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| author | Ionela Voinescu <ionela.voinescu@arm.com> | 2020-03-05 09:06:23 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-03-06 16:02:50 +0000 |
| commit | 4fcdf106a4330bb5c2306a1efbb3af3b7c0db537 (patch) | |
| tree | f5e42cdd03427f310935e3e1b3378f8263a9d969 /arch/arm64/kvm/hyp/switch.c | |
| parent | 87a1f063464afd934f0f22aac710ca65bef77af3 (diff) | |
| download | linux-4fcdf106a4330bb5c2306a1efbb3af3b7c0db537.tar.bz2 | |
arm64/kvm: disable access to AMU registers from kvm guests
Access to the AMU counters should be disabled by default in kvm guests,
as information from the counters might reveal activity in other guests
or activity on the host.
Therefore, disable access to AMU registers from EL0 and EL1 in kvm
guests by:
- Hiding the presence of the extension in the feature register
(SYS_ID_AA64PFR0_EL1) on the VCPU.
- Disabling access to the AMU registers before switching to the guest.
- Trapping accesses and injecting an undefined instruction into the
guest.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kvm/hyp/switch.c')
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index dfe8dd172512..46292a370781 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -98,6 +98,18 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu) val = read_sysreg(cpacr_el1); val |= CPACR_EL1_TTA; val &= ~CPACR_EL1_ZEN; + + /* + * With VHE (HCR.E2H == 1), accesses to CPACR_EL1 are routed to + * CPTR_EL2. In general, CPACR_EL1 has the same layout as CPTR_EL2, + * except for some missing controls, such as TAM. + * In this case, CPTR_EL2.TAM has the same position with or without + * VHE (HCR.E2H == 1) which allows us to use here the CPTR_EL2.TAM + * shift value for trapping the AMU accesses. + */ + + val |= CPTR_EL2_TAM; + if (update_fp_enabled(vcpu)) { if (vcpu_has_sve(vcpu)) val |= CPACR_EL1_ZEN; @@ -119,7 +131,7 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) __activate_traps_common(vcpu); val = CPTR_EL2_DEFAULT; - val |= CPTR_EL2_TTA | CPTR_EL2_TZ; + val |= CPTR_EL2_TTA | CPTR_EL2_TZ | CPTR_EL2_TAM; if (!update_fp_enabled(vcpu)) { val |= CPTR_EL2_TFP; __activate_traps_fpsimd32(vcpu); |