linux/arch/arm64/kvm/reset.c

444 lines
11 KiB
C

/*
* 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>
*
* 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/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_coproc.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_mmu.h>
#include <asm/virt.h>
/* Maximum phys_shift supported for any VM on this host */
static u32 kvm_ipa_limit;
/*
* ARMv8 Reset Values
*/
static const struct kvm_regs default_regs_reset = {
.regs.pstate = (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT |
PSR_F_BIT | PSR_D_BIT),
};
static const struct kvm_regs default_regs_reset32 = {
.regs.pstate = (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT |
PSR_AA32_I_BIT | PSR_AA32_F_BIT),
};
static bool cpu_has_32bit_el1(void)
{
u64 pfr0;
pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
return !!(pfr0 & 0x20);
}
/**
* kvm_arch_vm_ioctl_check_extension
*
* We currently assume that the number of HW registers is uniform
* across all CPUs (see cpuinfo_sanity_check).
*/
int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext)
{
int r;
switch (ext) {
case KVM_CAP_ARM_EL1_32BIT:
r = cpu_has_32bit_el1();
break;
case KVM_CAP_GUEST_DEBUG_HW_BPS:
r = get_num_brps();
break;
case KVM_CAP_GUEST_DEBUG_HW_WPS:
r = get_num_wrps();
break;
case KVM_CAP_ARM_PMU_V3:
r = kvm_arm_support_pmu_v3();
break;
case KVM_CAP_ARM_INJECT_SERROR_ESR:
r = cpus_have_const_cap(ARM64_HAS_RAS_EXTN);
break;
case KVM_CAP_SET_GUEST_DEBUG:
case KVM_CAP_VCPU_ATTRIBUTES:
r = 1;
break;
case KVM_CAP_ARM_VM_IPA_SIZE:
r = kvm_ipa_limit;
break;
case KVM_CAP_ARM_SVE:
r = system_supports_sve();
break;
default:
r = 0;
}
return r;
}
unsigned int kvm_sve_max_vl;
int 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
* SVE_VL_ARCH_MAX:
*/
if (WARN_ON(kvm_sve_max_vl > SVE_VL_ARCH_MAX))
kvm_sve_max_vl = SVE_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;
/* Verify that KVM startup enforced this when SVE was detected: */
if (WARN_ON(!has_vhe()))
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->arch.flags |= KVM_ARM64_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;
vl = vcpu->arch.sve_max_vl;
/*
* Resposibility for these properties is shared between
* kvm_arm_init_arch_resources(), 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 > SVE_VL_ARCH_MAX))
return -EIO;
buf = kzalloc(SVE_SIG_REGS_SIZE(sve_vq_from_vl(vl)), GFP_KERNEL);
if (!buf)
return -ENOMEM;
vcpu->arch.sve_state = buf;
vcpu->arch.flags |= KVM_ARM64_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_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
kfree(vcpu->arch.sve_state);
}
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)
{
/* Support ptrauth only if the system supports these capabilities. */
if (!has_vhe())
return -EINVAL;
if (!system_supports_address_auth() ||
!system_supports_generic_auth())
return -EINVAL;
/*
* For now make sure that both address/generic pointer authentication
* features are requested by the userspace together.
*/
if (!test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, vcpu->arch.features) ||
!test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, vcpu->arch.features))
return -EINVAL;
vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_PTRAUTH;
return 0;
}
/**
* kvm_reset_vcpu - sets core registers and sys_regs to reset value
* @vcpu: The VCPU pointer
*
* This function finds the right table above and 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 valus 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)
{
const struct kvm_regs *cpu_reset;
int ret = -EINVAL;
bool loaded;
preempt_disable();
loaded = (vcpu->cpu != -1);
if (loaded)
kvm_arch_vcpu_put(vcpu);
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))
goto out;
}
switch (vcpu->arch.target) {
default:
if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
if (!cpu_has_32bit_el1())
goto out;
cpu_reset = &default_regs_reset32;
} else {
cpu_reset = &default_regs_reset;
}
break;
}
/* Reset core registers */
memcpy(vcpu_gp_regs(vcpu), cpu_reset, sizeof(*cpu_reset));
/* 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 (vcpu->arch.reset_state.reset) {
unsigned long target_pc = vcpu->arch.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 (vcpu->arch.reset_state.be)
kvm_vcpu_set_be(vcpu);
*vcpu_pc(vcpu) = target_pc;
vcpu_set_reg(vcpu, 0, vcpu->arch.reset_state.r0);
vcpu->arch.reset_state.reset = false;
}
/* Reset PMU */
kvm_pmu_vcpu_reset(vcpu);
/* Default workaround setup is enabled (if supported) */
if (kvm_arm_have_ssbd() == KVM_SSBD_KERNEL)
vcpu->arch.workaround_flags |= VCPU_WORKAROUND_2_FLAG;
/* Reset timer */
ret = kvm_timer_vcpu_reset(vcpu);
out:
if (loaded)
kvm_arch_vcpu_load(vcpu, smp_processor_id());
preempt_enable();
return ret;
}
void kvm_set_ipa_limit(void)
{
unsigned int ipa_max, pa_max, va_max, parange;
parange = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1) & 0x7;
pa_max = id_aa64mmfr0_parange_to_phys_shift(parange);
/* Clamp the IPA limit to the PA size supported by the kernel */
ipa_max = (pa_max > PHYS_MASK_SHIFT) ? PHYS_MASK_SHIFT : pa_max;
/*
* Since our stage2 table is dependent on the stage1 page table code,
* we must always honor the following condition:
*
* Number of levels in Stage1 >= Number of levels in Stage2.
*
* So clamp the ipa limit further down to limit the number of levels.
* Since we can concatenate upto 16 tables at entry level, we could
* go upto 4bits above the maximum VA addressible with the current
* number of levels.
*/
va_max = PGDIR_SHIFT + PAGE_SHIFT - 3;
va_max += 4;
if (va_max < ipa_max)
ipa_max = va_max;
/*
* If the final limit is lower than the real physical address
* limit of the CPUs, report the reason.
*/
if (ipa_max < pa_max)
pr_info("kvm: Limiting the IPA size due to kernel %s Address limit\n",
(va_max < pa_max) ? "Virtual" : "Physical");
WARN(ipa_max < KVM_PHYS_SHIFT,
"KVM IPA limit (%d bit) is smaller than default size\n", ipa_max);
kvm_ipa_limit = ipa_max;
kvm_info("IPA Size Limit: %dbits\n", kvm_ipa_limit);
}
/*
* Configure the VTCR_EL2 for this VM. The VTCR value is common
* across all the physical CPUs on the system. We use system wide
* sanitised values to fill in different fields, except for Hardware
* Management of Access Flags. HA Flag is set unconditionally on
* all CPUs, as it is safe to run with or without the feature and
* the bit is RES0 on CPUs that don't support it.
*/
int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
{
u64 vtcr = VTCR_EL2_FLAGS;
u32 parange, phys_shift;
u8 lvls;
if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
return -EINVAL;
phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
if (phys_shift) {
if (phys_shift > kvm_ipa_limit ||
phys_shift < 32)
return -EINVAL;
} else {
phys_shift = KVM_PHYS_SHIFT;
}
parange = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1) & 7;
if (parange > ID_AA64MMFR0_PARANGE_MAX)
parange = ID_AA64MMFR0_PARANGE_MAX;
vtcr |= parange << VTCR_EL2_PS_SHIFT;
vtcr |= VTCR_EL2_T0SZ(phys_shift);
/*
* Use a minimum 2 level page table to prevent splitting
* host PMD huge pages at stage2.
*/
lvls = stage2_pgtable_levels(phys_shift);
if (lvls < 2)
lvls = 2;
vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls);
/*
* Enable the Hardware Access Flag management, unconditionally
* on all CPUs. The features is RES0 on CPUs without the support
* and must be ignored by the CPUs.
*/
vtcr |= VTCR_EL2_HA;
/* Set the vmid bits */
vtcr |= (kvm_get_vmid_bits() == 16) ?
VTCR_EL2_VS_16BIT :
VTCR_EL2_VS_8BIT;
kvm->arch.vtcr = vtcr;
return 0;
}