On Fri, Aug 27, 2021 at 11:16:05AM +0100, Fuad Tabba wrote:
> Add trap handlers for protected VMs. These are mainly for Sys64
> and debug traps.
>
> No functional change intended as these are not hooked in yet to
> the guest exit handlers introduced earlier. So even when trapping
> is triggered, the exit handlers would let the host handle it, as
> before.
>
> Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_fixed_config.h | 164 +++++++
> arch/arm64/include/asm/kvm_hyp.h | 5 +
> arch/arm64/kvm/arm.c | 5 +
> arch/arm64/kvm/hyp/include/nvhe/sys_regs.h | 29 ++
> arch/arm64/kvm/hyp/nvhe/Makefile | 2 +-
> arch/arm64/kvm/hyp/nvhe/switch.c | 1 +
> arch/arm64/kvm/hyp/nvhe/sys_regs.c | 523 +++++++++++++++++++++
> 7 files changed, 728 insertions(+), 1 deletion(-)
> create mode 100644 arch/arm64/include/asm/kvm_fixed_config.h
> create mode 100644 arch/arm64/kvm/hyp/include/nvhe/sys_regs.h
> create mode 100644 arch/arm64/kvm/hyp/nvhe/sys_regs.c
>
> diff --git a/arch/arm64/include/asm/kvm_fixed_config.h b/arch/arm64/include/asm/kvm_fixed_config.h
> new file mode 100644
> index 000000000000..9085301d159e
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_fixed_config.h
> @@ -0,0 +1,164 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2021 Google LLC
> + * Author: Fuad Tabba <tabba@xxxxxxxxxx>
> + */
> +
> +#ifndef __ARM64_KVM_FIXED_CONFIG_H__
> +#define __ARM64_KVM_FIXED_CONFIG_H__
> +
> +#include <asm/sysreg.h>
> +
> +/*
> + * This file contains definitions for features to be allowed or restricted for
> + * guest virtual machines, depending on the mode KVM is running in and on the
> + * type of guest that is running.
> + *
> + * The ALLOW masks represent a bitmask of feature fields that are allowed
> + * without any restrictions as long as they are supported by the system.
> + *
> + * The RESTRICT_UNSIGNED masks, if present, represent unsigned fields for
> + * features that are restricted to support at most the specified feature.
> + *
> + * If a feature field is not present in either, than it is not supported.
> + *
> + * The approach taken for protected VMs is to allow features that are:
> + * - Needed by common Linux distributions (e.g., floating point)
> + * - Trivial to support, e.g., supporting the feature does not introduce or
> + * require tracking of additional state in KVM
> + * - Cannot be trapped or prevent the guest from using anyway
> + */
> +
> +/*
> + * Allow for protected VMs:
> + * - Floating-point and Advanced SIMD
> + * - Data Independent Timing
> + */
> +#define PVM_ID_AA64PFR0_ALLOW (\
> + ARM64_FEATURE_MASK(ID_AA64PFR0_FP) | \
> + ARM64_FEATURE_MASK(ID_AA64PFR0_ASIMD) | \
> + ARM64_FEATURE_MASK(ID_AA64PFR0_DIT) \
> + )
> +
> +/*
> + * Restrict to the following *unsigned* features for protected VMs:
> + * - AArch64 guests only (no support for AArch32 guests):
> + * AArch32 adds complexity in trap handling, emulation, condition codes,
> + * etc...
> + * - RAS (v1)
> + * Supported by KVM
> + */
> +#define PVM_ID_AA64PFR0_RESTRICT_UNSIGNED (\
> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL0), ID_AA64PFR0_ELx_64BIT_ONLY) | \
> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1), ID_AA64PFR0_ELx_64BIT_ONLY) | \
> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL2), ID_AA64PFR0_ELx_64BIT_ONLY) | \
> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL3), ID_AA64PFR0_ELx_64BIT_ONLY) | \
> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_RAS), ID_AA64PFR0_RAS_V1) \
> + )
> +
> +/*
> + * Allow for protected VMs:
> + * - Branch Target Identification
> + * - Speculative Store Bypassing
> + */
> +#define PVM_ID_AA64PFR1_ALLOW (\
> + ARM64_FEATURE_MASK(ID_AA64PFR1_BT) | \
> + ARM64_FEATURE_MASK(ID_AA64PFR1_SSBS) \
> + )
> +
> +/*
> + * Allow for protected VMs:
> + * - Mixed-endian
> + * - Distinction between Secure and Non-secure Memory
> + * - Mixed-endian at EL0 only
> + * - Non-context synchronizing exception entry and exit
> + */
> +#define PVM_ID_AA64MMFR0_ALLOW (\
> + ARM64_FEATURE_MASK(ID_AA64MMFR0_BIGENDEL) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR0_SNSMEM) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR0_BIGENDEL0) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR0_EXS) \
> + )
> +
> +/*
> + * Restrict to the following *unsigned* features for protected VMs:
> + * - 40-bit IPA
> + * - 16-bit ASID
> + */
> +#define PVM_ID_AA64MMFR0_RESTRICT_UNSIGNED (\
> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64MMFR0_PARANGE), ID_AA64MMFR0_PARANGE_40) | \
> + FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64MMFR0_ASID), ID_AA64MMFR0_ASID_16) \
> + )
> +
> +/*
> + * Allow for protected VMs:
> + * - Hardware translation table updates to Access flag and Dirty state
> + * - Number of VMID bits from CPU
> + * - Hierarchical Permission Disables
> + * - Privileged Access Never
> + * - SError interrupt exceptions from speculative reads
> + * - Enhanced Translation Synchronization
> + */
> +#define PVM_ID_AA64MMFR1_ALLOW (\
> + ARM64_FEATURE_MASK(ID_AA64MMFR1_HADBS) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR1_VMIDBITS) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR1_HPD) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR1_PAN) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR1_SPECSEI) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR1_ETS) \
> + )
> +
> +/*
> + * Allow for protected VMs:
> + * - Common not Private translations
> + * - User Access Override
> + * - IESB bit in the SCTLR_ELx registers
> + * - Unaligned single-copy atomicity and atomic functions
> + * - ESR_ELx.EC value on an exception by read access to feature ID space
> + * - TTL field in address operations.
> + * - Break-before-make sequences when changing translation block size
> + * - E0PDx mechanism
> + */
> +#define PVM_ID_AA64MMFR2_ALLOW (\
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_CNP) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_UAO) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_IESB) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_AT) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_IDS) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_TTL) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_BBM) | \
> + ARM64_FEATURE_MASK(ID_AA64MMFR2_E0PD) \
> + )
> +
> +/*
> + * No support for Scalable Vectors for protected VMs:
> + * Requires additional support from KVM, e.g., context-switching and
> + * trapping at EL2
> + */
> +#define PVM_ID_AA64ZFR0_ALLOW (0ULL)
> +
> +/*
> + * No support for debug, including breakpoints, and watchpoints for protected
> + * VMs:
> + * The Arm architecture mandates support for at least the Armv8 debug
> + * architecture, which would include at least 2 hardware breakpoints and
> + * watchpoints. Providing that support to protected guests adds
> + * considerable state and complexity. Therefore, the reserved value of 0 is
> + * used for debug-related fields.
> + */
> +#define PVM_ID_AA64DFR0_ALLOW (0ULL)
> +#define PVM_ID_AA64DFR1_ALLOW (0ULL)
> +
> +/*
> + * No support for implementation defined features.
> + */
> +#define PVM_ID_AA64AFR0_ALLOW (0ULL)
> +#define PVM_ID_AA64AFR1_ALLOW (0ULL)
> +
> +/*
> + * No restrictions on instructions implemented in AArch64.
> + */
> +#define PVM_ID_AA64ISAR0_ALLOW (~0ULL)
> +#define PVM_ID_AA64ISAR1_ALLOW (~0ULL)
Hmm, I really like the explicit allow masks, but these are no longer
explicit. Why not set just the safe, supported features like we do
with the other registers? In fact, I feel it's a bit wrong to set the
res0 fields for ID_AA64ISAR0.
> +
> +#endif /* __ARM64_KVM_FIXED_CONFIG_H__ */
> diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
> index 657d0c94cf82..5afd14ab15b9 100644
> --- a/arch/arm64/include/asm/kvm_hyp.h
> +++ b/arch/arm64/include/asm/kvm_hyp.h
> @@ -115,7 +115,12 @@ int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
> void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
> #endif
>
> +extern u64 kvm_nvhe_sym(id_aa64pfr0_el1_sys_val);
> +extern u64 kvm_nvhe_sym(id_aa64pfr1_el1_sys_val);
> +extern u64 kvm_nvhe_sym(id_aa64isar0_el1_sys_val);
> +extern u64 kvm_nvhe_sym(id_aa64isar1_el1_sys_val);
> extern u64 kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val);
> extern u64 kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val);
> +extern u64 kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val);
>
> #endif /* __ARM64_KVM_HYP_H__ */
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index fe102cd2e518..6aa7b0c5bf21 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1802,8 +1802,13 @@ static int kvm_hyp_init_protection(u32 hyp_va_bits)
> void *addr = phys_to_virt(hyp_mem_base);
> int ret;
>
> + kvm_nvhe_sym(id_aa64pfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
> + kvm_nvhe_sym(id_aa64pfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1);
> + kvm_nvhe_sym(id_aa64isar0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64ISAR0_EL1);
> + kvm_nvhe_sym(id_aa64isar1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64ISAR1_EL1);
> kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
> kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
> + kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR2_EL1);
>
> ret = create_hyp_mappings(addr, addr + hyp_mem_size, PAGE_HYP);
> if (ret)
> diff --git a/arch/arm64/kvm/hyp/include/nvhe/sys_regs.h b/arch/arm64/kvm/hyp/include/nvhe/sys_regs.h
> new file mode 100644
> index 000000000000..f5c94a46bc74
> --- /dev/null
> +++ b/arch/arm64/kvm/hyp/include/nvhe/sys_regs.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2021 Google LLC
> + * Author: Fuad Tabba <tabba@xxxxxxxxxx>
> + */
> +
> +#ifndef __ARM64_KVM_NVHE_SYS_REGS_H__
> +#define __ARM64_KVM_NVHE_SYS_REGS_H__
> +
> +#include <asm/kvm_host.h>
> +
> +bool kvm_handle_pvm_restricted(struct kvm_vcpu *vcpu, u64 *exit_code);
> +bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code);
> +bool kvm_handle_pvm_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code);
> +
> +u64 get_pvm_id_aa64pfr0(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64pfr1(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64zfr0(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64dfr0(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64dfr1(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64afr0(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64afr1(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64isar0(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64isar1(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64mmfr0(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64mmfr1(const struct kvm_vcpu *vcpu);
> +u64 get_pvm_id_aa64mmfr2(const struct kvm_vcpu *vcpu);
> +
> +#endif /* __ARM64_KVM_NVHE_SYS_REGS_H__ */
> diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
> index 5df6193fc430..a23f417a0c20 100644
> --- a/arch/arm64/kvm/hyp/nvhe/Makefile
> +++ b/arch/arm64/kvm/hyp/nvhe/Makefile
> @@ -14,7 +14,7 @@ lib-objs := $(addprefix ../../../lib/, $(lib-objs))
>
> obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \
> hyp-main.o hyp-smp.o psci-relay.o early_alloc.o stub.o page_alloc.o \
> - cache.o setup.o mm.o mem_protect.o
> + cache.o setup.o mm.o mem_protect.o sys_regs.o
> obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
> ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o
> obj-y += $(lib-objs)
> diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
> index ebc0a5a4dd6a..41f05bf88f61 100644
> --- a/arch/arm64/kvm/hyp/nvhe/switch.c
> +++ b/arch/arm64/kvm/hyp/nvhe/switch.c
> @@ -28,6 +28,7 @@
> #include <asm/thread_info.h>
>
> #include <nvhe/mem_protect.h>
> +#include <nvhe/sys_regs.h>
>
> /* Non-VHE specific context */
> DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
> diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
> new file mode 100644
> index 000000000000..a7e836537154
> --- /dev/null
> +++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
> @@ -0,0 +1,523 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2021 Google LLC
> + * Author: Fuad Tabba <tabba@xxxxxxxxxx>
> + */
> +
> +#include <linux/kvm_host.h>
> +
> +#include <asm/kvm_asm.h>
> +#include <asm/kvm_emulate.h>
> +#include <asm/kvm_fixed_config.h>
> +#include <asm/kvm_mmu.h>
> +
> +#include <hyp/adjust_pc.h>
> +#include <hyp/switch.h>
> +
> +#include "../../sys_regs.h"
> +
> +/*
> + * Copies of the host's CPU features registers holding sanitized values at hyp.
> + */
> +u64 id_aa64pfr0_el1_sys_val;
> +u64 id_aa64pfr1_el1_sys_val;
> +u64 id_aa64isar0_el1_sys_val;
> +u64 id_aa64isar1_el1_sys_val;
> +u64 id_aa64mmfr2_el1_sys_val;
> +
> +static inline void inject_undef(struct kvm_vcpu *vcpu)
> +{
> + u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
> +
> + vcpu->arch.flags |= (KVM_ARM64_EXCEPT_AA64_EL1 |
> + KVM_ARM64_EXCEPT_AA64_ELx_SYNC |
> + KVM_ARM64_PENDING_EXCEPTION);
> +
> + __kvm_adjust_pc(vcpu);
> +
> + write_sysreg_el1(esr, SYS_ESR);
> + write_sysreg_el1(read_sysreg_el2(SYS_ELR), SYS_ELR);
> +}
> +
> +/*
> + * Inject an unknown/undefined exception to the guest while most of its sysregs
> + * are live.
> + */
> +static inline void __inject_undef(struct kvm_vcpu *vcpu)
> +{
> + *vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
> + *vcpu_cpsr(vcpu) = read_sysreg_el2(SYS_SPSR);
> +
> + inject_undef(vcpu);
> +
> + write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
> + write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR);
> +}
> +
> +/*
> + * Accessor for undefined accesses.
> + */
> +static bool undef_access(struct kvm_vcpu *vcpu,
> + struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + __inject_undef(vcpu);
> + return false;
> +}
> +
> +/*
> + * Returns the restricted features values of the feature register based on the
> + * limitations in restrict_fields.
> + * A feature id field value of 0b0000 does not impose any restrictions.
> + * Note: Use only for unsigned feature field values.
> + */
> +static u64 get_restricted_features_unsigned(u64 sys_reg_val,
> + u64 restrict_fields)
> +{
> + u64 value = 0UL;
> + u64 mask = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
> +
> + /*
> + * According to the Arm Architecture Reference Manual, feature fields
> + * use increasing values to indicate increases in functionality.
> + * Iterate over the restricted feature fields and calculate the minimum
> + * unsigned value between the one supported by the system, and what the
> + * value is being restricted to.
> + */
> + while (sys_reg_val && restrict_fields) {
> + value |= min(sys_reg_val & mask, restrict_fields & mask);
> + sys_reg_val &= ~mask;
> + restrict_fields &= ~mask;
> + mask <<= ARM64_FEATURE_FIELD_BITS;
> + }
> +
> + return value;
> +}
> +
> +/*
> + * Functions that return the value of feature id registers for protected VMs
> + * based on allowed features, system features, and KVM support.
> + */
> +
> +u64 get_pvm_id_aa64pfr0(const struct kvm_vcpu *vcpu)
> +{
> + const struct kvm *kvm = (const struct kvm *) kern_hyp_va(vcpu->kvm);
I didn't think checkpatch liked spaces after casts.
> + u64 set_mask = 0;
> + u64 allow_mask = PVM_ID_AA64PFR0_ALLOW;
> +
> + if (!vcpu_has_sve(vcpu))
> + allow_mask &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_SVE);
I'm not sure why this is here. SVE is not set in PVM_ID_AA64PFR0_ALLOW
and there's even a comment for PVM_ID_AA64ZFR0_ALLOW stating that SVE
is not supported for protected VMs.
> +
> + set_mask |= get_restricted_features_unsigned(id_aa64pfr0_el1_sys_val,
> + PVM_ID_AA64PFR0_RESTRICT_UNSIGNED);
> +
> + /* Spectre and Meltdown mitigation in KVM */
> + set_mask |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_CSV2),
> + (u64)kvm->arch.pfr0_csv2);
> + set_mask |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_CSV3),
> + (u64)kvm->arch.pfr0_csv3);
> +
> + return (id_aa64pfr0_el1_sys_val & allow_mask) | set_mask;
> +}
> +
> +u64 get_pvm_id_aa64pfr1(const struct kvm_vcpu *vcpu)
> +{
> + const struct kvm *kvm = (const struct kvm *) kern_hyp_va(vcpu->kvm);
> + u64 allow_mask = PVM_ID_AA64PFR1_ALLOW;
> +
> + if (!kvm_has_mte(kvm))
> + allow_mask &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_MTE);
Again, I'm not sure why we're clearing bits we never set.
> +
> + return id_aa64pfr1_el1_sys_val & allow_mask;
> +}
> +
> +u64 get_pvm_id_aa64zfr0(const struct kvm_vcpu *vcpu)
> +{
> + /*
> + * No support for Scalable Vectors, therefore, hyp has no sanitized
> + * copy of the feature id register.
> + */
> + BUILD_BUG_ON(PVM_ID_AA64ZFR0_ALLOW != 0ULL);
> + return 0;
> +}
> +
> +u64 get_pvm_id_aa64dfr0(const struct kvm_vcpu *vcpu)
> +{
> + /*
> + * No support for debug, including breakpoints, and watchpoints,
> + * therefore, pKVM has no sanitized copy of the feature id register.
> + */
> + BUILD_BUG_ON(PVM_ID_AA64DFR0_ALLOW != 0ULL);
> + return 0;
> +}
> +
> +u64 get_pvm_id_aa64dfr1(const struct kvm_vcpu *vcpu)
> +{
> + /*
> + * No support for debug, therefore, hyp has no sanitized copy of the
> + * feature id register.
> + */
> + BUILD_BUG_ON(PVM_ID_AA64DFR1_ALLOW != 0ULL);
> + return 0;
> +}
> +
> +u64 get_pvm_id_aa64afr0(const struct kvm_vcpu *vcpu)
> +{
> + /*
> + * No support for implementation defined features, therefore, hyp has no
> + * sanitized copy of the feature id register.
> + */
> + BUILD_BUG_ON(PVM_ID_AA64AFR0_ALLOW != 0ULL);
> + return 0;
> +}
> +
> +u64 get_pvm_id_aa64afr1(const struct kvm_vcpu *vcpu)
> +{
> + /*
> + * No support for implementation defined features, therefore, hyp has no
> + * sanitized copy of the feature id register.
> + */
> + BUILD_BUG_ON(PVM_ID_AA64AFR1_ALLOW != 0ULL);
> + return 0;
> +}
> +
> +u64 get_pvm_id_aa64isar0(const struct kvm_vcpu *vcpu)
> +{
> + return id_aa64isar0_el1_sys_val & PVM_ID_AA64ISAR0_ALLOW;
> +}
> +
> +u64 get_pvm_id_aa64isar1(const struct kvm_vcpu *vcpu)
> +{
> + u64 allow_mask = PVM_ID_AA64ISAR1_ALLOW;
> +
> + if (!vcpu_has_ptrauth(vcpu))
> + allow_mask &= ~(ARM64_FEATURE_MASK(ID_AA64ISAR1_APA) |
> + ARM64_FEATURE_MASK(ID_AA64ISAR1_API) |
> + ARM64_FEATURE_MASK(ID_AA64ISAR1_GPA) |
> + ARM64_FEATURE_MASK(ID_AA64ISAR1_GPI));
So here, since PVM_ID_AA64ISAR1_ALLOW is ~0, we do actually clear bits
when the vcpu doesn't support ptrauth. I presume the trap handling for
ptrauth will be covered for protected VMs too when we don't clear them.
> +
> + return id_aa64isar1_el1_sys_val & allow_mask;
> +}
> +
> +u64 get_pvm_id_aa64mmfr0(const struct kvm_vcpu *vcpu)
> +{
> + u64 set_mask =
> + get_restricted_features_unsigned(id_aa64mmfr0_el1_sys_val,
> + PVM_ID_AA64MMFR0_RESTRICT_UNSIGNED);
Rather than the above style, how about
u64 set_mask;
set_mask = get_restricted_features_unsigned(id_aa64mmfr0_el1_sys_val,
PVM_ID_AA64MMFR0_RESTRICT_UNSIGNED);
which is a best effort at staying in 80 chars and definitely stays
under 100, which is checkpatch's max. Alternatively, the local
function get_restricted_features_unsigned could be named more tersely.
> +
> + return (id_aa64mmfr0_el1_sys_val & PVM_ID_AA64MMFR0_ALLOW) | set_mask;
> +}
> +
> +u64 get_pvm_id_aa64mmfr1(const struct kvm_vcpu *vcpu)
> +{
> + return id_aa64mmfr1_el1_sys_val & PVM_ID_AA64MMFR1_ALLOW;
> +}
> +
> +u64 get_pvm_id_aa64mmfr2(const struct kvm_vcpu *vcpu)
> +{
> + return id_aa64mmfr2_el1_sys_val & PVM_ID_AA64MMFR2_ALLOW;
> +}
> +
> +/* Read a sanitized cpufeature ID register by its sys_reg_desc. */
> +static u64 read_id_reg(const struct kvm_vcpu *vcpu,
> + struct sys_reg_desc const *r)
> +{
> + u32 id = reg_to_encoding(r);
> +
> + switch (id) {
> + case SYS_ID_AA64PFR0_EL1:
> + return get_pvm_id_aa64pfr0(vcpu);
> + case SYS_ID_AA64PFR1_EL1:
> + return get_pvm_id_aa64pfr1(vcpu);
> + case SYS_ID_AA64ZFR0_EL1:
> + return get_pvm_id_aa64zfr0(vcpu);
> + case SYS_ID_AA64DFR0_EL1:
> + return get_pvm_id_aa64dfr0(vcpu);
> + case SYS_ID_AA64DFR1_EL1:
> + return get_pvm_id_aa64dfr1(vcpu);
> + case SYS_ID_AA64AFR0_EL1:
> + return get_pvm_id_aa64afr0(vcpu);
> + case SYS_ID_AA64AFR1_EL1:
> + return get_pvm_id_aa64afr1(vcpu);
> + case SYS_ID_AA64ISAR0_EL1:
> + return get_pvm_id_aa64isar0(vcpu);
> + case SYS_ID_AA64ISAR1_EL1:
> + return get_pvm_id_aa64isar1(vcpu);
> + case SYS_ID_AA64MMFR0_EL1:
> + return get_pvm_id_aa64mmfr0(vcpu);
> + case SYS_ID_AA64MMFR1_EL1:
> + return get_pvm_id_aa64mmfr1(vcpu);
> + case SYS_ID_AA64MMFR2_EL1:
> + return get_pvm_id_aa64mmfr2(vcpu);
> + default:
> + /*
> + * Should never happen because all cases are covered in
> + * pvm_sys_reg_descs[] below.
> + */
> + BUG();
> + break;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Accessor for AArch32 feature id registers.
> + *
> + * The value of these registers is "unknown" according to the spec if AArch32
> + * isn't supported.
> + */
> +static bool pvm_access_id_aarch32(struct kvm_vcpu *vcpu,
> + struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + if (p->is_write)
> + return undef_access(vcpu, p, r);
> +
> + /*
> + * No support for AArch32 guests, therefore, pKVM has no sanitized copy
> + * of AArch32 feature id registers.
> + */
> + BUILD_BUG_ON(FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1),
> + PVM_ID_AA64PFR0_RESTRICT_UNSIGNED) >
> + ID_AA64PFR0_ELx_64BIT_ONLY);
I'd prefer to blow the 80 char soft limit here and do
PVM_ID_AA64PFR0_RESTRICT_UNSIGNED) > ID_AA64PFR0_ELx_64BIT_ONLY);
> +
> + /* Use 0 for architecturally "unknown" values. */
> + p->regval = 0;
> + return true;
> +}
> +
> +/*
> + * Accessor for AArch64 feature id registers.
> + *
> + * If access is allowed, set the regval to the protected VM's view of the
> + * register and return true.
> + * Otherwise, inject an undefined exception and return false.
> + */
> +static bool pvm_access_id_aarch64(struct kvm_vcpu *vcpu,
> + struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + if (p->is_write)
> + return undef_access(vcpu, p, r);
> +
> + p->regval = read_id_reg(vcpu, r);
> + return true;
> +}
> +
> +/* Mark the specified system register as an AArch32 feature id register. */
> +#define AARCH32(REG) { SYS_DESC(REG), .access = pvm_access_id_aarch32 }
> +
> +/* Mark the specified system register as an AArch64 feature id register. */
> +#define AARCH64(REG) { SYS_DESC(REG), .access = pvm_access_id_aarch64 }
> +
> +/* Mark the specified system register as not being handled in hyp. */
> +#define HOST_HANDLED(REG) { SYS_DESC(REG), .access = NULL }
> +
> +/*
> + * Architected system registers.
> + * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
> + *
> + * NOTE: Anything not explicitly listed here is *restricted by default*, i.e.,
> + * it will lead to injecting an exception into the guest.
> + */
> +static const struct sys_reg_desc pvm_sys_reg_descs[] = {
> + /* Cache maintenance by set/way operations are restricted. */
> +
> + /* Debug and Trace Registers are restricted. */
> +
> + /* AArch64 mappings of the AArch32 ID registers */
> + /* CRm=1 */
> + AARCH32(SYS_ID_PFR0_EL1),
> + AARCH32(SYS_ID_PFR1_EL1),
> + AARCH32(SYS_ID_DFR0_EL1),
> + AARCH32(SYS_ID_AFR0_EL1),
> + AARCH32(SYS_ID_MMFR0_EL1),
> + AARCH32(SYS_ID_MMFR1_EL1),
> + AARCH32(SYS_ID_MMFR2_EL1),
> + AARCH32(SYS_ID_MMFR3_EL1),
> +
> + /* CRm=2 */
> + AARCH32(SYS_ID_ISAR0_EL1),
> + AARCH32(SYS_ID_ISAR1_EL1),
> + AARCH32(SYS_ID_ISAR2_EL1),
> + AARCH32(SYS_ID_ISAR3_EL1),
> + AARCH32(SYS_ID_ISAR4_EL1),
> + AARCH32(SYS_ID_ISAR5_EL1),
> + AARCH32(SYS_ID_MMFR4_EL1),
> + AARCH32(SYS_ID_ISAR6_EL1),
> +
> + /* CRm=3 */
> + AARCH32(SYS_MVFR0_EL1),
> + AARCH32(SYS_MVFR1_EL1),
> + AARCH32(SYS_MVFR2_EL1),
> + AARCH32(SYS_ID_PFR2_EL1),
> + AARCH32(SYS_ID_DFR1_EL1),
> + AARCH32(SYS_ID_MMFR5_EL1),
> +
> + /* AArch64 ID registers */
> + /* CRm=4 */
> + AARCH64(SYS_ID_AA64PFR0_EL1),
> + AARCH64(SYS_ID_AA64PFR1_EL1),
> + AARCH64(SYS_ID_AA64ZFR0_EL1),
> + AARCH64(SYS_ID_AA64DFR0_EL1),
> + AARCH64(SYS_ID_AA64DFR1_EL1),
> + AARCH64(SYS_ID_AA64AFR0_EL1),
> + AARCH64(SYS_ID_AA64AFR1_EL1),
> + AARCH64(SYS_ID_AA64ISAR0_EL1),
> + AARCH64(SYS_ID_AA64ISAR1_EL1),
> + AARCH64(SYS_ID_AA64MMFR0_EL1),
> + AARCH64(SYS_ID_AA64MMFR1_EL1),
> + AARCH64(SYS_ID_AA64MMFR2_EL1),
> +
> + HOST_HANDLED(SYS_SCTLR_EL1),
> + HOST_HANDLED(SYS_ACTLR_EL1),
> + HOST_HANDLED(SYS_CPACR_EL1),
> +
> + HOST_HANDLED(SYS_RGSR_EL1),
> + HOST_HANDLED(SYS_GCR_EL1),
> +
> + /* Scalable Vector Registers are restricted. */
> +
> + HOST_HANDLED(SYS_TTBR0_EL1),
> + HOST_HANDLED(SYS_TTBR1_EL1),
> + HOST_HANDLED(SYS_TCR_EL1),
> +
> + HOST_HANDLED(SYS_APIAKEYLO_EL1),
> + HOST_HANDLED(SYS_APIAKEYHI_EL1),
> + HOST_HANDLED(SYS_APIBKEYLO_EL1),
> + HOST_HANDLED(SYS_APIBKEYHI_EL1),
> + HOST_HANDLED(SYS_APDAKEYLO_EL1),
> + HOST_HANDLED(SYS_APDAKEYHI_EL1),
> + HOST_HANDLED(SYS_APDBKEYLO_EL1),
> + HOST_HANDLED(SYS_APDBKEYHI_EL1),
> + HOST_HANDLED(SYS_APGAKEYLO_EL1),
> + HOST_HANDLED(SYS_APGAKEYHI_EL1),
> +
> + HOST_HANDLED(SYS_AFSR0_EL1),
> + HOST_HANDLED(SYS_AFSR1_EL1),
> + HOST_HANDLED(SYS_ESR_EL1),
> +
> + HOST_HANDLED(SYS_ERRIDR_EL1),
> + HOST_HANDLED(SYS_ERRSELR_EL1),
> + HOST_HANDLED(SYS_ERXFR_EL1),
> + HOST_HANDLED(SYS_ERXCTLR_EL1),
> + HOST_HANDLED(SYS_ERXSTATUS_EL1),
> + HOST_HANDLED(SYS_ERXADDR_EL1),
> + HOST_HANDLED(SYS_ERXMISC0_EL1),
> + HOST_HANDLED(SYS_ERXMISC1_EL1),
> +
> + HOST_HANDLED(SYS_TFSR_EL1),
> + HOST_HANDLED(SYS_TFSRE0_EL1),
> +
> + HOST_HANDLED(SYS_FAR_EL1),
> + HOST_HANDLED(SYS_PAR_EL1),
> +
> + /* Performance Monitoring Registers are restricted. */
> +
> + HOST_HANDLED(SYS_MAIR_EL1),
> + HOST_HANDLED(SYS_AMAIR_EL1),
> +
> + /* Limited Ordering Regions Registers are restricted. */
> +
> + HOST_HANDLED(SYS_VBAR_EL1),
> + HOST_HANDLED(SYS_DISR_EL1),
> +
> + /* GIC CPU Interface registers are restricted. */
> +
> + HOST_HANDLED(SYS_CONTEXTIDR_EL1),
> + HOST_HANDLED(SYS_TPIDR_EL1),
> +
> + HOST_HANDLED(SYS_SCXTNUM_EL1),
> +
> + HOST_HANDLED(SYS_CNTKCTL_EL1),
> +
> + HOST_HANDLED(SYS_CCSIDR_EL1),
> + HOST_HANDLED(SYS_CLIDR_EL1),
> + HOST_HANDLED(SYS_CSSELR_EL1),
> + HOST_HANDLED(SYS_CTR_EL0),
> +
> + /* Performance Monitoring Registers are restricted. */
> +
> + HOST_HANDLED(SYS_TPIDR_EL0),
> + HOST_HANDLED(SYS_TPIDRRO_EL0),
> +
> + HOST_HANDLED(SYS_SCXTNUM_EL0),
> +
> + /* Activity Monitoring Registers are restricted. */
> +
> + HOST_HANDLED(SYS_CNTP_TVAL_EL0),
> + HOST_HANDLED(SYS_CNTP_CTL_EL0),
> + HOST_HANDLED(SYS_CNTP_CVAL_EL0),
> +
> + /* Performance Monitoring Registers are restricted. */
> +
> + HOST_HANDLED(SYS_DACR32_EL2),
> + HOST_HANDLED(SYS_IFSR32_EL2),
> + HOST_HANDLED(SYS_FPEXC32_EL2),
> +};
> +
> +/*
> + * Handler for protected VM restricted exceptions.
> + *
> + * Inject an undefined exception into the guest and return true to indicate that
> + * the hypervisor has handled the exit, and control should go back to the guest.
> + */
> +bool kvm_handle_pvm_restricted(struct kvm_vcpu *vcpu, u64 *exit_code)
> +{
> + __inject_undef(vcpu);
> + return true;
> +}
> +
> +/*
> + * 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.
> + */
> +bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code)
> +{
> + const struct sys_reg_desc *r;
> + struct sys_reg_params params;
> + unsigned long esr = kvm_vcpu_get_esr(vcpu);
> + int Rt = kvm_vcpu_sys_get_rt(vcpu);
> +
> + params = esr_sys64_to_params(esr);
> + params.regval = vcpu_get_reg(vcpu, Rt);
> +
> + r = find_reg(¶ms, pvm_sys_reg_descs, ARRAY_SIZE(pvm_sys_reg_descs));
> +
> + /* Undefined access (RESTRICTED). */
> + if (r == NULL)
> + return kvm_handle_pvm_restricted(vcpu, exit_code);
> +
> + /* Handled by the host (HOST_HANDLED) */
> + if (r->access == NULL)
> + return kvm_hyp_handle_sysreg(vcpu, exit_code);
> +
> + /* Handled by hyp: skip instruction if instructed to do so. */
> + if (r->access(vcpu, ¶ms, r))
> + __kvm_skip_instr(vcpu);
> +
> + if (!params.is_write)
> + vcpu_set_reg(vcpu, Rt, params.regval);
> +
> + return true;
> +}
> +
> +/*
> + * Handler for protected floating-point and Advanced SIMD accesses.
> + *
> + * Returns true if the hypervisor has handled the exit, and control should go
> + * back to the guest, or false if it hasn't.
> + */
> +bool kvm_handle_pvm_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
> +{
> + /* Linux guests assume support for floating-point and Advanced SIMD. */
> + BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_FP),
> + PVM_ID_AA64PFR0_ALLOW));
> + BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_ASIMD),
> + PVM_ID_AA64PFR0_ALLOW));
> +
> + return kvm_hyp_handle_fpsimd(vcpu, exit_code);
> +}
> --
> 2.33.0.259.gc128427fd7-goog
>
Thanks,
drew
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