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

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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 <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Atish Patra 2023-02-07 01:55:24 -08:00 committed by Anup Patel
parent cbddc4c4cb
commit 470926a290
1 changed files with 8 additions and 0 deletions
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8
arch/riscv/kvm/vcpu_pmu.c
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@ -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;