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Message-Id: <20251202050844.2520762-4-yilun.xu@linux.intel.com>
Date: Tue, 2 Dec 2025 13:08:41 +0800
From: Xu Yilun <yilun.xu@...ux.intel.com>
To: x86@...nel.org,
dave.hansen@...ux.intel.com,
kas@...nel.org,
linux-kernel@...r.kernel.org
Cc: chao.gao@...el.com,
rick.p.edgecombe@...el.com,
dan.j.williams@...el.com,
baolu.lu@...ux.intel.com,
yilun.xu@...ux.intel.com,
yilun.xu@...el.com,
zhenzhong.duan@...el.com,
kvm@...r.kernel.org,
adrian.hunter@...el.com
Subject: [PATCH 3/6] x86/virt/tdx: Refactor metadata reading with a clearer for loop
Replace confusing "ret = ret ?: " code pattern with a normal for loop.
The existing code pattern is compact and friendly to auto-generation.
However, hiding the stop-on-failure logic within the sequential
execution pattern reduces readability. Revive the field mapping table
which lists the field_ids to read and where to store each readout value.
Iterate the table with a normal for loop.
For now this metadata reading process doesn't work well with array typed
fields. Use dedicated method to read these 2 array typed fields. Will
improve in later patches.
Cc: Kai Huang <kai.huang@...el.com>
Signed-off-by: Xu Yilun <yilun.xu@...ux.intel.com>
---
arch/x86/virt/vmx/tdx/tdx_global_metadata.c | 172 ++++++++++----------
1 file changed, 86 insertions(+), 86 deletions(-)
diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
index 0dfb3a9995fe..3db87c4accd6 100644
--- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
+++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
@@ -7,8 +7,50 @@
* Include this file to other C file instead.
*/
-static int read_sys_metadata_field(u64 field_id, u64 *data)
+struct field_mapping {
+ u64 field_id;
+ int offset;
+ int size;
+};
+
+#define TD_SYSINFO_MAP(_field_id, _member) \
+ { .field_id = _field_id, \
+ .offset = offsetof(struct tdx_sys_info, _member), \
+ .size = sizeof_field(struct tdx_sys_info, _member) }
+
+/* Map TD_SYSINFO fields into 'struct tdx_sys_info': */
+static const struct field_mapping mappings[] = {
+ TD_SYSINFO_MAP(0x0A00000300000008, features.tdx_features0),
+
+ TD_SYSINFO_MAP(0x9100000100000008, tdmr.max_tdmrs),
+ TD_SYSINFO_MAP(0x9100000100000009, tdmr.max_reserved_per_tdmr),
+ TD_SYSINFO_MAP(0x9100000100000010, tdmr.pamt_4k_entry_size),
+ TD_SYSINFO_MAP(0x9100000100000011, tdmr.pamt_2m_entry_size),
+ TD_SYSINFO_MAP(0x9100000100000012, tdmr.pamt_1g_entry_size),
+
+ TD_SYSINFO_MAP(0x9800000100000000, td_ctrl.tdr_base_size),
+ TD_SYSINFO_MAP(0x9800000100000100, td_ctrl.tdcs_base_size),
+ TD_SYSINFO_MAP(0x9800000100000200, td_ctrl.tdvps_base_size),
+
+ TD_SYSINFO_MAP(0x1900000300000000, td_conf.attributes_fixed0),
+ TD_SYSINFO_MAP(0x1900000300000001, td_conf.attributes_fixed1),
+ TD_SYSINFO_MAP(0x1900000300000002, td_conf.xfam_fixed0),
+ TD_SYSINFO_MAP(0x1900000300000003, td_conf.xfam_fixed1),
+ TD_SYSINFO_MAP(0x9900000100000004, td_conf.num_cpuid_config),
+ TD_SYSINFO_MAP(0x9900000100000008, td_conf.max_vcpus_per_td),
+};
+
+/* Populate the following fields in special manner, separate them out. */
+static const struct field_mapping cpuid_config_leaves =
+ TD_SYSINFO_MAP(0x9900000300000400, td_conf.cpuid_config_leaves[0]);
+
+static const struct field_mapping cpuid_config_values =
+ TD_SYSINFO_MAP(0x9900000300000500, td_conf.cpuid_config_values[0][0]);
+
+static int read_sys_metadata_field(u64 field_id, int offset, int size,
+ struct tdx_sys_info *ts)
{
+ void *field = ((void *)ts) + offset;
struct tdx_module_args args = {};
int ret;
@@ -22,97 +64,55 @@ static int read_sys_metadata_field(u64 field_id, u64 *data)
if (ret)
return ret;
- *data = args.r8;
+ memcpy(field, &args.r8, size);
return 0;
}
-static int get_tdx_sys_info_features(struct tdx_sys_info_features *sysinfo_features)
-{
- int ret = 0;
- u64 val;
-
- if (!ret && !(ret = read_sys_metadata_field(0x0A00000300000008, &val)))
- sysinfo_features->tdx_features0 = val;
-
- return ret;
-}
-
-static int get_tdx_sys_info_tdmr(struct tdx_sys_info_tdmr *sysinfo_tdmr)
-{
- int ret = 0;
- u64 val;
-
- if (!ret && !(ret = read_sys_metadata_field(0x9100000100000008, &val)))
- sysinfo_tdmr->max_tdmrs = val;
- if (!ret && !(ret = read_sys_metadata_field(0x9100000100000009, &val)))
- sysinfo_tdmr->max_reserved_per_tdmr = val;
- if (!ret && !(ret = read_sys_metadata_field(0x9100000100000010, &val)))
- sysinfo_tdmr->pamt_4k_entry_size = val;
- if (!ret && !(ret = read_sys_metadata_field(0x9100000100000011, &val)))
- sysinfo_tdmr->pamt_2m_entry_size = val;
- if (!ret && !(ret = read_sys_metadata_field(0x9100000100000012, &val)))
- sysinfo_tdmr->pamt_1g_entry_size = val;
-
- 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;
+ struct tdx_sys_info_td_conf *td_conf = &sysinfo->td_conf;
+ int ret, i;
+
+ /* Populate 'tdx_sys_info' fields using the mapping structure above: */
+ for (i = 0; i < ARRAY_SIZE(mappings); i++) {
+ ret = read_sys_metadata_field(mappings[i].field_id,
+ mappings[i].offset,
+ mappings[i].size,
+ sysinfo);
+ if (ret)
+ return ret;
+ }
+
+ if (td_conf->num_cpuid_config > ARRAY_SIZE(td_conf->cpuid_config_leaves) ||
+ td_conf->num_cpuid_config > ARRAY_SIZE(td_conf->cpuid_config_values))
+ return -EINVAL;
- 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);
+ /*
+ * Populate 2 special fields, td_conf.cpuid_config_leaves[] and
+ * td_conf.cpuid_config_values[][]
+ */
+ for (i = 0; i < td_conf->num_cpuid_config; i++) {
+ ret = read_sys_metadata_field(cpuid_config_leaves.field_id + i,
+ cpuid_config_leaves.offset +
+ cpuid_config_leaves.size * i,
+ cpuid_config_leaves.size,
+ sysinfo);
+ if (ret)
+ return ret;
+ }
+
+ for (i = 0;
+ i < td_conf->num_cpuid_config * ARRAY_SIZE(td_conf->cpuid_config_values[0]);
+ i++) {
+ ret = read_sys_metadata_field(cpuid_config_values.field_id + i,
+ cpuid_config_values.offset +
+ cpuid_config_values.size * i,
+ cpuid_config_values.size,
+ sysinfo);
+ if (ret)
+ return ret;
+ }
- return ret;
+ return 0;
}
--
2.25.1
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