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Commit 688c50aa authored by Christoffer Dall's avatar Christoffer Dall Committed by Christoffer Dall
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KVM: arm/arm64: Move timer save/restore out of the hyp code 



As we are about to be lazy with saving and restoring the timer
registers, we prepare by moving all possible timer configuration logic
out of the hyp code.  All virtual timer registers can be programmed from
EL1 and since the arch timer is always a level triggered interrupt we
can safely do this with interrupts disabled in the host kernel on the
way to the guest without taking vtimer interrupts in the host kernel
(yet).

The downside is that the cntvoff register can only be programmed from
hyp mode, so we jump into hyp mode and back to program it.  This is also
safe, because the host kernel doesn't use the virtual timer in the KVM
code.  It may add a little performance performance penalty, but only
until following commits where we move this operation to vcpu load/put.

Signed-off-by: default avatarChristoffer Dall <cdall@linaro.org>
Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent f2a2129e

arch/arm/include/asm/kvm_asm.h

+2 −0
Original line number Diff line number Diff line
@@ -68,6 +68,8 @@ extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa); 
extern void __kvm_tlb_flush_vmid(struct kvm *kvm);

extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);



extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);



extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);



extern void __init_stage2_translation(void);

arch/arm/include/asm/kvm_hyp.h

+2 −2
Original line number Diff line number Diff line
@@ -98,8 +98,8 @@ 
#define cntvoff_el2			CNTVOFF

#define cnthctl_el2			CNTHCTL



void __timer_save_state(struct kvm_vcpu *vcpu);

void __timer_restore_state(struct kvm_vcpu *vcpu);

void __timer_enable_traps(struct kvm_vcpu *vcpu);

void __timer_disable_traps(struct kvm_vcpu *vcpu);



void __vgic_v2_save_state(struct kvm_vcpu *vcpu);

void __vgic_v2_restore_state(struct kvm_vcpu *vcpu);

arch/arm/kvm/hyp/switch.c

+4 −3
Original line number Diff line number Diff line
@@ -174,7 +174,7 @@ int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu) 
	__activate_vm(vcpu);



	__vgic_restore_state(vcpu);

	__timer_restore_state(vcpu);

	__timer_enable_traps(vcpu);



	__sysreg_restore_state(guest_ctxt);

	__banked_restore_state(guest_ctxt);
@@ -191,7 +191,8 @@ int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu) 


	__banked_save_state(guest_ctxt);

	__sysreg_save_state(guest_ctxt);

	__timer_save_state(vcpu);

	__timer_disable_traps(vcpu);



	__vgic_save_state(vcpu);



	__deactivate_traps(vcpu);
@@ -237,7 +238,7 @@ void __hyp_text __noreturn __hyp_panic(int cause) 


		vcpu = (struct kvm_vcpu *)read_sysreg(HTPIDR);

		host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);

		__timer_save_state(vcpu);

		__timer_disable_traps(vcpu);

		__deactivate_traps(vcpu);

		__deactivate_vm(vcpu);

		__banked_restore_state(host_ctxt);

arch/arm64/include/asm/kvm_asm.h

+2 −0
Original line number Diff line number Diff line
@@ -55,6 +55,8 @@ extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa); 
extern void __kvm_tlb_flush_vmid(struct kvm *kvm);

extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);



extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);



extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);



extern u64 __vgic_v3_get_ich_vtr_el2(void);

arch/arm64/include/asm/kvm_hyp.h

+2 −2
Original line number Diff line number Diff line
@@ -129,8 +129,8 @@ void __vgic_v3_save_state(struct kvm_vcpu *vcpu); 
void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);

int __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu);



void __timer_save_state(struct kvm_vcpu *vcpu);

void __timer_restore_state(struct kvm_vcpu *vcpu);

void __timer_enable_traps(struct kvm_vcpu *vcpu);

void __timer_disable_traps(struct kvm_vcpu *vcpu);



void __sysreg_save_host_state(struct kvm_cpu_context *ctxt);

void __sysreg_restore_host_state(struct kvm_cpu_context *ctxt);