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arm64: KVM: Implement the core world switch

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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@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier 2015-10-21 09:57:10 +01:00
parent c1bf6e18e9
commit be901e9b15
2 changed files with 136 additions and 0 deletions
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1
arch/arm64/kvm/hyp/Makefile
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@ -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

135
arch/arm64/kvm/hyp/switch.c Normal file
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@ -0,0 +1,135 @@
/*
* Copyright (C) 2015 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* 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);
/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
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;
}