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[2003:f6:af0e:4d00:dda5:3016:e366:575f]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4396b5267eesm85091845e9.0.2025.02.18.08.34.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Feb 2025 08:34:48 -0800 (PST) From: Sebastian Ott To: Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Shameer Kolothum Cc: Cornelia Huck , Eric Auger , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/4] KVM: arm64: Allow userspace to change AIDR_EL1 Date: Tue, 18 Feb 2025 17:34:42 +0100 Message-ID: <20250218163443.32836-4-sebott@redhat.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250218163443.32836-1-sebott@redhat.com> References: <20250218163443.32836-1-sebott@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Enable VMMs to write AIDR_EL1 by treating it as a VM ID register. Trap guest access of AIDR_EL1 when the VMs value differs from hardware. Since this was the last invariant register remove all the stuff that was needed to handle these. Signed-off-by: Sebastian Ott --- arch/arm64/include/asm/kvm_host.h | 3 ++ arch/arm64/kvm/sys_regs.c | 90 +++---------------------------- 2 files changed, 10 insertions(+), 83 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm= _host.h index c8fba4111b77..de735e2ad9ce 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -375,6 +375,7 @@ struct kvm_arch { =20 u64 midr_el1; u64 revidr_el1; + u64 aidr_el1; u64 ctr_el0; =20 /* Masks for VNCR-backed and general EL2 sysregs */ @@ -1475,6 +1476,8 @@ static inline u64 *__vm_id_reg(struct kvm_arch *ka, u= 32 reg) return &ka->midr_el1; case SYS_REVIDR_EL1: return &ka->revidr_el1; + case SYS_AIDR_EL1: + return &ka->aidr_el1; case SYS_CTR_EL0: return &ka->ctr_el0; default: diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c12fd91574ab..a1a683ba6bb9 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1667,7 +1667,7 @@ static bool is_feature_id_reg(u32 encoding) static inline bool is_vm_ftr_id_reg(u32 id) { if (id =3D=3D SYS_CTR_EL0 || id =3D=3D SYS_MIDR_EL1 || - id =3D=3D SYS_REVIDR_EL1) + id =3D=3D SYS_REVIDR_EL1 || id =3D=3D SYS_AIDR_EL1) return true; =20 return (sys_reg_Op0(id) =3D=3D 3 && sys_reg_Op1(id) =3D=3D 0 && @@ -2530,6 +2530,7 @@ static bool access_mdcr(struct kvm_vcpu *vcpu, =20 FUNCTION_RESET(midr_el1) FUNCTION_RESET(revidr_el1) +FUNCTION_RESET(aidr_el1) =20 =20 /* @@ -2856,6 +2857,8 @@ static const struct sys_reg_desc sys_reg_descs[] =3D { .set_user =3D set_clidr, .val =3D ~CLIDR_EL1_RES0 }, { SYS_DESC(SYS_CCSIDR2_EL1), undef_access }, { SYS_DESC(SYS_SMIDR_EL1), undef_access }, + { ID_DESC(AIDR_EL1), .set_user =3D set_id_reg_non_ftr, .visibility =3D id= _visibility, + .reset =3D reset_aidr_el1, .val =3D -1ULL }, { SYS_DESC(SYS_CSSELR_EL1), access_csselr, reset_unknown, CSSELR_EL1 }, ID_FILTERED(CTR_EL0, ctr_el0, CTR_EL0_DIC_MASK | @@ -4620,61 +4623,6 @@ id_to_sys_reg_desc(struct kvm_vcpu *vcpu, u64 id, return r; } =20 -/* - * These are the invariant sys_reg registers: we let the guest see the - * host versions of these, so they're part of the guest state. - * - * A future CPU may provide a mechanism to present different values to - * the guest, or a future kvm may trap them. - */ - -#define FUNCTION_INVARIANT(reg) \ - static u64 reset_##reg(struct kvm_vcpu *v, \ - const struct sys_reg_desc *r) \ - { \ - ((struct sys_reg_desc *)r)->val =3D read_sysreg(reg); \ - return ((struct sys_reg_desc *)r)->val; \ - } - -FUNCTION_INVARIANT(aidr_el1) - -/* ->val is filled in by kvm_sys_reg_table_init() */ -static struct sys_reg_desc invariant_sys_regs[] __ro_after_init =3D { - { SYS_DESC(SYS_AIDR_EL1), NULL, reset_aidr_el1 }, -}; - -static int get_invariant_sys_reg(u64 id, u64 __user *uaddr) -{ - const struct sys_reg_desc *r; - - r =3D get_reg_by_id(id, invariant_sys_regs, - ARRAY_SIZE(invariant_sys_regs)); - if (!r) - return -ENOENT; - - return put_user(r->val, uaddr); -} - -static int set_invariant_sys_reg(u64 id, u64 __user *uaddr) -{ - const struct sys_reg_desc *r; - u64 val; - - r =3D get_reg_by_id(id, invariant_sys_regs, - ARRAY_SIZE(invariant_sys_regs)); - if (!r) - return -ENOENT; - - if (get_user(val, uaddr)) - return -EFAULT; - - /* This is what we mean by invariant: you can't change it. */ - if (r->val !=3D val) - return -EINVAL; - - return 0; -} - static int demux_c15_get(struct kvm_vcpu *vcpu, u64 id, void __user *uaddr) { u32 val; @@ -4756,15 +4704,10 @@ int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, con= st struct kvm_one_reg *reg, int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_re= g *reg) { void __user *uaddr =3D (void __user *)(unsigned long)reg->addr; - int err; =20 if ((reg->id & KVM_REG_ARM_COPROC_MASK) =3D=3D KVM_REG_ARM_DEMUX) return demux_c15_get(vcpu, reg->id, uaddr); =20 - err =3D get_invariant_sys_reg(reg->id, uaddr); - if (err !=3D -ENOENT) - return err; - return kvm_sys_reg_get_user(vcpu, reg, sys_reg_descs, ARRAY_SIZE(sys_reg_descs)); } @@ -4800,15 +4743,10 @@ int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, con= st struct kvm_one_reg *reg, int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_re= g *reg) { void __user *uaddr =3D (void __user *)(unsigned long)reg->addr; - int err; =20 if ((reg->id & KVM_REG_ARM_COPROC_MASK) =3D=3D KVM_REG_ARM_DEMUX) return demux_c15_set(vcpu, reg->id, uaddr); =20 - err =3D set_invariant_sys_reg(reg->id, uaddr); - if (err !=3D -ENOENT) - return err; - return kvm_sys_reg_set_user(vcpu, reg, sys_reg_descs, ARRAY_SIZE(sys_reg_descs)); } @@ -4897,23 +4835,13 @@ static int walk_sys_regs(struct kvm_vcpu *vcpu, u64= __user *uind) =20 unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu) { - return ARRAY_SIZE(invariant_sys_regs) - + num_demux_regs() - + walk_sys_regs(vcpu, (u64 __user *)NULL); + return num_demux_regs() + walk_sys_regs(vcpu, (u64 __user *)NULL); } =20 int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindic= es) { - unsigned int i; int err; =20 - /* Then give them all the invariant registers' indices. */ - for (i =3D 0; i < ARRAY_SIZE(invariant_sys_regs); i++) { - if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices)) - return -EFAULT; - uindices++; - } - err =3D walk_sys_regs(vcpu, uindices); if (err < 0) return err; @@ -4987,7 +4915,8 @@ static void vcpu_set_hcr(struct kvm_vcpu *vcpu) else vcpu->arch.hcr_el2 |=3D HCR_TID2; =20 - if (kvm_read_vm_id_reg(kvm, SYS_REVIDR_EL1) !=3D read_sysreg(REVIDR_EL1)) + if ((kvm_read_vm_id_reg(kvm, SYS_REVIDR_EL1) !=3D read_sysreg(REVIDR_EL1)= ) || + (kvm_read_vm_id_reg(kvm, SYS_AIDR_EL1) !=3D read_sysreg(AIDR_EL1))) vcpu->arch.hcr_el2 |=3D HCR_TID1; =20 if (vcpu_el1_is_32bit(vcpu)) @@ -5142,16 +5071,11 @@ int __init kvm_sys_reg_table_init(void) valid &=3D check_sysreg_table(cp14_64_regs, ARRAY_SIZE(cp14_64_regs), tru= e); valid &=3D check_sysreg_table(cp15_regs, ARRAY_SIZE(cp15_regs), true); valid &=3D check_sysreg_table(cp15_64_regs, ARRAY_SIZE(cp15_64_regs), tru= e); - valid &=3D check_sysreg_table(invariant_sys_regs, ARRAY_SIZE(invariant_sy= s_regs), false); valid &=3D check_sysreg_table(sys_insn_descs, ARRAY_SIZE(sys_insn_descs),= false); =20 if (!valid) return -EINVAL; =20 - /* We abuse the reset function to overwrite the table itself. */ - for (i =3D 0; i < ARRAY_SIZE(invariant_sys_regs); i++) - invariant_sys_regs[i].reset(NULL, &invariant_sys_regs[i]); - ret =3D populate_nv_trap_config(); =20 for (i =3D 0; !ret && i < ARRAY_SIZE(sys_reg_descs); i++) --=20 2.42.0