diff options
Diffstat (limited to 'arch/arm64/kvm/fpsimd.c')
| -rw-r--r-- | arch/arm64/kvm/fpsimd.c | 137 |
1 files changed, 11 insertions, 126 deletions
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index ea5484ce1f3b..15e17aca1dec 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -15,32 +15,6 @@ #include <asm/sysreg.h> /* - * Called on entry to KVM_RUN unless this vcpu previously ran at least - * once and the most recent prior KVM_RUN for this vcpu was called from - * the same task as current (highly likely). - * - * This is guaranteed to execute before kvm_arch_vcpu_load_fp(vcpu), - * such that on entering hyp the relevant parts of current are already - * mapped. - */ -int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) -{ - struct user_fpsimd_state *fpsimd = ¤t->thread.uw.fpsimd_state; - int ret; - - /* pKVM has its own tracking of the host fpsimd state. */ - if (is_protected_kvm_enabled()) - return 0; - - /* Make sure the host task fpsimd state is visible to hyp: */ - ret = kvm_share_hyp(fpsimd, fpsimd + 1); - if (ret) - return ret; - - return 0; -} - -/* * Prepare vcpu for saving the host's FPSIMD state and loading the guest's. * The actual loading is done by the FPSIMD access trap taken to hyp. * @@ -54,50 +28,18 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) if (!system_supports_fpsimd()) return; - fpsimd_kvm_prepare(); - /* - * We will check TIF_FOREIGN_FPSTATE just before entering the - * guest in kvm_arch_vcpu_ctxflush_fp() and override this to - * FP_STATE_FREE if the flag set. + * Ensure that any host FPSIMD/SVE/SME state is saved and unbound such + * that the host kernel is responsible for restoring this state upon + * return to userspace, and the hyp code doesn't need to save anything. + * + * When the host may use SME, fpsimd_save_and_flush_cpu_state() ensures + * that PSTATE.{SM,ZA} == {0,0}. */ - *host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED; - *host_data_ptr(fpsimd_state) = kern_hyp_va(¤t->thread.uw.fpsimd_state); - *host_data_ptr(fpmr_ptr) = kern_hyp_va(¤t->thread.uw.fpmr); - - vcpu_clear_flag(vcpu, HOST_SVE_ENABLED); - if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN) - vcpu_set_flag(vcpu, HOST_SVE_ENABLED); - - if (system_supports_sme()) { - vcpu_clear_flag(vcpu, HOST_SME_ENABLED); - if (read_sysreg(cpacr_el1) & CPACR_EL1_SMEN_EL0EN) - vcpu_set_flag(vcpu, HOST_SME_ENABLED); - - /* - * If PSTATE.SM is enabled then save any pending FP - * state and disable PSTATE.SM. If we leave PSTATE.SM - * enabled and the guest does not enable SME via - * CPACR_EL1.SMEN then operations that should be valid - * may generate SME traps from EL1 to EL1 which we - * can't intercept and which would confuse the guest. - * - * Do the same for PSTATE.ZA in the case where there - * is state in the registers which has not already - * been saved, this is very unlikely to happen. - */ - if (read_sysreg_s(SYS_SVCR) & (SVCR_SM_MASK | SVCR_ZA_MASK)) { - *host_data_ptr(fp_owner) = FP_STATE_FREE; - fpsimd_save_and_flush_cpu_state(); - } - } + fpsimd_save_and_flush_cpu_state(); + *host_data_ptr(fp_owner) = FP_STATE_FREE; - /* - * If normal guests gain SME support, maintain this behavior for pKVM - * guests, which don't support SME. - */ - WARN_ON(is_protected_kvm_enabled() && system_supports_sme() && - read_sysreg_s(SYS_SVCR)); + WARN_ON_ONCE(system_supports_sme() && read_sysreg_s(SYS_SVCR)); } /* @@ -135,8 +77,8 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) fp_state.sve_state = vcpu->arch.sve_state; fp_state.sve_vl = vcpu->arch.sve_max_vl; fp_state.sme_state = NULL; - fp_state.svcr = &__vcpu_sys_reg(vcpu, SVCR); - fp_state.fpmr = &__vcpu_sys_reg(vcpu, FPMR); + fp_state.svcr = __ctxt_sys_reg(&vcpu->arch.ctxt, SVCR); + fp_state.fpmr = __ctxt_sys_reg(&vcpu->arch.ctxt, FPMR); fp_state.fp_type = &vcpu->arch.fp_type; if (vcpu_has_sve(vcpu)) @@ -162,52 +104,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) local_irq_save(flags); - /* - * If we have VHE then the Hyp code will reset CPACR_EL1 to - * the default value and we need to reenable SME. - */ - if (has_vhe() && system_supports_sme()) { - /* Also restore EL0 state seen on entry */ - if (vcpu_get_flag(vcpu, HOST_SME_ENABLED)) - sysreg_clear_set(CPACR_EL1, 0, CPACR_ELx_SMEN); - else - sysreg_clear_set(CPACR_EL1, - CPACR_EL1_SMEN_EL0EN, - CPACR_EL1_SMEN_EL1EN); - isb(); - } - if (guest_owns_fp_regs()) { - if (vcpu_has_sve(vcpu)) { - u64 zcr = read_sysreg_el1(SYS_ZCR); - - /* - * If the vCPU is in the hyp context then ZCR_EL1 is - * loaded with its vEL2 counterpart. - */ - __vcpu_sys_reg(vcpu, vcpu_sve_zcr_elx(vcpu)) = zcr; - - /* - * Restore the VL that was saved when bound to the CPU, - * which is the maximum VL for the guest. Because the - * layout of the data when saving the sve state depends - * on the VL, we need to use a consistent (i.e., the - * maximum) VL. - * Note that this means that at guest exit ZCR_EL1 is - * not necessarily the same as on guest entry. - * - * ZCR_EL2 holds the guest hypervisor's VL when running - * a nested guest, which could be smaller than the - * max for the vCPU. Similar to above, we first need to - * switch to a VL consistent with the layout of the - * vCPU's SVE state. KVM support for NV implies VHE, so - * using the ZCR_EL1 alias is safe. - */ - if (!has_vhe() || (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu))) - 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 @@ -219,18 +116,6 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) * when needed. */ fpsimd_save_and_flush_cpu_state(); - } else if (has_vhe() && system_supports_sve()) { - /* - * The FPSIMD/SVE state in the CPU has not been touched, and we - * have SVE (and VHE): CPACR_EL1 (alias CPTR_EL2) has been - * reset by kvm_reset_cptr_el2() in the Hyp code, disabling SVE - * for EL0. To avoid spurious traps, restore the trap state - * seen by kvm_arch_vcpu_load_fp(): - */ - if (vcpu_get_flag(vcpu, HOST_SVE_ENABLED)) - sysreg_clear_set(CPACR_EL1, 0, CPACR_EL1_ZEN_EL0EN); - else - sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0); } local_irq_restore(flags); |