x86/virt/tdx: Read essential global metadata for KVM

KVM needs two classes of global metadata to create and run TDX guests:

 - "TD Control Structures"
 - "TD Configurability"

The first class contains the sizes of TDX guest per-VM and per-vCPU
control structures.  KVM will need to use them to allocate enough space
for those control structures.

The second class contains info which reports things like which features
are configurable to TDX guest etc.  KVM will need to use them to
properly configure TDX guests.

Read them for KVM TDX to use.

The code change is auto-generated by re-running the script in [1] after
uncommenting the "td_conf" and "td_ctrl" part to regenerate the
tdx_global_metadata.{hc} and update them to the existing ones in the
kernel.

  #python tdx.py global_metadata.json tdx_global_metadata.h \
	tdx_global_metadata.c

The 'global_metadata.json' can be fetched from [2].

Note that as of this writing, the JSON file only allows a maximum of 32
CPUID entries.  While this is enough for current contents of the CPUID
leaves, there were plans to change the JSON per TDX module release which
would change the ABI and potentially prevent future versions of the TDX
module from working with older kernels.

While discussions are ongoing with the TDX module team on what exactly
constitutes an ABI breakage, in the meantime the TDX module team has
agreed to not increase the number of CPUID entries beyond 128 without
an opt in.  Therefore the file was tweaked by hand to change the maximum
number of CPUID_CONFIGs.

Link: https://lore.kernel.org/kvm/0853b155ec9aac09c594caa60914ed6ea4dc0a71.camel@intel.com/
Link: https://cdrdv2.intel.com/v1/dl/getContent/795381
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20241030190039.77971-4-rick.p.edgecombe@intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
index 8027a24d1c6e3b470126b3ebcf56cb7c629d54a6..13ad2663488b17db6f82a8a684552d96c30e7c92 100644 (file)
--- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
+++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
@@ -37,12 +37,62 @@ static int get_tdx_sys_info_tdmr(struct tdx_sys_info_tdmr *sysinfo_tdmr)
        return ret;
 }
 
+static int get_tdx_sys_info_td_ctrl(struct tdx_sys_info_td_ctrl *sysinfo_td_ctrl)
+{
+       int ret = 0;
+       u64 val;
+
+       if (!ret && !(ret = read_sys_metadata_field(0x9800000100000000, &val)))
+               sysinfo_td_ctrl->tdr_base_size = val;
+       if (!ret && !(ret = read_sys_metadata_field(0x9800000100000100, &val)))
+               sysinfo_td_ctrl->tdcs_base_size = val;
+       if (!ret && !(ret = read_sys_metadata_field(0x9800000100000200, &val)))
+               sysinfo_td_ctrl->tdvps_base_size = val;
+
+       return ret;
+}
+
+static int get_tdx_sys_info_td_conf(struct tdx_sys_info_td_conf *sysinfo_td_conf)
+{
+       int ret = 0;
+       u64 val;
+       int i, j;
+
+       if (!ret && !(ret = read_sys_metadata_field(0x1900000300000000, &val)))
+               sysinfo_td_conf->attributes_fixed0 = val;
+       if (!ret && !(ret = read_sys_metadata_field(0x1900000300000001, &val)))
+               sysinfo_td_conf->attributes_fixed1 = val;
+       if (!ret && !(ret = read_sys_metadata_field(0x1900000300000002, &val)))
+               sysinfo_td_conf->xfam_fixed0 = val;
+       if (!ret && !(ret = read_sys_metadata_field(0x1900000300000003, &val)))
+               sysinfo_td_conf->xfam_fixed1 = val;
+       if (!ret && !(ret = read_sys_metadata_field(0x9900000100000004, &val)))
+               sysinfo_td_conf->num_cpuid_config = val;
+       if (!ret && !(ret = read_sys_metadata_field(0x9900000100000008, &val)))
+               sysinfo_td_conf->max_vcpus_per_td = val;
+       if (sysinfo_td_conf->num_cpuid_config > ARRAY_SIZE(sysinfo_td_conf->cpuid_config_leaves))
+               return -EINVAL;
+       for (i = 0; i < sysinfo_td_conf->num_cpuid_config; i++)
+               if (!ret && !(ret = read_sys_metadata_field(0x9900000300000400 + i, &val)))
+                       sysinfo_td_conf->cpuid_config_leaves[i] = val;
+       if (sysinfo_td_conf->num_cpuid_config > ARRAY_SIZE(sysinfo_td_conf->cpuid_config_values))
+               return -EINVAL;
+       for (i = 0; i < sysinfo_td_conf->num_cpuid_config; i++)
+               for (j = 0; j < 2; j++)
+                       if (!ret && !(ret = read_sys_metadata_field(0x9900000300000500 + i * 2 + j, &val)))
+                               sysinfo_td_conf->cpuid_config_values[i][j] = val;
+
+       return ret;
+}
+
 static int get_tdx_sys_info(struct tdx_sys_info *sysinfo)
 {
        int ret = 0;
 
        ret = ret ?: get_tdx_sys_info_features(&sysinfo->features);
        ret = ret ?: get_tdx_sys_info_tdmr(&sysinfo->tdmr);
+       ret = ret ?: get_tdx_sys_info_td_ctrl(&sysinfo->td_ctrl);
+       ret = ret ?: get_tdx_sys_info_td_conf(&sysinfo->td_conf);
 
        return ret;
 }

diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.h b/arch/x86/virt/vmx/tdx/tdx_global_metadata.h
index 6dd3c9695f594a2b77b1a78902ecd013b8e71570..060a2ad744bff831e1526085862a2598f98b8dba 100644 (file)
--- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.h
+++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.h
@@ -17,9 +17,28 @@ struct tdx_sys_info_tdmr {
        u16 pamt_1g_entry_size;
 };
 
+struct tdx_sys_info_td_ctrl {
+       u16 tdr_base_size;
+       u16 tdcs_base_size;
+       u16 tdvps_base_size;
+};
+
+struct tdx_sys_info_td_conf {
+       u64 attributes_fixed0;
+       u64 attributes_fixed1;
+       u64 xfam_fixed0;
+       u64 xfam_fixed1;
+       u16 num_cpuid_config;
+       u16 max_vcpus_per_td;
+       u64 cpuid_config_leaves[128];
+       u64 cpuid_config_values[128][2];
+};
+
 struct tdx_sys_info {
        struct tdx_sys_info_features features;
        struct tdx_sys_info_tdmr tdmr;
+       struct tdx_sys_info_td_ctrl td_ctrl;
+       struct tdx_sys_info_td_conf td_conf;
 };
 
 #endif