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[0/3] Add SEV-SNP CipherTextHiding feature support

Message ID cover.1723490152.git.ashish.kalra@amd.com (mailing list archive)
Headers show
Series Add SEV-SNP CipherTextHiding feature support | expand

Message

Kalra, Ashish Aug. 12, 2024, 7:41 p.m. UTC 
From: Ashish Kalra <ashish.kalra@amd.com>

Ciphertext hiding prevents host accesses from reading the ciphertext
of SNP guest private memory. Instead of reading ciphertext, the host
will see constant default values (0xff).

Ciphertext hiding separates the ASID space into SNP guest ASIDs and 
host ASIDs. All SNP active guests must have an ASID less than or
equal to MAX_SNP_ASID provided to the SNP_INIT_EX command.
All SEV-legacy guests must be greater than MAX_SNP_ASID.

This patch-set adds a new module parameter to the CCP driver defined
as psp_max_snp_asid which is a user configurable MAX_SNP_ASID to
define the system-wide maximum SNP ASID value. If this value is
not set, then the ASID space is equally divided between SEV-SNP
and SEV-ES guests.

Ashish Kalra (3):
  crypto: ccp: Extend SNP_PLATFORM_STATUS command
  crypto: ccp: Add support for SNP_FEATURE_INFO command
  x86/sev: Add SEV-SNP CipherTextHiding support

 arch/x86/kvm/svm/sev.c       | 24 ++++++++--
 drivers/crypto/ccp/sev-dev.c | 90 ++++++++++++++++++++++++++++++++++++
 drivers/crypto/ccp/sev-dev.h |  3 ++
 include/linux/psp-sev.h      | 41 +++++++++++++++-
 include/uapi/linux/psp-sev.h | 10 +++-
 5 files changed, 162 insertions(+), 6 deletions(-)