diff options
| author | Marc Zyngier <maz@kernel.org> | 2025-02-20 13:48:55 +0000 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2025-02-24 11:06:55 -0800 |
| commit | 9d6745572899599966fb76a868acca1cae9518af (patch) | |
| tree | bfd600d778da516c12e1cfa4f2100d01862b15df | |
| parent | 88aea41b9bc5f6cb325396c3311f581c5a1aad65 (diff) | |
KVM: arm64: Hide ID_AA64MMFR2_EL1.NV from guest and userspace
Since our take on FEAT_NV is to only support FEAT_NV2, we should
never expose ID_AA64MMFR2_EL1.NV to a guest nor userspace.
Make sure we mask this field for good.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250220134907.554085-3-maz@kernel.org
[oliver: squash diff for NV field]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 82430c1e1dd0..4f675f4ae536 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1627,6 +1627,7 @@ static u64 __kvm_read_sanitised_id_reg(const struct kvm_vcpu *vcpu, break; case SYS_ID_AA64MMFR2_EL1: val &= ~ID_AA64MMFR2_EL1_CCIDX_MASK; + val &= ~ID_AA64MMFR2_EL1_NV; break; case SYS_ID_AA64MMFR3_EL1: val &= ID_AA64MMFR3_EL1_TCRX | ID_AA64MMFR3_EL1_S1POE | @@ -1945,6 +1946,22 @@ static int set_id_aa64pfr1_el1(struct kvm_vcpu *vcpu, return set_id_reg(vcpu, rd, user_val); } +static int set_id_aa64mmfr2_el1(struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd, u64 user_val) +{ + u64 hw_val = read_sanitised_ftr_reg(SYS_ID_AA64MMFR2_EL1); + u64 nv_mask = ID_AA64MMFR2_EL1_NV_MASK; + + /* + * We made the mistake to expose the now deprecated NV field, + * so allow userspace to write it, but silently ignore it. + */ + if ((hw_val & nv_mask) == (user_val & nv_mask)) + user_val &= ~nv_mask; + + return set_id_reg(vcpu, rd, user_val); +} + static int set_ctr_el0(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 user_val) { @@ -2671,7 +2688,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { ID_AA64MMFR1_EL1_XNX | ID_AA64MMFR1_EL1_VH | ID_AA64MMFR1_EL1_VMIDBits)), - ID_WRITABLE(ID_AA64MMFR2_EL1, ~(ID_AA64MMFR2_EL1_RES0 | + ID_FILTERED(ID_AA64MMFR2_EL1, + id_aa64mmfr2_el1, ~(ID_AA64MMFR2_EL1_RES0 | ID_AA64MMFR2_EL1_EVT | ID_AA64MMFR2_EL1_FWB | ID_AA64MMFR2_EL1_IDS | |