blob: d496ef579859627edd1ba98c1233d9584cd407e3 [file] [log] [blame]
/*
* Copyright (C) 2015 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/arm-smccc.h>
#include <linux/types.h>
#include <linux/jump_label.h>
#include <uapi/linux/psci.h>
#include <kvm/arm_psci.h>
#include <asm/cpufeature.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_host.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/fpsimd.h>
#include <asm/debug-monitors.h>
#include <asm/processor.h>
#include <asm/thread_info.h>
/* Check whether the FP regs were dirtied while in the host-side run loop: */
static bool __hyp_text update_fp_enabled(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE)
vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
KVM_ARM64_FP_HOST);
return !!(vcpu->arch.flags & KVM_ARM64_FP_ENABLED);
}
/* Save the 32-bit only FPSIMD system register state */
static void __hyp_text __fpsimd_save_fpexc32(struct kvm_vcpu *vcpu)
{
if (!vcpu_el1_is_32bit(vcpu))
return;
vcpu->arch.ctxt.sys_regs[FPEXC32_EL2] = read_sysreg(fpexc32_el2);
}
static void __hyp_text __activate_traps_fpsimd32(struct kvm_vcpu *vcpu)
{
/*
* We are about to set CPTR_EL2.TFP to trap all floating point
* register accesses to EL2, however, the ARM ARM clearly states that
* traps are only taken to EL2 if the operation would not otherwise
* trap to EL1. Therefore, always make sure that for 32-bit guests,
* we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
* If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
* it will cause an exception.
*/
if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {
write_sysreg(1 << 30, fpexc32_el2);
isb();
}
}
static void __hyp_text __activate_traps_common(struct kvm_vcpu *vcpu)
{
/* Trap on AArch32 cp15 c15 (impdef sysregs) accesses (EL1 or EL0) */
write_sysreg(1 << 15, hstr_el2);
/*
* Make sure we trap PMU access from EL0 to EL2. Also sanitize
* PMSELR_EL0 to make sure it never contains the cycle
* counter, which could make a PMXEVCNTR_EL0 access UNDEF at
* EL1 instead of being trapped to EL2.
*/
write_sysreg(0, pmselr_el0);
write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
}
static void __hyp_text __deactivate_traps_common(void)
{
write_sysreg(0, hstr_el2);
write_sysreg(0, pmuserenr_el0);
}
static void activate_traps_vhe(struct kvm_vcpu *vcpu)
{
u64 val;
val = read_sysreg(cpacr_el1);
val |= CPACR_EL1_TTA;
val &= ~CPACR_EL1_ZEN;
if (!update_fp_enabled(vcpu))
val &= ~CPACR_EL1_FPEN;
write_sysreg(val, cpacr_el1);
write_sysreg(kvm_get_hyp_vector(), vbar_el1);
}
static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)
{
u64 val;
__activate_traps_common(vcpu);
val = CPTR_EL2_DEFAULT;
val |= CPTR_EL2_TTA | CPTR_EL2_TZ;
if (!update_fp_enabled(vcpu))
val |= CPTR_EL2_TFP;
write_sysreg(val, cptr_el2);
}
static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
{
u64 hcr = vcpu->arch.hcr_el2;
write_sysreg(hcr, hcr_el2);
if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE))
write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2);
__activate_traps_fpsimd32(vcpu);
if (has_vhe())
activate_traps_vhe(vcpu);
else
__activate_traps_nvhe(vcpu);
}
static void deactivate_traps_vhe(void)
{
extern char vectors[]; /* kernel exception vectors */
write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1);
write_sysreg(vectors, vbar_el1);
}
static void __hyp_text __deactivate_traps_nvhe(void)
{
u64 mdcr_el2 = read_sysreg(mdcr_el2);
__deactivate_traps_common();
mdcr_el2 &= MDCR_EL2_HPMN_MASK;
mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;
write_sysreg(mdcr_el2, mdcr_el2);
write_sysreg(HCR_RW, hcr_el2);
write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
}
static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
{
/*
* If we pended a virtual abort, preserve it until it gets
* cleared. See D1.14.3 (Virtual Interrupts) for details, but
* the crucial bit is "On taking a vSError interrupt,
* HCR_EL2.VSE is cleared to 0."
*/
if (vcpu->arch.hcr_el2 & HCR_VSE)
vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);
if (has_vhe())
deactivate_traps_vhe();
else
__deactivate_traps_nvhe();
}
void activate_traps_vhe_load(struct kvm_vcpu *vcpu)
{
__activate_traps_common(vcpu);
}
void deactivate_traps_vhe_put(void)
{
u64 mdcr_el2 = read_sysreg(mdcr_el2);
mdcr_el2 &= MDCR_EL2_HPMN_MASK |
MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT |
MDCR_EL2_TPMS;
write_sysreg(mdcr_el2, mdcr_el2);
__deactivate_traps_common();
}
static void __hyp_text __activate_vm(struct kvm *kvm)
{
write_sysreg(kvm->arch.vttbr, vttbr_el2);
}
static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
{
write_sysreg(0, vttbr_el2);
}
/* Save VGICv3 state on non-VHE systems */
static void __hyp_text __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
{
if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_save_state(vcpu);
__vgic_v3_deactivate_traps(vcpu);
}
}
/* Restore VGICv3 state on non_VEH systems */
static void __hyp_text __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
{
if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_activate_traps(vcpu);
__vgic_v3_restore_state(vcpu);
}
}
static bool __hyp_text __true_value(void)
{
return true;
}
static bool __hyp_text __false_value(void)
{
return false;
}
static hyp_alternate_select(__check_arm_834220,
__false_value, __true_value,
ARM64_WORKAROUND_834220);
static bool __hyp_text __translate_far_to_hpfar(u64 far, u64 *hpfar)
{
u64 par, tmp;
/*
* Resolve the IPA the hard way using the guest VA.
*
* Stage-1 translation already validated the memory access
* rights. As such, we can use the EL1 translation regime, and
* don't have to distinguish between EL0 and EL1 access.
*
* We do need to save/restore PAR_EL1 though, as we haven't
* saved the guest context yet, and we may return early...
*/
par = read_sysreg(par_el1);
asm volatile("at s1e1r, %0" : : "r" (far));
isb();
tmp = read_sysreg(par_el1);
write_sysreg(par, par_el1);
if (unlikely(tmp & 1))
return false; /* Translation failed, back to guest */
/* Convert PAR to HPFAR format */
*hpfar = ((tmp >> 12) & ((1UL << 36) - 1)) << 4;
return true;
}
static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
{
u8 ec;
u64 esr;
u64 hpfar, far;
esr = vcpu->arch.fault.esr_el2;
ec = ESR_ELx_EC(esr);
if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW)
return true;
far = read_sysreg_el2(far);
/*
* The HPFAR can be invalid if the stage 2 fault did not
* happen during a stage 1 page table walk (the ESR_EL2.S1PTW
* bit is clear) and one of the two following cases are true:
* 1. The fault was due to a permission fault
* 2. The processor carries errata 834220
*
* Therefore, for all non S1PTW faults where we either have a
* permission fault or the errata workaround is enabled, we
* resolve the IPA using the AT instruction.
*/
if (!(esr & ESR_ELx_S1PTW) &&
(__check_arm_834220()() || (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) {
if (!__translate_far_to_hpfar(far, &hpfar))
return false;
} else {
hpfar = read_sysreg(hpfar_el2);
}
vcpu->arch.fault.far_el2 = far;
vcpu->arch.fault.hpfar_el2 = hpfar;
return true;
}
/* Skip an instruction which has been emulated. Returns true if
* execution can continue or false if we need to exit hyp mode because
* single-step was in effect.
*/
static bool __hyp_text __skip_instr(struct kvm_vcpu *vcpu)
{
*vcpu_pc(vcpu) = read_sysreg_el2(elr);
if (vcpu_mode_is_32bit(vcpu)) {
vcpu->arch.ctxt.gp_regs.regs.pstate = read_sysreg_el2(spsr);
kvm_skip_instr32(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
write_sysreg_el2(vcpu->arch.ctxt.gp_regs.regs.pstate, spsr);
} else {
*vcpu_pc(vcpu) += 4;
}
write_sysreg_el2(*vcpu_pc(vcpu), elr);
if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
vcpu->arch.fault.esr_el2 =
(ESR_ELx_EC_SOFTSTP_LOW << ESR_ELx_EC_SHIFT) | 0x22;
return false;
} else {
return true;
}
}
static bool __hyp_text __hyp_switch_fpsimd(struct kvm_vcpu *vcpu)
{
struct user_fpsimd_state *host_fpsimd = vcpu->arch.host_fpsimd_state;
if (has_vhe())
write_sysreg(read_sysreg(cpacr_el1) | CPACR_EL1_FPEN,
cpacr_el1);
else
write_sysreg(read_sysreg(cptr_el2) & ~(u64)CPTR_EL2_TFP,
cptr_el2);
isb();
if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
/*
* In the SVE case, VHE is assumed: it is enforced by
* Kconfig and kvm_arch_init().
*/
if (system_supports_sve() &&
(vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE)) {
struct thread_struct *thread = container_of(
host_fpsimd,
struct thread_struct, uw.fpsimd_state);
sve_save_state(sve_pffr(thread), &host_fpsimd->fpsr);
} else {
__fpsimd_save_state(host_fpsimd);
}
vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
}
__fpsimd_restore_state(&vcpu->arch.ctxt.gp_regs.fp_regs);
/* Skip restoring fpexc32 for AArch64 guests */
if (!(read_sysreg(hcr_el2) & HCR_RW))
write_sysreg(vcpu->arch.ctxt.sys_regs[FPEXC32_EL2],
fpexc32_el2);
vcpu->arch.flags |= KVM_ARM64_FP_ENABLED;
return true;
}
/*
* Return true when we were able to fixup the guest exit and should return to
* the guest, false when we should restore the host state and return to the
* main run loop.
*/
static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
{
if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ)
vcpu->arch.fault.esr_el2 = read_sysreg_el2(esr);
/*
* We're using the raw exception code in order to only process
* the trap if no SError is pending. We will come back to the
* same PC once the SError has been injected, and replay the
* trapping instruction.
*/
if (*exit_code != ARM_EXCEPTION_TRAP)
goto exit;
/*
* We trap the first access to the FP/SIMD to save the host context
* and restore the guest context lazily.
* If FP/SIMD is not implemented, handle the trap and inject an
* undefined instruction exception to the guest.
*/
if (system_supports_fpsimd() &&
kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_FP_ASIMD)
return __hyp_switch_fpsimd(vcpu);
if (!__populate_fault_info(vcpu))
return true;
if (static_branch_unlikely(&vgic_v2_cpuif_trap)) {
bool valid;
valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW &&
kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT &&
kvm_vcpu_dabt_isvalid(vcpu) &&
!kvm_vcpu_dabt_isextabt(vcpu) &&
!kvm_vcpu_dabt_iss1tw(vcpu);
if (valid) {
int ret = __vgic_v2_perform_cpuif_access(vcpu);
if (ret == 1 && __skip_instr(vcpu))
return true;
if (ret == -1) {
/* Promote an illegal access to an
* SError. If we would be returning
* due to single-step clear the SS
* bit so handle_exit knows what to
* do after dealing with the error.
*/
if (!__skip_instr(vcpu))
*vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS;
*exit_code = ARM_EXCEPTION_EL1_SERROR;
}
goto exit;
}
}
if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
(kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_SYS64 ||
kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_CP15_32)) {
int ret = __vgic_v3_perform_cpuif_access(vcpu);
if (ret == 1 && __skip_instr(vcpu))
return true;
}
exit:
/* Return to the host kernel and handle the exit */
return false;
}
static inline bool __hyp_text __needs_ssbd_off(struct kvm_vcpu *vcpu)
{
if (!cpus_have_const_cap(ARM64_SSBD))
return false;
return !(vcpu->arch.workaround_flags & VCPU_WORKAROUND_2_FLAG);
}
static void __hyp_text __set_guest_arch_workaround_state(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_ARM64_SSBD
/*
* The host runs with the workaround always present. If the
* guest wants it disabled, so be it...
*/
if (__needs_ssbd_off(vcpu) &&
__hyp_this_cpu_read(arm64_ssbd_callback_required))
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 0, NULL);
#endif
}
static void __hyp_text __set_host_arch_workaround_state(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_ARM64_SSBD
/*
* If the guest has disabled the workaround, bring it back on.
*/
if (__needs_ssbd_off(vcpu) &&
__hyp_this_cpu_read(arm64_ssbd_callback_required))
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 1, NULL);
#endif
}
/* Switch to the guest for VHE systems running in EL2 */
int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
u64 exit_code;
host_ctxt = vcpu->arch.host_cpu_context;
host_ctxt->__hyp_running_vcpu = vcpu;
guest_ctxt = &vcpu->arch.ctxt;
sysreg_save_host_state_vhe(host_ctxt);
__activate_traps(vcpu);
__activate_vm(vcpu->kvm);
sysreg_restore_guest_state_vhe(guest_ctxt);
__debug_switch_to_guest(vcpu);
__set_guest_arch_workaround_state(vcpu);
do {
/* Jump in the fire! */
exit_code = __guest_enter(vcpu, host_ctxt);
/* And we're baaack! */
} while (fixup_guest_exit(vcpu, &exit_code));
__set_host_arch_workaround_state(vcpu);
sysreg_save_guest_state_vhe(guest_ctxt);
__deactivate_traps(vcpu);
sysreg_restore_host_state_vhe(host_ctxt);
if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
__fpsimd_save_fpexc32(vcpu);
__debug_switch_to_host(vcpu);
return exit_code;
}
/* Switch to the guest for legacy non-VHE systems */
int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
u64 exit_code;
vcpu = kern_hyp_va(vcpu);
host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
host_ctxt->__hyp_running_vcpu = vcpu;
guest_ctxt = &vcpu->arch.ctxt;
__sysreg_save_state_nvhe(host_ctxt);
__activate_traps(vcpu);
__activate_vm(kern_hyp_va(vcpu->kvm));
__hyp_vgic_restore_state(vcpu);
__timer_enable_traps(vcpu);
/*
* We must restore the 32-bit state before the sysregs, thanks
* to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
*/
__sysreg32_restore_state(vcpu);
__sysreg_restore_state_nvhe(guest_ctxt);
__debug_switch_to_guest(vcpu);
__set_guest_arch_workaround_state(vcpu);
do {
/* Jump in the fire! */
exit_code = __guest_enter(vcpu, host_ctxt);
/* And we're baaack! */
} while (fixup_guest_exit(vcpu, &exit_code));
__set_host_arch_workaround_state(vcpu);
__sysreg_save_state_nvhe(guest_ctxt);
__sysreg32_save_state(vcpu);
__timer_disable_traps(vcpu);
__hyp_vgic_save_state(vcpu);
__deactivate_traps(vcpu);
__deactivate_vm(vcpu);
__sysreg_restore_state_nvhe(host_ctxt);
if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
__fpsimd_save_fpexc32(vcpu);
/*
* This must come after restoring the host sysregs, since a non-VHE
* system may enable SPE here and make use of the TTBRs.
*/
__debug_switch_to_host(vcpu);
return exit_code;
}
static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";
static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par,
struct kvm_cpu_context *__host_ctxt)
{
struct kvm_vcpu *vcpu;
unsigned long str_va;
vcpu = __host_ctxt->__hyp_running_vcpu;
if (read_sysreg(vttbr_el2)) {
__timer_disable_traps(vcpu);
__deactivate_traps(vcpu);
__deactivate_vm(vcpu);
__sysreg_restore_state_nvhe(__host_ctxt);
}
/*
* Force the panic string to be loaded from the literal pool,
* making sure it is a kernel address and not a PC-relative
* reference.
*/
asm volatile("ldr %0, =__hyp_panic_string" : "=r" (str_va));
__hyp_do_panic(str_va,
spsr, elr,
read_sysreg(esr_el2), read_sysreg_el2(far),
read_sysreg(hpfar_el2), par, vcpu);
}
static void __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par,
struct kvm_cpu_context *host_ctxt)
{
struct kvm_vcpu *vcpu;
vcpu = host_ctxt->__hyp_running_vcpu;
__deactivate_traps(vcpu);
sysreg_restore_host_state_vhe(host_ctxt);
panic(__hyp_panic_string,
spsr, elr,
read_sysreg_el2(esr), read_sysreg_el2(far),
read_sysreg(hpfar_el2), par, vcpu);
}
void __hyp_text __noreturn hyp_panic(struct kvm_cpu_context *host_ctxt)
{
u64 spsr = read_sysreg_el2(spsr);
u64 elr = read_sysreg_el2(elr);
u64 par = read_sysreg(par_el1);
if (!has_vhe())
__hyp_call_panic_nvhe(spsr, elr, par, host_ctxt);
else
__hyp_call_panic_vhe(spsr, elr, par, host_ctxt);
unreachable();
}