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    Subject[PATCH v19 036/130] 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>
    ---
    v18:
    - drop the use of tdhsysinfo_struct and TDH.SYS.INFO, use TDH.SYS.RD().
    For that, dynamically allocate/free tdx_info.
    - drop the change of tools/arch/x86/include/uapi/asm/kvm.h.

    v14 -> v15:
    - ABI change: added supported_gpaw and reserved area.

    Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
    ---
    arch/x86/include/uapi/asm/kvm.h | 17 ++++++++++
    arch/x86/kvm/vmx/tdx.c | 56 +++++++++++++++++++++++++++++++++
    arch/x86/kvm/vmx/tdx.h | 3 ++
    3 files changed, 76 insertions(+)

    diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
    index 9ea46d143bef..e28189c81691 100644
    --- a/arch/x86/include/uapi/asm/kvm.h
    +++ b/arch/x86/include/uapi/asm/kvm.h
    @@ -604,4 +604,21 @@ struct kvm_tdx_cpuid_config {
    __u32 edx;
    };

    +/* supported_gpaw */
    +#define TDX_CAP_GPAW_48 (1 << 0)
    +#define TDX_CAP_GPAW_52 (1 << 1)
    +
    +struct kvm_tdx_capabilities {
    + __u64 attrs_fixed0;
    + __u64 attrs_fixed1;
    + __u64 xfam_fixed0;
    + __u64 xfam_fixed1;
    + __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 07a3f0f75f87..816ccdb4bc41 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_arch.h"
    #include "tdx.h"

    @@ -55,6 +56,58 @@ struct tdx_info {
    /* Info about the TDX module. */
    static struct tdx_info *tdx_info;

    +static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
    +{
    + struct kvm_tdx_capabilities __user *user_caps;
    + struct kvm_tdx_capabilities *caps = NULL;
    + int ret = 0;
    +
    + if (cmd->flags)
    + return -EINVAL;
    +
    + 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 < tdx_info->num_cpuid_config) {
    + ret = -E2BIG;
    + goto out;
    + }
    +
    + *caps = (struct kvm_tdx_capabilities) {
    + .attrs_fixed0 = tdx_info->attributes_fixed0,
    + .attrs_fixed1 = tdx_info->attributes_fixed1,
    + .xfam_fixed0 = tdx_info->xfam_fixed0,
    + .xfam_fixed1 = tdx_info->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 = tdx_info->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, &tdx_info->cpuid_configs,
    + tdx_info->num_cpuid_config *
    + sizeof(tdx_info->cpuid_configs[0]))) {
    + 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;
    @@ -68,6 +121,9 @@ 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/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
    index 473013265bd8..22c0b57f69ca 100644
    --- a/arch/x86/kvm/vmx/tdx.h
    +++ b/arch/x86/kvm/vmx/tdx.h
    @@ -3,6 +3,9 @@
    #define __KVM_X86_TDX_H

    #ifdef CONFIG_INTEL_TDX_HOST
    +
    +#include "tdx_ops.h"
    +
    struct kvm_tdx {
    struct kvm kvm;
    /* TDX specific members follow. */
    --
    2.25.1

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