On 4/8/2025 3:02 PM, Nikunj A Dadhania wrote: > The hypervisor controls TSC value calculations for the guest. A malicious > hypervisor can prevent the guest from progressing. The Secure TSC feature for > SEV-SNP allows guests to securely use the RDTSC and RDTSCP instructions. This > ensures the guest has a consistent view of time and prevents a malicious > hypervisor from manipulating time, such as making it appear to move backward or > advance too quickly. For more details, refer to the "Secure Nested Paging > (SEV-SNP)" section, subsection "Secure TSC" in APM Volume 2. > > This patch set is also available at: > > https://github.com/AMDESE/linux-kvm/tree/sectsc-host-latest > > and is based on kvm/master > > Testing Secure TSC > ----------------- > > Secure TSC guest patches are available as part of v6.14-rc1. > > QEMU changes: > https://github.com/nikunjad/qemu/tree/snp-securetsc-latest > > QEMU command line SEV-SNP with Secure TSC: > > qemu-system-x86_64 -cpu EPYC-Milan-v2 -smp 4 \ > -object memory-backend-memfd,id=ram1,size=1G,share=true,prealloc=false,reserve=false \ > -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on,stsc-freq=2000000000 \ > -machine q35,confidential-guest-support=sev0,memory-backend=ram1 \ > ... > > Changelog: > ---------- > v6: > * Rebased on top of kvm/master > * Collected Reviewed-by/Tested-by > * s/svm->vcpu/vcpu/ in snp_launch_update_vmsa() as vcpu pointer is already available (Tom) > * Simplify assignment of guest_protected_tsc (Tom) A gentle reminder, any other suggestions/improvement ? Regards Nikunj
