VTCR_EL2 holds the following key stage2 translation table parameters: SL0 - Entry level in the page table lookup. T0SZ - Denotes the size of the memory addressed by the table. We have been using fixed values for the SL0 depending on the page size as we have a fixed IPA size. But since we are about to make it dynamic, we need to calculate the SL0 at runtime per VM. This patch adds a helper to compute the value of SL0 for a VM based on the IPA size. Cc: Marc Zyngier <marc.zyngier@xxxxxxx> Cc: Christoffer Dall <cdall@xxxxxxxxxx> Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> --- Changes since v5: - Improve commentary. Changes since v3: - Update reference to latest ARM ARM. - Update per-vm VTCR value of SL0. - Add helpers to decode levels from SL0. - Didn't pick up Reviewed-by tag from Eric, as there are some new changes in this version --- arch/arm64/include/asm/kvm_arm.h | 69 +++++++++++++++++++++++--------- arch/arm64/kvm/reset.c | 1 + 2 files changed, 50 insertions(+), 20 deletions(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index b236d90ca056..f913adb44f93 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -121,7 +121,6 @@ #define VTCR_EL2_IRGN0_WBWA TCR_IRGN0_WBWA #define VTCR_EL2_SL0_SHIFT 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_VS_SHIFT 19 #define VTCR_EL2_VS_8BIT (0 << VTCR_EL2_VS_SHIFT) @@ -144,30 +143,60 @@ #define VTCR_EL2_COMMON_BITS (VTCR_EL2_SH0_INNER | VTCR_EL2_ORGN0_WBWA | \ VTCR_EL2_IRGN0_WBWA | VTCR_EL2_RES1) +/* + * VTCR_EL2:SL0 indicates the entry level for Stage2 translation. + * Interestingly, it depends on the page size. + * See D.10.2.121, VTCR_EL2, in ARM DDI 0487C.a + * + * ----------------------------------------- + * | Entry level | 4K | 16K/64K | + * ------------------------------------------ + * | Level: 0 | 2 | - | + * ------------------------------------------ + * | Level: 1 | 1 | 2 | + * ------------------------------------------ + * | Level: 2 | 0 | 1 | + * ------------------------------------------ + * | Level: 3 | - | 0 | + * ------------------------------------------ + * + * The table roughly translates to : + * + * SL0(PAGE_SIZE, Entry_level) = TGRAN_SL0_BASE - Entry_Level + * + * Where TGRAN_SL0_BASE is a magic number depending on the page size: + * TGRAN_SL0_BASE(4K) = 2 + * TGRAN_SL0_BASE(16K) = 3 + * TGRAN_SL0_BASE(64K) = 3 + * provided we take care of ruling out the unsupported cases and + * Entry_Level = 4 - Number_of_levels. + * + */ #ifdef CONFIG_ARM64_64K_PAGES -/* - * Stage2 translation configuration: - * 64kB pages (TG0 = 1) - * 2 level page tables (SL = 1) - */ -#define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_64K | VTCR_EL2_SL0_LVL1) + +#define VTCR_EL2_TGRAN VTCR_EL2_TG0_64K +#define VTCR_EL2_TGRAN_SL0_BASE 3UL + #elif defined(CONFIG_ARM64_16K_PAGES) -/* - * Stage2 translation configuration: - * 16kB pages (TG0 = 2) - * 2 level page tables (SL = 1) - */ -#define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_16K | VTCR_EL2_SL0_LVL1) + +#define VTCR_EL2_TGRAN VTCR_EL2_TG0_16K +#define VTCR_EL2_TGRAN_SL0_BASE 3UL + #else /* 4K */ -/* - * Stage2 translation configuration: - * 4kB pages (TG0 = 0) - * 3 level page tables (SL = 1) - */ -#define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_4K | VTCR_EL2_SL0_LVL1) + +#define VTCR_EL2_TGRAN VTCR_EL2_TG0_4K +#define VTCR_EL2_TGRAN_SL0_BASE 2UL + #endif -#define VTCR_EL2_FLAGS (VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN_FLAGS) +#define VTCR_EL2_LVLS_TO_SL0(levels) \ + ((VTCR_EL2_TGRAN_SL0_BASE - (4 - (levels))) << VTCR_EL2_SL0_SHIFT) +#define VTCR_EL2_SL0_TO_LVLS(sl0) \ + ((sl0) + 4 - VTCR_EL2_TGRAN_SL0_BASE) +#define VTCR_EL2_LVLS(vtcr) \ + VTCR_EL2_SL0_TO_LVLS(((vtcr) & VTCR_EL2_SL0_MASK) >> VTCR_EL2_SL0_SHIFT) + +#define VTCR_EL2_FLAGS (VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN) /* * ARM VMSAv8-64 defines an algorithm for finding the translation table * descriptors in section D4.2.8 in ARM DDI 0487C.a. diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 616120c4176b..1ced1e37374e 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -160,6 +160,7 @@ int kvm_arm_config_vm(struct kvm *kvm, unsigned long type) if (phys_shift > KVM_PHYS_SHIFT) phys_shift = KVM_PHYS_SHIFT; vtcr |= VTCR_EL2_T0SZ(phys_shift); + vtcr |= VTCR_EL2_LVLS_TO_SL0(kvm_stage2_levels(kvm)); /* * Enable the Hardware Access Flag management, unconditionally -- 2.19.0
