Commit 3f1e0727 authored by Sebastian Ott's avatar Sebastian Ott Committed by Oliver Upton
Browse files

KVM: arm64: Allow userspace to write ID_AA64MMFR0_EL1.TGRAN*_2 



Allow userspace to write the safe (NI) value for ID_AA64MMFR0_EL1.TGRAN*_2.
Disallow to change these fields for NV since kvm provides a sanitized view
for them based on the PAGE_SIZE.

Signed-off-by: default avatarSebastian Ott <sebott@redhat.com>
Link: https://lore.kernel.org/kvmarm/20250306184013.30008-1-sebott@redhat.com/


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 8b0b98eb

arch/arm64/kvm/sys_regs.c

+17 −4
Original line number Diff line number Diff line
@@ -1939,6 +1939,21 @@ static int set_id_aa64pfr1_el1(struct kvm_vcpu *vcpu, 
	return set_id_reg(vcpu, rd, user_val);

}



static int set_id_aa64mmfr0_el1(struct kvm_vcpu *vcpu,

				const struct sys_reg_desc *rd, u64 user_val)

{

	u64 sanitized_val = kvm_read_sanitised_id_reg(vcpu, rd);

	u64 tgran2_mask = ID_AA64MMFR0_EL1_TGRAN4_2_MASK |

			  ID_AA64MMFR0_EL1_TGRAN16_2_MASK |

			  ID_AA64MMFR0_EL1_TGRAN64_2_MASK;



	if (vcpu_has_nv(vcpu) &&

	    ((sanitized_val & tgran2_mask) != (user_val & tgran2_mask)))

		return -EINVAL;



	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)

{
@@ -2662,10 +2677,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { 
	ID_UNALLOCATED(6,7),



	/* CRm=7 */

	ID_WRITABLE(ID_AA64MMFR0_EL1, ~(ID_AA64MMFR0_EL1_RES0 |

					ID_AA64MMFR0_EL1_TGRAN4_2 |

					ID_AA64MMFR0_EL1_TGRAN64_2 |

					ID_AA64MMFR0_EL1_TGRAN16_2 |

	ID_FILTERED(ID_AA64MMFR0_EL1, id_aa64mmfr0_el1,

				      ~(ID_AA64MMFR0_EL1_RES0 |

					ID_AA64MMFR0_EL1_ASIDBITS)),

	ID_WRITABLE(ID_AA64MMFR1_EL1, ~(ID_AA64MMFR1_EL1_RES0 |

					ID_AA64MMFR1_EL1_HCX |