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linux-zen-desktop/arch/arm64/kvm/reset.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2012,2013 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* Derived from arch/arm/kvm/reset.c
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
* Author: Christoffer Dall <c.dall@virtualopensystems.com>
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/hw_breakpoint.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>
#include <kvm/arm_arch_timer.h>
#include <asm/cpufeature.h>
#include <asm/cputype.h>
#include <asm/fpsimd.h>
#include <asm/ptrace.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_nested.h>
#include <asm/virt.h>
/* Maximum phys_shift supported for any VM on this host */
static u32 __ro_after_init kvm_ipa_limit;
/*
* ARMv8 Reset Values
*/
#define VCPU_RESET_PSTATE_EL1 (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
PSR_F_BIT | PSR_D_BIT)
#define VCPU_RESET_PSTATE_EL2 (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT | \
PSR_F_BIT | PSR_D_BIT)
#define VCPU_RESET_PSTATE_SVC (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
PSR_AA32_I_BIT | PSR_AA32_F_BIT)
unsigned int __ro_after_init kvm_sve_max_vl;
int __init kvm_arm_init_sve(void)
{
if (system_supports_sve()) {
kvm_sve_max_vl = sve_max_virtualisable_vl();
/*
* The get_sve_reg()/set_sve_reg() ioctl interface will need
* to be extended with multiple register slice support in
* order to support vector lengths greater than
* VL_ARCH_MAX:
*/
if (WARN_ON(kvm_sve_max_vl > VL_ARCH_MAX))
kvm_sve_max_vl = VL_ARCH_MAX;
/*
* Don't even try to make use of vector lengths that
* aren't available on all CPUs, for now:
*/
if (kvm_sve_max_vl < sve_max_vl())
pr_warn("KVM: SVE vector length for guests limited to %u bytes\n",
kvm_sve_max_vl);
}
return 0;
}
static int kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
{
if (!system_supports_sve())
return -EINVAL;
vcpu->arch.sve_max_vl = kvm_sve_max_vl;
/*
* Userspace can still customize the vector lengths by writing
* KVM_REG_ARM64_SVE_VLS. Allocation is deferred until
* kvm_arm_vcpu_finalize(), which freezes the configuration.
*/
vcpu_set_flag(vcpu, GUEST_HAS_SVE);
return 0;
}
/*
* Finalize vcpu's maximum SVE vector length, allocating
* vcpu->arch.sve_state as necessary.
*/
static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
{
void *buf;
unsigned int vl;
size_t reg_sz;
int ret;
vl = vcpu->arch.sve_max_vl;
/*
* Responsibility for these properties is shared between
* kvm_arm_init_sve(), kvm_vcpu_enable_sve() and
* set_sve_vls(). Double-check here just to be sure:
*/
if (WARN_ON(!sve_vl_valid(vl) || vl > sve_max_virtualisable_vl() ||
vl > VL_ARCH_MAX))
return -EIO;
reg_sz = vcpu_sve_state_size(vcpu);
buf = kzalloc(reg_sz, GFP_KERNEL_ACCOUNT);
if (!buf)
return -ENOMEM;
ret = kvm_share_hyp(buf, buf + reg_sz);
if (ret) {
kfree(buf);
return ret;
}
vcpu->arch.sve_state = buf;
vcpu_set_flag(vcpu, VCPU_SVE_FINALIZED);
return 0;
}
int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
{
switch (feature) {
case KVM_ARM_VCPU_SVE:
if (!vcpu_has_sve(vcpu))
return -EINVAL;
if (kvm_arm_vcpu_sve_finalized(vcpu))
return -EPERM;
return kvm_vcpu_finalize_sve(vcpu);
}
return -EINVAL;
}
bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
{
if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
return false;
return true;
}
void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
void *sve_state = vcpu->arch.sve_state;
kvm_vcpu_unshare_task_fp(vcpu);
kvm_unshare_hyp(vcpu, vcpu + 1);
if (sve_state)
kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));
kfree(sve_state);
kfree(vcpu->arch.ccsidr);
}
static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
{
if (vcpu_has_sve(vcpu))
memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu));
}
static int kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
{
/*
* For now make sure that both address/generic pointer authentication
* features are requested by the userspace together and the system
* supports these capabilities.
*/
if (!test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
!test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features) ||
!system_has_full_ptr_auth())
return -EINVAL;
vcpu_set_flag(vcpu, GUEST_HAS_PTRAUTH);
return 0;
}
/**
* kvm_reset_vcpu - sets core registers and sys_regs to reset value
* @vcpu: The VCPU pointer
*
* This function sets the registers on the virtual CPU struct to their
* architecturally defined reset values, except for registers whose reset is
* deferred until kvm_arm_vcpu_finalize().
*
* Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT
* ioctl or as part of handling a request issued by another VCPU in the PSCI
* handling code. In the first case, the VCPU will not be loaded, and in the
* second case the VCPU will be loaded. Because this function operates purely
* on the memory-backed values of system registers, we want to do a full put if
* we were loaded (handling a request) and load the values back at the end of
* the function. Otherwise we leave the state alone. In both cases, we
* disable preemption around the vcpu reset as we would otherwise race with
* preempt notifiers which also call put/load.
*/
int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
{
struct vcpu_reset_state reset_state;
int ret;
bool loaded;
u32 pstate;
spin_lock(&vcpu->arch.mp_state_lock);
reset_state = vcpu->arch.reset_state;
vcpu->arch.reset_state.reset = false;
spin_unlock(&vcpu->arch.mp_state_lock);
/* Reset PMU outside of the non-preemptible section */
kvm_pmu_vcpu_reset(vcpu);
preempt_disable();
loaded = (vcpu->cpu != -1);
if (loaded)
kvm_arch_vcpu_put(vcpu);
/* Disallow NV+SVE for the time being */
if (vcpu_has_nv(vcpu) && vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {
ret = -EINVAL;
goto out;
}
if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features)) {
ret = kvm_vcpu_enable_sve(vcpu);
if (ret)
goto out;
}
} else {
kvm_vcpu_reset_sve(vcpu);
}
if (test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features)) {
if (kvm_vcpu_enable_ptrauth(vcpu)) {
ret = -EINVAL;
goto out;
}
}
switch (vcpu->arch.target) {
default:
if (vcpu_el1_is_32bit(vcpu)) {
pstate = VCPU_RESET_PSTATE_SVC;
} else if (vcpu_has_nv(vcpu)) {
pstate = VCPU_RESET_PSTATE_EL2;
} else {
pstate = VCPU_RESET_PSTATE_EL1;
}
if (kvm_vcpu_has_pmu(vcpu) && !kvm_arm_support_pmu_v3()) {
ret = -EINVAL;
goto out;
}
break;
}
/* Reset core registers */
memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
vcpu->arch.ctxt.spsr_abt = 0;
vcpu->arch.ctxt.spsr_und = 0;
vcpu->arch.ctxt.spsr_irq = 0;
vcpu->arch.ctxt.spsr_fiq = 0;
vcpu_gp_regs(vcpu)->pstate = pstate;
/* Reset system registers */
kvm_reset_sys_regs(vcpu);
/*
* Additional reset state handling that PSCI may have imposed on us.
* Must be done after all the sys_reg reset.
*/
if (reset_state.reset) {
unsigned long target_pc = reset_state.pc;
/* Gracefully handle Thumb2 entry point */
if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
target_pc &= ~1UL;
vcpu_set_thumb(vcpu);
}
/* Propagate caller endianness */
if (reset_state.be)
kvm_vcpu_set_be(vcpu);
*vcpu_pc(vcpu) = target_pc;
vcpu_set_reg(vcpu, 0, reset_state.r0);
}
/* Reset timer */
ret = kvm_timer_vcpu_reset(vcpu);
out:
if (loaded)
kvm_arch_vcpu_load(vcpu, smp_processor_id());
preempt_enable();
return ret;
}
u32 get_kvm_ipa_limit(void)
{
return kvm_ipa_limit;
}
int __init kvm_set_ipa_limit(void)
{
unsigned int parange;
u64 mmfr0;
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
parange = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_EL1_PARANGE_SHIFT);
/*
* IPA size beyond 48 bits could not be supported
* on either 4K or 16K page size. Hence let's cap
* it to 48 bits, in case it's reported as larger
* on the system.
*/
if (PAGE_SIZE != SZ_64K)
parange = min(parange, (unsigned int)ID_AA64MMFR0_EL1_PARANGE_48);
/*
* Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
* Stage-2. If not, things will stop very quickly.
*/
switch (cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_EL1_TGRAN_2_SHIFT)) {
case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_NONE:
kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
return -EINVAL;
case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_DEFAULT:
kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
break;
case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MAX:
kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
break;
default:
kvm_err("Unsupported value for TGRAN_2, giving up\n");
return -EINVAL;
}
kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange);
kvm_info("IPA Size Limit: %d bits%s\n", kvm_ipa_limit,
((kvm_ipa_limit < KVM_PHYS_SHIFT) ?
" (Reduced IPA size, limited VM/VMM compatibility)" : ""));
return 0;
}
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