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    Subject[PATCH v15 018/115] KVM: TDX: x86: Add ioctl to get TDX systemwide parameters
    Date
    From: Sean Christopherson <sean.j.christopherson@intel.com>

    Implement an ioctl to get system-wide parameters for TDX. Although the
    function is systemwide, vm scoped mem_enc ioctl works for userspace VMM
    like qemu and device scoped version is not define, re-use vm scoped
    mem_enc.

    Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
    Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
    ---
    v14 -> v15:
    - ABI change: added supported_gpaw and reserved area,
    ---
    arch/x86/include/uapi/asm/kvm.h | 24 ++++++++++
    arch/x86/kvm/vmx/tdx.c | 64 +++++++++++++++++++++++++++
    tools/arch/x86/include/uapi/asm/kvm.h | 52 ++++++++++++++++++++++
    3 files changed, 140 insertions(+)

    diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
    index 615fb60b3717..3fbd43d5177b 100644
    --- a/arch/x86/include/uapi/asm/kvm.h
    +++ b/arch/x86/include/uapi/asm/kvm.h
    @@ -593,4 +593,28 @@ struct kvm_tdx_cmd {
    __u64 error;
    };

    +struct kvm_tdx_cpuid_config {
    + __u32 leaf;
    + __u32 sub_leaf;
    + __u32 eax;
    + __u32 ebx;
    + __u32 ecx;
    + __u32 edx;
    +};
    +
    +struct kvm_tdx_capabilities {
    + __u64 attrs_fixed0;
    + __u64 attrs_fixed1;
    + __u64 xfam_fixed0;
    + __u64 xfam_fixed1;
    +#define TDX_CAP_GPAW_48 (1 << 0)
    +#define TDX_CAP_GPAW_52 (1 << 1)
    + __u32 supported_gpaw;
    + __u32 padding;
    + __u64 reserved[251];
    +
    + __u32 nr_cpuid_configs;
    + struct kvm_tdx_cpuid_config cpuid_configs[];
    +};
    +
    #endif /* _ASM_X86_KVM_H */
    diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
    index ead229e34813..229c079d7686 100644
    --- a/arch/x86/kvm/vmx/tdx.c
    +++ b/arch/x86/kvm/vmx/tdx.c
    @@ -6,6 +6,7 @@
    #include "capabilities.h"
    #include "x86_ops.h"
    #include "x86.h"
    +#include "mmu.h"
    #include "tdx.h"

    #undef pr_fmt
    @@ -16,6 +17,66 @@
    offsetof(struct tdsysinfo_struct, cpuid_configs)) \
    / sizeof(struct tdx_cpuid_config))

    +static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
    +{
    + struct kvm_tdx_capabilities __user *user_caps;
    + const struct tdsysinfo_struct *tdsysinfo;
    + struct kvm_tdx_capabilities *caps = NULL;
    + int ret;
    +
    + BUILD_BUG_ON(sizeof(struct kvm_tdx_cpuid_config) !=
    + sizeof(struct tdx_cpuid_config));
    +
    + if (cmd->flags)
    + return -EINVAL;
    +
    + tdsysinfo = tdx_get_sysinfo();
    + if (!tdsysinfo)
    + return -EOPNOTSUPP;
    +
    + caps = kmalloc(sizeof(*caps), GFP_KERNEL);
    + if (!caps)
    + return -ENOMEM;
    +
    + user_caps = (void __user *)cmd->data;
    + if (copy_from_user(caps, user_caps, sizeof(*caps))) {
    + ret = -EFAULT;
    + goto out;
    + }
    +
    + if (caps->nr_cpuid_configs < tdsysinfo->num_cpuid_config) {
    + ret = -E2BIG;
    + goto out;
    + }
    +
    + *caps = (struct kvm_tdx_capabilities) {
    + .attrs_fixed0 = tdsysinfo->attributes_fixed0,
    + .attrs_fixed1 = tdsysinfo->attributes_fixed1,
    + .xfam_fixed0 = tdsysinfo->xfam_fixed0,
    + .xfam_fixed1 = tdsysinfo->xfam_fixed1,
    + .supported_gpaw = TDX_CAP_GPAW_48 |
    + (kvm_get_shadow_phys_bits() >= 52 &&
    + cpu_has_vmx_ept_5levels()) ? TDX_CAP_GPAW_52 : 0,
    + .nr_cpuid_configs = tdsysinfo->num_cpuid_config,
    + .padding = 0,
    + };
    +
    + if (copy_to_user(user_caps, caps, sizeof(*caps))) {
    + ret = -EFAULT;
    + goto out;
    + }
    + if (copy_to_user(user_caps->cpuid_configs, &tdsysinfo->cpuid_configs,
    + tdsysinfo->num_cpuid_config *
    + sizeof(struct tdx_cpuid_config))) {
    + ret = -EFAULT;
    + }
    +
    +out:
    + /* kfree() accepts NULL. */
    + kfree(caps);
    + return ret;
    +}
    +
    int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
    {
    struct kvm_tdx_cmd tdx_cmd;
    @@ -29,6 +90,9 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
    mutex_lock(&kvm->lock);

    switch (tdx_cmd.id) {
    + case KVM_TDX_CAPABILITIES:
    + r = tdx_get_capabilities(&tdx_cmd);
    + break;
    default:
    r = -EINVAL;
    goto out;
    diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
    index 1a6a1f987949..7a08723e99e2 100644
    --- a/tools/arch/x86/include/uapi/asm/kvm.h
    +++ b/tools/arch/x86/include/uapi/asm/kvm.h
    @@ -562,4 +562,56 @@ struct kvm_pmu_event_filter {
    /* x86-specific KVM_EXIT_HYPERCALL flags. */
    #define KVM_EXIT_HYPERCALL_LONG_MODE BIT(0)

    +/* Trust Domain eXtension sub-ioctl() commands. */
    +enum kvm_tdx_cmd_id {
    + KVM_TDX_CAPABILITIES = 0,
    +
    + KVM_TDX_CMD_NR_MAX,
    +};
    +
    +struct kvm_tdx_cmd {
    + /* enum kvm_tdx_cmd_id */
    + __u32 id;
    + /* flags for sub-commend. If sub-command doesn't use this, set zero. */
    + __u32 flags;
    + /*
    + * data for each sub-command. An immediate or a pointer to the actual
    + * data in process virtual address. If sub-command doesn't use it,
    + * set zero.
    + */
    + __u64 data;
    + /*
    + * Auxiliary error code. The sub-command may return TDX SEAMCALL
    + * status code in addition to -Exxx.
    + * Defined for consistency with struct kvm_sev_cmd.
    + */
    + __u64 error;
    + /* Reserved: Defined for consistency with struct kvm_sev_cmd. */
    + __u64 unused;
    +};
    +
    +struct kvm_tdx_cpuid_config {
    + __u32 leaf;
    + __u32 sub_leaf;
    + __u32 eax;
    + __u32 ebx;
    + __u32 ecx;
    + __u32 edx;
    +};
    +
    +struct kvm_tdx_capabilities {
    + __u64 attrs_fixed0;
    + __u64 attrs_fixed1;
    + __u64 xfam_fixed0;
    + __u64 xfam_fixed1;
    +#define TDX_CAP_GPAW_48 (1 << 0)
    +#define TDX_CAP_GPAW_52 (1 << 1)
    + __u32 supported_gpaw;
    + __u32 padding;
    + __u64 reserved[251];
    +
    + __u32 nr_cpuid_configs;
    + struct kvm_tdx_cpuid_config cpuid_configs[];
    +};
    +
    #endif /* _ASM_X86_KVM_H */
    --
    2.25.1
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