Commit f9ea835e authored by Reiji Watanabe's avatar Reiji Watanabe Committed by Oliver Upton
Browse files

KVM: arm64: PMU: Restore the guest's EL0 event counting after migration 



Currently, with VHE, KVM enables the EL0 event counting for the
guest on vcpu_load() or KVM enables it as a part of the PMU
register emulation process, when needed.  However, in the migration
case (with VHE), the same handling is lacking, as vPMU register
values that were restored by userspace haven't been propagated yet
(the PMU events haven't been created) at the vcpu load-time on the
first KVM_RUN (kvm_vcpu_pmu_restore_guest() called from vcpu_load()
on the first KVM_RUN won't do anything as events_{guest,host} of
kvm_pmu_events are still zero).

So, with VHE, enable the guest's EL0 event counting on the first
KVM_RUN (after the migration) when needed.  More specifically,
have kvm_pmu_handle_pmcr() call kvm_vcpu_pmu_restore_guest()
so that kvm_pmu_handle_pmcr() on the first KVM_RUN can take
care of it.

Fixes: d0c94c49 ("KVM: arm64: Restore PMU configuration on first run")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarReiji Watanabe <reijiw@google.com>
Link: https://lore.kernel.org/r/20230329023944.2488484-1-reijiw@google.com


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 8c2e8ac8

arch/arm64/kvm/pmu-emul.c

+1 −0
Original line number Diff line number Diff line
@@ -558,6 +558,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) 
		for_each_set_bit(i, &mask, 32)

			kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, i), 0, true);

	}

	kvm_vcpu_pmu_restore_guest(vcpu);

}



static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)

arch/arm64/kvm/sys_regs.c

+0 −1
Original line number Diff line number Diff line
@@ -794,7 +794,6 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, 
		if (!kvm_supports_32bit_el0())

			val |= ARMV8_PMU_PMCR_LC;

		kvm_pmu_handle_pmcr(vcpu, val);

		kvm_vcpu_pmu_restore_guest(vcpu);

	} else {

		/* PMCR.P & PMCR.C are RAZ */

		val = __vcpu_sys_reg(vcpu, PMCR_EL0)