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authorLinus Torvalds <torvalds@linux-foundation.org>2024-03-11 17:44:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-03-11 17:44:11 -0700
commit38b334fc767e44816be087b3ec5d84b1438b735f (patch)
tree6ee0cc2a1f738df713708ab6d83d6d3b44327eda /Documentation
parent2edfd1046f555db6456514bc8ffe0847537e54f4 (diff)
parentc0935fca6ba4799e5efc6daeee37887e84707d01 (diff)
downloadlinux-38b334fc767e44816be087b3ec5d84b1438b735f.tar.gz
Merge tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov: - Add the x86 part of the SEV-SNP host support. This will allow the kernel to be used as a KVM hypervisor capable of running SNP (Secure Nested Paging) guests. Roughly speaking, SEV-SNP is the ultimate goal of the AMD confidential computing side, providing the most comprehensive confidential computing environment up to date. This is the x86 part and there is a KVM part which did not get ready in time for the merge window so latter will be forthcoming in the next cycle. - Rework the early code's position-dependent SEV variable references in order to allow building the kernel with clang and -fPIE/-fPIC and -mcmodel=kernel - The usual set of fixes, cleanups and improvements all over the place * tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) x86/sev: Disable KMSAN for memory encryption TUs x86/sev: Dump SEV_STATUS crypto: ccp - Have it depend on AMD_IOMMU iommu/amd: Fix failure return from snp_lookup_rmpentry() x86/sev: Fix position dependent variable references in startup code crypto: ccp: Make snp_range_list static x86/Kconfig: Remove CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT Documentation: virt: Fix up pre-formatted text block for SEV ioctls crypto: ccp: Add the SNP_SET_CONFIG command crypto: ccp: Add the SNP_COMMIT command crypto: ccp: Add the SNP_PLATFORM_STATUS command x86/cpufeatures: Enable/unmask SEV-SNP CPU feature KVM: SEV: Make AVIC backing, VMSA and VMCB memory allocation SNP safe crypto: ccp: Add panic notifier for SEV/SNP firmware shutdown on kdump iommu/amd: Clean up RMP entries for IOMMU pages during SNP shutdown crypto: ccp: Handle legacy SEV commands when SNP is enabled crypto: ccp: Handle non-volatile INIT_EX data when SNP is enabled crypto: ccp: Handle the legacy TMR allocation when SNP is enabled x86/sev: Introduce an SNP leaked pages list crypto: ccp: Provide an API to issue SEV and SNP commands ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt4
-rw-r--r--Documentation/arch/x86/amd-memory-encryption.rst16
-rw-r--r--Documentation/virt/coco/sev-guest.rst52
3 files changed, 61 insertions, 11 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f5bfb0dbc560b9..a727d082e4c218 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3318,9 +3318,7 @@
mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
Valid arguments: on, off
- Default (depends on kernel configuration option):
- on (CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y)
- off (CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=n)
+ Default: off
mem_encrypt=on: Activate SME
mem_encrypt=off: Do not activate SME
diff --git a/Documentation/arch/x86/amd-memory-encryption.rst b/Documentation/arch/x86/amd-memory-encryption.rst
index 07caa8fff852ee..414bc7402ae7db 100644
--- a/Documentation/arch/x86/amd-memory-encryption.rst
+++ b/Documentation/arch/x86/amd-memory-encryption.rst
@@ -87,14 +87,14 @@ The state of SME in the Linux kernel can be documented as follows:
kernel is non-zero).
SME can also be enabled and activated in the BIOS. If SME is enabled and
-activated in the BIOS, then all memory accesses will be encrypted and it will
-not be necessary to activate the Linux memory encryption support. If the BIOS
-merely enables SME (sets bit 23 of the MSR_AMD64_SYSCFG), then Linux can activate
-memory encryption by default (CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y) or
-by supplying mem_encrypt=on on the kernel command line. However, if BIOS does
-not enable SME, then Linux will not be able to activate memory encryption, even
-if configured to do so by default or the mem_encrypt=on command line parameter
-is specified.
+activated in the BIOS, then all memory accesses will be encrypted and it
+will not be necessary to activate the Linux memory encryption support.
+
+If the BIOS merely enables SME (sets bit 23 of the MSR_AMD64_SYSCFG),
+then memory encryption can be enabled by supplying mem_encrypt=on on the
+kernel command line. However, if BIOS does not enable SME, then Linux
+will not be able to activate memory encryption, even if configured to do
+so by default or the mem_encrypt=on command line parameter is specified.
Secure Nested Paging (SNP)
==========================
diff --git a/Documentation/virt/coco/sev-guest.rst b/Documentation/virt/coco/sev-guest.rst
index 68b0d2363af820..e1eaf6a830ce4d 100644
--- a/Documentation/virt/coco/sev-guest.rst
+++ b/Documentation/virt/coco/sev-guest.rst
@@ -67,6 +67,23 @@ counter (e.g. counter overflow), then -EIO will be returned.
};
};
+The host ioctls are issued to a file descriptor of the /dev/sev device.
+The ioctl accepts the command ID/input structure documented below.
+
+::
+
+ struct sev_issue_cmd {
+ /* Command ID */
+ __u32 cmd;
+
+ /* Command request structure */
+ __u64 data;
+
+ /* Firmware error code on failure (see psp-sev.h) */
+ __u32 error;
+ };
+
+
2.1 SNP_GET_REPORT
------------------
@@ -124,6 +141,41 @@ be updated with the expected value.
See GHCB specification for further detail on how to parse the certificate blob.
+2.4 SNP_PLATFORM_STATUS
+-----------------------
+:Technology: sev-snp
+:Type: hypervisor ioctl cmd
+:Parameters (out): struct sev_user_data_snp_status
+:Returns (out): 0 on success, -negative on error
+
+The SNP_PLATFORM_STATUS command is used to query the SNP platform status. The
+status includes API major, minor version and more. See the SEV-SNP
+specification for further details.
+
+2.5 SNP_COMMIT
+--------------
+:Technology: sev-snp
+:Type: hypervisor ioctl cmd
+:Returns (out): 0 on success, -negative on error
+
+SNP_COMMIT is used to commit the currently installed firmware using the
+SEV-SNP firmware SNP_COMMIT command. This prevents roll-back to a previously
+committed firmware version. This will also update the reported TCB to match
+that of the currently installed firmware.
+
+2.6 SNP_SET_CONFIG
+------------------
+:Technology: sev-snp
+:Type: hypervisor ioctl cmd
+:Parameters (in): struct sev_user_data_snp_config
+:Returns (out): 0 on success, -negative on error
+
+SNP_SET_CONFIG is used to set the system-wide configuration such as
+reported TCB version in the attestation report. The command is similar
+to SNP_CONFIG command defined in the SEV-SNP spec. The current values of
+the firmware parameters affected by this command can be queried via
+SNP_PLATFORM_STATUS.
+
3. SEV-SNP CPUID Enforcement
============================