diff options
| -rw-r--r-- | arch/arm64/kvm/nested.c | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 25 |
2 files changed, 25 insertions, 1 deletions
diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index 53c57d105c93..4044dc66fa39 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -1582,7 +1582,6 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val) ID_AA64DFR0_EL1_MTPMU | ID_AA64DFR0_EL1_TraceBuffer | ID_AA64DFR0_EL1_TraceFilt | - ID_AA64DFR0_EL1_DoubleLock | ID_AA64DFR0_EL1_PMSVer | ID_AA64DFR0_EL1_CTX_CMPs | ID_AA64DFR0_EL1_SEBEP | diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index e6ec971eb9d1..caf80c324b35 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1997,6 +1997,26 @@ static u64 sanitise_id_aa64dfr0_el1(const struct kvm_vcpu *vcpu, u64 val) return val; } +/* + * Older versions of KVM erroneously claim support for FEAT_DoubleLock with + * NV-enabled VMs on unsupporting hardware. Silently ignore the incorrect + * value if it is consistent with the bug. + */ +static bool ignore_feat_doublelock(struct kvm_vcpu *vcpu, u64 val) +{ + u8 host, user; + + if (!vcpu_has_nv(vcpu)) + return false; + + host = SYS_FIELD_GET(ID_AA64DFR0_EL1, DoubleLock, + read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1)); + user = SYS_FIELD_GET(ID_AA64DFR0_EL1, DoubleLock, val); + + return host == ID_AA64DFR0_EL1_DoubleLock_NI && + user == ID_AA64DFR0_EL1_DoubleLock_IMP; +} + static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 val) @@ -2028,6 +2048,11 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, if (debugver < ID_AA64DFR0_EL1_DebugVer_IMP) return -EINVAL; + if (ignore_feat_doublelock(vcpu, val)) { + val &= ~ID_AA64DFR0_EL1_DoubleLock; + val |= SYS_FIELD_PREP_ENUM(ID_AA64DFR0_EL1, DoubleLock, NI); + } + return set_id_reg(vcpu, rd, val); } |