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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 09/11] virt: sev-guest: Choose the VMPCK key based on executing VMPL
Date: Fri, 26 Jan 2024 16:16:02 -0600	[thread overview]
Message-ID: <bd81dc55740417649e9b72dc3fe1e83e517b5672.1706307364.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1706307364.git.thomas.lendacky@amd.com>

Currently, the sev-guest driver uses the vmpck-0 key by default. When an
SVSM is present the kernel is running at a VMPL other than 0 and the
vmpck-0 key is no longer available. So choose the vmpck key based on the
active VMPL level.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/include/asm/sev.h              |  2 ++
 arch/x86/kernel/sev.c                   |  6 ++++++
 drivers/virt/coco/sev-guest/sev-guest.c | 10 +++++++---
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 372bc6183b29..b126e50a1358 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -291,6 +291,7 @@ void snp_accept_memory(phys_addr_t start, phys_addr_t end);
 u64 snp_get_unsupported_features(u64 status);
 u64 sev_get_status(void);
 void __init snp_remap_svsm_ca(void);
+int snp_get_vmpl(void);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -320,6 +321,7 @@ static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
 static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
 static inline u64 sev_get_status(void) { return 0; }
 static inline void snp_remap_svsm_ca(void) { }
+static inline int snp_get_vmpl(void) { return 0; }
 #endif
 
 #endif
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 9844c772099c..849df3aae4e1 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2442,6 +2442,12 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct sn
 }
 EXPORT_SYMBOL_GPL(snp_issue_guest_request);
 
+int snp_get_vmpl(void)
+{
+	return vmpl;
+}
+EXPORT_SYMBOL_GPL(snp_get_vmpl);
+
 static struct platform_device sev_guest_device = {
 	.name		= "sev-guest",
 	.id		= -1,
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 87f241825bc3..1ff897913bf4 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -2,7 +2,7 @@
 /*
  * AMD Secure Encrypted Virtualization (SEV) guest driver interface
  *
- * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ * Copyright (C) 2021-2024 Advanced Micro Devices, Inc.
  *
  * Author: Brijesh Singh <brijesh.singh@amd.com>
  */
@@ -70,8 +70,8 @@ struct snp_guest_dev {
 	u8 *vmpck;
 };
 
-static u32 vmpck_id;
-module_param(vmpck_id, uint, 0444);
+static int vmpck_id = -1;
+module_param(vmpck_id, int, 0444);
 MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
 
 /* Mutex to serialize the shared buffer access and command handling. */
@@ -923,6 +923,10 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 	if (!snp_dev)
 		goto e_unmap;
 
+	/* Adjust the default VMPCK key based on the executing VMPL level */
+	if (vmpck_id == -1)
+		vmpck_id = snp_get_vmpl();
+
 	ret = -EINVAL;
 	snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
 	if (!snp_dev->vmpck) {
-- 
2.42.0


  parent reply	other threads:[~2024-01-26 22:17 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
2024-01-27 15:43     ` Tom Lendacky
2024-01-26 22:16 ` Tom Lendacky [this message]
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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