Commit 470926a2 authored by Atish Patra's avatar Atish Patra Committed by Anup Patel
Browse files

RISC-V: KVM: Make PMU functionality depend on Sscofpmf 



The privilege mode filtering feature must be available in the host so
that the host can inhibit the counters while the execution is in HS mode.
Otherwise, the guests may have access to critical guest information.

Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Signed-off-by: default avatarAtish Patra <atishp@rivosinc.com>
Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent cbddc4c4

arch/riscv/kvm/vcpu_pmu.c

+8 −0
Original line number Diff line number Diff line
@@ -80,6 +80,14 @@ void kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu) 
	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);

	struct kvm_pmc *pmc;



	/*

	 * PMU functionality should be only available to guests if privilege mode

	 * filtering is available in the host. Otherwise, guest will always count

	 * events while the execution is in hypervisor mode.

	 */

	if (!riscv_isa_extension_available(NULL, SSCOFPMF))

		return;



	ret = riscv_pmu_get_hpm_info(&hpm_width, &num_hw_ctrs);

	if (ret < 0 || !hpm_width || !num_hw_ctrs)

		return;