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    SubjectRe: [RFC PATCH 06/28] arm64: RME: ioctls to create and configure realms
    From
    On 06/03/2023 19:10, Zhi Wang wrote:
    > On Fri, 27 Jan 2023 11:29:10 +0000
    > Steven Price <steven.price@arm.com> wrote:
    >
    >> Add the KVM_CAP_ARM_RME_CREATE_FD ioctl to create a realm. This involves
    >> delegating pages to the RMM to hold the Realm Descriptor (RD) and for
    >> the base level of the Realm Translation Tables (RTT). A VMID also need
    >> to be picked, since the RMM has a separate VMID address space a
    >> dedicated allocator is added for this purpose.
    >>
    >> KVM_CAP_ARM_RME_CONFIG_REALM is provided to allow configuring the realm
    >> before it is created.
    >>
    >> Signed-off-by: Steven Price <steven.price@arm.com>
    >> ---
    >> arch/arm64/include/asm/kvm_rme.h | 14 ++
    >> arch/arm64/kvm/arm.c | 19 ++
    >> arch/arm64/kvm/mmu.c | 6 +
    >> arch/arm64/kvm/reset.c | 33 +++
    >> arch/arm64/kvm/rme.c | 357 +++++++++++++++++++++++++++++++
    >> 5 files changed, 429 insertions(+)
    >>
    >> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
    >> index c26bc2c6770d..055a22accc08 100644
    >> --- a/arch/arm64/include/asm/kvm_rme.h
    >> +++ b/arch/arm64/include/asm/kvm_rme.h
    >> @@ -6,6 +6,8 @@
    >> #ifndef __ASM_KVM_RME_H
    >> #define __ASM_KVM_RME_H
    >>
    >> +#include <uapi/linux/kvm.h>
    >> +
    >> enum realm_state {
    >> REALM_STATE_NONE,
    >> REALM_STATE_NEW,
    >> @@ -15,8 +17,20 @@ enum realm_state {
    >>
    >> struct realm {
    >> enum realm_state state;
    >> +
    >> + void *rd;
    >> + struct realm_params *params;
    >> +
    >> + unsigned long num_aux;
    >> + unsigned int vmid;
    >> + unsigned int ia_bits;
    >> };
    >>
    >> int kvm_init_rme(void);
    >> +u32 kvm_realm_ipa_limit(void);
    >> +
    >> +int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
    >> +int kvm_init_realm_vm(struct kvm *kvm);
    >> +void kvm_destroy_realm(struct kvm *kvm);
    >>
    >> #endif
    >> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
    >> index d97b39d042ab..50f54a63732a 100644
    >> --- a/arch/arm64/kvm/arm.c
    >> +++ b/arch/arm64/kvm/arm.c
    >> @@ -103,6 +103,13 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
    >> r = 0;
    >> set_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags);
    >> break;
    >> + case KVM_CAP_ARM_RME:
    >> + if (!static_branch_unlikely(&kvm_rme_is_available))
    >> + return -EINVAL;
    >> + mutex_lock(&kvm->lock);
    >> + r = kvm_realm_enable_cap(kvm, cap);
    >> + mutex_unlock(&kvm->lock);
    >> + break;
    >> default:
    >> r = -EINVAL;
    >> break;
    >> @@ -172,6 +179,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
    >> */
    >> kvm->arch.dfr0_pmuver.imp = kvm_arm_pmu_get_pmuver_limit();
    >>
    >> + /* Initialise the realm bits after the generic bits are enabled */
    >> + if (kvm_is_realm(kvm)) {
    >> + ret = kvm_init_realm_vm(kvm);
    >> + if (ret)
    >> + goto err_free_cpumask;
    >> + }
    >> +
    >> return 0;
    >>
    >> err_free_cpumask:
    >> @@ -204,6 +218,8 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
    >> kvm_destroy_vcpus(kvm);
    >>
    >> kvm_unshare_hyp(kvm, kvm + 1);
    >> +
    >> + kvm_destroy_realm(kvm);
    >> }
    >>
    >> int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
    >> @@ -300,6 +316,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
    >> case KVM_CAP_ARM_PTRAUTH_GENERIC:
    >> r = system_has_full_ptr_auth();
    >> break;
    >> + case KVM_CAP_ARM_RME:
    >> + r = static_key_enabled(&kvm_rme_is_available);
    >> + break;
    >> default:
    >> r = 0;
    >> }
    >> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
    >> index 31d7fa4c7c14..d0f707767d05 100644
    >> --- a/arch/arm64/kvm/mmu.c
    >> +++ b/arch/arm64/kvm/mmu.c
    >> @@ -840,6 +840,12 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
    >> struct kvm_pgtable *pgt = NULL;
    >>
    >> write_lock(&kvm->mmu_lock);
    >> + if (kvm_is_realm(kvm) &&
    >> + kvm_realm_state(kvm) != REALM_STATE_DYING) {
    >> + /* TODO: teardown rtts */
    >> + write_unlock(&kvm->mmu_lock);
    >> + return;
    >> + }
    >> pgt = mmu->pgt;
    >> if (pgt) {
    >> mmu->pgd_phys = 0;
    >> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
    >> index e0267f672b8a..c165df174737 100644
    >> --- a/arch/arm64/kvm/reset.c
    >> +++ b/arch/arm64/kvm/reset.c
    >> @@ -395,3 +395,36 @@ int kvm_set_ipa_limit(void)
    >>
    >> return 0;
    >> }
    >> +
    >
    > The below function doesn't have an user in this patch. Also,
    > it looks like a part of copy from kvm_init_stage2_mmu()
    > in arch/arm64/kvm/mmu.c.

    Good spot ;) Yes I discovered this, it should have been removed - it's
    no longer used. I think this was an error when I was rebasing:
    kvm_arm_setup-stage2() was removed in 315775ff7c6d ("KVM: arm64:
    Consolidate stage-2 initialisation into a single function").

    Steve

    >> +int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
    >> +{
    >> + u64 mmfr0, mmfr1;
    >> + u32 phys_shift;
    >> + u32 ipa_limit = kvm_ipa_limit;
    >> +
    >> + if (kvm_is_realm(kvm))
    >> + ipa_limit = kvm_realm_ipa_limit();
    >> +
    >> + 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 > ipa_limit ||
    >> + phys_shift < ARM64_MIN_PARANGE_BITS)
    >> + return -EINVAL;
    >> + } else {
    >> + phys_shift = KVM_PHYS_SHIFT;
    >> + if (phys_shift > ipa_limit) {
    >> + pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
    >> + current->comm);
    >> + return -EINVAL;
    >> + }
    >> + }
    >> +
    >> + mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
    >> + mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
    >> + kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
    >> +
    >> + return 0;
    >> +}
    >> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
    >> index f6b587bc116e..9f8c5a91b8fc 100644
    >> --- a/arch/arm64/kvm/rme.c
    >> +++ b/arch/arm64/kvm/rme.c
    >> @@ -5,9 +5,49 @@
    >>
    >> #include <linux/kvm_host.h>
    >>
    >> +#include <asm/kvm_emulate.h>
    >> +#include <asm/kvm_mmu.h>
    >> #include <asm/rmi_cmds.h>
    >> #include <asm/virt.h>
    >>
    >> +/************ FIXME: Copied from kvm/hyp/pgtable.c **********/
    >> +#include <asm/kvm_pgtable.h>
    >> +
    >> +struct kvm_pgtable_walk_data {
    >> + struct kvm_pgtable *pgt;
    >> + struct kvm_pgtable_walker *walker;
    >> +
    >> + u64 addr;
    >> + u64 end;
    >> +};
    >> +
    >> +static u32 __kvm_pgd_page_idx(struct kvm_pgtable *pgt, u64 addr)
    >> +{
    >> + u64 shift = kvm_granule_shift(pgt->start_level - 1); /* May underflow */
    >> + u64 mask = BIT(pgt->ia_bits) - 1;
    >> +
    >> + return (addr & mask) >> shift;
    >> +}
    >> +
    >> +static u32 kvm_pgd_pages(u32 ia_bits, u32 start_level)
    >> +{
    >> + struct kvm_pgtable pgt = {
    >> + .ia_bits = ia_bits,
    >> + .start_level = start_level,
    >> + };
    >> +
    >> + return __kvm_pgd_page_idx(&pgt, -1ULL) + 1;
    >> +}
    >> +
    >> +/******************/
    >> +
    >> +static unsigned long rmm_feat_reg0;
    >> +
    >> +static bool rme_supports(unsigned long feature)
    >> +{
    >> + return !!u64_get_bits(rmm_feat_reg0, feature);
    >> +}
    >> +
    >> static int rmi_check_version(void)
    >> {
    >> struct arm_smccc_res res;
    >> @@ -33,8 +73,319 @@ static int rmi_check_version(void)
    >> return 0;
    >> }
    >>
    >> +static unsigned long create_realm_feat_reg0(struct kvm *kvm)
    >> +{
    >> + unsigned long ia_bits = VTCR_EL2_IPA(kvm->arch.vtcr);
    >> + u64 feat_reg0 = 0;
    >> +
    >> + int num_bps = u64_get_bits(rmm_feat_reg0,
    >> + RMI_FEATURE_REGISTER_0_NUM_BPS);
    >> + int num_wps = u64_get_bits(rmm_feat_reg0,
    >> + RMI_FEATURE_REGISTER_0_NUM_WPS);
    >> +
    >> + feat_reg0 |= u64_encode_bits(ia_bits, RMI_FEATURE_REGISTER_0_S2SZ);
    >> + feat_reg0 |= u64_encode_bits(num_bps, RMI_FEATURE_REGISTER_0_NUM_BPS);
    >> + feat_reg0 |= u64_encode_bits(num_wps, RMI_FEATURE_REGISTER_0_NUM_WPS);
    >> +
    >> + return feat_reg0;
    >> +}
    >> +
    >> +u32 kvm_realm_ipa_limit(void)
    >> +{
    >> + return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
    >> +}
    >> +
    >> +static u32 get_start_level(struct kvm *kvm)
    >> +{
    >> + long sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, kvm->arch.vtcr);
    >> +
    >> + return VTCR_EL2_TGRAN_SL0_BASE - sl0;
    >> +}
    >> +
    >> +static int realm_create_rd(struct kvm *kvm)
    >> +{
    >> + struct realm *realm = &kvm->arch.realm;
    >> + struct realm_params *params = realm->params;
    >> + void *rd = NULL;
    >> + phys_addr_t rd_phys, params_phys;
    >> + struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
    >> + unsigned int pgd_sz;
    >> + int i, r;
    >> +
    >> + if (WARN_ON(realm->rd) || WARN_ON(!realm->params))
    >> + return -EEXIST;
    >> +
    >> + rd = (void *)__get_free_page(GFP_KERNEL);
    >> + if (!rd)
    >> + return -ENOMEM;
    >> +
    >> + rd_phys = virt_to_phys(rd);
    >> + if (rmi_granule_delegate(rd_phys)) {
    >> + r = -ENXIO;
    >> + goto out;
    >> + }
    >> +
    >> + pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level);
    >> + for (i = 0; i < pgd_sz; i++) {
    >> + phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
    >> +
    >> + if (rmi_granule_delegate(pgd_phys)) {
    >> + r = -ENXIO;
    >> + goto out_undelegate_tables;
    >> + }
    >> + }
    >> +
    >> + params->rtt_level_start = get_start_level(kvm);
    >> + params->rtt_num_start = pgd_sz;
    >> + params->rtt_base = kvm->arch.mmu.pgd_phys;
    >> + params->vmid = realm->vmid;
    >> +
    >> + params_phys = virt_to_phys(params);
    >> +
    >> + if (rmi_realm_create(rd_phys, params_phys)) {
    >> + r = -ENXIO;
    >> + goto out_undelegate_tables;
    >> + }
    >> +
    >> + realm->rd = rd;
    >> + realm->ia_bits = VTCR_EL2_IPA(kvm->arch.vtcr);
    >> +
    >> + if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) {
    >> + WARN_ON(rmi_realm_destroy(rd_phys));
    >> + goto out_undelegate_tables;
    >> + }
    >> +
    >> + return 0;
    >> +
    >> +out_undelegate_tables:
    >> + while (--i >= 0) {
    >> + phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
    >> +
    >> + WARN_ON(rmi_granule_undelegate(pgd_phys));
    >> + }
    >> + WARN_ON(rmi_granule_undelegate(rd_phys));
    >> +out:
    >> + free_page((unsigned long)rd);
    >> + return r;
    >> +}
    >> +
    >> +/* Protects access to rme_vmid_bitmap */
    >> +static DEFINE_SPINLOCK(rme_vmid_lock);
    >> +static unsigned long *rme_vmid_bitmap;
    >> +
    >> +static int rme_vmid_init(void)
    >> +{
    >> + unsigned int vmid_count = 1 << kvm_get_vmid_bits();
    >> +
    >> + rme_vmid_bitmap = bitmap_zalloc(vmid_count, GFP_KERNEL);
    >> + if (!rme_vmid_bitmap) {
    >> + kvm_err("%s: Couldn't allocate rme vmid bitmap\n", __func__);
    >> + return -ENOMEM;
    >> + }
    >> +
    >> + return 0;
    >> +}
    >> +
    >> +static int rme_vmid_reserve(void)
    >> +{
    >> + int ret;
    >> + unsigned int vmid_count = 1 << kvm_get_vmid_bits();
    >> +
    >> + spin_lock(&rme_vmid_lock);
    >> + ret = bitmap_find_free_region(rme_vmid_bitmap, vmid_count, 0);
    >> + spin_unlock(&rme_vmid_lock);
    >> +
    >> + return ret;
    >> +}
    >> +
    >> +static void rme_vmid_release(unsigned int vmid)
    >> +{
    >> + spin_lock(&rme_vmid_lock);
    >> + bitmap_release_region(rme_vmid_bitmap, vmid, 0);
    >> + spin_unlock(&rme_vmid_lock);
    >> +}
    >> +
    >> +static int kvm_create_realm(struct kvm *kvm)
    >> +{
    >> + struct realm *realm = &kvm->arch.realm;
    >> + int ret;
    >> +
    >> + if (!kvm_is_realm(kvm) || kvm_realm_state(kvm) != REALM_STATE_NONE)
    >> + return -EEXIST;
    >> +
    >> + ret = rme_vmid_reserve();
    >> + if (ret < 0)
    >> + return ret;
    >> + realm->vmid = ret;
    >> +
    >> + ret = realm_create_rd(kvm);
    >> + if (ret) {
    >> + rme_vmid_release(realm->vmid);
    >> + return ret;
    >> + }
    >> +
    >> + WRITE_ONCE(realm->state, REALM_STATE_NEW);
    >> +
    >> + /* The realm is up, free the parameters. */
    >> + free_page((unsigned long)realm->params);
    >> + realm->params = NULL;
    >> +
    >> + return 0;
    >> +}
    >> +
    >> +static int config_realm_hash_algo(struct realm *realm,
    >> + struct kvm_cap_arm_rme_config_item *cfg)
    >> +{
    >> + switch (cfg->hash_algo) {
    >> + case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA256:
    >> + if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_256))
    >> + return -EINVAL;
    >> + break;
    >> + case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA512:
    >> + if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_512))
    >> + return -EINVAL;
    >> + break;
    >> + default:
    >> + return -EINVAL;
    >> + }
    >> + realm->params->measurement_algo = cfg->hash_algo;
    >> + return 0;
    >> +}
    >> +
    >> +static int config_realm_sve(struct realm *realm,
    >> + struct kvm_cap_arm_rme_config_item *cfg)
    >> +{
    >> + u64 features_0 = realm->params->features_0;
    >> + int max_sve_vq = u64_get_bits(rmm_feat_reg0,
    >> + RMI_FEATURE_REGISTER_0_SVE_VL);
    >> +
    >> + if (!rme_supports(RMI_FEATURE_REGISTER_0_SVE_EN))
    >> + return -EINVAL;
    >> +
    >> + if (cfg->sve_vq > max_sve_vq)
    >> + return -EINVAL;
    >> +
    >> + features_0 &= ~(RMI_FEATURE_REGISTER_0_SVE_EN |
    >> + RMI_FEATURE_REGISTER_0_SVE_VL);
    >> + features_0 |= u64_encode_bits(1, RMI_FEATURE_REGISTER_0_SVE_EN);
    >> + features_0 |= u64_encode_bits(cfg->sve_vq,
    >> + RMI_FEATURE_REGISTER_0_SVE_VL);
    >> +
    >> + realm->params->features_0 = features_0;
    >> + return 0;
    >> +}
    >> +
    >> +static int kvm_rme_config_realm(struct kvm *kvm, struct kvm_enable_cap *cap)
    >> +{
    >> + struct kvm_cap_arm_rme_config_item cfg;
    >> + struct realm *realm = &kvm->arch.realm;
    >> + int r = 0;
    >> +
    >> + if (kvm_realm_state(kvm) != REALM_STATE_NONE)
    >> + return -EBUSY;
    >> +
    >> + if (copy_from_user(&cfg, (void __user *)cap->args[1], sizeof(cfg)))
    >> + return -EFAULT;
    >> +
    >> + switch (cfg.cfg) {
    >> + case KVM_CAP_ARM_RME_CFG_RPV:
    >> + memcpy(&realm->params->rpv, &cfg.rpv, sizeof(cfg.rpv));
    >> + break;
    >> + case KVM_CAP_ARM_RME_CFG_HASH_ALGO:
    >> + r = config_realm_hash_algo(realm, &cfg);
    >> + break;
    >> + case KVM_CAP_ARM_RME_CFG_SVE:
    >> + r = config_realm_sve(realm, &cfg);
    >> + break;
    >> + default:
    >> + r = -EINVAL;
    >> + }
    >> +
    >> + return r;
    >> +}
    >> +
    >> +int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
    >> +{
    >> + int r = 0;
    >> +
    >> + switch (cap->args[0]) {
    >> + case KVM_CAP_ARM_RME_CONFIG_REALM:
    >> + r = kvm_rme_config_realm(kvm, cap);
    >> + break;
    >> + case KVM_CAP_ARM_RME_CREATE_RD:
    >> + if (kvm->created_vcpus) {
    >> + r = -EBUSY;
    >> + break;
    >> + }
    >> +
    >> + r = kvm_create_realm(kvm);
    >> + break;
    >> + default:
    >> + r = -EINVAL;
    >> + break;
    >> + }
    >> +
    >> + return r;
    >> +}
    >> +
    >> +void kvm_destroy_realm(struct kvm *kvm)
    >> +{
    >> + struct realm *realm = &kvm->arch.realm;
    >> + struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
    >> + unsigned int pgd_sz;
    >> + int i;
    >> +
    >> + if (realm->params) {
    >> + free_page((unsigned long)realm->params);
    >> + realm->params = NULL;
    >> + }
    >> +
    >> + if (kvm_realm_state(kvm) == REALM_STATE_NONE)
    >> + return;
    >> +
    >> + WRITE_ONCE(realm->state, REALM_STATE_DYING);
    >> +
    >> + rme_vmid_release(realm->vmid);
    >> +
    >> + if (realm->rd) {
    >> + phys_addr_t rd_phys = virt_to_phys(realm->rd);
    >> +
    >> + if (WARN_ON(rmi_realm_destroy(rd_phys)))
    >> + return;
    >> + if (WARN_ON(rmi_granule_undelegate(rd_phys)))
    >> + return;
    >> + free_page((unsigned long)realm->rd);
    >> + realm->rd = NULL;
    >> + }
    >> +
    >> + pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level);
    >> + for (i = 0; i < pgd_sz; i++) {
    >> + phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
    >> +
    >> + if (WARN_ON(rmi_granule_undelegate(pgd_phys)))
    >> + return;
    >> + }
    >> +
    >> + kvm_free_stage2_pgd(&kvm->arch.mmu);
    >> +}
    >> +
    >> +int kvm_init_realm_vm(struct kvm *kvm)
    >> +{
    >> + struct realm_params *params;
    >> +
    >> + params = (struct realm_params *)get_zeroed_page(GFP_KERNEL);
    >> + if (!params)
    >> + return -ENOMEM;
    >> +
    >> + params->features_0 = create_realm_feat_reg0(kvm);
    >> + kvm->arch.realm.params = params;
    >> + return 0;
    >> +}
    >> +
    >> int kvm_init_rme(void)
    >> {
    >> + int ret;
    >> +
    >> if (PAGE_SIZE != SZ_4K)
    >> /* Only 4k page size on the host is supported */
    >> return 0;
    >> @@ -43,6 +394,12 @@ int kvm_init_rme(void)
    >> /* Continue without realm support */
    >> return 0;
    >>
    >> + ret = rme_vmid_init();
    >> + if (ret)
    >> + return ret;
    >> +
    >> + WARN_ON(rmi_features(0, &rmm_feat_reg0));
    >> +
    >> /* Future patch will enable static branch kvm_rme_is_available */
    >>
    >> return 0;
    >

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      Last update: 2023-03-27 00:53    [W:8.621 / U:0.484 seconds]
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