TDX depends on a platform firmware module that is invoked via
instructions similar to vmenter (i.e. enter into a new privileged
"root-mode" context to manage private memory and private device
mechanisms). It is a software construct that depends on the CPU vmxon
state to enable invocation of TDX-module ABIs. Unlike other
Trusted Execution Environment (TEE) platform implementations that employ
a firmware module running on a PCI device with an MMIO mailbox for
communication, TDX has no hardware device to point to as the "TSM".
The "/sys/devices/virtual" hierarchy is intended for "software
constructs which need sysfs interface", which aligns with what TDX
needs.
The new tdx_subsys will export global attributes populated by the
TDX-module "sysinfo". A tdx_tsm device is published on this bus to
enable a typical driver model for the low level "TEE Security Manager"
(TSM) flows that talk TDISP to capable PCIe devices.
For now, this is only the base tdx_subsys and tdx_tsm device
registration with attribute definition and TSM driver to follow later.
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
arch/x86/virt/vmx/tdx/tdx.c | 63 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index 4d6826a76f78..e23bddf31daa 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -28,6 +28,8 @@
#include <linux/acpi.h>
#include <linux/suspend.h>
#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/cleanup.h>
#include <asm/page.h>
#include <asm/special_insns.h>
#include <asm/msr-index.h>
@@ -1097,9 +1099,56 @@ static int init_tdmrs(struct tdmr_info_list *tdmr_list)
return 0;
}
+static const struct bus_type tdx_subsys = {
+ .name = "tdx",
+};
+
+struct tdx_tsm {
+ struct device dev;
+};
+
+static struct tdx_tsm *alloc_tdx_tsm(void)
+{
+ struct tdx_tsm *tsm = kzalloc(sizeof(*tsm), GFP_KERNEL);
+ struct device *dev;
+
+ if (!tsm)
+ return ERR_PTR(-ENOMEM);
+
+ dev = &tsm->dev;
+ dev->bus = &tdx_subsys;
+ device_initialize(dev);
+
+ return tsm;
+}
+
+DEFINE_FREE(tdx_tsm_put, struct tdx_tsm *,
+ if (!IS_ERR_OR_NULL(_T)) put_device(&_T->dev))
+static struct tdx_tsm *init_tdx_tsm(void)
+{
+ struct device *dev;
+ int ret;
+
+ struct tdx_tsm *tsm __free(tdx_tsm_put) = alloc_tdx_tsm();
+ if (IS_ERR(tsm))
+ return tsm;
+
+ dev = &tsm->dev;
+ ret = dev_set_name(dev, "tdx_tsm");
+ if (ret)
+ return ERR_PTR(ret);
+
+ ret = device_add(dev);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return no_free_ptr(tsm);
+}
+
static int init_tdx_module(void)
{
struct tdx_tdmr_sysinfo tdmr_sysinfo;
+ struct tdx_tsm *tsm;
int ret;
/*
@@ -1122,10 +1171,15 @@ static int init_tdx_module(void)
if (ret)
goto err_free_tdxmem;
+ /* Establish subsystem for global TDX module attributes */
+ ret = subsys_virtual_register(&tdx_subsys, NULL);
+ if (ret)
+ goto err_free_tdxmem;
+
/* Allocate enough space for constructing TDMRs */
ret = alloc_tdmr_list(&tdx_tdmr_list, &tdmr_sysinfo);
if (ret)
- goto err_free_tdxmem;
+ goto err_unregister_subsys;
/* Cover all TDX-usable memory regions in TDMRs */
ret = construct_tdmrs(&tdx_memlist, &tdx_tdmr_list, &tdmr_sysinfo);
@@ -1149,6 +1203,11 @@ static int init_tdx_module(void)
pr_info("%lu KB allocated for PAMT\n", tdmrs_count_pamt_kb(&tdx_tdmr_list));
+ /* Register 'tdx_tsm' for driving optional TDX Connect functionality */
+ tsm = init_tdx_tsm();
+ if (IS_ERR(tsm))
+ pr_err("failed to initialize TSM device (%pe)\n", tsm);
+
out_put_tdxmem:
/*
* @tdx_memlist is written here and read at memory hotplug time.
@@ -1177,6 +1236,8 @@ static int init_tdx_module(void)
tdmrs_free_pamt_all(&tdx_tdmr_list);
err_free_tdmrs:
free_tdmr_list(&tdx_tdmr_list);
+err_unregister_subsys:
+ bus_unregister(&tdx_subsys);
err_free_tdxmem:
free_tdx_memlist(&tdx_memlist);
goto out_put_tdxmem;
