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[2003:f6:af0e:4d00:dda5:3016:e366:575f]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38dcc9bd251sm11745833f8f.9.2025.02.11.06.39.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Feb 2025 06:39:13 -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 v2 2/4] KVM: arm64: Allow userspace to change REVIDR_EL1 Date: Tue, 11 Feb 2025 15:39:08 +0100 Message-ID: <20250211143910.16775-3-sebott@redhat.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250211143910.16775-1-sebott@redhat.com> References: <20250211143910.16775-1-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 REVIDR_EL1 by treating it as a VM ID register. Trap guest access of REVIDR_EL1 when the VMs value differs from hardware. Signed-off-by: Sebastian Ott --- arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/kvm/sys_regs.c | 11 ++++++++--- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm= _host.h index 3db8c773339e..c8fba4111b77 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -374,6 +374,7 @@ struct kvm_arch { u64 id_regs[KVM_ARM_ID_REG_NUM]; =20 u64 midr_el1; + u64 revidr_el1; u64 ctr_el0; =20 /* Masks for VNCR-backed and general EL2 sysregs */ @@ -1472,6 +1473,8 @@ static inline u64 *__vm_id_reg(struct kvm_arch *ka, u= 32 reg) return &ka->id_regs[IDREG_IDX(reg)]; case SYS_MIDR_EL1: return &ka->midr_el1; + case SYS_REVIDR_EL1: + return &ka->revidr_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 7e1c9884f62a..646c0a04e58a 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1666,7 +1666,8 @@ 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) + if (id =3D=3D SYS_CTR_EL0 || id =3D=3D SYS_MIDR_EL1 || + id =3D=3D SYS_REVIDR_EL1) return true; =20 return (sys_reg_Op0(id) =3D=3D 3 && sys_reg_Op1(id) =3D=3D 0 && @@ -2542,6 +2543,7 @@ static bool access_mdcr(struct kvm_vcpu *vcpu, } =20 FUNCTION_RESET(midr_el1) +FUNCTION_RESET(revidr_el1) =20 =20 /* @@ -2595,6 +2597,8 @@ static const struct sys_reg_desc sys_reg_descs[] =3D { { ID_DESC(MIDR_EL1), .set_user =3D set_id_reg_non_ftr, .visibility =3D id= _visibility, .reset =3D reset_midr_el1, .val =3D GENMASK_ULL(31, 0) }, { SYS_DESC(SYS_MPIDR_EL1), NULL, reset_mpidr, MPIDR_EL1 }, + { ID_DESC(REVIDR_EL1), .set_user =3D set_id_reg_non_ftr, .visibility =3D = id_visibility, + .reset =3D reset_revidr_el1, .val =3D -1ULL }, =20 /* * ID regs: all ID_SANITISED() entries here must have corresponding @@ -4646,12 +4650,10 @@ id_to_sys_reg_desc(struct kvm_vcpu *vcpu, u64 id, return ((struct sys_reg_desc *)r)->val; \ } =20 -FUNCTION_INVARIANT(revidr_el1) FUNCTION_INVARIANT(aidr_el1) =20 /* ->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_REVIDR_EL1), NULL, reset_revidr_el1 }, { SYS_DESC(SYS_AIDR_EL1), NULL, reset_aidr_el1 }, }; =20 @@ -4999,6 +5001,9 @@ 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)) + vcpu->arch.hcr_el2 |=3D HCR_TID1; + if (vcpu_el1_is_32bit(vcpu)) vcpu->arch.hcr_el2 &=3D ~HCR_RW; =20 --=20 2.42.0