)
> diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
> index ef3ba99068d3..3acd75f97b61 100644
> --- a/arch/x86/kernel/relocate_kernel_64.S
> +++ b/arch/x86/kernel/relocate_kernel_64.S
> @@ -15,7 +15,7 @@
> */
>
> #define PTR(x) (x << 3)
> -#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
> +#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY_HW)
>
> /*
> * control_page + KEXEC_CONTROL_CODE_MAX_SIZE
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index e3394c839dea..fbbbf621b0d9 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -3503,7 +3503,7 @@ static int init_rmode_identity_map(struct kvm *kvm)
> /* Set up identity-mapping pagetable for EPT in real mode */
> for (i = 0; i < PT32_ENT_PER_PAGE; i++) {
> tmp = (i << 22) + (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |
> - _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE);
> + _PAGE_ACCESSED | _PAGE_DIRTY_HW | _PAGE_PSE);
> r = kvm_write_guest_page(kvm, identity_map_pfn,
> &tmp, i * sizeof(tmp), sizeof(tmp));
> if (r < 0)
> --
> 2.21.0
>

--
Kees Cook