From: Sebastian Ott <sebott@redhat.com> mainline inclusion from mainline-v6.11-rc1 commit 2843cae26644fbc922e93c7c4c279f70fb3275f1 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IBN3WI CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------------------------------------ CTR_EL0 is currently handled as an invariant register, thus guests will be presented with the host value of that register. Add emulation for CTR_EL0 based on a per VM value. Userspace can switch off DIC and IDC bits and reduce DminLine and IminLine sizes. Naturally, ensure CTR_EL0 is trapped (HCR_EL2.TID2=1) any time that a VM's CTR_EL0 differs from hardware. Signed-off-by: Sebastian Ott <sebott@redhat.com> Reviewed-by: Shaoqin Huang <shahuang@redhat.com> Link: https://lore.kernel.org/r/20240619174036.483943-8-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev> --- arch/arm64/include/asm/kvm_emulate.h | 3 ++- arch/arm64/include/asm/kvm_host.h | 4 ++++ arch/arm64/kvm/sys_regs.c | 17 ++++++++--------- 3 files changed, 14 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 2293caab9f8f..025b830882c2 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -91,7 +91,8 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) } if (cpus_have_final_cap(ARM64_HAS_EVT) && - !cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE)) + !cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE) && + kvm_read_vm_id_reg(vcpu->kvm, SYS_CTR_EL0) == read_sanitised_ftr_reg(SYS_CTR_EL0)) vcpu->arch.hcr_el2 |= HCR_TID4; else vcpu->arch.hcr_el2 |= HCR_TID2; diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index fbeeea91c1dd..78aa3ff7eeb8 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -280,6 +280,8 @@ struct kvm_arch { #define KVM_ARM_ID_REG_NUM (IDREG_IDX(sys_reg(3, 0, 0, 7, 7)) + 1) u64 id_regs[KVM_ARM_ID_REG_NUM]; + u64 ctr_el0; + /* * For an untrusted host VM, 'pkvm.handle' is used to lookup * the associated pKVM instance in the hypervisor. @@ -1253,6 +1255,8 @@ static inline u64 *__vm_id_reg(struct kvm_arch *ka, u32 reg) switch (reg) { case sys_reg(3, 0, 0, 1, 0) ... sys_reg(3, 0, 0, 7, 7): return &ka->id_regs[IDREG_IDX(reg)]; + case SYS_CTR_EL0: + return &ka->ctr_el0; default: WARN_ON_ONCE(1); return NULL; diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index cf7e8a42a9d8..a33b2d86b35a 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1417,6 +1417,9 @@ static bool is_feature_id_reg(u32 encoding) */ static inline bool is_vm_ftr_id_reg(u32 id) { + if (id == SYS_CTR_EL0) + return true; + return (sys_reg_Op0(id) == 3 && sys_reg_Op1(id) == 0 && sys_reg_CRn(id) == 0 && sys_reg_CRm(id) >= 1 && sys_reg_CRm(id) < 8); @@ -1795,7 +1798,7 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, if (p->is_write) return write_to_read_only(vcpu, p, r); - p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0); + p->regval = kvm_read_vm_id_reg(vcpu->kvm, SYS_CTR_EL0); return true; } @@ -2380,7 +2383,10 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_CCSIDR2_EL1), undef_access }, { SYS_DESC(SYS_SMIDR_EL1), undef_access }, { SYS_DESC(SYS_CSSELR_EL1), access_csselr, reset_unknown, CSSELR_EL1 }, - { SYS_DESC(SYS_CTR_EL0), access_ctr }, + ID_WRITABLE(CTR_EL0, CTR_EL0_DIC_MASK | + CTR_EL0_IDC_MASK | + CTR_EL0_DminLine_MASK | + CTR_EL0_IminLine_MASK), { SYS_DESC(SYS_SVCR), undef_access }, { PMU_SYS_REG(PMCR_EL0), .access = access_pmcr, @@ -3509,18 +3515,11 @@ FUNCTION_INVARIANT(midr_el1) FUNCTION_INVARIANT(revidr_el1) FUNCTION_INVARIANT(aidr_el1) -static u64 get_ctr_el0(struct kvm_vcpu *v, const struct sys_reg_desc *r) -{ - ((struct sys_reg_desc *)r)->val = read_sanitised_ftr_reg(SYS_CTR_EL0); - return ((struct sys_reg_desc *)r)->val; -} - /* ->val is filled in by kvm_sys_reg_table_init() */ static struct sys_reg_desc invariant_sys_regs[] __ro_after_init = { { SYS_DESC(SYS_MIDR_EL1), NULL, get_midr_el1 }, { SYS_DESC(SYS_REVIDR_EL1), NULL, get_revidr_el1 }, { SYS_DESC(SYS_AIDR_EL1), NULL, get_aidr_el1 }, - { SYS_DESC(SYS_CTR_EL0), NULL, get_ctr_el0 }, }; static int get_invariant_sys_reg(u64 id, u64 __user *uaddr) -- 2.33.0