mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-27 06:33:08 -04:00
a311fce2b6
Add support for Secure TSC, allowing userspace to configure the Secure TSC feature for SNP guests. Use the SNP specification's desired TSC frequency parameter during the SNP_LAUNCH_START command to set the mean TSC frequency in KHz for Secure TSC enabled guests. Always use kvm->arch.arch.default_tsc_khz as the TSC frequency that is passed to SNP guests in the SNP_LAUNCH_START command. The default value is the host TSC frequency. The userspace can optionally change the TSC frequency via the KVM_SET_TSC_KHZ ioctl before calling the SNP_LAUNCH_START ioctl. Introduce the read-only MSR GUEST_TSC_FREQ (0xc0010134) that returns guest's effective frequency in MHZ when Secure TSC is enabled for SNP guests. Disable interception of this MSR when Secure TSC is enabled. Note that GUEST_TSC_FREQ MSR is accessible only to the guest and not from the hypervisor context. Co-developed-by: Ketan Chaturvedi <Ketan.Chaturvedi@amd.com> Signed-off-by: Ketan Chaturvedi <Ketan.Chaturvedi@amd.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> [sean: contain Secure TSC to sev.c] Link: https://lore.kernel.org/r/20250819234833.3080255-9-seanjc@google.com [sean: return -EINVAL if TSC frequency is '0'] Signed-off-by: Sean Christopherson <seanjc@google.com>