Messages in this thread | | | Date | Sun, 7 Apr 2024 15:05:21 +0800 | Subject | Re: [PATCH v19 083/130] KVM: TDX: Add TSX_CTRL msr into uret_msrs list | From | Binbin Wu <> |
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On 2/26/2024 4:26 PM, isaku.yamahata@intel.com wrote: > From: Yang Weijiang <weijiang.yang@intel.com> > > TDX module resets the TSX_CTRL MSR to 0 at TD exit if TSX is enabled for > TD. Or it preserves the TSX_CTRL MSR if TSX is disabled for TD. VMM can > rely on uret_msrs mechanism to defer the reload of host value until exiting > to user space. > > Signed-off-by: Yang Weijiang <weijiang.yang@intel.com> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > v19: > - fix the type of tdx_uret_tsx_ctrl_slot. unguent int => int. > --- > arch/x86/kvm/vmx/tdx.c | 33 +++++++++++++++++++++++++++++++-- > arch/x86/kvm/vmx/tdx.h | 8 ++++++++ > 2 files changed, 39 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index 7e2b1e554246..83dcaf5b6fbd 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -547,14 +547,21 @@ static struct tdx_uret_msr tdx_uret_msrs[] = { > {.msr = MSR_LSTAR,}, > {.msr = MSR_TSC_AUX,}, > }; > +static int tdx_uret_tsx_ctrl_slot; > > -static void tdx_user_return_update_cache(void) > +static void tdx_user_return_update_cache(struct kvm_vcpu *vcpu) > { > int i; > > for (i = 0; i < ARRAY_SIZE(tdx_uret_msrs); i++) > kvm_user_return_update_cache(tdx_uret_msrs[i].slot, > tdx_uret_msrs[i].defval); > + /* > + * TSX_CTRL is reset to 0 if guest TSX is supported. Otherwise > + * preserved. > + */ > + if (to_kvm_tdx(vcpu->kvm)->tsx_supported && tdx_uret_tsx_ctrl_slot != -1)
If to_kvm_tdx(vcpu->kvm)->tsx_supported is true, tdx_uret_tsx_ctrl_slot shouldn't be -1 at this point. Otherwise, it's a KVM bug, right? Not sure if it needs a warning if tdx_uret_tsx_ctrl_slot is -1, or just remove the check?
> + kvm_user_return_update_cache(tdx_uret_tsx_ctrl_slot, 0); > } > > static void tdx_restore_host_xsave_state(struct kvm_vcpu *vcpu) > @@ -649,7 +656,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) > > tdx_vcpu_enter_exit(tdx); > > - tdx_user_return_update_cache(); > + tdx_user_return_update_cache(vcpu); > tdx_restore_host_xsave_state(vcpu); > tdx->host_state_need_restore = true; > > @@ -1167,6 +1174,22 @@ static int setup_tdparams_xfam(struct kvm_cpuid2 *cpuid, struct td_params *td_pa > return 0; > } > > +static bool tdparams_tsx_supported(struct kvm_cpuid2 *cpuid) > +{ > + const struct kvm_cpuid_entry2 *entry; > + u64 mask; > + u32 ebx; > + > + entry = kvm_find_cpuid_entry2(cpuid->entries, cpuid->nent, 0x7, 0); > + if (entry) > + ebx = entry->ebx; > + else > + ebx = 0; > + > + mask = __feature_bit(X86_FEATURE_HLE) | __feature_bit(X86_FEATURE_RTM); > + return ebx & mask; > +} > + > static int setup_tdparams(struct kvm *kvm, struct td_params *td_params, > struct kvm_tdx_init_vm *init_vm) > { > @@ -1209,6 +1232,7 @@ static int setup_tdparams(struct kvm *kvm, struct td_params *td_params, > MEMCPY_SAME_SIZE(td_params->mrowner, init_vm->mrowner); > MEMCPY_SAME_SIZE(td_params->mrownerconfig, init_vm->mrownerconfig); > > + to_kvm_tdx(kvm)->tsx_supported = tdparams_tsx_supported(cpuid); > return 0; > } > > @@ -2014,6 +2038,11 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops) > return -EIO; > } > } > + tdx_uret_tsx_ctrl_slot = kvm_find_user_return_msr(MSR_IA32_TSX_CTRL); > + if (tdx_uret_tsx_ctrl_slot == -1 && boot_cpu_has(X86_FEATURE_MSR_TSX_CTRL)) { > + pr_err("MSR_IA32_TSX_CTRL isn't included by kvm_find_user_return_msr\n"); > + return -EIO; > + } > > max_pkgs = topology_max_packages(); > tdx_mng_key_config_lock = kcalloc(max_pkgs, sizeof(*tdx_mng_key_config_lock), > diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h > index e96c416e73bf..44eab734e702 100644 > --- a/arch/x86/kvm/vmx/tdx.h > +++ b/arch/x86/kvm/vmx/tdx.h > @@ -17,6 +17,14 @@ struct kvm_tdx { > u64 xfam; > int hkid; > > + /* > + * Used on each TD-exit, see tdx_user_return_update_cache(). > + * TSX_CTRL value on TD exit > + * - set 0 if guest TSX enabled > + * - preserved if guest TSX disabled > + */ > + bool tsx_supported; > + > bool finalized; > atomic_t tdh_mem_track; >
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