From 07da1ffaa1373f99331712faa67a00b5b807dfe8 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 5 Jun 2020 14:08:13 +0100 Subject: [PATCH] KVM: arm64: Remove host_cpu_context member from vcpu structure For very long, we have kept this pointer back to the per-cpu host state, despite having working per-cpu accessors at EL2 for some time now. Recent investigations have shown that this pointer is easy to abuse in preemptible context, which is a sure sign that it would better be gone. Not to mention that a per-cpu pointer is faster to access at all times. Reported-by: Andrew Scull Acked-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_host.h | 3 --- arch/arm64/kvm/arm.c | 3 --- arch/arm64/kvm/hyp/debug-sr.c | 4 ++-- arch/arm64/kvm/hyp/switch.c | 6 +++--- arch/arm64/kvm/hyp/sysreg-sr.c | 6 ++++-- arch/arm64/kvm/pmu.c | 8 ++------ 6 files changed, 11 insertions(+), 19 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 59029e9..ada1faa 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -284,9 +284,6 @@ struct kvm_vcpu_arch { struct kvm_guest_debug_arch vcpu_debug_state; struct kvm_guest_debug_arch external_debug_state; - /* Pointer to host CPU context */ - struct kvm_cpu_context *host_cpu_context; - struct thread_info *host_thread_info; /* hyp VA */ struct user_fpsimd_state *host_fpsimd_state; /* hyp VA */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 14b7472..6ddaa23e 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -340,10 +340,8 @@ void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { int *last_ran; - kvm_host_data_t *cpu_data; last_ran = this_cpu_ptr(vcpu->kvm->arch.last_vcpu_ran); - cpu_data = this_cpu_ptr(&kvm_host_data); /* * We might get preempted before the vCPU actually runs, but @@ -355,7 +353,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) } vcpu->cpu = cpu; - vcpu->arch.host_cpu_context = &cpu_data->host_ctxt; kvm_vgic_load(vcpu); kvm_timer_vcpu_load(vcpu); diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c index 0fc9872..e95af20 100644 --- a/arch/arm64/kvm/hyp/debug-sr.c +++ b/arch/arm64/kvm/hyp/debug-sr.c @@ -185,7 +185,7 @@ void __hyp_text __debug_switch_to_guest(struct kvm_vcpu *vcpu) if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)) return; - host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt; guest_ctxt = &vcpu->arch.ctxt; host_dbg = &vcpu->arch.host_debug_state.regs; guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr); @@ -207,7 +207,7 @@ void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu) if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)) return; - host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt; guest_ctxt = &vcpu->arch.ctxt; host_dbg = &vcpu->arch.host_debug_state.regs; guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr); diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index d60c2ef..1853c17 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -532,7 +532,7 @@ static bool __hyp_text __hyp_handle_ptrauth(struct kvm_vcpu *vcpu) !esr_is_ptrauth_trap(kvm_vcpu_get_hsr(vcpu))) return false; - ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt; __ptrauth_save_key(ctxt->sys_regs, APIA); __ptrauth_save_key(ctxt->sys_regs, APIB); __ptrauth_save_key(ctxt->sys_regs, APDA); @@ -703,7 +703,7 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) struct kvm_cpu_context *guest_ctxt; u64 exit_code; - host_ctxt = vcpu->arch.host_cpu_context; + host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt; host_ctxt->__hyp_running_vcpu = vcpu; guest_ctxt = &vcpu->arch.ctxt; @@ -808,7 +808,7 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) vcpu = kern_hyp_va(vcpu); - host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt; host_ctxt->__hyp_running_vcpu = vcpu; guest_ctxt = &vcpu->arch.ctxt; diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c index 6d2df9f..143d7b7 100644 --- a/arch/arm64/kvm/hyp/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/sysreg-sr.c @@ -265,12 +265,13 @@ void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu) */ void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) { - struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context; struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt; + struct kvm_cpu_context *host_ctxt; if (!has_vhe()) return; + host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt; __sysreg_save_user_state(host_ctxt); /* @@ -301,12 +302,13 @@ void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) */ void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) { - struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context; struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt; + struct kvm_cpu_context *host_ctxt; if (!has_vhe()) return; + host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt; deactivate_traps_vhe_put(); __sysreg_save_el1_state(guest_ctxt); diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c index e71d00b..b5ae3a5 100644 --- a/arch/arm64/kvm/pmu.c +++ b/arch/arm64/kvm/pmu.c @@ -163,15 +163,13 @@ static void kvm_vcpu_pmu_disable_el0(unsigned long events) */ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) { - struct kvm_cpu_context *host_ctxt; struct kvm_host_data *host; u32 events_guest, events_host; if (!has_vhe()) return; - host_ctxt = vcpu->arch.host_cpu_context; - host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); + host = this_cpu_ptr(&kvm_host_data); events_guest = host->pmu_events.events_guest; events_host = host->pmu_events.events_host; @@ -184,15 +182,13 @@ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) */ void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu) { - struct kvm_cpu_context *host_ctxt; struct kvm_host_data *host; u32 events_guest, events_host; if (!has_vhe()) return; - host_ctxt = vcpu->arch.host_cpu_context; - host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); + host = this_cpu_ptr(&kvm_host_data); events_guest = host->pmu_events.events_guest; events_host = host->pmu_events.events_host; -- 2.7.4