Commit b86fc215 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Handle counter access early in non-HYP context 



We already deal with CNTPCT_EL0 accesses in non-HYP context.
Let's add CNTVCT_EL0 as a good measure.

This is also an opportunity to simplify things and make it
plain that this code is only for non-HYP context handling.

Acked-by: default avatarOliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241217142321.763801-8-maz@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 9b3b2f00

arch/arm64/kvm/hyp/include/hyp/switch.h

+21 −13
Original line number Diff line number Diff line
@@ -506,7 +506,7 @@ static inline u64 compute_counter_value(struct arch_timer_context *ctxt) 
	return arch_timer_read_cntpct_el0() - timer_get_offset(ctxt);

}



static bool kvm_hyp_handle_cntpct(struct kvm_vcpu *vcpu)

static bool kvm_handle_cntxct(struct kvm_vcpu *vcpu)

{

	struct arch_timer_context *ctxt;

	u32 sysreg;
@@ -516,18 +516,19 @@ static bool kvm_hyp_handle_cntpct(struct kvm_vcpu *vcpu) 
	 * We only get here for 64bit guests, 32bit guests will hit

	 * the long and winding road all the way to the standard

	 * handling. Yes, it sucks to be irrelevant.

	 *

	 * Also, we only deal with non-hypervisor context here (either

	 * an EL1 guest, or a non-HYP context of an EL2 guest).

	 */

	if (is_hyp_ctxt(vcpu))

		return false;



	sysreg = esr_sys64_to_sysreg(kvm_vcpu_get_esr(vcpu));



	switch (sysreg) {

	case SYS_CNTPCT_EL0:

	case SYS_CNTPCTSS_EL0:

		if (vcpu_has_nv(vcpu)) {

			if (is_hyp_ctxt(vcpu)) {

				ctxt = vcpu_hptimer(vcpu);

				break;

			}



			/* Check for guest hypervisor trapping */

			val = __vcpu_sys_reg(vcpu, CNTHCTL_EL2);

			if (!vcpu_el2_e2h_is_set(vcpu))
@@ -539,16 +540,23 @@ static bool kvm_hyp_handle_cntpct(struct kvm_vcpu *vcpu) 


		ctxt = vcpu_ptimer(vcpu);

		break;

	default:

	case SYS_CNTVCT_EL0:

	case SYS_CNTVCTSS_EL0:

		if (vcpu_has_nv(vcpu)) {

			/* Check for guest hypervisor trapping */

			val = __vcpu_sys_reg(vcpu, CNTHCTL_EL2);



			if (val & CNTHCTL_EL1TVCT)

				return false;

		}



	val = arch_timer_read_cntpct_el0();

		ctxt = vcpu_vtimer(vcpu);

		break;

	default:

		return false;

	}



	if (ctxt->offset.vm_offset)

		val -= *kern_hyp_va(ctxt->offset.vm_offset);

	if (ctxt->offset.vcpu_offset)

		val -= *kern_hyp_va(ctxt->offset.vcpu_offset);

	val = compute_counter_value(ctxt);



	vcpu_set_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu), val);

	__kvm_skip_instr(vcpu);
@@ -593,7 +601,7 @@ static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code) 
	    __vgic_v3_perform_cpuif_access(vcpu) == 1)

		return true;



	if (kvm_hyp_handle_cntpct(vcpu))

	if (kvm_handle_cntxct(vcpu))

		return true;



	return false;