return vgic_present ? kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS;
}
+static void set_default_csv2(struct kvm *kvm)
+{
+ /*
+ * The default is to expose CSV2 == 1 if the HW isn't affected.
+ * Although this is a per-CPU feature, we make it global because
+ * asymmetric systems are just a nuisance.
+ *
+ * Userspace can override this as long as it doesn't promise
+ * the impossible.
+ */
+ if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED)
+ kvm->arch.pfr0_csv2 = 1;
+}
+
/**
* kvm_arch_init_vm - initializes a VM data structure
* @kvm: pointer to the KVM struct
/* The maximum number of VCPUs is limited by the host's GIC model */
kvm->arch.max_vcpus = kvm_arm_default_max_vcpus();
+ set_default_csv2(kvm);
+
return ret;
out_free_stage2_pgd:
kvm_free_stage2_pgd(&kvm->arch.mmu);
if (!vcpu_has_sve(vcpu))
val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
val &= ~(0xfUL << ID_AA64PFR0_AMU_SHIFT);
- if (!(val & (0xfUL << ID_AA64PFR0_CSV2_SHIFT)) &&
- arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED)
- val |= (1UL << ID_AA64PFR0_CSV2_SHIFT);
+ val &= ~(0xfUL << ID_AA64PFR0_CSV2_SHIFT);
+ val |= ((u64)vcpu->kvm->arch.pfr0_csv2 << ID_AA64PFR0_CSV2_SHIFT);
} else if (id == SYS_ID_AA64PFR1_EL1) {
val &= ~(0xfUL << ID_AA64PFR1_MTE_SHIFT);
} else if (id == SYS_ID_AA64ISAR1_EL1 && !vcpu_has_ptrauth(vcpu)) {
return REG_HIDDEN;
}
+static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ const struct kvm_one_reg *reg, void __user *uaddr)
+{
+ const u64 id = sys_reg_to_index(rd);
+ int err;
+ u64 val;
+ u8 csv2;
+
+ err = reg_from_user(&val, uaddr, id);
+ if (err)
+ return err;
+
+ /*
+ * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
+ * it doesn't promise more than what is actually provided (the
+ * guest could otherwise be covered in ectoplasmic residue).
+ */
+ csv2 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_CSV2_SHIFT);
+ if (csv2 > 1 ||
+ (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
+ return -EINVAL;
+
+ /* We can only differ with CSV2, and anything else is an error */
+ val ^= read_id_reg(vcpu, rd, false);
+ val &= ~(0xFUL << ID_AA64PFR0_CSV2_SHIFT);
+ if (val)
+ return -EINVAL;
+
+ vcpu->kvm->arch.pfr0_csv2 = csv2;
+
+ return 0;
+}
+
/*
* cpufeature ID register user accessors
*
/* AArch64 ID registers */
/* CRm=4 */
- ID_SANITISED(ID_AA64PFR0_EL1),
+ { SYS_DESC(SYS_ID_AA64PFR0_EL1), .access = access_id_reg,
+ .get_user = get_id_reg, .set_user = set_id_aa64pfr0_el1, },
ID_SANITISED(ID_AA64PFR1_EL1),
ID_UNALLOCATED(4,2),
ID_UNALLOCATED(4,3),