diff options
Diffstat (limited to 'arch/arm64/kvm/hyp/vhe/switch.c')
| -rw-r--r-- | arch/arm64/kvm/hyp/vhe/switch.c | 151 |
1 files changed, 56 insertions, 95 deletions
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 731a0378ed13..477f1580ffea 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -48,102 +48,46 @@ DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); static u64 __compute_hcr(struct kvm_vcpu *vcpu) { + u64 guest_hcr = __vcpu_sys_reg(vcpu, HCR_EL2); u64 hcr = vcpu->arch.hcr_el2; if (!vcpu_has_nv(vcpu)) return hcr; + /* + * We rely on the invariant that a vcpu entered from HYP + * context must also exit in the same context, as only an ERET + * instruction can kick us out of it, and we obviously trap + * that sucker. PSTATE.M will get fixed-up on exit. + */ if (is_hyp_ctxt(vcpu)) { + host_data_set_flag(VCPU_IN_HYP_CONTEXT); + hcr |= HCR_NV | HCR_NV2 | HCR_AT | HCR_TTLB; if (!vcpu_el2_e2h_is_set(vcpu)) hcr |= HCR_NV1; write_sysreg_s(vcpu->arch.ctxt.vncr_array, SYS_VNCR_EL2); - } - - return hcr | (__vcpu_sys_reg(vcpu, HCR_EL2) & ~NV_HCR_GUEST_EXCLUDE); -} - -static void __activate_cptr_traps(struct kvm_vcpu *vcpu) -{ - u64 cptr; - - /* - * With VHE (HCR.E2H == 1), accesses to CPACR_EL1 are routed to - * CPTR_EL2. In general, CPACR_EL1 has the same layout as CPTR_EL2, - * except for some missing controls, such as TAM. - * In this case, CPTR_EL2.TAM has the same position with or without - * VHE (HCR.E2H == 1) which allows us to use here the CPTR_EL2.TAM - * shift value for trapping the AMU accesses. - */ - u64 val = CPACR_EL1_TTA | CPTR_EL2_TAM; - - if (guest_owns_fp_regs()) { - val |= CPACR_EL1_FPEN; - if (vcpu_has_sve(vcpu)) - val |= CPACR_EL1_ZEN; } else { - __activate_traps_fpsimd32(vcpu); - } - - if (!vcpu_has_nv(vcpu)) - goto write; - - /* - * The architecture is a bit crap (what a surprise): an EL2 guest - * writing to CPTR_EL2 via CPACR_EL1 can't set any of TCPAC or TTA, - * as they are RES0 in the guest's view. To work around it, trap the - * sucker using the very same bit it can't set... - */ - if (vcpu_el2_e2h_is_set(vcpu) && is_hyp_ctxt(vcpu)) - val |= CPTR_EL2_TCPAC; - - /* - * Layer the guest hypervisor's trap configuration on top of our own if - * we're in a nested context. - */ - if (is_hyp_ctxt(vcpu)) - goto write; - - cptr = vcpu_sanitised_cptr_el2(vcpu); - - /* - * Pay attention, there's some interesting detail here. - * - * The CPTR_EL2.xEN fields are 2 bits wide, although there are only two - * meaningful trap states when HCR_EL2.TGE = 0 (running a nested guest): - * - * - CPTR_EL2.xEN = x0, traps are enabled - * - CPTR_EL2.xEN = x1, traps are disabled - * - * In other words, bit[0] determines if guest accesses trap or not. In - * the interest of simplicity, clear the entire field if the guest - * hypervisor has traps enabled to dispel any illusion of something more - * complicated taking place. - */ - if (!(SYS_FIELD_GET(CPACR_EL1, FPEN, cptr) & BIT(0))) - val &= ~CPACR_EL1_FPEN; - if (!(SYS_FIELD_GET(CPACR_EL1, ZEN, cptr) & BIT(0))) - val &= ~CPACR_EL1_ZEN; + host_data_clear_flag(VCPU_IN_HYP_CONTEXT); - if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR3_EL1, S2POE, IMP)) - val |= cptr & CPACR_EL1_E0POE; + if (guest_hcr & HCR_NV) { + u64 va = __fix_to_virt(vncr_fixmap(smp_processor_id())); - val |= cptr & CPTR_EL2_TCPAC; + /* Inherit the low bits from the actual register */ + va |= __vcpu_sys_reg(vcpu, VNCR_EL2) & GENMASK(PAGE_SHIFT - 1, 0); + write_sysreg_s(va, SYS_VNCR_EL2); -write: - write_sysreg(val, cpacr_el1); -} - -static void __deactivate_cptr_traps(struct kvm_vcpu *vcpu) -{ - u64 val = CPACR_EL1_FPEN | CPACR_EL1_ZEN_EL1EN; + /* Force NV2 in case the guest is forgetful... */ + guest_hcr |= HCR_NV2; + } + } - if (cpus_have_final_cap(ARM64_SME)) - val |= CPACR_EL1_SMEN_EL1EN; + BUG_ON(host_data_test_flag(VCPU_IN_HYP_CONTEXT) && + host_data_test_flag(L1_VNCR_MAPPED)); - write_sysreg(val, cpacr_el1); + return hcr | (guest_hcr & ~NV_HCR_GUEST_EXCLUDE); } static void __activate_traps(struct kvm_vcpu *vcpu) @@ -184,7 +128,7 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu) ___deactivate_traps(vcpu); - write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); + write_sysreg_hcr(HCR_HOST_VHE_FLAGS); if (has_cntpoff()) { struct timer_map map; @@ -198,9 +142,9 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu) */ val = read_sysreg_el0(SYS_CNTP_CVAL); if (map.direct_ptimer == vcpu_ptimer(vcpu)) - __vcpu_sys_reg(vcpu, CNTP_CVAL_EL0) = val; + __vcpu_assign_sys_reg(vcpu, CNTP_CVAL_EL0, val); if (map.direct_ptimer == vcpu_hptimer(vcpu)) - __vcpu_sys_reg(vcpu, CNTHP_CVAL_EL2) = val; + __vcpu_assign_sys_reg(vcpu, CNTHP_CVAL_EL2, val); offset = read_sysreg_s(SYS_CNTPOFF_EL2); @@ -459,6 +403,14 @@ static bool kvm_hyp_handle_tlbi_el2(struct kvm_vcpu *vcpu, u64 *exit_code) if (ret) return false; + /* + * If we have to check for any VNCR mapping being invalidated, + * go back to the slow path for further processing. + */ + if (vcpu_el2_e2h_is_set(vcpu) && vcpu_el2_tge_is_set(vcpu) && + atomic_read(&vcpu->kvm->arch.vncr_map_count)) + return false; + __kvm_skip_instr(vcpu); return true; @@ -568,9 +520,12 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) /* * If we were in HYP context on entry, adjust the PSTATE view - * so that the usual helpers work correctly. + * so that the usual helpers work correctly. This enforces our + * invariant that the guest's HYP context status is preserved + * across a run. */ - if (vcpu_has_nv(vcpu) && (read_sysreg(hcr_el2) & HCR_NV)) { + if (vcpu_has_nv(vcpu) && + unlikely(host_data_test_flag(VCPU_IN_HYP_CONTEXT))) { u64 mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT); switch (mode) { @@ -586,6 +541,10 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) *vcpu_cpsr(vcpu) |= mode; } + /* Apply extreme paranoia! */ + BUG_ON(vcpu_has_nv(vcpu) && + !!host_data_test_flag(VCPU_IN_HYP_CONTEXT) != is_hyp_ctxt(vcpu)); + return __fixup_guest_exit(vcpu, exit_code, hyp_exit_handlers); } @@ -599,10 +558,10 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) host_ctxt = host_data_ptr(host_ctxt); guest_ctxt = &vcpu->arch.ctxt; - sysreg_save_host_state_vhe(host_ctxt); - fpsimd_lazy_switch_to_guest(vcpu); + sysreg_save_host_state_vhe(host_ctxt); + /* * Note that ARM erratum 1165522 requires us to configure both stage 1 * and stage 2 translation for the guest context before we clear @@ -627,15 +586,23 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) __deactivate_traps(vcpu); - fpsimd_lazy_switch_to_host(vcpu); - sysreg_restore_host_state_vhe(host_ctxt); + __debug_switch_to_host(vcpu); + + /* + * Ensure that all system register writes above have taken effect + * before returning to the host. In VHE mode, CPTR traps for + * FPSIMD/SVE/SME also apply to EL2, so FPSIMD/SVE/SME state must be + * manipulated after the ISB. + */ + isb(); + + fpsimd_lazy_switch_to_host(vcpu); + if (guest_owns_fp_regs()) __fpsimd_save_fpexc32(vcpu); - __debug_switch_to_host(vcpu); - return exit_code; } NOKPROBE_SYMBOL(__kvm_vcpu_run_vhe); @@ -665,12 +632,6 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu) */ local_daif_restore(DAIF_PROCCTX_NOIRQ); - /* - * When we exit from the guest we change a number of CPU configuration - * parameters, such as traps. We rely on the isb() in kvm_call_hyp*() - * to make sure these changes take effect before running the host or - * additional guests. - */ return ret; } |