From: Tom Lendacky <thomas.lendacky@amd.com>
To: <linux-kernel@vger.kernel.org>, <x86@kernel.org>,
<linux-coco@lists.linux.dev>, <svsm-devel@coconut-svsm.dev>
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 v4 03/15] x86/sev: Make the VMPL0 checking more straight forward
Date: Wed, 24 Apr 2024 10:57:59 -0500 [thread overview]
Message-ID: <ed01ddf04bfb475596b24b634fd26cffaa85173a.1713974291.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1713974291.git.thomas.lendacky@amd.com>
Currently, the enforce_vmpl0() function uses a set argument when modifying
the VMPL1 permissions used to test for VMPL0. If the guest is not running
at VMPL0, the guest self-terminates.
The function is just a wrapper for a fixed RMPADJUST function. Eliminate
the function and perform the RMPADJUST directly.
No functional change.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/boot/compressed/sev.c | 35 ++++++++++++++--------------------
1 file changed, 14 insertions(+), 21 deletions(-)
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 5ad0ff4664f1..0457a9d7e515 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -335,26 +335,6 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
}
-static void enforce_vmpl0(void)
-{
- u64 attrs;
- int err;
-
- /*
- * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
- * higher) privilege level. Here, clear the VMPL1 permission mask of the
- * GHCB page. If the guest is not running at VMPL0, this will fail.
- *
- * If the guest is running at VMPL0, it will succeed. Even if that operation
- * modifies permission bits, it is still ok to do so currently because Linux
- * SNP guests are supported only on VMPL0 so VMPL1 or higher permission masks
- * changing is a don't-care.
- */
- attrs = 1;
- if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, attrs))
- sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
-}
-
/*
* SNP_FEATURES_IMPL_REQ is the mask of SNP features that will need
* guest side implementation for proper functioning of the guest. If any
@@ -588,7 +568,20 @@ void sev_enable(struct boot_params *bp)
if (!(get_hv_features() & GHCB_HV_FT_SNP))
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
- enforce_vmpl0();
+ /*
+ * Enforce running at VMPL0.
+ *
+ * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
+ * higher) privilege level. Here, clear the VMPL1 permission mask of the
+ * GHCB page. If the guest is not running at VMPL0, this will fail.
+ *
+ * If the guest is running at VMPL0, it will succeed. Even if that operation
+ * modifies permission bits, it is still ok to do so currently because Linux
+ * SNP guests running at VMPL0 only run at VMPL0, so VMPL1 or higher
+ * permission mask changes are a don't-care.
+ */
+ if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, 1))
+ sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
}
if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
--
2.43.2
next prev parent reply other threads:[~2024-04-24 15:58 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 15:57 [PATCH v4 00/15] Provide SEV-SNP support for running under an SVSM Tom Lendacky
2024-04-24 15:57 ` [PATCH v4 01/15] x86/sev: Shorten snp_secrets_page_layout to snp_secrets_page Tom Lendacky
2024-04-25 13:30 ` Borislav Petkov
2024-04-24 15:57 ` [PATCH v4 02/15] x86/sev: Rename snp_init() in the boot/compressed/sev.c file Tom Lendacky
2024-04-24 15:57 ` Tom Lendacky [this message]
2024-04-24 15:58 ` [PATCH v4 04/15] x86/sev: Check for the presence of an SVSM in the SNP Secrets page Tom Lendacky
2024-05-02 9:35 ` Borislav Petkov
2024-05-02 15:29 ` Tom Lendacky
2024-05-17 15:58 ` Borislav Petkov
2024-05-20 13:57 ` Tom Lendacky
2024-05-22 15:27 ` Borislav Petkov
2024-05-22 16:15 ` Tom Lendacky
2024-05-22 17:23 ` Borislav Petkov
2024-04-24 15:58 ` [PATCH v4 05/15] x86/sev: Use kernel provided SVSM Calling Areas Tom Lendacky
2024-05-03 10:34 ` Borislav Petkov
2024-05-06 10:09 ` Borislav Petkov
2024-05-06 13:14 ` Tom Lendacky
2024-05-06 14:14 ` Borislav Petkov
2024-05-08 8:05 ` Borislav Petkov
2024-05-08 19:13 ` Tom Lendacky
2024-05-08 19:40 ` Tom Lendacky
2024-05-08 19:58 ` Borislav Petkov
2024-05-08 20:09 ` Tom Lendacky
2024-05-17 19:23 ` Borislav Petkov
2024-04-24 15:58 ` [PATCH v4 06/15] x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0 Tom Lendacky
2024-05-22 18:24 ` Borislav Petkov
2024-05-22 21:14 ` Tom Lendacky
2024-05-27 12:01 ` Borislav Petkov
2024-04-24 15:58 ` [PATCH v4 07/15] x86/sev: Use the SVSM to create a vCPU when not in VMPL0 Tom Lendacky
2024-05-27 12:33 ` Borislav Petkov
2024-04-24 15:58 ` [PATCH v4 08/15] x86/sev: Provide SVSM discovery support Tom Lendacky
2024-05-27 13:10 ` Borislav Petkov
2024-04-24 15:58 ` [PATCH v4 09/15] x86/sev: Provide guest VMPL level to userspace Tom Lendacky
2024-05-27 13:51 ` Borislav Petkov
2024-04-24 15:58 ` [PATCH v4 10/15] virt: sev-guest: Choose the VMPCK key based on executing VMPL Tom Lendacky
2024-05-01 23:57 ` [svsm-devel] " Jacob Xu
2024-05-02 13:17 ` Tom Lendacky
2024-04-24 15:58 ` [PATCH v4 11/15] configfs-tsm: Allow the privlevel_floor attribute to be updated Tom Lendacky
2024-04-26 20:51 ` Dan Williams
2024-04-24 15:58 ` [PATCH v4 12/15] fs/configfs: Add a callback to determine attribute visibility Tom Lendacky
2024-04-26 21:48 ` Dan Williams
2024-04-29 13:26 ` Tom Lendacky
2024-04-24 15:58 ` [PATCH v4 13/15] x86/sev: Take advantage of configfs visibility support in TSM Tom Lendacky
2024-04-26 21:58 ` Dan Williams
2024-04-29 13:35 ` Tom Lendacky
2024-04-29 14:28 ` Tom Lendacky
2024-05-01 19:28 ` Dan Williams
2024-05-01 5:18 ` Kuppuswamy Sathyanarayanan
2024-05-01 20:15 ` Dan Williams
2024-05-02 3:40 ` Kuppuswamy Sathyanarayanan
2024-05-02 17:29 ` Dan Williams
2024-05-03 16:10 ` Kuppuswamy Sathyanarayanan
2024-04-24 15:58 ` [PATCH v4 14/15] x86/sev: Extend the config-fs attestation support for an SVSM Tom Lendacky
2024-04-24 15:58 ` [PATCH v4 15/15] x86/sev: Allow non-VMPL0 execution when an SVSM is present Tom Lendacky
2024-05-03 11:37 ` [svsm-devel] " Jörg Rödel
2024-05-03 16:04 ` Borislav Petkov
2024-05-06 7:43 ` Jörg Rödel
2024-05-03 11:38 ` [svsm-devel] [PATCH v4 00/15] Provide SEV-SNP support for running under an SVSM Jörg Rödel
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