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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 02/11] x86/sev: Make the VMPL0 checking function more generic
Date: Fri, 26 Jan 2024 16:15:55 -0600	[thread overview]
Message-ID: <69c954113a51e3a152c9f5308017c13441f29911.1706307364.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1706307364.git.thomas.lendacky@amd.com>

Currently, the enforce_vmpl0() function uses a set argument when testing
for VMPL0 and terminates the guest if the guest is not running at VMPL0.

Make the function more generic by moving it into the common code, renaming
it, allowing it to take an argument for use in the VMPL0 check (RMPADJUST
instruction) and return the result of the check, allowing the caller to
determine the action taken based on the result.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/boot/compressed/sev.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index c3030cfb6484..c44fa52d2914 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -327,10 +327,9 @@ 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)
+static bool running_at_vmpl0(void *va)
 {
 	u64 attrs;
-	int err;
 
 	/*
 	 * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
@@ -339,12 +338,11 @@ static void enforce_vmpl0(void)
 	 *
 	 * 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.
+	 * SNP guests running at VMPL0 only run at VMPL0, so VMPL1 or higher
+	 * permission mask changes are 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);
+	return !rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
 }
 
 /*
@@ -580,7 +578,8 @@ 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();
+		if (!running_at_vmpl0(&boot_ghcb_page))
+			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
 	}
 
 	if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
-- 
2.42.0


  parent reply	other threads:[~2024-01-26 22:16 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 ` Tom Lendacky [this message]
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
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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