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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2015 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#include <hyp/switch.h>
#include <hyp/sysreg-sr.h>
#include <linux/arm-smccc.h>
#include <linux/kvm_host.h>
#include <linux/types.h>
#include <linux/jump_label.h>
#include <uapi/linux/psci.h>
#include <kvm/arm_psci.h>
#include <asm/barrier.h>
#include <asm/cpufeature.h>
#include <asm/kprobes.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.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 <nvhe/fixed_config.h>
#include <nvhe/mem_protect.h>
/* Non-VHE specific context */
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);
extern void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
static void __activate_traps(struct kvm_vcpu *vcpu)
{
u64 val;
___activate_traps(vcpu);
__activate_traps_common(vcpu);
val = vcpu->arch.cptr_el2;
val |= CPTR_EL2_TAM; /* Same bit irrespective of E2H */
val |= has_hvhe() ? CPACR_EL1_TTA : CPTR_EL2_TTA;
if (cpus_have_final_cap(ARM64_SME)) {
if (has_hvhe())
val &= ~(CPACR_EL1_SMEN_EL1EN | CPACR_EL1_SMEN_EL0EN);
else
val |= CPTR_EL2_TSM;
}
if (!guest_owns_fp_regs(vcpu)) {
if (has_hvhe())
val &= ~(CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN |
CPACR_EL1_ZEN_EL0EN | CPACR_EL1_ZEN_EL1EN);
else
val |= CPTR_EL2_TFP | CPTR_EL2_TZ;
__activate_traps_fpsimd32(vcpu);
}
kvm_write_cptr_el2(val);
write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el2);
if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
isb();
/*
* At this stage, and thanks to the above isb(), S2 is
* configured and enabled. We can now restore the guest's S1
* configuration: SCTLR, and only then TCR.
*/
write_sysreg_el1(ctxt_sys_reg(ctxt, SCTLR_EL1), SYS_SCTLR);
isb();
write_sysreg_el1(ctxt_sys_reg(ctxt, TCR_EL1), SYS_TCR);
}
}
static void __deactivate_traps(struct kvm_vcpu *vcpu)
{
extern char __kvm_hyp_host_vector[];
___deactivate_traps(vcpu);
if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
u64 val;
/*
* Set the TCR and SCTLR registers in the exact opposite
* sequence as __activate_traps (first prevent walks,
* then force the MMU on). A generous sprinkling of isb()
* ensure that things happen in this exact order.
*/
val = read_sysreg_el1(SYS_TCR);
write_sysreg_el1(val | TCR_EPD1_MASK | TCR_EPD0_MASK, SYS_TCR);
isb();
val = read_sysreg_el1(SYS_SCTLR);
write_sysreg_el1(val | SCTLR_ELx_M, SYS_SCTLR);
isb();
}
__deactivate_traps_common(vcpu);
write_sysreg(this_cpu_ptr(&kvm_init_params)->hcr_el2, hcr_el2);
kvm_reset_cptr_el2(vcpu);
write_sysreg(__kvm_hyp_host_vector, vbar_el2);
}
/* Save VGICv3 state on non-VHE systems */
static void __hyp_vgic_save_state(struct kvm_vcpu *vcpu)
{
if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_save_state(&vcpu->arch.vgic_cpu.vgic_v3);
__vgic_v3_deactivate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
}
}
/* Restore VGICv3 state on non-VHE systems */
static void __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
{
if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_activate_traps(&vcpu->arch.vgic_cpu.vgic_v3);
__vgic_v3_restore_state(&vcpu->arch.vgic_cpu.vgic_v3);
}
}
/*
* Disable host events, enable guest events
*/
#ifdef CONFIG_HW_PERF_EVENTS
static bool __pmu_switch_to_guest(struct kvm_vcpu *vcpu)
{
struct kvm_pmu_events *pmu = &vcpu->arch.pmu.events;
if (pmu->events_host)
write_sysreg(pmu->events_host, pmcntenclr_el0);
if (pmu->events_guest)
write_sysreg(pmu->events_guest, pmcntenset_el0);
return (pmu->events_host || pmu->events_guest);
}
/*
* Disable guest events, enable host events
*/
static void __pmu_switch_to_host(struct kvm_vcpu *vcpu)
{
struct kvm_pmu_events *pmu = &vcpu->arch.pmu.events;
if (pmu->events_guest)
write_sysreg(pmu->events_guest, pmcntenclr_el0);
if (pmu->events_host)
write_sysreg(pmu->events_host, pmcntenset_el0);
}
#else
#define __pmu_switch_to_guest(v) ({ false; })
#define __pmu_switch_to_host(v) do {} while (0)
#endif
/*
* Handler for protected VM MSR, MRS or System instruction execution in AArch64.
*
* Returns true if the hypervisor has handled the exit, and control should go
* back to the guest, or false if it hasn't.
*/
static bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code)
{
/*
* Make sure we handle the exit for workarounds and ptrauth
* before the pKVM handling, as the latter could decide to
* UNDEF.
*/
return (kvm_hyp_handle_sysreg(vcpu, exit_code) ||
kvm_handle_pvm_sysreg(vcpu, exit_code));
}
static const exit_handler_fn hyp_exit_handlers[] = {
[0 ... ESR_ELx_EC_MAX] = NULL,
[ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15_32,
[ESR_ELx_EC_SYS64] = kvm_hyp_handle_sysreg,
[ESR_ELx_EC_SVE] = kvm_hyp_handle_fpsimd,
[ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd,
[ESR_ELx_EC_IABT_LOW] = kvm_hyp_handle_iabt_low,
[ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low,
[ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low,
[ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth,
};
static const exit_handler_fn pvm_exit_handlers[] = {
[0 ... ESR_ELx_EC_MAX] = NULL,
[ESR_ELx_EC_SYS64] = kvm_handle_pvm_sys64,
[ESR_ELx_EC_SVE] = kvm_handle_pvm_restricted,
[ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd,
[ESR_ELx_EC_IABT_LOW] = kvm_hyp_handle_iabt_low,
[ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low,
[ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low,
[ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth,
};
static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu)
{
if (unlikely(kvm_vm_is_protected(kern_hyp_va(vcpu->kvm))))
return pvm_exit_handlers;
return hyp_exit_handlers;
}
/*
* Some guests (e.g., protected VMs) are not be allowed to run in AArch32.
* The ARMv8 architecture does not give the hypervisor a mechanism to prevent a
* guest from dropping to AArch32 EL0 if implemented by the CPU. If the
* hypervisor spots a guest in such a state ensure it is handled, and don't
* trust the host to spot or fix it. The check below is based on the one in
* kvm_arch_vcpu_ioctl_run().
*
* Returns false if the guest ran in AArch32 when it shouldn't have, and
* thus should exit to the host, or true if a the guest run loop can continue.
*/
static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code)
{
struct kvm *kvm = kern_hyp_va(vcpu->kvm);
if (kvm_vm_is_protected(kvm) && vcpu_mode_is_32bit(vcpu)) {
/*
* As we have caught the guest red-handed, decide that it isn't
* fit for purpose anymore by making the vcpu invalid. The VMM
* can try and fix it by re-initializing the vcpu with
* KVM_ARM_VCPU_INIT, however, this is likely not possible for
* protected VMs.
*/
vcpu->arch.target = -1;
*exit_code &= BIT(ARM_EXIT_WITH_SERROR_BIT);
*exit_code |= ARM_EXCEPTION_IL;
}
}
/* Switch to the guest for legacy non-VHE systems */
int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
struct kvm_s2_mmu *mmu;
bool pmu_switch_needed;
u64 exit_code;
/*
* Having IRQs masked via PMR when entering the guest means the GIC
* will not signal the CPU of interrupts of lower priority, and the
* only way to get out will be via guest exceptions.
* Naturally, we want to avoid this.
*/
if (system_uses_irq_prio_masking()) {
gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
pmr_sync();
}
host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
host_ctxt->__hyp_running_vcpu = vcpu;
guest_ctxt = &vcpu->arch.ctxt;
pmu_switch_needed = __pmu_switch_to_guest(vcpu);
__sysreg_save_state_nvhe(host_ctxt);
/*
* We must flush and disable the SPE buffer for nVHE, as
* the translation regime(EL1&0) is going to be loaded with
* that of the guest. And we must do this before we change the
* translation regime to EL2 (via MDCR_EL2_E2PB == 0) and
* before we load guest Stage1.
*/
__debug_save_host_buffers_nvhe(vcpu);
/*
* We're about to restore some new MMU state. Make sure
* ongoing page-table walks that have started before we
* trapped to EL2 have completed. This also synchronises the
* above disabling of SPE and TRBE.
*
* See DDI0487I.a D8.1.5 "Out-of-context translation regimes",
* rule R_LFHQG and subsequent information statements.
*/
dsb(nsh);
__kvm_adjust_pc(vcpu);
/*
* We must restore the 32-bit state before the sysregs, thanks
* to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
*
* Also, and in order to be able to deal with erratum #1319537 (A57)
* and #1319367 (A72), we must ensure that all VM-related sysreg are
* restored before we enable S2 translation.
*/
__sysreg32_restore_state(vcpu);
__sysreg_restore_state_nvhe(guest_ctxt);
mmu = kern_hyp_va(vcpu->arch.hw_mmu);
__load_stage2(mmu, kern_hyp_va(mmu->arch));
__activate_traps(vcpu);
__hyp_vgic_restore_state(vcpu);
__timer_enable_traps(vcpu);
__debug_switch_to_guest(vcpu);
do {
/* Jump in the fire! */
exit_code = __guest_enter(vcpu);
/* And we're baaack! */
} while (fixup_guest_exit(vcpu, &exit_code));
__sysreg_save_state_nvhe(guest_ctxt);
__sysreg32_save_state(vcpu);
__timer_disable_traps(vcpu);
__hyp_vgic_save_state(vcpu);
/*
* Same thing as before the guest run: we're about to switch
* the MMU context, so let's make sure we don't have any
* ongoing EL1&0 translations.
*/
dsb(nsh);
__deactivate_traps(vcpu);
__load_host_stage2();
__sysreg_restore_state_nvhe(host_ctxt);
if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED)
__fpsimd_save_fpexc32(vcpu);
__debug_switch_to_host(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_restore_host_buffers_nvhe(vcpu);
if (pmu_switch_needed)
__pmu_switch_to_host(vcpu);
/* Returning to host will clear PSR.I, remask PMR if needed */
if (system_uses_irq_prio_masking())
gic_write_pmr(GIC_PRIO_IRQOFF);
host_ctxt->__hyp_running_vcpu = NULL;
return exit_code;
}
asmlinkage void __noreturn hyp_panic(void)
{
u64 spsr = read_sysreg_el2(SYS_SPSR);
u64 elr = read_sysreg_el2(SYS_ELR);
u64 par = read_sysreg_par();
struct kvm_cpu_context *host_ctxt;
struct kvm_vcpu *vcpu;
host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
vcpu = host_ctxt->__hyp_running_vcpu;
if (vcpu) {
__timer_disable_traps(vcpu);
__deactivate_traps(vcpu);
__load_host_stage2();
__sysreg_restore_state_nvhe(host_ctxt);
}
/* Prepare to dump kvm nvhe hyp stacktrace */
kvm_nvhe_prepare_backtrace((unsigned long)__builtin_frame_address(0),
_THIS_IP_);
__hyp_do_panic(host_ctxt, spsr, elr, par);
unreachable();
}
asmlinkage void __noreturn hyp_panic_bad_stack(void)
{
hyp_panic();
}
asmlinkage void kvm_unexpected_el2_exception(void)
{
__kvm_unexpected_el2_exception();
}
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