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Message-ID: <20251001025442.427697-15-chao.gao@intel.com>
Date: Tue, 30 Sep 2025 19:52:58 -0700
From: Chao Gao <chao.gao@...el.com>
To: linux-coco@...ts.linux.dev,
linux-kernel@...r.kernel.org,
x86@...nel.org,
reinette.chatre@...el.com,
ira.weiny@...el.com,
kai.huang@...el.com,
dan.j.williams@...el.com,
yilun.xu@...ux.intel.com,
sagis@...gle.com,
vannapurve@...gle.com,
paulmck@...nel.org,
nik.borisov@...e.com
Cc: Chao Gao <chao.gao@...el.com>,
Farrah Chen <farrah.chen@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>,
"Kirill A. Shutemov" <kas@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>
Subject: [PATCH v2 14/21] x86/virt/seamldr: Shut down the current TDX module
TDX Module updates request shutting down the existing TDX module.
During this shutdown, the module generates hand-off data, which captures
the module's states essential for preserving running TDs. The new TDX
Module can utilize this hand-off data to establish its states.
Invoke the TDH_SYS_SHUTDOWN SEAMCALL on one CPU to perform the shutdown.
This SEAMCALL requires a hand-off module version. Use the module's own
hand-off version, as it is the highest version the module can produce and
is more likely to be compatible with new modules as new modules likely have
higher hand-off version.
Generate changes to tdx_global_metadata.{hc} by following the
instructions detailed in [1], after adding the following section to the
tdx.py script:
"handoff": [
"MODULE_HV",
],
Manually add a check in get_tdx_sys_info_handoff() to guard reading the
"module_hv" field with TDX Module update support as otherwise the field
doesn't exist.
Signed-off-by: Chao Gao <chao.gao@...el.com>
Tested-by: Farrah Chen <farrah.chen@...el.com>
Link: https://lore.kernel.org/kvm/20250226181453.2311849-12-pbonzini@redhat.com/ # [1]
---
v2:
- add a comment about how handoff version is chosen.
- remove the first !ret in get_tdx_sys_info_handoff() as we edited the
auto-generated code anyway
- remove !! when determining whether a CPU is the primary one
- remove unnecessary if-break nesting in TDP_SHUTDOWN
---
arch/x86/include/asm/tdx_global_metadata.h | 5 +++++
arch/x86/virt/vmx/tdx/seamldr.c | 10 ++++++++++
arch/x86/virt/vmx/tdx/tdx.c | 16 ++++++++++++++++
arch/x86/virt/vmx/tdx/tdx.h | 3 +++
arch/x86/virt/vmx/tdx/tdx_global_metadata.c | 13 +++++++++++++
5 files changed, 47 insertions(+)
diff --git a/arch/x86/include/asm/tdx_global_metadata.h b/arch/x86/include/asm/tdx_global_metadata.h
index 40689c8dc67e..8a9ebd895e70 100644
--- a/arch/x86/include/asm/tdx_global_metadata.h
+++ b/arch/x86/include/asm/tdx_global_metadata.h
@@ -40,12 +40,17 @@ struct tdx_sys_info_td_conf {
u64 cpuid_config_values[128][2];
};
+struct tdx_sys_info_handoff {
+ u16 module_hv;
+};
+
struct tdx_sys_info {
struct tdx_sys_info_version version;
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;
+ struct tdx_sys_info_handoff handoff;
};
#endif
diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c
index fca558b90f72..b9daf11e1064 100644
--- a/arch/x86/virt/vmx/tdx/seamldr.c
+++ b/arch/x86/virt/vmx/tdx/seamldr.c
@@ -19,6 +19,7 @@
#include <asm/seamldr.h>
#include "seamcall.h"
+#include "tdx.h"
/* P-SEAMLDR SEAMCALL leaf function */
#define P_SEAMLDR_INFO 0x8000000000000000
@@ -229,6 +230,7 @@ static struct seamldr_params *init_seamldr_params(const u8 *data, u32 size)
*/
enum tdp_state {
TDP_START,
+ TDP_SHUTDOWN,
TDP_DONE,
};
@@ -269,8 +271,12 @@ static void ack_state(void)
static int do_seamldr_install_module(void *params)
{
enum tdp_state newstate, curstate = TDP_START;
+ int cpu = smp_processor_id();
+ bool primary;
int ret = 0;
+ primary = cpumask_first(cpu_online_mask) == cpu;
+
do {
/* Chill out and ensure we re-read tdp_data. */
cpu_relax();
@@ -279,6 +285,10 @@ static int do_seamldr_install_module(void *params)
if (newstate != curstate) {
curstate = newstate;
switch (curstate) {
+ case TDP_SHUTDOWN:
+ if (primary)
+ ret = tdx_module_shutdown();
+ break;
default:
break;
}
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index b367bb1d94ed..89b51e270274 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -1191,6 +1191,22 @@ int tdx_enable(void)
}
EXPORT_SYMBOL_GPL(tdx_enable);
+int tdx_module_shutdown(void)
+{
+ struct tdx_module_args args = {};
+
+ /*
+ * Shut down the TDX Module and prepare handoff data for the next
+ * TDX Module. This SEAMCALL requires a hand-off module version.
+ * Use the module's own hand-off version, as it is the highest
+ * version the module can produce and is more likely to be
+ * compatible with new modules as new modules likely have higher
+ * hand-off version.
+ */
+ args.rcx = tdx_sysinfo.handoff.module_hv;
+ return seamcall_prerr(TDH_SYS_SHUTDOWN, &args);
+}
+
static bool is_pamt_page(unsigned long phys)
{
struct tdmr_info_list *tdmr_list = &tdx_tdmr_list;
diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
index 82bb82be8567..1c4da9540ae0 100644
--- a/arch/x86/virt/vmx/tdx/tdx.h
+++ b/arch/x86/virt/vmx/tdx/tdx.h
@@ -46,6 +46,7 @@
#define TDH_PHYMEM_PAGE_WBINVD 41
#define TDH_VP_WR 43
#define TDH_SYS_CONFIG 45
+#define TDH_SYS_SHUTDOWN 52
/*
* SEAMCALL leaf:
@@ -118,4 +119,6 @@ struct tdmr_info_list {
int max_tdmrs; /* How many 'tdmr_info's are allocated */
};
+int tdx_module_shutdown(void);
+
#endif
diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
index 0454124803f3..3fdd5cbc21d8 100644
--- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
+++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c
@@ -100,6 +100,18 @@ static int get_tdx_sys_info_td_conf(struct tdx_sys_info_td_conf *sysinfo_td_conf
return ret;
}
+static int get_tdx_sys_info_handoff(struct tdx_sys_info_handoff *sysinfo_handoff)
+{
+ int ret = 0;
+ u64 val;
+
+ if (tdx_supports_runtime_update(&tdx_sysinfo) &&
+ !(ret = read_sys_metadata_field(0x8900000100000000, &val)))
+ sysinfo_handoff->module_hv = val;
+
+ return ret;
+}
+
static int get_tdx_sys_info(struct tdx_sys_info *sysinfo)
{
int ret = 0;
@@ -109,6 +121,7 @@ static int get_tdx_sys_info(struct tdx_sys_info *sysinfo)
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);
+ ret = ret ?: get_tdx_sys_info_handoff(&sysinfo->handoff);
return ret;
}
--
2.47.3
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