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KVM: arm64: Introduce VHE-specific kvm_vcpu_run

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So far this is mostly (see below) a copy of the legacy non-VHE switch
function, but we will start reworking these functions in separate
directions to work on VHE and non-VHE in the most optimal way in later
patches.

The only difference after this patch between the VHE and non-VHE run
functions is that we omit the branch-predictor variant-2 hardening for
QC Falkor CPUs, because this workaround is specific to a series of
non-VHE ARMv8.0 CPUs.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Christoffer Dall 2017-10-03 14:02:12 +02:00 committed by Marc Zyngier
parent dc251406bf
commit 3f5c90b890
6 changed files with 87 additions and 9 deletions
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5
arch/arm/include/asm/kvm_asm.h
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@ -70,7 +70,10 @@ 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);
/* no VHE on 32-bit :( */
static inline int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) { BUG(); return 0; }
extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
extern void __init_stage2_translation(void);

2
arch/arm/kvm/hyp/switch.c
View File

@ -154,7 +154,7 @@ static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
return true;
}
int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;

4
arch/arm64/include/asm/kvm_asm.h
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@ -58,7 +58,9 @@ 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 int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu);
extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
extern u64 __vgic_v3_get_ich_vtr_el2(void);
extern u64 __vgic_v3_read_vmcr(void);

7
arch/arm64/include/asm/kvm_host.h
View File

@ -428,6 +428,13 @@ static inline void kvm_arm_vhe_guest_enter(void)
static inline void kvm_arm_vhe_guest_exit(void)
{
local_daif_restore(DAIF_PROCCTX_NOIRQ);
/*
* When we exit from the guest we change a number of CPU configuration
* parameters, such as traps. Make sure these changes take effect
* before running the host or additional guests.
*/
isb();
}
static inline bool kvm_arm_harden_branch_predictor(void)

66
arch/arm64/kvm/hyp/switch.c
View File

@ -362,7 +362,71 @@ static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
return false;
}
int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
/* Switch to the guest for VHE systems running in EL2 */
int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
bool fp_enabled;
u64 exit_code;
vcpu = kern_hyp_va(vcpu);
host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
host_ctxt->__hyp_running_vcpu = vcpu;
guest_ctxt = &vcpu->arch.ctxt;
__sysreg_save_host_state(host_ctxt);
__activate_traps(vcpu);
__activate_vm(vcpu);
__vgic_restore_state(vcpu);
__timer_enable_traps(vcpu);
/*
* We must restore the 32-bit state before the sysregs, thanks
* to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
*/
__sysreg32_restore_state(vcpu);
__sysreg_restore_guest_state(guest_ctxt);
__debug_switch_to_guest(vcpu);
do {
/* Jump in the fire! */
exit_code = __guest_enter(vcpu, host_ctxt);
/* And we're baaack! */
} while (fixup_guest_exit(vcpu, &exit_code));
fp_enabled = __fpsimd_enabled();
__sysreg_save_guest_state(guest_ctxt);
__sysreg32_save_state(vcpu);
__timer_disable_traps(vcpu);
__vgic_save_state(vcpu);
__deactivate_traps(vcpu);
__deactivate_vm(vcpu);
__sysreg_restore_host_state(host_ctxt);
if (fp_enabled) {
__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
}
/*
* This must come after restoring the host sysregs, since a non-VHE
* system may enable SPE here and make use of the TTBRs.
*/
__debug_switch_to_host(vcpu);
return exit_code;
}
/* Switch to the guest for legacy non-VHE systems */
int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;

12
virt/kvm/arm/arm.c
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@ -733,13 +733,15 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
*/
trace_kvm_entry(*vcpu_pc(vcpu));
guest_enter_irqoff();
if (has_vhe())
if (has_vhe()) {
kvm_arm_vhe_guest_enter();
ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
if (has_vhe())
ret = kvm_vcpu_run_vhe(vcpu);
kvm_arm_vhe_guest_exit();
} else {
ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
}
vcpu->mode = OUTSIDE_GUEST_MODE;
vcpu->stat.exits++;
/*