diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 2e0952134e2e..6d7b6b5d076d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -64,6 +64,7 @@ enum kvm_mode kvm_get_mode(void); DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); extern unsigned int kvm_sve_max_vl; +extern unsigned int kvm_host_sve_max_vl; int kvm_arm_init_sve(void); u32 __attribute_const__ kvm_target_cpu(void); diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 657d0c94cf82..308df86f9a4b 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -117,5 +117,12 @@ void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt); extern u64 kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val); extern u64 kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val); +extern unsigned int kvm_nvhe_sym(kvm_host_sve_max_vl); + +static inline bool guest_owns_fp_regs(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.flags & KVM_ARM64_FP_ENABLED; +} + #endif /* __ARM64_KVM_HYP_H__ */ diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 1360ddd4137b..cfda503c8b3f 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -129,15 +129,16 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) local_irq_save(flags); if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) { - if (vcpu_has_sve(vcpu)) { - __vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR); - - /* Restore the VL that was saved when bound to the CPU */ - if (!has_vhe()) - sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, - SYS_ZCR_EL1); - } - + /* + * Flush (save and invalidate) the fpsimd/sve state so that if + * the host tries to use fpsimd/sve, it's not using stale data + * from the guest. + * + * Flushing the state sets the TIF_FOREIGN_FPSTATE bit for the + * context unconditionally, in both nVHE and VHE. This allows + * the kernel to restore the fpsimd/sve state, including ZCR_EL1 + * when needed. + */ fpsimd_save_and_flush_cpu_state(); } diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index 435346ea1504..d8c94c45cb2f 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -44,6 +44,11 @@ alternative_if ARM64_HAS_RAS_EXTN alternative_else_nop_endif mrs x1, isr_el1 cbz x1, 1f + + // Ensure that __guest_enter() always provides a context + // synchronization event so that callers don't need ISBs for anything + // that would usually be synchonized by the ERET. + isb mov x0, #ARM_EXCEPTION_IRQ ret diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index cc102e46b0e2..797544662a95 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -215,6 +215,61 @@ static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu) write_sysreg_el1(__vcpu_sys_reg(vcpu, ZCR_EL1), SYS_ZCR); } +static inline void fpsimd_lazy_switch_to_guest(struct kvm_vcpu *vcpu) +{ + u64 zcr_el1, zcr_el2; + + if (!guest_owns_fp_regs(vcpu)) + return; + + if (vcpu_has_sve(vcpu)) { + zcr_el2 = vcpu_sve_max_vq(vcpu) - 1; + + write_sysreg_el2(zcr_el2, SYS_ZCR); + + zcr_el1 = __vcpu_sys_reg(vcpu, ZCR_EL1); + write_sysreg_el1(zcr_el1, SYS_ZCR); + } +} + +static inline void fpsimd_lazy_switch_to_host(struct kvm_vcpu *vcpu) +{ + u64 zcr_el1, zcr_el2; + + if (!guest_owns_fp_regs(vcpu)) + return; + + /* + * When the guest owns the FP regs, we know that guest+hyp traps for + * any FPSIMD/SVE/SME features exposed to the guest have been disabled + * by either fpsimd_lazy_switch_to_guest() or kvm_hyp_handle_fpsimd() + * prior to __guest_entry(). As __guest_entry() guarantees a context + * synchronization event, we don't need an ISB here to avoid taking + * traps for anything that was exposed to the guest. + */ + if (vcpu_has_sve(vcpu)) { + zcr_el1 = read_sysreg_el1(SYS_ZCR); + __vcpu_sys_reg(vcpu, ZCR_EL1) = zcr_el1; + + /* + * The guest's state is always saved using the guest's max VL. + * Ensure that the host has the guest's max VL active such that + * the host can save the guest's state lazily, but don't + * artificially restrict the host to the guest's max VL. + */ + if (has_vhe()) { + zcr_el2 = vcpu_sve_max_vq(vcpu) - 1; + write_sysreg_el2(zcr_el2, SYS_ZCR); + } else { + zcr_el2 = sve_vq_from_vl(kvm_host_sve_max_vl) - 1; + write_sysreg_el2(zcr_el2, SYS_ZCR); + + zcr_el1 = vcpu_sve_max_vq(vcpu) - 1; + write_sysreg_el1(zcr_el1, SYS_ZCR); + } + } +} + /* Check for an FPSIMD/SVE trap and handle as appropriate */ static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu) { diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 2da6aa8da868..a446883d5b9a 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -19,13 +19,17 @@ DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); +unsigned int kvm_host_sve_max_vl; + void __kvm_hyp_host_forward_smc(struct kvm_cpu_context *host_ctxt); static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1); + fpsimd_lazy_switch_to_guest(kern_hyp_va(vcpu)); cpu_reg(host_ctxt, 1) = __kvm_vcpu_run(kern_hyp_va(vcpu)); + fpsimd_lazy_switch_to_host(kern_hyp_va(vcpu)); } static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt) @@ -237,11 +241,6 @@ void handle_trap(struct kvm_cpu_context *host_ctxt) case ESR_ELx_EC_SMC64: handle_host_smc(host_ctxt); break; - case ESR_ELx_EC_SVE: - sysreg_clear_set(cptr_el2, CPTR_EL2_TZ, 0); - isb(); - sve_cond_update_zcr_vq(ZCR_ELx_LEN_MASK, SYS_ZCR_EL2); - break; case ESR_ELx_EC_IABT_LOW: case ESR_ELx_EC_DABT_LOW: handle_host_mem_abort(host_ctxt); diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index c0885197f2a5..fff7491d8351 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -34,15 +34,13 @@ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data); DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt); DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); -static bool guest_owns_fp_regs(struct kvm_vcpu *vcpu) -{ - return vcpu->arch.flags & KVM_ARM64_FP_ENABLED; -} - static void __activate_cptr_traps(struct kvm_vcpu *vcpu) { u64 val = CPTR_EL2_TAM; /* Same bit irrespective of E2H */ + if (!guest_owns_fp_regs(vcpu)) + __activate_traps_fpsimd32(vcpu); + /* !hVHE case upstream */ if (1) { val |= CPTR_EL2_TTA | CPTR_NVHE_EL2_RES1; @@ -52,12 +50,22 @@ static void __activate_cptr_traps(struct kvm_vcpu *vcpu) if (!guest_owns_fp_regs(vcpu)) val |= CPTR_EL2_TFP; + + write_sysreg(val, cptr_el2); } +} - if (!guest_owns_fp_regs(vcpu)) - __activate_traps_fpsimd32(vcpu); +static void __deactivate_cptr_traps(struct kvm_vcpu *vcpu) +{ + /* !hVHE case upstream */ + if (1) { + u64 val = CPTR_NVHE_EL2_RES1; - write_sysreg(val, cptr_el2); + if (!cpus_have_final_cap(ARM64_SVE)) + val |= CPTR_EL2_TZ; + + write_sysreg(val, cptr_el2); + } } static void __activate_traps(struct kvm_vcpu *vcpu) @@ -86,7 +94,6 @@ static void __activate_traps(struct kvm_vcpu *vcpu) static void __deactivate_traps(struct kvm_vcpu *vcpu) { extern char __kvm_hyp_host_vector[]; - u64 cptr; ___deactivate_traps(vcpu); @@ -111,11 +118,7 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu) write_sysreg(this_cpu_ptr(&kvm_init_params)->hcr_el2, hcr_el2); - cptr = CPTR_EL2_DEFAULT; - if (vcpu_has_sve(vcpu) && (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)) - cptr |= CPTR_EL2_TZ; - - write_sysreg(cptr, cptr_el2); + __deactivate_cptr_traps(vcpu); write_sysreg(__kvm_hyp_host_vector, vbar_el2); } diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 813e6e2178c1..d8a8628a9d70 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -114,6 +114,8 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) sysreg_save_host_state_vhe(host_ctxt); + fpsimd_lazy_switch_to_guest(vcpu); + /* * ARM erratum 1165522 requires us to configure both stage 1 and * stage 2 translation for the guest context before we clear @@ -144,6 +146,8 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) __deactivate_traps(vcpu); + fpsimd_lazy_switch_to_host(vcpu); + sysreg_restore_host_state_vhe(host_ctxt); if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 5ce36b0a3343..deb205638279 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -42,11 +42,14 @@ static u32 kvm_ipa_limit; PSR_AA32_I_BIT | PSR_AA32_F_BIT) unsigned int kvm_sve_max_vl; +unsigned int kvm_host_sve_max_vl; int kvm_arm_init_sve(void) { if (system_supports_sve()) { kvm_sve_max_vl = sve_max_virtualisable_vl; + kvm_host_sve_max_vl = sve_max_vl; + kvm_nvhe_sym(kvm_host_sve_max_vl) = kvm_host_sve_max_vl; /* * The get_sve_reg()/set_sve_reg() ioctl interface will need