diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index e7e160954e798e..8fd7ed9aee4edb 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -605,6 +605,18 @@ Description: Umwait control Note that a value of zero means there is no limit. Low order two bits must be zero. +What: /sys/devices/system/cpu/sev + /sys/devices/system/cpu/sev/vmpl +Date: May 2024 +Contact: Linux kernel mailing list +Description: Secure Encrypted Virtualization (SEV) information + + This directory is only present when running as an SEV-SNP guest. + + vmpl: Reports the Virtual Machine Privilege Level (VMPL) at which + the SEV-SNP guest is running. + + What: /sys/devices/system/cpu/svm Date: August 2019 Contact: Linux kernel mailing list diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 84f37315563584..4dc7ae33eac9ee 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2504,3 +2504,49 @@ void __init snp_update_svsm_ca(void) /* Update the CAA to a proper kernel address */ boot_svsm_caa = &boot_svsm_ca_page; } + +#ifdef CONFIG_SYSFS +static ssize_t vmpl_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%d\n", snp_vmpl); +} + +static struct kobj_attribute vmpl_attr = __ATTR_RO(vmpl); + +static struct attribute *vmpl_attrs[] = { + &vmpl_attr.attr, + NULL +}; + +static struct attribute_group sev_attr_group = { + .attrs = vmpl_attrs, +}; + +static int __init sev_sysfs_init(void) +{ + struct kobject *sev_kobj; + struct device *dev_root; + int ret; + + if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) + return -ENODEV; + + dev_root = bus_get_dev_root(&cpu_subsys); + if (!dev_root) + return -ENODEV; + + sev_kobj = kobject_create_and_add("sev", &dev_root->kobj); + put_device(dev_root); + + if (!sev_kobj) + return -ENOMEM; + + ret = sysfs_create_group(sev_kobj, &sev_attr_group); + if (ret) + kobject_put(sev_kobj); + + return ret; +} +arch_initcall(sev_sysfs_init); +#endif // CONFIG_SYSFS