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SubjectRe: [RFC PATCH v5 024/104] KVM: TDX: create/destroy VM structure
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On 3/4/22 20:48, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> As the first step to create TDX guest, create/destroy VM struct. Assign
> Host Key ID (HKID) to the TDX guest for memory encryption and allocate
> extra pages for the TDX guest. On destruction, free allocated pages, and
> HKID.
>
> Add a second kvm_x86_ops hook in kvm_arch_vm_destroy() to support TDX's
> destruction path, which needs to first put the VM into a teardown state,
> then free per-vCPU resources, and finally free per-VM resources.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> arch/x86/kvm/vmx/main.c | 16 +-
> arch/x86/kvm/vmx/tdx.c | 312 +++++++++++++++++++++++++++++++++++
> arch/x86/kvm/vmx/tdx.h | 2 +
> arch/x86/kvm/vmx/tdx_errno.h | 2 +-
> arch/x86/kvm/vmx/tdx_ops.h | 8 +
> arch/x86/kvm/vmx/x86_ops.h | 8 +
> 6 files changed, 346 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 6111c6485d8e..5c3a904a30e8 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -39,12 +39,24 @@ static int vt_vm_init(struct kvm *kvm)
> ret = tdx_module_setup();
> if (ret)
> return ret;
> - return -EOPNOTSUPP; /* Not ready to create guest TD yet. */
> + return tdx_vm_init(kvm);
> }
>
> return vmx_vm_init(kvm);
> }
>
> +static void vt_mmu_prezap(struct kvm *kvm)
> +{
> + if (is_td(kvm))
> + return tdx_mmu_prezap(kvm);
> +}

Please rename the function to explain what it does, for example
tdx_mmu_release_hkid.

Paolo

> +static void vt_vm_free(struct kvm *kvm)
> +{
> + if (is_td(kvm))
> + return tdx_vm_free(kvm);
> +}

> +
> struct kvm_x86_ops vt_x86_ops __initdata = {
> .name = "kvm_intel",
>
> @@ -58,6 +70,8 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
> .is_vm_type_supported = vt_is_vm_type_supported,
> .vm_size = sizeof(struct kvm_vmx),
> .vm_init = vt_vm_init,
> + .mmu_prezap = vt_mmu_prezap,
> + .vm_free = vt_vm_free,
>
> .vcpu_create = vmx_vcpu_create,
> .vcpu_free = vmx_vcpu_free,
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 1c8222f54764..702953fd365f 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -31,14 +31,324 @@ struct tdx_capabilities {
> struct tdx_cpuid_config cpuid_configs[TDX_MAX_NR_CPUID_CONFIGS];
> };
>
> +/* KeyID used by TDX module */
> +static u32 tdx_global_keyid __read_mostly;
> +
> /* Capabilities of KVM + the TDX module. */
> struct tdx_capabilities tdx_caps;
>
> +static DEFINE_MUTEX(tdx_lock);
> static struct mutex *tdx_mng_key_config_lock;
>
> static u64 hkid_mask __ro_after_init;
> static u8 hkid_start_pos __ro_after_init;
>
> +static __always_inline hpa_t set_hkid_to_hpa(hpa_t pa, u16 hkid)
> +{
> + pa &= ~hkid_mask;
> + pa |= (u64)hkid << hkid_start_pos;
> +
> + return pa;
> +}
> +
> +static inline bool is_td_created(struct kvm_tdx *kvm_tdx)
> +{
> + return kvm_tdx->tdr.added;
> +}
> +
> +static inline void tdx_hkid_free(struct kvm_tdx *kvm_tdx)
> +{
> + tdx_keyid_free(kvm_tdx->hkid);
> + kvm_tdx->hkid = -1;
> +}
> +
> +static inline bool is_hkid_assigned(struct kvm_tdx *kvm_tdx)
> +{
> + return kvm_tdx->hkid > 0;
> +}
> +
> +static void tdx_clear_page(unsigned long page)
> +{
> + const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
> + unsigned long i;
> +
> + /* Zeroing the page is only necessary for systems with MKTME-i. */
> + if (!static_cpu_has(X86_FEATURE_MOVDIR64B))
> + return;
> +
> + for (i = 0; i < 4096; i += 64)
> + /* MOVDIR64B [rdx], es:rdi */
> + asm (".byte 0x66, 0x0f, 0x38, 0xf8, 0x3a"
> + : : "d" (zero_page), "D" (page + i) : "memory");
> +}
> +
> +static int __tdx_reclaim_page(unsigned long va, hpa_t pa, bool do_wb, u16 hkid)
> +{
> + struct tdx_module_output out;
> + u64 err;
> +
> + err = tdh_phymem_page_reclaim(pa, &out);
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_PHYMEM_PAGE_RECLAIM, err, &out);
> + return -EIO;
> + }
> +
> + if (do_wb) {
> + err = tdh_phymem_page_wbinvd(set_hkid_to_hpa(pa, hkid));
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_PHYMEM_PAGE_WBINVD, err, NULL);
> + return -EIO;
> + }
> + }
> +
> + tdx_clear_page(va);
> + return 0;
> +}
> +
> +static int tdx_reclaim_page(unsigned long va, hpa_t pa)
> +{
> + return __tdx_reclaim_page(va, pa, false, 0);
> +}
> +
> +static int tdx_alloc_td_page(struct tdx_td_page *page)
> +{
> + page->va = __get_free_page(GFP_KERNEL_ACCOUNT);
> + if (!page->va)
> + return -ENOMEM;
> +
> + page->pa = __pa(page->va);
> + return 0;
> +}
> +
> +static void tdx_mark_td_page_added(struct tdx_td_page *page)
> +{
> + WARN_ON_ONCE(page->added);
> + page->added = true;
> +}
> +
> +static void tdx_reclaim_td_page(struct tdx_td_page *page)
> +{
> + if (page->added) {
> + if (tdx_reclaim_page(page->va, page->pa))
> + return;
> +
> + page->added = false;
> + }
> + free_page(page->va);
> +}
> +
> +static int tdx_do_tdh_phymem_cache_wb(void *param)
> +{
> + u64 err = 0;
> +
> + /*
> + * We can destroy multiple the guest TDs simultaneously. Prevent
> + * tdh_phymem_cache_wb from returning TDX_BUSY by serialization.
> + */
> + mutex_lock(&tdx_lock);
> + do {
> + err = tdh_phymem_cache_wb(!!err);
> + } while (err == TDX_INTERRUPTED_RESUMABLE);
> + mutex_unlock(&tdx_lock);
> +
> + /* Other thread may have done for us. */
> + if (err == TDX_NO_HKID_READY_TO_WBCACHE)
> + err = TDX_SUCCESS;
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_PHYMEM_CACHE_WB, err, NULL);
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +void tdx_mmu_prezap(struct kvm *kvm)
> +{
> + struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
> + cpumask_var_t packages;
> + bool cpumask_allocated;
> + u64 err;
> + int ret;
> + int i;
> +
> + if (!is_hkid_assigned(kvm_tdx))
> + return;
> +
> + if (!is_td_created(kvm_tdx))
> + goto free_hkid;
> +
> + mutex_lock(&tdx_lock);
> + err = tdh_mng_key_reclaimid(kvm_tdx->tdr.pa);
> + mutex_unlock(&tdx_lock);
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_MNG_KEY_RECLAIMID, err, NULL);
> + return;
> + }
> +
> + cpumask_allocated = zalloc_cpumask_var(&packages, GFP_KERNEL);
> + for_each_online_cpu(i) {
> + if (cpumask_allocated &&
> + cpumask_test_and_set_cpu(topology_physical_package_id(i),
> + packages))
> + continue;
> +
> + ret = smp_call_on_cpu(i, tdx_do_tdh_phymem_cache_wb, NULL, 1);
> + if (ret)
> + break;
> + }
> + free_cpumask_var(packages);
> +
> + mutex_lock(&tdx_lock);
> + err = tdh_mng_key_freeid(kvm_tdx->tdr.pa);
> + mutex_unlock(&tdx_lock);
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_MNG_KEY_FREEID, err, NULL);
> + return;
> + }
> +
> +free_hkid:
> + tdx_hkid_free(kvm_tdx);
> +}
> +
> +void tdx_vm_free(struct kvm *kvm)
> +{
> + struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
> + int i;
> +
> + /* Can't reclaim or free TD pages if teardown failed. */
> + if (is_hkid_assigned(kvm_tdx))
> + return;
> +
> + for (i = 0; i < tdx_caps.tdcs_nr_pages; i++)
> + tdx_reclaim_td_page(&kvm_tdx->tdcs[i]);
> + kfree(kvm_tdx->tdcs);
> +
> + if (kvm_tdx->tdr.added &&
> + __tdx_reclaim_page(kvm_tdx->tdr.va, kvm_tdx->tdr.pa, true,
> + tdx_global_keyid))
> + return;
> +
> + free_page(kvm_tdx->tdr.va);
> +}
> +
> +static int tdx_do_tdh_mng_key_config(void *param)
> +{
> + hpa_t *tdr_p = param;
> + int cpu, cur_pkg;
> + u64 err;
> +
> + cpu = raw_smp_processor_id();
> + cur_pkg = topology_physical_package_id(cpu);
> +
> + mutex_lock(&tdx_mng_key_config_lock[cur_pkg]);
> + do {
> + err = tdh_mng_key_config(*tdr_p);
> + } while (err == TDX_KEY_GENERATION_FAILED);
> + mutex_unlock(&tdx_mng_key_config_lock[cur_pkg]);
> +
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_MNG_KEY_CONFIG, err, NULL);
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +int tdx_vm_init(struct kvm *kvm)
> +{
> + struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
> + cpumask_var_t packages;
> + int ret, i;
> + u64 err;
> +
> + /* vCPUs can't be created until after KVM_TDX_INIT_VM. */
> + kvm->max_vcpus = 0;
> +
> + kvm_tdx->hkid = tdx_keyid_alloc();
> + if (kvm_tdx->hkid < 0)
> + return -EBUSY;
> +
> + ret = tdx_alloc_td_page(&kvm_tdx->tdr);
> + if (ret)
> + goto free_hkid;
> +
> + kvm_tdx->tdcs = kcalloc(tdx_caps.tdcs_nr_pages, sizeof(*kvm_tdx->tdcs),
> + GFP_KERNEL_ACCOUNT);
> + if (!kvm_tdx->tdcs)
> + goto free_tdr;
> + for (i = 0; i < tdx_caps.tdcs_nr_pages; i++) {
> + ret = tdx_alloc_td_page(&kvm_tdx->tdcs[i]);
> + if (ret)
> + goto free_tdcs;
> + }
> +
> + mutex_lock(&tdx_lock);
> + err = tdh_mng_create(kvm_tdx->tdr.pa, kvm_tdx->hkid);
> + mutex_unlock(&tdx_lock);
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_MNG_CREATE, err, NULL);
> + ret = -EIO;
> + goto free_tdcs;
> + }
> + tdx_mark_td_page_added(&kvm_tdx->tdr);
> +
> + if (!zalloc_cpumask_var(&packages, GFP_KERNEL)) {
> + ret = -ENOMEM;
> + goto free_tdcs;
> + }
> + for_each_online_cpu(i) {
> + if (cpumask_test_and_set_cpu(topology_physical_package_id(i),
> + packages))
> + continue;
> +
> + ret = smp_call_on_cpu(i, tdx_do_tdh_mng_key_config,
> + &kvm_tdx->tdr.pa, 1);
> + if (ret)
> + break;
> + }
> + free_cpumask_var(packages);
> + if (ret)
> + goto teardown;
> +
> + for (i = 0; i < tdx_caps.tdcs_nr_pages; i++) {
> + err = tdh_mng_addcx(kvm_tdx->tdr.pa, kvm_tdx->tdcs[i].pa);
> + if (WARN_ON_ONCE(err)) {
> + pr_tdx_error(TDH_MNG_ADDCX, err, NULL);
> + ret = -EIO;
> + goto teardown;
> + }
> + tdx_mark_td_page_added(&kvm_tdx->tdcs[i]);
> + }
> +
> + /*
> + * Note, TDH_MNG_INIT cannot be invoked here. TDH_MNG_INIT requires a dedicated
> + * ioctl() to define the configure CPUID values for the TD.
> + */
> + return 0;
> +
> + /*
> + * The sequence for freeing resources from a partially initialized TD
> + * varies based on where in the initialization flow failure occurred.
> + * Simply use the full teardown and destroy, which naturally play nice
> + * with partial initialization.
> + */
> +teardown:
> + tdx_mmu_prezap(kvm);
> + tdx_vm_free(kvm);
> + return ret;
> +
> +free_tdcs:
> + /* @i points at the TDCS page that failed allocation. */
> + for (--i; i >= 0; i--)
> + free_page(kvm_tdx->tdcs[i].va);
> + kfree(kvm_tdx->tdcs);
> +free_tdr:
> + free_page(kvm_tdx->tdr.va);
> +free_hkid:
> + tdx_hkid_free(kvm_tdx);
> + return ret;
> +}
> +
> static int __tdx_module_setup(void)
> {
> const struct tdsysinfo_struct *tdsysinfo;
> @@ -59,6 +369,8 @@ static int __tdx_module_setup(void)
> return ret;
> }
>
> + tdx_global_keyid = tdx_get_global_keyid();
> +
> tdsysinfo = tdx_get_sysinfo();
> if (tdx_caps.nr_cpuid_configs > TDX_MAX_NR_CPUID_CONFIGS)
> return -EIO;
> diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
> index e4bb8831764e..860136ed70f5 100644
> --- a/arch/x86/kvm/vmx/tdx.h
> +++ b/arch/x86/kvm/vmx/tdx.h
> @@ -19,6 +19,8 @@ struct kvm_tdx {
>
> struct tdx_td_page tdr;
> struct tdx_td_page *tdcs;
> +
> + int hkid;
> };
>
> struct vcpu_tdx {
> diff --git a/arch/x86/kvm/vmx/tdx_errno.h b/arch/x86/kvm/vmx/tdx_errno.h
> index 5c878488795d..590fcfdd1899 100644
> --- a/arch/x86/kvm/vmx/tdx_errno.h
> +++ b/arch/x86/kvm/vmx/tdx_errno.h
> @@ -12,11 +12,11 @@
> #define TDX_SUCCESS 0x0000000000000000ULL
> #define TDX_NON_RECOVERABLE_VCPU 0x4000000100000000ULL
> #define TDX_INTERRUPTED_RESUMABLE 0x8000000300000000ULL
> -#define TDX_LIFECYCLE_STATE_INCORRECT 0xC000060700000000ULL
> #define TDX_VCPU_NOT_ASSOCIATED 0x8000070200000000ULL
> #define TDX_KEY_GENERATION_FAILED 0x8000080000000000ULL
> #define TDX_KEY_STATE_INCORRECT 0xC000081100000000ULL
> #define TDX_KEY_CONFIGURED 0x0000081500000000ULL
> +#define TDX_NO_HKID_READY_TO_WBCACHE 0x0000082100000000ULL
> #define TDX_EPT_WALK_FAILED 0xC0000B0000000000ULL
>
> /*
> diff --git a/arch/x86/kvm/vmx/tdx_ops.h b/arch/x86/kvm/vmx/tdx_ops.h
> index 0bed43879b82..3dd5b4c3f04c 100644
> --- a/arch/x86/kvm/vmx/tdx_ops.h
> +++ b/arch/x86/kvm/vmx/tdx_ops.h
> @@ -6,6 +6,7 @@
>
> #include <linux/compiler.h>
>
> +#include <asm/cacheflush.h>
> #include <asm/asm.h>
> #include <asm/kvm_host.h>
>
> @@ -15,8 +16,14 @@
>
> #ifdef CONFIG_INTEL_TDX_HOST
>
> +static inline void tdx_clflush_page(hpa_t addr)
> +{
> + clflush_cache_range(__va(addr), PAGE_SIZE);
> +}
> +
> static inline u64 tdh_mng_addcx(hpa_t tdr, hpa_t addr)
> {
> + tdx_clflush_page(addr);
> return kvm_seamcall(TDH_MNG_ADDCX, addr, tdr, 0, 0, 0, NULL);
> }
>
> @@ -56,6 +63,7 @@ static inline u64 tdh_mng_key_config(hpa_t tdr)
>
> static inline u64 tdh_mng_create(hpa_t tdr, int hkid)
> {
> + tdx_clflush_page(tdr);
> return kvm_seamcall(TDH_MNG_CREATE, tdr, hkid, 0, 0, 0, NULL);
> }
>
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index da32b4b86b19..2b2738c768d6 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -132,12 +132,20 @@ void __init tdx_pre_kvm_init(unsigned int *vcpu_size,
> bool tdx_is_vm_type_supported(unsigned long type);
> void __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops);
> void tdx_hardware_unsetup(void);
> +
> +int tdx_vm_init(struct kvm *kvm);
> +void tdx_mmu_prezap(struct kvm *kvm);
> +void tdx_vm_free(struct kvm *kvm);
> #else
> static inline void tdx_pre_kvm_init(
> unsigned int *vcpu_size, unsigned int *vcpu_align, unsigned int *vm_size) {}
> static inline bool tdx_is_vm_type_supported(unsigned long type) { return false; }
> static inline void tdx_hardware_setup(struct kvm_x86_ops *x86_ops) {}
> static inline void tdx_hardware_unsetup(void) {}
> +
> +static inline int tdx_vm_init(struct kvm *kvm) { return -EOPNOTSUPP; }
> +static inline void tdx_mmu_prezap(struct kvm *kvm) {}
> +static inline void tdx_vm_free(struct kvm *kvm) {}
> #endif
>
> #endif /* __KVM_X86_VMX_X86_OPS_H */

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