/*
* Write back the vcpu FPSIMD regs if they are dirty, and invalidate the
* cpu FPSIMD regs so that they can't be spuriously reused if this vcpu
* disappears and another task or vcpu appears that recycles the same
* struct fpsimd_state.
*/
void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
{
unsigned long flags;
local_irq_save(flags);
if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
/* Clean guest FP state to memory and invalidate cpu view */
fpsimd_save();
fpsimd_flush_cpu_state();
} else if (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 to CPACR_EL1_DEFAULT by the Hyp code, disabling SVE
* for EL0. To avoid spurious traps, restore the trap state
* seen by kvm_arch_vcpu_load_fp():
*/
if (vcpu->arch.flags & KVM_ARM64_HOST_SVE_ENABLED)
sysreg_clear_set(CPACR_EL1, 0, CPACR_EL1_ZEN_EL0EN);
else
sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0);
}
update_thread_flag(TIF_SVE,
vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
local_irq_restore(flags);
}
/*
* Write back the vcpu FPSIMD regs if they are dirty, and invalidate the
* cpu FPSIMD regs so that they can't be spuriously reused if this vcpu
* disappears and another task or vcpu appears that recycles the same
* struct fpsimd_state.
*/
void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
{
local_bh_disable();
update_thread_flag(TIF_SVE,
vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
/* Clean guest FP state to memory and invalidate cpu view */
fpsimd_save();
fpsimd_flush_cpu_state();
} else if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {
/* Ensure user trap controls are correctly restored */
fpsimd_bind_task_to_cpu();
}
local_bh_enable();
}
int sve_set_vector_length(struct task_struct *task,
unsigned long vl, unsigned long flags)
{
if (flags & ~(unsigned long)(PR_SVE_VL_INHERIT |
PR_SVE_SET_VL_ONEXEC))
return -EINVAL;
if (!sve_vl_valid(vl))
return -EINVAL;
/*
* Clamp to the maximum vector length that VL-agnostic SVE code can
* work with. A flag may be assigned in the future to allow setting
* of larger vector lengths without confusing older software.
*/
if (vl > SVE_VL_ARCH_MAX)
vl = SVE_VL_ARCH_MAX;
vl = find_supported_vector_length(vl);
if (flags & (PR_SVE_VL_INHERIT |
PR_SVE_SET_VL_ONEXEC))
task->thread.sve_vl_onexec = vl;
else
/* Reset VL to system default on next exec: */
task->thread.sve_vl_onexec = 0;
/* Only actually set the VL if not deferred: */
if (flags & PR_SVE_SET_VL_ONEXEC)
goto out;
if (vl == task->thread.sve_vl)
goto out;
/*
* To ensure the FPSIMD bits of the SVE vector registers are preserved,
* write any live register state back to task_struct, and convert to a
* non-SVE thread.
*/
if (task == current) {
local_bh_disable();
fpsimd_save();
set_thread_flag(TIF_FOREIGN_FPSTATE);
}
fpsimd_flush_task_state(task);
if (test_and_clear_tsk_thread_flag(task, TIF_SVE))
sve_to_fpsimd(task);
if (task == current)
local_bh_enable();
/*
* Force reallocation of task SVE state to the correct size
* on next use:
*/
sve_free(task);
task->thread.sve_vl = vl;
out:
update_tsk_thread_flag(task, TIF_SVE_VL_INHERIT,
flags & PR_SVE_VL_INHERIT);
return 0;
}
