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authorPaolo Bonzini <pbonzini@redhat.com>2023-02-15 12:33:28 -0500
committerPaolo Bonzini <pbonzini@redhat.com>2023-02-15 12:33:28 -0500
commit33436335e93a1788a58443fc99c5ab320ce4b9d9 (patch)
treed92f88768c8dbd00f8b65164f47a8a091768b95a /Documentation/x86/amd-memory-encryption.rst
parent27b025ebb0f6092d5c0a88de2ab73545bc1c496e (diff)
parentc39cea6f38eefe356d64d0bc1e1f2267e282cdd3 (diff)
Merge tag 'kvm-riscv-6.3-1' of https://github.com/kvm-riscv/linux into HEAD
KVM/riscv changes for 6.3 - Fix wrong usage of PGDIR_SIZE to check page sizes - Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() - Redirect illegal instruction traps to guest - SBI PMU support for guest
Diffstat (limited to 'Documentation/x86/amd-memory-encryption.rst')
-rw-r--r--Documentation/x86/amd-memory-encryption.rst36
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diff --git a/Documentation/x86/amd-memory-encryption.rst b/Documentation/x86/amd-memory-encryption.rst
index a1940ebe7be5..934310ce7258 100644
--- a/Documentation/x86/amd-memory-encryption.rst
+++ b/Documentation/x86/amd-memory-encryption.rst
@@ -95,3 +95,39 @@ 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)
+==========================
+
+SEV-SNP introduces new features (SEV_FEATURES[1:63]) which can be enabled
+by the hypervisor for security enhancements. Some of these features need
+guest side implementation to function correctly. The below table lists the
+expected guest behavior with various possible scenarios of guest/hypervisor
+SNP feature support.
+
++-----------------+---------------+---------------+------------------+
+| Feature Enabled | Guest needs | Guest has | Guest boot |
+| by the HV | implementation| implementation| behaviour |
++=================+===============+===============+==================+
+| No | No | No | Boot |
+| | | | |
++-----------------+---------------+---------------+------------------+
+| No | Yes | No | Boot |
+| | | | |
++-----------------+---------------+---------------+------------------+
+| No | Yes | Yes | Boot |
+| | | | |
++-----------------+---------------+---------------+------------------+
+| Yes | No | No | Boot with |
+| | | | feature enabled |
++-----------------+---------------+---------------+------------------+
+| Yes | Yes | No | Graceful boot |
+| | | | failure |
++-----------------+---------------+---------------+------------------+
+| Yes | Yes | Yes | Boot with |
+| | | | feature enabled |
++-----------------+---------------+---------------+------------------+
+
+More details in AMD64 APM[1] Vol 2: 15.34.10 SEV_STATUS MSR
+
+[1] https://www.amd.com/system/files/TechDocs/40332.pdf