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    Subject[PATCH v19 075/130] KVM: TDX: Extend memory measurement with initial guest memory
    Date
    From: Isaku Yamahata <isaku.yamahata@intel.com>

    TDX allows to extned memory measurement with the initial memory. Define
    new subcommand, KVM_TDX_EXTEND_MEMORY, of VM-scoped KVM_MEMORY_ENCRYPT_OP.
    it extends memory measurement of the TDX guest. The memory region must
    be populated with KVM_MEMORY_MAPPING command.

    Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
    ---
    v19:
    - newly added
    - Split KVM_TDX_INIT_MEM_REGION into only extension function
    ---
    arch/x86/include/uapi/asm/kvm.h | 1 +
    arch/x86/kvm/vmx/tdx.c | 64 +++++++++++++++++++++++++++++++++
    2 files changed, 65 insertions(+)

    diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
    index 4000a2e087a8..34167404020c 100644
    --- a/arch/x86/include/uapi/asm/kvm.h
    +++ b/arch/x86/include/uapi/asm/kvm.h
    @@ -572,6 +572,7 @@ enum kvm_tdx_cmd_id {
    KVM_TDX_CAPABILITIES = 0,
    KVM_TDX_INIT_VM,
    KVM_TDX_INIT_VCPU,
    + KVM_TDX_EXTEND_MEMORY,

    KVM_TDX_CMD_NR_MAX,
    };
    diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
    index 8cf6e5dab3e9..3cfba63a7762 100644
    --- a/arch/x86/kvm/vmx/tdx.c
    +++ b/arch/x86/kvm/vmx/tdx.c
    @@ -1339,6 +1339,67 @@ void tdx_flush_tlb_current(struct kvm_vcpu *vcpu)
    tdx_track(vcpu->kvm);
    }

    +static int tdx_extend_memory(struct kvm *kvm, struct kvm_tdx_cmd *cmd)
    +{
    + struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
    + struct kvm_memory_mapping mapping;
    + struct tdx_module_args out;
    + bool extended = false;
    + int idx, ret = 0;
    + gpa_t gpa;
    + u64 err;
    + int i;
    +
    + /* Once TD is finalized, the initial guest memory is fixed. */
    + if (is_td_finalized(kvm_tdx))
    + return -EINVAL;
    +
    + if (cmd->flags)
    + return -EINVAL;
    +
    + if (copy_from_user(&mapping, (void __user *)cmd->data, sizeof(mapping)))
    + return -EFAULT;
    +
    + /* Sanity check */
    + if (mapping.source || !mapping.nr_pages ||
    + mapping.nr_pages & GENMASK_ULL(63, 63 - PAGE_SHIFT) ||
    + mapping.base_gfn + (mapping.nr_pages << PAGE_SHIFT) <= mapping.base_gfn ||
    + !kvm_is_private_gpa(kvm, mapping.base_gfn) ||
    + !kvm_is_private_gpa(kvm, mapping.base_gfn + (mapping.nr_pages << PAGE_SHIFT)))
    + return -EINVAL;
    +
    + idx = srcu_read_lock(&kvm->srcu);
    + while (mapping.nr_pages) {
    + if (signal_pending(current)) {
    + ret = -ERESTARTSYS;
    + break;
    + }
    +
    + if (need_resched())
    + cond_resched();
    +
    + gpa = gfn_to_gpa(mapping.base_gfn);
    + for (i = 0; i < PAGE_SIZE; i += TDX_EXTENDMR_CHUNKSIZE) {
    + err = tdh_mr_extend(kvm_tdx->tdr_pa, gpa + i, &out);
    + if (err) {
    + ret = -EIO;
    + break;
    + }
    + }
    + mapping.base_gfn++;
    + mapping.nr_pages--;
    + extended = true;
    + }
    + srcu_read_unlock(&kvm->srcu, idx);
    +
    + if (extended && mapping.nr_pages > 0)
    + ret = -EAGAIN;
    + if (copy_to_user((void __user *)cmd->data, &mapping, sizeof(mapping)))
    + ret = -EFAULT;
    +
    + return ret;
    +}
    +
    int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
    {
    struct kvm_tdx_cmd tdx_cmd;
    @@ -1358,6 +1419,9 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
    case KVM_TDX_INIT_VM:
    r = tdx_td_init(kvm, &tdx_cmd);
    break;
    + case KVM_TDX_EXTEND_MEMORY:
    + r = tdx_extend_memory(kvm, &tdx_cmd);
    + break;
    default:
    r = -EINVAL;
    goto out;
    --
    2.25.1

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