From 470926a2900cfdc39b300d87a0ccdf037fa67b9a Mon Sep 17 00:00:00 2001 From: Atish Patra Date: Tue, 7 Feb 2023 01:55:24 -0800 Subject: [PATCH] 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: Anup Patel Reviewed-by: Andrew Jones Signed-off-by: Atish Patra Signed-off-by: Anup Patel --- arch/riscv/kvm/vcpu_pmu.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index dc3c118efb578..921340413846c 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -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; -- 2.30.2