From: Suzuki K Poulose suzuki.poulose@arm.com
mainline inclusion from mainline-v4.20-rc1 commit 595583306434caafac4a71102dca5a8d32d1a769 category: feature feature: Dynamic IPA and 52bit IPA support
-------------------------------------------------
On arm64 VTTBR_EL2:BADDR holds the base address for the stage2 translation table. The Arm ARM mandates that the bits BADDR[x-1:0] should be 0, where 'x' is defined for a given IPA Size and the number of levels for a translation granule size. It is defined using some magical constants. This patch is a reverse engineered implementation to calculate the 'x' at runtime for a given ipa and number of page table levels. See patch for more details.
Cc: Marc Zyngier marc.zyngier@arm.com Cc: Christoffer Dall cdall@kernel.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Zenghui Yu yuzenghui@huawei.com Reviewed-by: Hailiang Zhang zhang.zhanghailiang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/arm64/include/asm/kvm_arm.h | 73 +++++++++++++++++++++++++++++++++++----- arch/arm64/include/asm/kvm_mmu.h | 25 +++++++++++++- 2 files changed, 88 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index de37143..4454546 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -126,7 +126,6 @@ #define VTCR_EL2_SL0_MASK (3 << VTCR_EL2_SL0_SHIFT) #define VTCR_EL2_SL0_LVL1 (1 << VTCR_EL2_SL0_SHIFT) #define VTCR_EL2_T0SZ_MASK 0x3f -#define VTCR_EL2_T0SZ_40B 24 #define VTCR_EL2_VS_SHIFT 19 #define VTCR_EL2_VS_8BIT (0 << VTCR_EL2_VS_SHIFT) #define VTCR_EL2_VS_16BIT (1 << VTCR_EL2_VS_SHIFT) @@ -143,11 +142,8 @@ * Note that when using 4K pages, we concatenate two first level page tables * together. With 16K pages, we concatenate 16 first level page tables. * - * The magic numbers used for VTTBR_X in this patch can be found in Tables - * D4-23 and D4-25 in ARM DDI 0487A.b. */
-#define VTCR_EL2_T0SZ_IPA VTCR_EL2_T0SZ_40B #define VTCR_EL2_COMMON_BITS (VTCR_EL2_SH0_INNER | VTCR_EL2_ORGN0_WBWA | \ VTCR_EL2_IRGN0_WBWA | VTCR_EL2_RES1)
@@ -158,7 +154,6 @@ * 2 level page tables (SL = 1) */ #define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_64K | VTCR_EL2_SL0_LVL1) -#define VTTBR_X_TGRAN_MAGIC 38 #elif defined(CONFIG_ARM64_16K_PAGES) /* * Stage2 translation configuration: @@ -166,7 +161,6 @@ * 2 level page tables (SL = 1) */ #define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_16K | VTCR_EL2_SL0_LVL1) -#define VTTBR_X_TGRAN_MAGIC 42 #else /* 4K */ /* * Stage2 translation configuration: @@ -174,13 +168,74 @@ * 3 level page tables (SL = 1) */ #define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_4K | VTCR_EL2_SL0_LVL1) -#define VTTBR_X_TGRAN_MAGIC 37 #endif
#define VTCR_EL2_FLAGS (VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN_FLAGS) -#define VTTBR_X (VTTBR_X_TGRAN_MAGIC - VTCR_EL2_T0SZ_IPA) +/* + * ARM VMSAv8-64 defines an algorithm for finding the translation table + * descriptors in section D4.2.8 in ARM DDI 0487C.a. + * + * The algorithm defines the expectations on the translation table + * addresses for each level, based on PAGE_SIZE, entry level + * and the translation table size (T0SZ). The variable "x" in the + * algorithm determines the alignment of a table base address at a given + * level and thus determines the alignment of VTTBR:BADDR for stage2 + * page table entry level. + * Since the number of bits resolved at the entry level could vary + * depending on the T0SZ, the value of "x" is defined based on a + * Magic constant for a given PAGE_SIZE and Entry Level. The + * intermediate levels must be always aligned to the PAGE_SIZE (i.e, + * x = PAGE_SHIFT). + * + * The value of "x" for entry level is calculated as : + * x = Magic_N - T0SZ + * + * where Magic_N is an integer depending on the page size and the entry + * level of the page table as below: + * + * -------------------------------------------- + * | Entry level | 4K 16K 64K | + * -------------------------------------------- + * | Level: 0 (4 levels) | 28 | - | - | + * -------------------------------------------- + * | Level: 1 (3 levels) | 37 | 31 | 25 | + * -------------------------------------------- + * | Level: 2 (2 levels) | 46 | 42 | 38 | + * -------------------------------------------- + * | Level: 3 (1 level) | - | 53 | 51 | + * -------------------------------------------- + * + * We have a magic formula for the Magic_N below: + * + * Magic_N(PAGE_SIZE, Level) = 64 - ((PAGE_SHIFT - 3) * Number_of_levels) + * + * where Number_of_levels = (4 - Level). We are only interested in the + * value for Entry_Level for the stage2 page table. + * + * So, given that T0SZ = (64 - IPA_SHIFT), we can compute 'x' as follows: + * + * x = (64 - ((PAGE_SHIFT - 3) * Number_of_levels)) - (64 - IPA_SHIFT) + * = IPA_SHIFT - ((PAGE_SHIFT - 3) * Number of levels) + * + * Here is one way to explain the Magic Formula: + * + * x = log2(Size_of_Entry_Level_Table) + * + * Since, we can resolve (PAGE_SHIFT - 3) bits at each level, and another + * PAGE_SHIFT bits in the PTE, we have : + * + * Bits_Entry_level = IPA_SHIFT - ((PAGE_SHIFT - 3) * (n - 1) + PAGE_SHIFT) + * = IPA_SHIFT - (PAGE_SHIFT - 3) * n - 3 + * where n = number of levels, and since each pointer is 8bytes, we have: + * + * x = Bits_Entry_Level + 3 + * = IPA_SHIFT - (PAGE_SHIFT - 3) * n + * + * The only constraint here is that, we have to find the number of page table + * levels for a given IPA size (which we do, see stage2_pt_levels()) + */ +#define ARM64_VTTBR_X(ipa, levels) ((ipa) - ((levels) * (PAGE_SHIFT - 3)))
-#define VTTBR_BADDR_MASK (((UL(1) << (PHYS_MASK_SHIFT - VTTBR_X)) - 1) << VTTBR_X) #define VTTBR_VMID_SHIFT (UL(48)) #define VTTBR_VMID_MASK(size) (_AT(u64, (1 << size) - 1) << VTTBR_VMID_SHIFT)
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index f63f710..f1e3cbb 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -145,7 +145,6 @@ static inline unsigned long __kern_hyp_va(unsigned long v) #define kvm_phys_shift(kvm) KVM_PHYS_SHIFT #define kvm_phys_size(kvm) (_AC(1, ULL) << kvm_phys_shift(kvm)) #define kvm_phys_mask(kvm) (kvm_phys_size(kvm) - _AC(1, ULL)) -#define kvm_vttbr_baddr_mask(kvm) VTTBR_BADDR_MASK
static inline bool kvm_page_empty(void *ptr) { @@ -531,5 +530,29 @@ static inline int hyp_map_aux_data(void)
#define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr)
+/* + * Get the magic number 'x' for VTTBR:BADDR of this KVM instance. + * With v8.2 LVA extensions, 'x' should be a minimum of 6 with + * 52bit IPS. + */ +static inline int arm64_vttbr_x(u32 ipa_shift, u32 levels) +{ + int x = ARM64_VTTBR_X(ipa_shift, levels); + + return (IS_ENABLED(CONFIG_ARM64_PA_BITS_52) && x < 6) ? 6 : x; +} + +static inline u64 vttbr_baddr_mask(u32 ipa_shift, u32 levels) +{ + unsigned int x = arm64_vttbr_x(ipa_shift, levels); + + return GENMASK_ULL(PHYS_MASK_SHIFT - 1, x); +} + +static inline u64 kvm_vttbr_baddr_mask(struct kvm *kvm) +{ + return vttbr_baddr_mask(kvm_phys_shift(kvm), kvm_stage2_levels(kvm)); +} + #endif /* __ASSEMBLY__ */ #endif /* __ARM64_KVM_MMU_H__ */