| Message ID | 65e96a61c497c78b41fa670e20fbeb3593f56bfe.1705965635.git.isaku.yamahata@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM TDX basic feature support | expand |
On 1/23/2024 7:53 AM, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > Several user ret MSRs are clobbered on TD exit. Restore those values on > TD exit and before returning to ring 3. Because TSX_CTRL requires special > treat, this patch doesn't address it. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/vmx/tdx.c | 43 ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 43 insertions(+) > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index fe818cfde9e7..4685ff6aa5f8 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -585,6 +585,28 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > */ > } > > +struct tdx_uret_msr { > + u32 msr; > + unsigned int slot; > + u64 defval; > +}; > + > +static struct tdx_uret_msr tdx_uret_msrs[] = { > + {.msr = MSR_SYSCALL_MASK, .defval = 0x20200 }, > + {.msr = MSR_STAR,}, > + {.msr = MSR_LSTAR,}, > + {.msr = MSR_TSC_AUX,}, > +}; > + > +static void tdx_user_return_update_cache(void) > +{ > + 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); > +} > + > static void tdx_restore_host_xsave_state(struct kvm_vcpu *vcpu) > { > struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm); > @@ -677,6 +699,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) > > tdx_vcpu_enter_exit(tdx); > > + tdx_user_return_update_cache(); > tdx_restore_host_xsave_state(vcpu); > tdx->host_state_need_restore = true; > > @@ -1936,6 +1959,26 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops) > return -EINVAL; > } > > + for (i = 0; i < ARRAY_SIZE(tdx_uret_msrs); i++) { > + /* > + * Here it checks if MSRs (tdx_uret_msrs) can be saved/restored > + * before returning to user space. > + * > + * this_cpu_ptr(user_return_msrs)->registered isn't checked > + * because the registration is done at vcpu runtime by > + * kvm_set_user_return_msr(). For tdx, it's done by kvm_user_return_update_cache(), right? > + * Here is setting up cpu feature before running vcpu, > + * registered is already false. > + */ > + tdx_uret_msrs[i].slot = kvm_find_user_return_msr(tdx_uret_msrs[i].msr); > + if (tdx_uret_msrs[i].slot == -1) { > + /* If any MSR isn't supported, it is a KVM bug */ > + pr_err("MSR %x isn't included by kvm_find_user_return_msr\n", > + tdx_uret_msrs[i].msr); > + return -EIO; > + } > + } > + > max_pkgs = topology_max_packages(); > tdx_mng_key_config_lock = kcalloc(max_pkgs, sizeof(*tdx_mng_key_config_lock), > GFP_KERNEL);
On Tue, Feb 20, 2024 at 05:14:02PM +0800, Binbin Wu <binbin.wu@linux.intel.com> wrote: > > @@ -1936,6 +1959,26 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops) > > return -EINVAL; > > } > > + for (i = 0; i < ARRAY_SIZE(tdx_uret_msrs); i++) { > > + /* > > + * Here it checks if MSRs (tdx_uret_msrs) can be saved/restored > > + * before returning to user space. > > + * > > + * this_cpu_ptr(user_return_msrs)->registered isn't checked > > + * because the registration is done at vcpu runtime by > > + * kvm_set_user_return_msr(). > > For tdx, it's done by kvm_user_return_update_cache(), right? Right, fixed the comment.
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index fe818cfde9e7..4685ff6aa5f8 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -585,6 +585,28 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) */ } +struct tdx_uret_msr { + u32 msr; + unsigned int slot; + u64 defval; +}; + +static struct tdx_uret_msr tdx_uret_msrs[] = { + {.msr = MSR_SYSCALL_MASK, .defval = 0x20200 }, + {.msr = MSR_STAR,}, + {.msr = MSR_LSTAR,}, + {.msr = MSR_TSC_AUX,}, +}; + +static void tdx_user_return_update_cache(void) +{ + 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); +} + static void tdx_restore_host_xsave_state(struct kvm_vcpu *vcpu) { struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm); @@ -677,6 +699,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) tdx_vcpu_enter_exit(tdx); + tdx_user_return_update_cache(); tdx_restore_host_xsave_state(vcpu); tdx->host_state_need_restore = true; @@ -1936,6 +1959,26 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops) return -EINVAL; } + for (i = 0; i < ARRAY_SIZE(tdx_uret_msrs); i++) { + /* + * Here it checks if MSRs (tdx_uret_msrs) can be saved/restored + * before returning to user space. + * + * this_cpu_ptr(user_return_msrs)->registered isn't checked + * because the registration is done at vcpu runtime by + * kvm_set_user_return_msr(). + * Here is setting up cpu feature before running vcpu, + * registered is already false. + */ + tdx_uret_msrs[i].slot = kvm_find_user_return_msr(tdx_uret_msrs[i].msr); + if (tdx_uret_msrs[i].slot == -1) { + /* If any MSR isn't supported, it is a KVM bug */ + pr_err("MSR %x isn't included by kvm_find_user_return_msr\n", + tdx_uret_msrs[i].msr); + return -EIO; + } + } + max_pkgs = topology_max_packages(); tdx_mng_key_config_lock = kcalloc(max_pkgs, sizeof(*tdx_mng_key_config_lock), GFP_KERNEL);