From 3f1e07275341c691e0901ed7030f4980b9b517c2 Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Wed, 12 Mar 2025 13:39:50 -0700 Subject: [PATCH] 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: Sebastian Ott Link: https://lore.kernel.org/kvmarm/20250306184013.30008-1-sebott@redhat.com/ Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 1a18a0324d9f..a3f4599920d0 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -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 |