Commit 07da1ffa authored by Marc Zyngier's avatar Marc Zyngier
Browse files

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: default avatarAndrew Scull <ascull@google.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarAndrew Scull <ascull@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent b990d37f

arch/arm64/include/asm/kvm_host.h

+0 −3
Original line number Diff line number Diff line
@@ -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 */

arch/arm64/kvm/arm.c

+0 −3
Original line number Diff line number Diff line
@@ -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);

arch/arm64/kvm/hyp/debug-sr.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

arch/arm64/kvm/hyp/switch.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

arch/arm64/kvm/hyp/sysreg-sr.c

+4 −2
Original line number Diff line number Diff line
@@ -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);

CRA Git | Maintained and supported by SUSTech CRA and CCSE