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 <[email protected]> Cc: Christoffer Dall <[email protected]> Cc: Eric Auger <[email protected]> Signed-off-by: Suzuki K Poulose <[email protected]> --- 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 | 51 +++++++++++++++++++++++++------- arch/arm64/kvm/reset.c | 1 + 2 files changed, 41 insertions(+), 11 deletions(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 3fb1d440be6e..5c1487dc5dca 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) @@ -148,29 +147,59 @@ /* * 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 VTTBR_X_TGRAN_MAGIC 38 +#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 VTTBR_X_TGRAN_MAGIC 42 +#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 VTTBR_X_TGRAN_MAGIC 37 +#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_FLAGS (VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN) +/* + * 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 | + * ------------------------------------------ + * + * That table roughly translates to : + * + * SL0(PAGE_SIZE, Entry_level) = SL0_BASE(PAGE_SIZE) - Entry_Level + * + * Where SL0_BASE(4K) = 2 and SL0_BASE(16K) = 3, SL0_BASE(64K) = 3, provided + * we take care of ruling out the unsupported cases and + * Entry_Level = 4 - Number_of_levels. + * + */ +#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) /* * 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 e0c49377b771..d9b7a00993b6 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -167,6 +167,7 @@ int kvm_arm_config_vm(struct kvm *kvm, unsigned long type) vtcr |= (kvm_get_vmid_bits() == 16) ? VTCR_EL2_VS_16BIT : VTCR_EL2_VS_8BIT; + vtcr |= VTCR_EL2_LVLS_TO_SL0(kvm_stage2_levels(kvm)); kvm->arch.vtcr = vtcr; return 0; } -- 2.19.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
