Messages in this thread | | | Date | Tue, 1 Aug 2023 10:17:03 +0530 | Subject | Re: [PATCH v3 00/14] Add Secure TSC support for SNP guests | From | "Nikunj A. Dadhania" <> |
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On 7/22/2023 4:48 PM, Nikunj A Dadhania wrote: > Secure TSC allows guests to securely use RDTSC/RDTSCP instructions as the > parameters being used cannot be changed by hypervisor once the guest is > launched. More details in the AMD64 APM Vol 2, Section "Secure TSC". > > During the boot-up of the secondary cpus, SecureTSC enabled guests need to query > TSC info from AMD Security Processor. This communication channel is encrypted > between the AMD Security Processor and the guest, the hypervisor is just the > conduit to deliver the guest messages to the AMD Security Processor. Each > message is protected with an AEAD (AES-256 GCM). See "SEV Secure Nested Paging > Firmware ABI Specification" document (currently at > https://www.amd.com/system/files/TechDocs/56860.pdf) section "TSC Info" > > Use a minimal GCM library to encrypt/decrypt SNP Guest messages to communicate > with the AMD Security Processor which is available at early boot. > > SEV-guest driver has the implementation for guest and AMD Security Processor > communication. As the TSC_INFO needs to be initialized during early boot before > smp cpus are started, move most of the sev-guest driver code to kernel/sev.c and > provide well defined APIs to the sev-guest driver to use the interface to avoid > code-duplication. > > Patches: > 01-07: Preparation and movement of sev-guest driver code > 08-14: SecureTSC enablement patches.
A gentle reminder.
Thanks Nikunj
> > Testing SecureTSC > ----------------- > > SecureTSC hypervisor patches based on top of SEV-SNP UPM series: > https://github.com/nikunjad/linux/tree/snp-host-latest-securetsc > > QEMU changes: > https://github.com/nikunjad/qemu/tree/snp_securetsc > > QEMU commandline SEV-SNP-UPM with SecureTSC: > > qemu-system-x86_64 -cpu EPYC-Milan-v2,+secure-tsc \ > -object memory-backend-memfd-private,id=ram1,size=1G,share=true \ > -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on \ > -machine q35,confidential-guest-support=sev0,memory-backend=ram1,kvm-type=protected \ > ... > > Changelog: > ---------- > v3: > * Updated commit messages > * Made snp_setup_psp_messaging() generic that is accessed by both the > kernel and the driver > * Moved most of the context information to sev.c, sev-guest driver > does not need to know the secrets page layout anymore > * Add CC_ATTR_GUEST_SECURE_TSC early in the series therefore it can be > used in later patches. > * Removed data_gpa and data_npages from struct snp_req_data, as certs_data > and its size is passed to handle_guest_request_ext() > * Make vmpck_id as unsigned int > * Dropped unnecessary usage of memzero_explicit() > * Cache secrets_pa instead of remapping the cc_blob always > * Rebase on top of v6.4 kernel > > v2: > * Rebased on top of v6.3-rc3 that has Boris's sev-guest cleanup series > https://lore.kernel.org/r/20230307192449.24732-1-bp@alien8.de/ > > v1: https://lore.kernel.org/r/20230130120327.977460-1-nikunj@amd.com/ > > Nikunj A Dadhania (14): > virt: sev-guest: Use AES GCM crypto library > virt: sev-guest: Move mutex to SNP guest device structure > virt: sev-guest: Replace pr_debug with dev_dbg > virt: sev-guest: Add SNP guest request structure > virt: sev-guest: Add vmpck_id to snp_guest_dev struct > x86/sev: Cache the secrets page address > x86/sev: Move and reorganize sev guest request api > x86/mm: Add generic guest initialization hook > x86/sev: Add Secure TSC support for SNP guests > x86/sev: Change TSC MSR behavior for Secure TSC enabled guests > x86/sev: Prevent RDTSC/RDTSCP interception for Secure TSC enabled > guests > x86/kvmclock: Skip kvmclock when Secure TSC is available > x86/tsc: Mark Secure TSC as reliable clocksource > x86/sev: Enable Secure TSC for SNP guests > > arch/x86/Kconfig | 1 + > arch/x86/boot/compressed/sev.c | 2 +- > arch/x86/coco/core.c | 3 + > arch/x86/include/asm/sev-guest.h | 175 +++++++ > arch/x86/include/asm/sev.h | 19 +- > arch/x86/include/asm/svm.h | 6 +- > arch/x86/include/asm/x86_init.h | 2 + > arch/x86/kernel/kvmclock.c | 2 +- > arch/x86/kernel/sev-shared.c | 7 + > arch/x86/kernel/sev.c | 631 +++++++++++++++++++++-- > arch/x86/kernel/tsc.c | 2 +- > arch/x86/kernel/x86_init.c | 2 + > arch/x86/mm/mem_encrypt.c | 13 +- > arch/x86/mm/mem_encrypt_amd.c | 6 + > drivers/virt/coco/sev-guest/Kconfig | 2 - > drivers/virt/coco/sev-guest/sev-guest.c | 638 +++--------------------- > drivers/virt/coco/sev-guest/sev-guest.h | 63 --- > include/linux/cc_platform.h | 8 + > 18 files changed, 882 insertions(+), 700 deletions(-) > create mode 100644 arch/x86/include/asm/sev-guest.h > delete mode 100644 drivers/virt/coco/sev-guest/sev-guest.h > > > base-commit: 6995e2de6891c724bfeb2db33d7b87775f913ad1
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