From: Dionna Amalie Glaze <dionnaglaze@google.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
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: Re: [PATCH 08/11] x86/sev: Provide guest VMPL level to userspace
Date: Fri, 26 Jan 2024 17:06:29 -0800 [thread overview]
Message-ID: <CAAH4kHZjqq5OTyTqhCGxeCSrgw==_FyLqqLOaWK3JxQytF=k7A@mail.gmail.com> (raw)
In-Reply-To: <61316ac5a8217f0397da87c78c2db08580ad75a5.1706307364.git.thomas.lendacky@amd.com>
On Fri, Jan 26, 2024 at 2:19 PM Tom Lendacky <thomas.lendacky@amd.com> wrote:
>
> 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.
Is this not the intended meaning of privlevel_floor in
/sys/kernel/config/tsm/report/$report0/privlevel_floor?
>
> 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 121a9bad86c9..9844c772099c 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -2479,3 +2479,40 @@ 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);
> --
> 2.42.0
>
>
--
-Dionna Glaze, PhD (she/her)
next prev parent reply other threads:[~2024-01-27 1:06 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-26 22:15 [PATCH 00/11] Provide SEV-SNP support for running under an SVSM Tom Lendacky
2024-01-26 22:15 ` [PATCH 01/11] x86/sev: Rename snp_init() in the boot/compressed/sev.c file Tom Lendacky
2024-01-27 0:05 ` Dionna Amalie Glaze
2024-01-27 14:38 ` Tom Lendacky
2024-01-26 22:15 ` [PATCH 02/11] x86/sev: Make the VMPL0 checking function more generic Tom Lendacky
2024-01-26 22:15 ` [PATCH 03/11] x86/sev: Check for the presence of an SVSM in the SNP Secrets page Tom Lendacky
2024-01-26 22:15 ` [PATCH 04/11] x86/sev: Use kernel provided SVSM Calling Areas Tom Lendacky
2024-01-27 0:45 ` Dionna Amalie Glaze
2024-01-27 14:43 ` Tom Lendacky
2024-01-26 22:15 ` [PATCH 05/11] x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0 Tom Lendacky
2024-01-27 0:59 ` Dionna Amalie Glaze
2024-01-27 15:18 ` Tom Lendacky
2024-01-26 22:15 ` [PATCH 06/11] x86/sev: Use the SVSM to create a vCPU when not in VMPL0 Tom Lendacky
2024-01-26 22:16 ` [PATCH 07/11] x86/sev: Provide SVSM discovery support Tom Lendacky
2024-01-29 10:41 ` Jeremi Piotrowski
2024-01-29 15:18 ` Tom Lendacky
2024-01-26 22:16 ` [PATCH 08/11] x86/sev: Provide guest VMPL level to userspace Tom Lendacky
2024-01-27 1:06 ` Dionna Amalie Glaze [this message]
2024-01-27 15:43 ` Tom Lendacky
2024-01-26 22:16 ` [PATCH 09/11] virt: sev-guest: Choose the VMPCK key based on executing VMPL Tom Lendacky
2024-01-26 22:16 ` [PATCH 10/11] x86/sev: Extend the config-fs attestation support for an SVSM Tom Lendacky
2024-01-27 1:27 ` Dionna Amalie Glaze
2024-01-29 15:02 ` Tom Lendacky
2024-01-29 20:04 ` Dionna Amalie Glaze
2024-02-01 21:14 ` Tom Lendacky
2024-02-02 7:10 ` Dan Williams
2024-02-05 23:29 ` Kuppuswamy, Sathyanarayanan
2024-02-06 18:53 ` Tom Lendacky
2024-02-06 18:48 ` Tom Lendacky
2024-02-13 2:34 ` Dan Williams
2024-02-16 19:07 ` Tom Lendacky
2024-02-16 20:46 ` Dan Williams
2024-02-23 20:41 ` Tom Lendacky
2024-02-24 0:02 ` Dan Williams
2024-02-26 14:42 ` Tom Lendacky
2024-01-26 22:16 ` [PATCH 11/11] x86/sev: Allow non-VMPL0 execution when an SVSM is present Tom Lendacky
2024-02-12 10:40 ` [PATCH 00/11] Provide SEV-SNP support for running under an SVSM Reshetova, Elena
2024-02-16 19:46 ` Tom Lendacky
2024-02-19 16:57 ` Shutemov, Kirill
2024-02-19 17:54 ` Reshetova, Elena
2024-02-23 20:23 ` Tom Lendacky
2024-02-27 14:56 ` Reshetova, Elena
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