From: Chao Gao Date: Wed, 20 May 2026 22:28:53 +0000 (-0700) Subject: coco/tdx-host: Expose TDX module version X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=6fe8a33fdb93911934cd1c77624c1e02af45047c;p=thirdparty%2Fkernel%2Flinux.git coco/tdx-host: Expose TDX module version For TDX module updates, userspace needs to select compatible update versions based on the current module version. For example, the 1.5.x series runs on Sapphire Rapids but not Granite Rapids, which needs 2.0.x. Updates are also constrained by version distance, so a 1.5.6 module might permit updates to 1.5.7 but not to 1.5.20. Start the process of punting the version selection logic to userspace. Expose the TDX module version in the new faux device. Define TDX_VERSION_FMT macro for the TDX version format since it will be used multiple times. Also convert an existing print statement to use it. == Background == For posterity, here's what other firmware mechanisms do: 1. AMD SEV leverages an existing PCI device for the PSP to expose metadata. TDX uses a faux device as it doesn't have PCI device in its architecture. 2. Microcode uses per-CPU virtual devices to report microcode revisions because CPUs can have different revisions. But, there is only a single TDX module, so exposing the TDX module version through a global TDX faux device is appropriate 3. ARM's CCA implementation isn't in-tree yet, but will likely follow a similar faux device approach, though it's unclear whether they need to expose firmware version information [ dhansen: trim changelog ] Signed-off-by: Chao Gao Signed-off-by: Dave Hansen Reviewed-by: Binbin Wu Reviewed-by: Tony Lindgren Reviewed-by: Xu Yilun Reviewed-by: Kai Huang Reviewed-by: Kiryl Shutsemau (Meta) Reviewed-by: Xiaoyao Li Reviewed-by: Dave Hansen Link: https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh/ # [1] Link: https://patch.msgid.link/20260520133909.409394-8-chao.gao@intel.com --- diff --git a/Documentation/ABI/testing/sysfs-devices-faux-tdx-host b/Documentation/ABI/testing/sysfs-devices-faux-tdx-host new file mode 100644 index 0000000000000..47d73cb89f1e6 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-faux-tdx-host @@ -0,0 +1,5 @@ +What: /sys/devices/faux/tdx_host/version +Contact: linux-coco@lists.linux.dev +Description: (RO) Report the version of the loaded TDX module. + Formatted as "major.minor.update". Used by TDX module + update tooling. Example: "1.2.03". diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index 8b739ac014793..b7f4396b5cc56 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -41,6 +41,12 @@ #include #include +/* + * TDX module and P-SEAMLDR version convention: "major.minor.update" + * (e.g., "1.5.08") with zero-padded two-digit update field. + */ +#define TDX_VERSION_FMT "%u.%u.%02u" + /* * Used by the #VE exception handler to gather the #VE exception * info from the TDX module. This is a software only structure diff --git a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c index c7db393a9cfb1..d54d4227990c2 100644 --- a/arch/x86/virt/vmx/tdx/tdx_global_metadata.c +++ b/arch/x86/virt/vmx/tdx/tdx_global_metadata.c @@ -106,7 +106,7 @@ static __init int get_tdx_sys_info(struct tdx_sys_info *sysinfo) ret = ret ?: get_tdx_sys_info_version(&sysinfo->version); - pr_info("Module version: %u.%u.%02u\n", + pr_info("Module version: " TDX_VERSION_FMT "\n", sysinfo->version.major_version, sysinfo->version.minor_version, sysinfo->version.update_version); diff --git a/drivers/virt/coco/tdx-host/tdx-host.c b/drivers/virt/coco/tdx-host/tdx-host.c index c77885392b093..ef117a836b3a7 100644 --- a/drivers/virt/coco/tdx-host/tdx-host.c +++ b/drivers/virt/coco/tdx-host/tdx-host.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -18,6 +19,29 @@ static const struct x86_cpu_id tdx_host_ids[] = { }; MODULE_DEVICE_TABLE(x86cpu, tdx_host_ids); +static ssize_t version_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + const struct tdx_sys_info *tdx_sysinfo = tdx_get_sysinfo(); + const struct tdx_sys_info_version *ver; + + if (!tdx_sysinfo) + return -ENXIO; + + ver = &tdx_sysinfo->version; + + return sysfs_emit(buf, TDX_VERSION_FMT "\n", ver->major_version, + ver->minor_version, + ver->update_version); +} +static DEVICE_ATTR_RO(version); + +static struct attribute *tdx_host_attrs[] = { + &dev_attr_version.attr, + NULL, +}; +ATTRIBUTE_GROUPS(tdx_host); + static struct faux_device *fdev; static int __init tdx_host_init(void) @@ -25,7 +49,7 @@ static int __init tdx_host_init(void) if (!x86_match_cpu(tdx_host_ids) || !tdx_get_sysinfo()) return -ENODEV; - fdev = faux_device_create(KBUILD_MODNAME, NULL, NULL); + fdev = faux_device_create_with_groups(KBUILD_MODNAME, NULL, NULL, tdx_host_groups); if (!fdev) return -ENODEV;