Re: [PATCH v10 024/108] KVM: TDX: allocate/free TDX vcpu structure

Isaku Yamahata
2022-12-15T21:28:27Z

On Mon, Nov 14, 2022 at 02:46:22PM +0800,
Yuan Yao <yuan.yao@linux.intel.com> wrote:

> On Sat, Oct 29, 2022 at 11:22:25PM -0700, isaku.yamahata@intel.com wrote:
> > From: Isaku Yamahata <isaku.yamahata@intel.com>
> >
> > The next step of TDX guest creation is to create vcpu. Allocate TDX vcpu
> > structures, initialize it. Allocate pages of TDX vcpu for the TDX module.
> >
> > In the case of the conventional case, cpuid is empty at the initialization.
> > and cpuid is configured after the vcpu initialization. Because TDX
> > supports only X2APIC mode, cpuid is forcibly initialized to support X2APIC
> > on the vcpu initialization.
> >
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > ---
> > arch/x86/kvm/vmx/main.c | 40 +++++++++--
> > arch/x86/kvm/vmx/tdx.c | 138 +++++++++++++++++++++++++++++++++++++
> > arch/x86/kvm/vmx/x86_ops.h | 8 +++
> > 3 files changed, 182 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> > index b4e4c6c677f6..c125b2e3e8b4 100644
> > --- a/arch/x86/kvm/vmx/main.c
> > +++ b/arch/x86/kvm/vmx/main.c
> > @@ -63,6 +63,38 @@ static void vt_vm_free(struct kvm *kvm)
> > return tdx_vm_free(kvm);
> > }
> >
> > +static int vt_vcpu_precreate(struct kvm *kvm)
> > +{
> > + if (is_td(kvm))
> > + return 0;
> > +
> > + return vmx_vcpu_precreate(kvm);
> > +}
> > +
> > +static int vt_vcpu_create(struct kvm_vcpu *vcpu)
> > +{
> > + if (is_td_vcpu(vcpu))
> > + return tdx_vcpu_create(vcpu);
> > +
> > + return vmx_vcpu_create(vcpu);
> > +}
> > +
> > +static void vt_vcpu_free(struct kvm_vcpu *vcpu)
> > +{
> > + if (is_td_vcpu(vcpu))
> > + return tdx_vcpu_free(vcpu);
> > +
> > + return vmx_vcpu_free(vcpu);
> > +}
> > +
> > +static void vt_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
> > +{
> > + if (is_td_vcpu(vcpu))
> > + return tdx_vcpu_reset(vcpu, init_event);
> > +
> > + return vmx_vcpu_reset(vcpu, init_event);
> > +}
> > +
> > static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
> > {
> > if (!is_td(kvm))
> > @@ -89,10 +121,10 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
> > .vm_destroy = vt_vm_destroy,
> > .vm_free = vt_vm_free,
> >
> > - .vcpu_precreate = vmx_vcpu_precreate,
> > - .vcpu_create = vmx_vcpu_create,
> > - .vcpu_free = vmx_vcpu_free,
> > - .vcpu_reset = vmx_vcpu_reset,
> > + .vcpu_precreate = vt_vcpu_precreate,
> > + .vcpu_create = vt_vcpu_create,
> > + .vcpu_free = vt_vcpu_free,
> > + .vcpu_reset = vt_vcpu_reset,
> >
> > .prepare_switch_to_guest = vmx_prepare_switch_to_guest,
> > .vcpu_load = vmx_vcpu_load,
> > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> > index 54045e0576e7..0625c354b341 100644
> > --- a/arch/x86/kvm/vmx/tdx.c
> > +++ b/arch/x86/kvm/vmx/tdx.c
> > @@ -49,6 +49,11 @@ static __always_inline hpa_t set_hkid_to_hpa(hpa_t pa, u16 hkid)
> > return pa | ((hpa_t)hkid << boot_cpu_data.x86_phys_bits);
> > }
> >
> > +static inline bool is_td_vcpu_created(struct vcpu_tdx *tdx)
> > +{
> > + return tdx->tdvpr.added;
> > +}
> > +
> > static inline bool is_td_created(struct kvm_tdx *kvm_tdx)
> > {
> > return kvm_tdx->tdr.added;
> > @@ -296,6 +301,139 @@ int tdx_vm_init(struct kvm *kvm)
> > return 0;
> > }
> >
> > +int tdx_vcpu_create(struct kvm_vcpu *vcpu)
> > +{
> > + struct vcpu_tdx *tdx = to_tdx(vcpu);
> > + int ret, i;
> > +
> > + /* TDX only supports x2APIC, which requires an in-kernel local APIC. */
> > + if (!vcpu->arch.apic)
> > + return -EINVAL;
> > +
> > + fpstate_set_confidential(&vcpu->arch.guest_fpu);
> > +
> > + ret = tdx_alloc_td_page(&tdx->tdvpr);
> > + if (ret)
> > + return ret;
> > +
> > + tdx->tdvpx = kcalloc(tdx_caps.tdvpx_nr_pages, sizeof(*tdx->tdvpx),
> > + GFP_KERNEL_ACCOUNT);
> > + if (!tdx->tdvpx) {
> > + ret = -ENOMEM;
> > + goto free_tdvpr;
> > + }
> > + for (i = 0; i < tdx_caps.tdvpx_nr_pages; i++) {
> > + ret = tdx_alloc_td_page(&tdx->tdvpx[i]);
> > + if (ret)
> > + goto free_tdvpx;
> > + }
> > +
> > + vcpu->arch.efer = EFER_SCE | EFER_LME | EFER_LMA | EFER_NX;
> > +
> > + vcpu->arch.cr0_guest_owned_bits = -1ul;
> > + vcpu->arch.cr4_guest_owned_bits = -1ul;
> > +
> > + vcpu->arch.tsc_offset = to_kvm_tdx(vcpu->kvm)->tsc_offset;
> > + vcpu->arch.l1_tsc_offset = vcpu->arch.tsc_offset;
> > + vcpu->arch.guest_state_protected =
> > + !(to_kvm_tdx(vcpu->kvm)->attributes & TDX_TD_ATTRIBUTE_DEBUG);
> > +
> > + return 0;
> > +
> > +free_tdvpx:
> > + /* @i points at the TDVPX page that failed allocation. */
> > + for (--i; i >= 0; i--)
> > + free_page(tdx->tdvpx[i].va);
> > + kfree(tdx->tdvpx);
> > + tdx->tdvpx = NULL;
> > +free_tdvpr:
> > + free_page(tdx->tdvpr.va);
> > +
> > + return ret;
> > +}
> > +
> > +void tdx_vcpu_free(struct kvm_vcpu *vcpu)
> > +{
> > + struct vcpu_tdx *tdx = to_tdx(vcpu);
> > + int i;
> > +
> > + /* Can't reclaim or free pages if teardown failed. */
> > + if (is_hkid_assigned(to_kvm_tdx(vcpu->kvm)))
> > + return;
> > +
> > + if (tdx->tdvpx) {
> > + for (i = 0; i < tdx_caps.tdvpx_nr_pages; i++)
> > + tdx_reclaim_td_page(&tdx->tdvpx[i]);
> > + kfree(tdx->tdvpx);
> > + tdx->tdvpx = NULL;
> > + }
> > + tdx_reclaim_td_page(&tdx->tdvpr);
> > +}
> > +
> > +void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
> > +{
> > + struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
> > + struct vcpu_tdx *tdx = to_tdx(vcpu);
> > + struct msr_data apic_base_msr;
> > + u64 err;
> > + int i;
> > +
> > + /* TDX doesn't support INIT event. */
> > + if (WARN_ON_ONCE(init_event))
> > + goto td_bugged;
> > + if (WARN_ON_ONCE(is_td_vcpu_created(tdx)))
> > + goto td_bugged;
> > +
> > + err = tdh_vp_create(kvm_tdx->tdr.pa, tdx->tdvpr.pa);
> > + if (WARN_ON_ONCE(err)) {
> > + pr_tdx_error(TDH_VP_CREATE, err, NULL);
> > + goto td_bugged;
> > + }
> > + tdx_mark_td_page_added(&tdx->tdvpr);
> > +
> > + for (i = 0; i < tdx_caps.tdvpx_nr_pages; i++) {
> > + err = tdh_vp_addcx(tdx->tdvpr.pa, tdx->tdvpx[i].pa);
> > + if (WARN_ON_ONCE(err)) {
> > + pr_tdx_error(TDH_VP_ADDCX, err, NULL);
> > + goto td_bugged;
> > + }
> > + tdx_mark_td_page_added(&tdx->tdvpx[i]);
> > + }
> > +
> > + if (!vcpu->arch.cpuid_entries) {
> > + /*
> > + * On cpu creation, cpuid entry is blank. Forcibly enable
> > + * X2APIC feature to allow X2APIC.
> > + */
> > + struct kvm_cpuid_entry2 *e;
> > +
> > + e = kvmalloc_array(1, sizeof(*e), GFP_KERNEL_ACCOUNT);
>
> NULL checking is necessary for kvmalloc_array.

Fixed. Because vcpu_reset() function doesn't return error, this logic is
moved to tdx_vcpu_create().

Thanks,
--
Isaku Yamahata <isaku.yamahata@gmail.com>