From: Tom Lendacky <thomas.lendacky@amd.com>
To: <linux-kernel@vger.kernel.org>, <x86@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
Dan Williams <dan.j.williams@intel.com>,
Michael Roth <michael.roth@amd.com>,
Ashish Kalra <ashish.kalra@amd.com>
Subject: [PATCH v2 08/14] x86/sev: Provide guest VMPL level to userspace
Date: Fri, 8 Mar 2024 12:35:23 -0600 [thread overview]
Message-ID: <64d95521f3be31025e75bcd72b20499fb8d93582.1709922929.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1709922929.git.thomas.lendacky@amd.com>
Requesting an attestation report from userspace involves providing the
VMPL level for the report. Currently any value from 0-3 is valid because
Linux enforces running at VMPL0.
When an SVSM is present, though, Linux will not be running at VMPL0 and
only VMPL values starting at the VMPL level Linux is running at to 3 are
valid. In order to allow userspace to determine the minimum VMPL value
that can be supplied to an attestation report, create a sysfs entry that
can be used to retrieve the current VMPL level of Linux.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/kernel/sev.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index b85f1b455eb8..807bd6ea8d85 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2529,3 +2529,40 @@ void __init snp_remap_svsm_ca(void)
/* Update the CAA to a proper kernel address */
boot_svsm_caa = &boot_svsm_ca_page;
}
+
+static ssize_t vmpl_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", 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;
+ int ret;
+
+ if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+ return -ENODEV;
+
+ sev_kobj = kobject_create_and_add("sev", kernel_kobj);
+ 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);
--
2.43.2
next prev parent reply other threads:[~2024-03-08 18:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-08 18:35 [PATCH v2 00/14] Provide SEV-SNP support for running under an SVSM Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 01/14] x86/sev: Rename snp_init() in the boot/compressed/sev.c file Tom Lendacky
2024-03-10 21:25 ` Borislav Petkov
2024-03-11 16:16 ` Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 02/14] x86/sev: Make the VMPL0 checking function more generic Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 03/14] x86/sev: Check for the presence of an SVSM in the SNP Secrets page Tom Lendacky
2024-03-09 0:33 ` Dionna Amalie Glaze
2024-03-11 14:50 ` Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 04/14] x86/sev: Use kernel provided SVSM Calling Areas Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 05/14] x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0 Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 06/14] x86/sev: Use the SVSM to create a vCPU when not in VMPL0 Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 07/14] x86/sev: Provide SVSM discovery support Tom Lendacky
2024-03-08 18:35 ` Tom Lendacky [this message]
2024-03-08 18:35 ` [PATCH v2 09/14] virt: sev-guest: Choose the VMPCK key based on executing VMPL Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 10/14] configfs-tsm: Allow the privlevel_floor attribute to be updated Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 11/14] x86/sev: Extend the config-fs attestation support for an SVSM Tom Lendacky
2024-03-10 6:06 ` Kuppuswamy, Sathyanarayanan
2024-03-11 16:16 ` Tom Lendacky
2024-03-12 5:57 ` Kuppuswamy Sathyanarayanan
2024-03-12 13:29 ` Tom Lendacky
2024-03-08 18:35 ` [PATCH v2 12/14] fs/configfs: Add a callback to determine attribute visibility Tom Lendacky
2024-03-11 19:58 ` Tom Lendacky
2024-03-13 21:37 ` Joel Becker
2024-03-14 14:23 ` Tom Lendacky
2024-03-21 2:40 ` Dan Williams
2024-03-08 18:35 ` [PATCH v2 13/14] x86/sev: Hide SVSM attestation entries if not running under an SVSM Tom Lendacky
2024-03-23 17:24 ` Kuppuswamy, Sathyanarayanan
2024-03-25 14:05 ` Tom Lendacky
2024-03-26 1:10 ` Kuppuswamy Sathyanarayanan
2024-03-08 18:35 ` [PATCH v2 14/14] x86/sev: Allow non-VMPL0 execution when an SVSM is present Tom Lendacky
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