In order to be able to make S2 TLB invalidations more performant on NV, let's use a scheme derived from the ARMv8.4 TTL extension. If bits [56:55] in the descriptor are non-zero, they indicate a level which can be used as an invalidation range. Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> --- arch/arm64/include/asm/kvm_nested.h | 4 ++ arch/arm64/kvm/nested.c | 98 +++++++++++++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 13 ++-- 3 files changed, 110 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h index 7c47ad655e2e..34499c496ae6 100644 --- a/arch/arm64/include/asm/kvm_nested.h +++ b/arch/arm64/include/asm/kvm_nested.h @@ -123,6 +123,8 @@ extern bool __forward_traps(struct kvm_vcpu *vcpu, unsigned int reg, u64 control_bit); extern bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit); extern bool forward_nv_traps(struct kvm_vcpu *vcpu); +u8 get_guest_mapping_ttl(struct kvm_vcpu *vcpu, struct kvm_s2_mmu *mmu, + u64 addr); unsigned int ttl_to_size(u8 ttl); struct sys_reg_params; @@ -131,4 +133,6 @@ struct sys_reg_desc; void access_nested_id_reg(struct kvm_vcpu *v, struct sys_reg_params *p, const struct sys_reg_desc *r); +#define KVM_NV_GUEST_MAP_SZ GENMASK_ULL(56, 55) + #endif /* __ARM64_KVM_NESTED_H */ diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index 94d3011bcdd2..d48b37f034b8 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -16,6 +16,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/bitfield.h> #include <linux/kvm.h> #include <linux/kvm_host.h> @@ -351,6 +352,29 @@ int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, return ret; } +static int read_host_s2_desc(phys_addr_t pa, u64 *desc, void *data) +{ + u64 *va = phys_to_virt(pa); + + *desc = *va; + + return 0; +} + +static int kvm_walk_shadow_s2(struct kvm_s2_mmu *mmu, phys_addr_t gipa, + struct kvm_s2_trans *result) +{ + struct s2_walk_info wi = { }; + + wi.read_desc = read_host_s2_desc; + wi.baddr = mmu->pgd_phys; + + vtcr_to_walk_info(mmu->arch->vtcr, &wi); + + wi.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN); + + return walk_nested_s2_pgd(gipa, &wi, result); +} unsigned int ttl_to_size(u8 ttl) { @@ -408,6 +432,80 @@ unsigned int ttl_to_size(u8 ttl) return max_size; } +/* + * Compute the equivalent of the TTL field by parsing the shadow PT. + * The granule size is extracted from VTCR_EL2.TG0 while the level is + * retrieved from first entry carrying the level as a tag. + */ +u8 get_guest_mapping_ttl(struct kvm_vcpu *vcpu, struct kvm_s2_mmu *mmu, + u64 addr) +{ + u64 tmp, sz = 0, vtcr = vcpu_read_sys_reg(vcpu, VTCR_EL2); + struct kvm_s2_trans out; + u8 ttl, level; + + switch (vtcr & VTCR_EL2_TG0_MASK) { + case VTCR_EL2_TG0_4K: + ttl = (1 << 2); + break; + case VTCR_EL2_TG0_16K: + ttl = (2 << 2); + break; + case VTCR_EL2_TG0_64K: + ttl = (3 << 2); + break; + default: + BUG(); + } + + tmp = addr; + +again: + /* Iteratively compute the block sizes for a particular granule size */ + switch (vtcr & VTCR_EL2_TG0_MASK) { + case VTCR_EL2_TG0_4K: + if (sz < SZ_4K) sz = SZ_4K; + else if (sz < SZ_2M) sz = SZ_2M; + else if (sz < SZ_1G) sz = SZ_1G; + else sz = 0; + break; + case VTCR_EL2_TG0_16K: + if (sz < SZ_16K) sz = SZ_16K; + else if (sz < SZ_32M) sz = SZ_32M; + else sz = 0; + break; + case VTCR_EL2_TG0_64K: + if (sz < SZ_64K) sz = SZ_64K; + else if (sz < SZ_512M) sz = SZ_512M; + else sz = 0; + break; + default: + BUG(); + } + + if (sz == 0) + return 0; + + tmp &= ~(sz - 1); + out = (struct kvm_s2_trans) { }; + kvm_walk_shadow_s2(mmu, tmp, &out); + level = FIELD_GET(KVM_NV_GUEST_MAP_SZ, out.upper_attr); + if (!level) + goto again; + + ttl |= level; + + /* + * We now have found some level information in the shadow S2. Check + * that the resulting range is actually including the original IPA. + */ + sz = ttl_to_size(ttl); + if (addr < (tmp + sz)) + return ttl; + + return 0; +} + /* Must be called with kvm->lock held */ struct kvm_s2_mmu *lookup_s2_mmu(struct kvm *kvm, u64 vttbr, u64 hcr) { diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 4374962d43ff..4db1a9333afa 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2621,10 +2621,13 @@ static unsigned long compute_tlb_inval_range(struct kvm_vcpu *vcpu, u64 val) { unsigned long max_size; - u8 ttl = 0; + u8 ttl; - if (cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL)) { - ttl = FIELD_GET(GENMASK_ULL(47, 44), val); + ttl = FIELD_GET(GENMASK_ULL(47, 44), val); + + if (!(cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL) && ttl)) { + u64 addr = (val & GENMASK_ULL(35, 0)) << 12; + ttl = get_guest_mapping_ttl(vcpu, mmu, addr); } max_size = ttl_to_size(ttl); @@ -2665,6 +2668,8 @@ static bool handle_ipas2e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p, u64 base_addr; unsigned long max_size; + spin_lock(&vcpu->kvm->mmu_lock); + /* * We drop a number of things from the supplied value: * @@ -2676,8 +2681,6 @@ static bool handle_ipas2e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p, */ base_addr = (p->regval & GENMASK_ULL(35, 0)) << 12; - spin_lock(&vcpu->kvm->mmu_lock); - mmu = lookup_s2_mmu(vcpu->kvm, vttbr, HCR_VM); if (mmu) { max_size = compute_tlb_inval_range(vcpu, mmu, p->regval); -- 2.29.2 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
