From a71b4e5d1ce8bcb7cf076500a1fe8871a674b03c Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 18 Jul 2025 18:03:46 +0200 Subject: [PATCH 044/115] i386/tdx: Implement user specified tsc frequency MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Paolo Bonzini RH-MergeRequest: 391: TDX support, including attestation and device assignment RH-Jira: RHEL-15710 RHEL-20798 RHEL-49728 RH-Acked-by: Yash Mankad RH-Acked-by: Peter Xu RH-Acked-by: David Hildenbrand RH-Commit: [44/115] f12a5f1a60aa8bdd69d79e31b92dcf21380b7659 (bonzini/rhel-qemu-kvm) Reuse "-cpu,tsc-frequency=" to get user wanted tsc frequency and call VM scope VM_SET_TSC_KHZ to set the tsc frequency of TD before KVM_TDX_INIT_VM. Besides, sanity check the tsc frequency to be in the legal range and legal granularity (required by TDX module). Signed-off-by: Xiaoyao Li Acked-by: Gerd Hoffmann Reviewed-by: Daniel P. Berrangé Reviewed-by: Zhao Liu Link: https://lore.kernel.org/r/20250508150002.689633-16-xiaoyao.li@intel.com Signed-off-by: Paolo Bonzini (cherry picked from commit 0e73b843616e52882940ab89e1b0e86e22be2162) Signed-off-by: Paolo Bonzini --- target/i386/kvm/kvm.c | 9 +++++++++ target/i386/kvm/tdx.c | 25 +++++++++++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 3b71c182ab..fa61221190 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -861,6 +861,15 @@ static int kvm_arch_set_tsc_khz(CPUState *cs) int r, cur_freq; bool set_ioctl = false; + /* + * TSC of TD vcpu is immutable, it cannot be set/changed via vcpu scope + * VM_SET_TSC_KHZ, but only be initialized via VM scope VM_SET_TSC_KHZ + * before ioctl KVM_TDX_INIT_VM in tdx_pre_create_vcpu() + */ + if (is_tdx_vm()) { + return 0; + } + if (!env->tsc_khz) { return 0; } diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c index c96e8eb7b8..56ad5f599d 100644 --- a/target/i386/kvm/tdx.c +++ b/target/i386/kvm/tdx.c @@ -20,6 +20,9 @@ #include "kvm_i386.h" #include "tdx.h" +#define TDX_MIN_TSC_FREQUENCY_KHZ (100 * 1000) +#define TDX_MAX_TSC_FREQUENCY_KHZ (10 * 1000 * 1000) + #define TDX_TD_ATTRIBUTES_DEBUG BIT_ULL(0) #define TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE BIT_ULL(28) #define TDX_TD_ATTRIBUTES_PKS BIT_ULL(30) @@ -267,6 +270,28 @@ int tdx_pre_create_vcpu(CPUState *cpu, Error **errp) return r; } + if (env->tsc_khz && (env->tsc_khz < TDX_MIN_TSC_FREQUENCY_KHZ || + env->tsc_khz > TDX_MAX_TSC_FREQUENCY_KHZ)) { + error_setg(errp, "Invalid TSC %ld KHz, must specify cpu_frequency " + "between [%d, %d] kHz", env->tsc_khz, + TDX_MIN_TSC_FREQUENCY_KHZ, TDX_MAX_TSC_FREQUENCY_KHZ); + return -EINVAL; + } + + if (env->tsc_khz % (25 * 1000)) { + error_setg(errp, "Invalid TSC %ld KHz, it must be multiple of 25MHz", + env->tsc_khz); + return -EINVAL; + } + + /* it's safe even env->tsc_khz is 0. KVM uses host's tsc_khz in this case */ + r = kvm_vm_ioctl(kvm_state, KVM_SET_TSC_KHZ, env->tsc_khz); + if (r < 0) { + error_setg_errno(errp, -r, "Unable to set TSC frequency to %ld kHz", + env->tsc_khz); + return r; + } + if (tdx_guest->mrconfigid) { g_autofree uint8_t *data = qbase64_decode(tdx_guest->mrconfigid, strlen(tdx_guest->mrconfigid), &data_len, errp); -- 2.50.1