Implement the core of the world switch in C. Not everything is there yet, and there is nothing to re-enter the world switch either. But this already outlines the code structure well enough. Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> --- arch/arm64/kvm/hyp/Makefile | 1 + arch/arm64/kvm/hyp/switch.c | 134 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 135 insertions(+) create mode 100644 arch/arm64/kvm/hyp/switch.c diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile index 1e1ff06..9c11b0f 100644 --- a/arch/arm64/kvm/hyp/Makefile +++ b/arch/arm64/kvm/hyp/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o obj-$(CONFIG_KVM_ARM_HOST) += entry.o +obj-$(CONFIG_KVM_ARM_HOST) += switch.o diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c new file mode 100644 index 0000000..d67ed9e --- /dev/null +++ b/arch/arm64/kvm/hyp/switch.c @@ -0,0 +1,134 @@ +/* + * Copyright (C) 2015 - ARM Ltd + * Author: Marc Zyngier <marc.zyngier@xxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include "hyp.h" + +static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) +{ + u64 val; + + /* + * We are about to set CPTR_EL2.TFP to trap all floating point + * register accesses to EL2, however, the ARM ARM clearly states that + * traps are only taken to EL2 if the operation would not otherwise + * trap to EL1. Therefore, always make sure that for 32-bit guests, + * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit. + */ + val = vcpu->arch.hcr_el2; + if (!(val & HCR_RW)) { + write_sysreg(1 << 30, fpexc32_el2); + isb(); + } + write_sysreg(val, hcr_el2); + write_sysreg(1 << 15, hstr_el2); + write_sysreg(CPTR_EL2_TTA | CPTR_EL2_TFP, cptr_el2); + write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); +} + +static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) +{ + write_sysreg(HCR_RW, hcr_el2); + write_sysreg(0, hstr_el2); + write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2); + write_sysreg(0, cptr_el2); +} + +static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu) +{ + struct kvm *kvm = kern_hyp_va(vcpu->kvm); + write_sysreg(kvm->arch.vttbr, vttbr_el2); +} + +static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu) +{ + write_sysreg(0, vttbr_el2); +} + +static hyp_alternate_select(__vgic_call_save_state, + __vgic_v2_save_state, __vgic_v3_save_state, + ARM64_HAS_SYSREG_GIC_CPUIF); + +static hyp_alternate_select(__vgic_call_restore_state, + __vgic_v2_restore_state, __vgic_v3_restore_state, + ARM64_HAS_SYSREG_GIC_CPUIF); + +static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu) +{ + __vgic_call_save_state()(vcpu); + write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2); +} + +static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu) +{ + u64 val; + + val = read_sysreg(hcr_el2); + val |= HCR_INT_OVERRIDE; + val |= vcpu->arch.irq_lines; + write_sysreg(val, hcr_el2); + + __vgic_call_restore_state()(vcpu); +} + +int __hyp_text __guest_run(struct kvm_vcpu *vcpu) +{ + struct kvm_cpu_context *host_ctxt; + struct kvm_cpu_context *guest_ctxt; + u64 exit_code; + + vcpu = kern_hyp_va(vcpu); + write_sysreg(vcpu, tpidr_el2); + + host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + guest_ctxt = &vcpu->arch.ctxt; + + __sysreg_save_state(host_ctxt); + __debug_cond_save_host_state(vcpu); + + __activate_traps(vcpu); + __activate_vm(vcpu); + + __vgic_restore_state(vcpu); + __timer_restore_state(vcpu); + + /* + * We must restore the 32-bit state before the sysregs, thanks + * to Cortex-A57 erratum #852523. + */ + __sysreg32_restore_state(vcpu); + __sysreg_restore_state(guest_ctxt); + __debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt); + + /* Jump in the fire! */ + exit_code = __guest_enter(vcpu, host_ctxt); + /* And we're baaack! */ + + __sysreg_save_state(guest_ctxt); + __sysreg32_save_state(vcpu); + __timer_save_state(vcpu); + __vgic_save_state(vcpu); + + __deactivate_traps(vcpu); + __deactivate_vm(vcpu); + + __sysreg_restore_state(host_ctxt); + + __debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt); + __debug_cond_restore_host_state(vcpu); + + return exit_code; +} -- 2.1.4 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
