diff options
Diffstat (limited to 'arch/x86/virt/vmx/tdx/tdx.c')
| -rw-r--r-- | arch/x86/virt/vmx/tdx/tdx.c | 1492 |
1 files changed, 1492 insertions, 0 deletions
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c new file mode 100644 index 000000000000..4d6826a76f78 --- /dev/null +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -0,0 +1,1492 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright(c) 2023 Intel Corporation. + * + * Intel Trusted Domain Extensions (TDX) support + */ + +#define pr_fmt(fmt) "virt/tdx: " fmt + +#include <linux/types.h> +#include <linux/cache.h> +#include <linux/init.h> +#include <linux/errno.h> +#include <linux/printk.h> +#include <linux/cpu.h> +#include <linux/spinlock.h> +#include <linux/percpu-defs.h> +#include <linux/mutex.h> +#include <linux/list.h> +#include <linux/memblock.h> +#include <linux/memory.h> +#include <linux/minmax.h> +#include <linux/sizes.h> +#include <linux/pfn.h> +#include <linux/align.h> +#include <linux/sort.h> +#include <linux/log2.h> +#include <linux/acpi.h> +#include <linux/suspend.h> +#include <linux/acpi.h> +#include <asm/page.h> +#include <asm/special_insns.h> +#include <asm/msr-index.h> +#include <asm/msr.h> +#include <asm/cpufeature.h> +#include <asm/tdx.h> +#include <asm/intel-family.h> +#include <asm/processor.h> +#include <asm/mce.h> +#include "tdx.h" + +static u32 tdx_global_keyid __ro_after_init; +static u32 tdx_guest_keyid_start __ro_after_init; +static u32 tdx_nr_guest_keyids __ro_after_init; + +static DEFINE_PER_CPU(bool, tdx_lp_initialized); + +static struct tdmr_info_list tdx_tdmr_list; + +static enum tdx_module_status_t tdx_module_status; +static DEFINE_MUTEX(tdx_module_lock); + +/* All TDX-usable memory regions. Protected by mem_hotplug_lock. */ +static LIST_HEAD(tdx_memlist); + +typedef void (*sc_err_func_t)(u64 fn, u64 err, struct tdx_module_args *args); + +static inline void seamcall_err(u64 fn, u64 err, struct tdx_module_args *args) +{ + pr_err("SEAMCALL (0x%016llx) failed: 0x%016llx\n", fn, err); +} + +static inline void seamcall_err_ret(u64 fn, u64 err, + struct tdx_module_args *args) +{ + seamcall_err(fn, err, args); + pr_err("RCX 0x%016llx RDX 0x%016llx R08 0x%016llx\n", + args->rcx, args->rdx, args->r8); + pr_err("R09 0x%016llx R10 0x%016llx R11 0x%016llx\n", + args->r9, args->r10, args->r11); +} + +static inline int sc_retry_prerr(sc_func_t func, sc_err_func_t err_func, + u64 fn, struct tdx_module_args *args) +{ + u64 sret = sc_retry(func, fn, args); + + if (sret == TDX_SUCCESS) + return 0; + + if (sret == TDX_SEAMCALL_VMFAILINVALID) + return -ENODEV; + + if (sret == TDX_SEAMCALL_GP) + return -EOPNOTSUPP; + + if (sret == TDX_SEAMCALL_UD) + return -EACCES; + + err_func(fn, sret, args); + return -EIO; +} + +#define seamcall_prerr(__fn, __args) \ + sc_retry_prerr(__seamcall, seamcall_err, (__fn), (__args)) + +#define seamcall_prerr_ret(__fn, __args) \ + sc_retry_prerr(__seamcall_ret, seamcall_err_ret, (__fn), (__args)) + +/* + * Do the module global initialization once and return its result. + * It can be done on any cpu. It's always called with interrupts + * disabled. + */ +static int try_init_module_global(void) +{ + struct tdx_module_args args = {}; + static DEFINE_RAW_SPINLOCK(sysinit_lock); + static bool sysinit_done; + static int sysinit_ret; + + lockdep_assert_irqs_disabled(); + + raw_spin_lock(&sysinit_lock); + + if (sysinit_done) + goto out; + + /* RCX is module attributes and all bits are reserved */ + args.rcx = 0; + sysinit_ret = seamcall_prerr(TDH_SYS_INIT, &args); + + /* + * The first SEAMCALL also detects the TDX module, thus + * it can fail due to the TDX module is not loaded. + * Dump message to let the user know. + */ + if (sysinit_ret == -ENODEV) + pr_err("module not loaded\n"); + + sysinit_done = true; +out: + raw_spin_unlock(&sysinit_lock); + return sysinit_ret; +} + +/** + * tdx_cpu_enable - Enable TDX on local cpu + * + * Do one-time TDX module per-cpu initialization SEAMCALL (and TDX module + * global initialization SEAMCALL if not done) on local cpu to make this + * cpu be ready to run any other SEAMCALLs. + * + * Always call this function via IPI function calls. + * + * Return 0 on success, otherwise errors. + */ +int tdx_cpu_enable(void) +{ + struct tdx_module_args args = {}; + int ret; + + if (!boot_cpu_has(X86_FEATURE_TDX_HOST_PLATFORM)) + return -ENODEV; + + lockdep_assert_irqs_disabled(); + + if (__this_cpu_read(tdx_lp_initialized)) + return 0; + + /* + * The TDX module global initialization is the very first step + * to enable TDX. Need to do it first (if hasn't been done) + * before the per-cpu initialization. + */ + ret = try_init_module_global(); + if (ret) + return ret; + + ret = seamcall_prerr(TDH_SYS_LP_INIT, &args); + if (ret) + return ret; + + __this_cpu_write(tdx_lp_initialized, true); + + return 0; +} +EXPORT_SYMBOL_GPL(tdx_cpu_enable); + +/* + * Add a memory region as a TDX memory block. The caller must make sure + * all memory regions are added in address ascending order and don't + * overlap. + */ +static int add_tdx_memblock(struct list_head *tmb_list, unsigned long start_pfn, + unsigned long end_pfn, int nid) +{ + struct tdx_memblock *tmb; + + tmb = kmalloc(sizeof(*tmb), GFP_KERNEL); + if (!tmb) + return -ENOMEM; + + INIT_LIST_HEAD(&tmb->list); + tmb->start_pfn = start_pfn; + tmb->end_pfn = end_pfn; + tmb->nid = nid; + + /* @tmb_list is protected by mem_hotplug_lock */ + list_add_tail(&tmb->list, tmb_list); + return 0; +} + +static void free_tdx_memlist(struct list_head *tmb_list) +{ + /* @tmb_list is protected by mem_hotplug_lock */ + while (!list_empty(tmb_list)) { + struct tdx_memblock *tmb = list_first_entry(tmb_list, + struct tdx_memblock, list); + + list_del(&tmb->list); + kfree(tmb); + } +} + +/* + * Ensure that all memblock memory regions are convertible to TDX + * memory. Once this has been established, stash the memblock + * ranges off in a secondary structure because memblock is modified + * in memory hotplug while TDX memory regions are fixed. + */ +static int build_tdx_memlist(struct list_head *tmb_list) +{ + unsigned long start_pfn, end_pfn; + int i, nid, ret; + + for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { + /* + * The first 1MB is not reported as TDX convertible memory. + * Although the first 1MB is always reserved and won't end up + * to the page allocator, it is still in memblock's memory + * regions. Skip them manually to exclude them as TDX memory. + */ + start_pfn = max(start_pfn, PHYS_PFN(SZ_1M)); + if (start_pfn >= end_pfn) + continue; + + /* + * Add the memory regions as TDX memory. The regions in + * memblock has already guaranteed they are in address + * ascending order and don't overlap. + */ + ret = add_tdx_memblock(tmb_list, start_pfn, end_pfn, nid); + if (ret) + goto err; + } + + return 0; +err: + free_tdx_memlist(tmb_list); + return ret; +} + +static int read_sys_metadata_field(u64 field_id, u64 *data) +{ + struct tdx_module_args args = {}; + int ret; + + /* + * TDH.SYS.RD -- reads one global metadata field + * - RDX (in): the field to read + * - R8 (out): the field data + */ + args.rdx = field_id; + ret = seamcall_prerr_ret(TDH_SYS_RD, &args); + if (ret) + return ret; + + *data = args.r8; + + return 0; +} + +static int read_sys_metadata_field16(u64 field_id, + int offset, + struct tdx_tdmr_sysinfo *ts) +{ + u16 *ts_member = ((void *)ts) + offset; + u64 tmp; + int ret; + + if (WARN_ON_ONCE(MD_FIELD_ID_ELE_SIZE_CODE(field_id) != + MD_FIELD_ID_ELE_SIZE_16BIT)) + return -EINVAL; + + ret = read_sys_metadata_field(field_id, &tmp); + if (ret) + return ret; + + *ts_member = tmp; + + return 0; +} + +struct field_mapping { + u64 field_id; + int offset; +}; + +#define TD_SYSINFO_MAP(_field_id, _offset) \ + { .field_id = MD_FIELD_ID_##_field_id, \ + .offset = offsetof(struct tdx_tdmr_sysinfo, _offset) } + +/* Map TD_SYSINFO fields into 'struct tdx_tdmr_sysinfo': */ +static const struct field_mapping fields[] = { + TD_SYSINFO_MAP(MAX_TDMRS, max_tdmrs), + TD_SYSINFO_MAP(MAX_RESERVED_PER_TDMR, max_reserved_per_tdmr), + TD_SYSINFO_MAP(PAMT_4K_ENTRY_SIZE, pamt_entry_size[TDX_PS_4K]), + TD_SYSINFO_MAP(PAMT_2M_ENTRY_SIZE, pamt_entry_size[TDX_PS_2M]), + TD_SYSINFO_MAP(PAMT_1G_ENTRY_SIZE, pamt_entry_size[TDX_PS_1G]), +}; + +static int get_tdx_tdmr_sysinfo(struct tdx_tdmr_sysinfo *tdmr_sysinfo) +{ + int ret; + int i; + + /* Populate 'tdmr_sysinfo' fields using the mapping structure above: */ + for (i = 0; i < ARRAY_SIZE(fields); i++) { + ret = read_sys_metadata_field16(fields[i].field_id, + fields[i].offset, + tdmr_sysinfo); + if (ret) + return ret; + } + + return 0; +} + +/* Calculate the actual TDMR size */ +static int tdmr_size_single(u16 max_reserved_per_tdmr) +{ + int tdmr_sz; + + /* + * The actual size of TDMR depends on the maximum + * number of reserved areas. + */ + tdmr_sz = sizeof(struct tdmr_info); + tdmr_sz += sizeof(struct tdmr_reserved_area) * max_reserved_per_tdmr; + + return ALIGN(tdmr_sz, TDMR_INFO_ALIGNMENT); +} + +static int alloc_tdmr_list(struct tdmr_info_list *tdmr_list, + struct tdx_tdmr_sysinfo *tdmr_sysinfo) +{ + size_t tdmr_sz, tdmr_array_sz; + void *tdmr_array; + + tdmr_sz = tdmr_size_single(tdmr_sysinfo->max_reserved_per_tdmr); + tdmr_array_sz = tdmr_sz * tdmr_sysinfo->max_tdmrs; + + /* + * To keep things simple, allocate all TDMRs together. + * The buffer needs to be physically contiguous to make + * sure each TDMR is physically contiguous. + */ + tdmr_array = alloc_pages_exact(tdmr_array_sz, + GFP_KERNEL | __GFP_ZERO); + if (!tdmr_array) + return -ENOMEM; + + tdmr_list->tdmrs = tdmr_array; + + /* + * Keep the size of TDMR to find the target TDMR + * at a given index in the TDMR list. + */ + tdmr_list->tdmr_sz = tdmr_sz; + tdmr_list->max_tdmrs = tdmr_sysinfo->max_tdmrs; + tdmr_list->nr_consumed_tdmrs = 0; + + return 0; +} + +static void free_tdmr_list(struct tdmr_info_list *tdmr_list) +{ + free_pages_exact(tdmr_list->tdmrs, + tdmr_list->max_tdmrs * tdmr_list->tdmr_sz); +} + +/* Get the TDMR from the list at the given index. */ +static struct tdmr_info *tdmr_entry(struct tdmr_info_list *tdmr_list, + int idx) +{ + int tdmr_info_offset = tdmr_list->tdmr_sz * idx; + + return (void *)tdmr_list->tdmrs + tdmr_info_offset; +} + +#define TDMR_ALIGNMENT SZ_1G +#define TDMR_ALIGN_DOWN(_addr) ALIGN_DOWN((_addr), TDMR_ALIGNMENT) +#define TDMR_ALIGN_UP(_addr) ALIGN((_addr), TDMR_ALIGNMENT) + +static inline u64 tdmr_end(struct tdmr_info *tdmr) +{ + return tdmr->base + tdmr->size; +} + +/* + * Take the memory referenced in @tmb_list and populate the + * preallocated @tdmr_list, following all the special alignment + * and size rules for TDMR. + */ +static int fill_out_tdmrs(struct list_head *tmb_list, + struct tdmr_info_list *tdmr_list) +{ + struct tdx_memblock *tmb; + int tdmr_idx = 0; + + /* + * Loop over TDX memory regions and fill out TDMRs to cover them. + * To keep it simple, always try to use one TDMR to cover one + * memory region. + * + * In practice TDX supports at least 64 TDMRs. A 2-socket system + * typically only consumes less than 10 of those. This code is + * dumb and simple and may use more TMDRs than is strictly + * required. + */ + list_for_each_entry(tmb, tmb_list, list) { + struct tdmr_info *tdmr = tdmr_entry(tdmr_list, tdmr_idx); + u64 start, end; + + start = TDMR_ALIGN_DOWN(PFN_PHYS(tmb->start_pfn)); + end = TDMR_ALIGN_UP(PFN_PHYS(tmb->end_pfn)); + + /* + * A valid size indicates the current TDMR has already + * been filled out to cover the previous memory region(s). + */ + if (tdmr->size) { + /* + * Loop to the next if the current memory region + * has already been fully covered. + */ + if (end <= tdmr_end(tdmr)) + continue; + + /* Otherwise, skip the already covered part. */ + if (start < tdmr_end(tdmr)) + start = tdmr_end(tdmr); + + /* + * Create a new TDMR to cover the current memory + * region, or the remaining part of it. + */ + tdmr_idx++; + if (tdmr_idx >= tdmr_list->max_tdmrs) { + pr_warn("initialization failed: TDMRs exhausted.\n"); + return -ENOSPC; + } + + tdmr = tdmr_entry(tdmr_list, tdmr_idx); + } + + tdmr->base = start; + tdmr->size = end - start; + } + + /* @tdmr_idx is always the index of the last valid TDMR. */ + tdmr_list->nr_consumed_tdmrs = tdmr_idx + 1; + + /* + * Warn early that kernel is about to run out of TDMRs. + * + * This is an indication that TDMR allocation has to be + * reworked to be smarter to not run into an issue. + */ + if (tdmr_list->max_tdmrs - tdmr_list->nr_consumed_tdmrs < TDMR_NR_WARN) + pr_warn("consumed TDMRs reaching limit: %d used out of %d\n", + tdmr_list->nr_consumed_tdmrs, + tdmr_list->max_tdmrs); + + return 0; +} + +/* + * Calculate PAMT size given a TDMR and a page size. The returned + * PAMT size is always aligned up to 4K page boundary. + */ +static unsigned long tdmr_get_pamt_sz(struct tdmr_info *tdmr, int pgsz, + u16 pamt_entry_size) +{ + unsigned long pamt_sz, nr_pamt_entries; + + switch (pgsz) { + case TDX_PS_4K: + nr_pamt_entries = tdmr->size >> PAGE_SHIFT; + break; + case TDX_PS_2M: + nr_pamt_entries = tdmr->size >> PMD_SHIFT; + break; + case TDX_PS_1G: + nr_pamt_entries = tdmr->size >> PUD_SHIFT; + break; + default: + WARN_ON_ONCE(1); + return 0; + } + + pamt_sz = nr_pamt_entries * pamt_entry_size; + /* TDX requires PAMT size must be 4K aligned */ + pamt_sz = ALIGN(pamt_sz, PAGE_SIZE); + + return pamt_sz; +} + +/* + * Locate a NUMA node which should hold the allocation of the @tdmr + * PAMT. This node will have some memory covered by the TDMR. The + * relative amount of memory covered is not considered. + */ +static int tdmr_get_nid(struct tdmr_info *tdmr, struct list_head *tmb_list) +{ + struct tdx_memblock *tmb; + + /* + * A TDMR must cover at least part of one TMB. That TMB will end + * after the TDMR begins. But, that TMB may have started before + * the TDMR. Find the next 'tmb' that _ends_ after this TDMR + * begins. Ignore 'tmb' start addresses. They are irrelevant. + */ + list_for_each_entry(tmb, tmb_list, list) { + if (tmb->end_pfn > PHYS_PFN(tdmr->base)) + return tmb->nid; + } + + /* + * Fall back to allocating the TDMR's metadata from node 0 when + * no TDX memory block can be found. This should never happen + * since TDMRs originate from TDX memory blocks. + */ + pr_warn("TDMR [0x%llx, 0x%llx): unable to find local NUMA node for PAMT allocation, fallback to use node 0.\n", + tdmr->base, tdmr_end(tdmr)); + return 0; +} + +/* + * Allocate PAMTs from the local NUMA node of some memory in @tmb_list + * within @tdmr, and set up PAMTs for @tdmr. + */ +static int tdmr_set_up_pamt(struct tdmr_info *tdmr, + struct list_head *tmb_list, + u16 pamt_entry_size[]) +{ + unsigned long pamt_base[TDX_PS_NR]; + unsigned long pamt_size[TDX_PS_NR]; + unsigned long tdmr_pamt_base; + unsigned long tdmr_pamt_size; + struct page *pamt; + int pgsz, nid; + + nid = tdmr_get_nid(tdmr, tmb_list); + + /* + * Calculate the PAMT size for each TDX supported page size + * and the total PAMT size. + */ + tdmr_pamt_size = 0; + for (pgsz = TDX_PS_4K; pgsz < TDX_PS_NR; pgsz++) { + pamt_size[pgsz] = tdmr_get_pamt_sz(tdmr, pgsz, + pamt_entry_size[pgsz]); + tdmr_pamt_size += pamt_size[pgsz]; + } + + /* + * Allocate one chunk of physically contiguous memory for all + * PAMTs. This helps minimize the PAMT's use of reserved areas + * in overlapped TDMRs. + */ + pamt = alloc_contig_pages(tdmr_pamt_size >> PAGE_SHIFT, GFP_KERNEL, + nid, &node_online_map); + if (!pamt) + return -ENOMEM; + + /* + * Break the contiguous allocation back up into the + * individual PAMTs for each page size. + */ + tdmr_pamt_base = page_to_pfn(pamt) << PAGE_SHIFT; + for (pgsz = TDX_PS_4K; pgsz < TDX_PS_NR; pgsz++) { + pamt_base[pgsz] = tdmr_pamt_base; + tdmr_pamt_base += pamt_size[pgsz]; + } + + tdmr->pamt_4k_base = pamt_base[TDX_PS_4K]; + tdmr->pamt_4k_size = pamt_size[TDX_PS_4K]; + tdmr->pamt_2m_base = pamt_base[TDX_PS_2M]; + tdmr->pamt_2m_size = pamt_size[TDX_PS_2M]; + tdmr->pamt_1g_base = pamt_base[TDX_PS_1G]; + tdmr->pamt_1g_size = pamt_size[TDX_PS_1G]; + + return 0; +} + +static void tdmr_get_pamt(struct tdmr_info *tdmr, unsigned long *pamt_base, + unsigned long *pamt_size) +{ + unsigned long pamt_bs, pamt_sz; + + /* + * The PAMT was allocated in one contiguous unit. The 4K PAMT + * should always point to the beginning of that allocation. + */ + pamt_bs = tdmr->pamt_4k_base; + pamt_sz = tdmr->pamt_4k_size + tdmr->pamt_2m_size + tdmr->pamt_1g_size; + + WARN_ON_ONCE((pamt_bs & ~PAGE_MASK) || (pamt_sz & ~PAGE_MASK)); + + *pamt_base = pamt_bs; + *pamt_size = pamt_sz; +} + +static void tdmr_do_pamt_func(struct tdmr_info *tdmr, + void (*pamt_func)(unsigned long base, unsigned long size)) +{ + unsigned long pamt_base, pamt_size; + + tdmr_get_pamt(tdmr, &pamt_base, &pamt_size); + + /* Do nothing if PAMT hasn't been allocated for this TDMR */ + if (!pamt_size) + return; + + if (WARN_ON_ONCE(!pamt_base)) + return; + + pamt_func(pamt_base, pamt_size); +} + +static void free_pamt(unsigned long pamt_base, unsigned long pamt_size) +{ + free_contig_range(pamt_base >> PAGE_SHIFT, pamt_size >> PAGE_SHIFT); +} + +static void tdmr_free_pamt(struct tdmr_info *tdmr) +{ + tdmr_do_pamt_func(tdmr, free_pamt); +} + +static void tdmrs_free_pamt_all(struct tdmr_info_list *tdmr_list) +{ + int i; + + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) + tdmr_free_pamt(tdmr_entry(tdmr_list, i)); +} + +/* Allocate and set up PAMTs for all TDMRs */ +static int tdmrs_set_up_pamt_all(struct tdmr_info_list *tdmr_list, + struct list_head *tmb_list, + u16 pamt_entry_size[]) +{ + int i, ret = 0; + + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) { + ret = tdmr_set_up_pamt(tdmr_entry(tdmr_list, i), tmb_list, + pamt_entry_size); + if (ret) + goto err; + } + + return 0; +err: + tdmrs_free_pamt_all(tdmr_list); + return ret; +} + +/* + * Convert TDX private pages back to normal by using MOVDIR64B to + * clear these pages. Note this function doesn't flush cache of + * these TDX private pages. The caller should make sure of that. + */ +static void reset_tdx_pages(unsigned long base, unsigned long size) +{ + const void *zero_page = (const void *)page_address(ZERO_PAGE(0)); + unsigned long phys, end; + + end = base + size; + for (phys = base; phys < end; phys += 64) + movdir64b(__va(phys), zero_page); + + /* + * MOVDIR64B uses WC protocol. Use memory barrier to + * make sure any later user of these pages sees the + * updated data. + */ + mb(); +} + +static void tdmr_reset_pamt(struct tdmr_info *tdmr) +{ + tdmr_do_pamt_func(tdmr, reset_tdx_pages); +} + +static void tdmrs_reset_pamt_all(struct tdmr_info_list *tdmr_list) +{ + int i; + + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) + tdmr_reset_pamt(tdmr_entry(tdmr_list, i)); +} + +static unsigned long tdmrs_count_pamt_kb(struct tdmr_info_list *tdmr_list) +{ + unsigned long pamt_size = 0; + int i; + + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) { + unsigned long base, size; + + tdmr_get_pamt(tdmr_entry(tdmr_list, i), &base, &size); + pamt_size += size; + } + + return pamt_size / 1024; +} + +static int tdmr_add_rsvd_area(struct tdmr_info *tdmr, int *p_idx, u64 addr, + u64 size, u16 max_reserved_per_tdmr) +{ + struct tdmr_reserved_area *rsvd_areas = tdmr->reserved_areas; + int idx = *p_idx; + + /* Reserved area must be 4K aligned in offset and size */ + if (WARN_ON(addr & ~PAGE_MASK || size & ~PAGE_MASK)) + return -EINVAL; + + if (idx >= max_reserved_per_tdmr) { + pr_warn("initialization failed: TDMR [0x%llx, 0x%llx): reserved areas exhausted.\n", + tdmr->base, tdmr_end(tdmr)); + return -ENOSPC; + } + + /* + * Consume one reserved area per call. Make no effort to + * optimize or reduce the number of reserved areas which are + * consumed by contiguous reserved areas, for instance. + */ + rsvd_areas[idx].offset = addr - tdmr->base; + rsvd_areas[idx].size = size; + + *p_idx = idx + 1; + + return 0; +} + +/* + * Go through @tmb_list to find holes between memory areas. If any of + * those holes fall within @tdmr, set up a TDMR reserved area to cover + * the hole. + */ +static int tdmr_populate_rsvd_holes(struct list_head *tmb_list, + struct tdmr_info *tdmr, + int *rsvd_idx, + u16 max_reserved_per_tdmr) +{ + struct tdx_memblock *tmb; + u64 prev_end; + int ret; + + /* + * Start looking for reserved blocks at the + * beginning of the TDMR. + */ + prev_end = tdmr->base; + list_for_each_entry(tmb, tmb_list, list) { + u64 start, end; + + start = PFN_PHYS(tmb->start_pfn); + end = PFN_PHYS(tmb->end_pfn); + + /* Break if this region is after the TDMR */ + if (start >= tdmr_end(tdmr)) + break; + + /* Exclude regions before this TDMR */ + if (end < tdmr->base) + continue; + + /* + * Skip over memory areas that + * have already been dealt with. + */ + if (start <= prev_end) { + prev_end = end; + continue; + } + + /* Add the hole before this region */ + ret = tdmr_add_rsvd_area(tdmr, rsvd_idx, prev_end, + start - prev_end, + max_reserved_per_tdmr); + if (ret) + return ret; + + prev_end = end; + } + + /* Add the hole after the last region if it exists. */ + if (prev_end < tdmr_end(tdmr)) { + ret = tdmr_add_rsvd_area(tdmr, rsvd_idx, prev_end, + tdmr_end(tdmr) - prev_end, + max_reserved_per_tdmr); + if (ret) + return ret; + } + + return 0; +} + +/* + * Go through @tdmr_list to find all PAMTs. If any of those PAMTs + * overlaps with @tdmr, set up a TDMR reserved area to cover the + * overlapping part. + */ +static int tdmr_populate_rsvd_pamts(struct tdmr_info_list *tdmr_list, + struct tdmr_info *tdmr, + int *rsvd_idx, + u16 max_reserved_per_tdmr) +{ + int i, ret; + + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) { + struct tdmr_info *tmp = tdmr_entry(tdmr_list, i); + unsigned long pamt_base, pamt_size, pamt_end; + + tdmr_get_pamt(tmp, &pamt_base, &pamt_size); + /* Each TDMR must already have PAMT allocated */ + WARN_ON_ONCE(!pamt_size || !pamt_base); + + pamt_end = pamt_base + pamt_size; + /* Skip PAMTs outside of the given TDMR */ + if ((pamt_end <= tdmr->base) || + (pamt_base >= tdmr_end(tdmr))) + continue; + + /* Only mark the part within the TDMR as reserved */ + if (pamt_base < tdmr->base) + pamt_base = tdmr->base; + if (pamt_end > tdmr_end(tdmr)) + pamt_end = tdmr_end(tdmr); + + ret = tdmr_add_rsvd_area(tdmr, rsvd_idx, pamt_base, + pamt_end - pamt_base, + max_reserved_per_tdmr); + if (ret) + return ret; + } + + return 0; +} + +/* Compare function called by sort() for TDMR reserved areas */ +static int rsvd_area_cmp_func(const void *a, const void *b) +{ + struct tdmr_reserved_area *r1 = (struct tdmr_reserved_area *)a; + struct tdmr_reserved_area *r2 = (struct tdmr_reserved_area *)b; + + if (r1->offset + r1->size <= r2->offset) + return -1; + if (r1->offset >= r2->offset + r2->size) + return 1; + + /* Reserved areas cannot overlap. The caller must guarantee. */ + WARN_ON_ONCE(1); + return -1; +} + +/* + * Populate reserved areas for the given @tdmr, including memory holes + * (via @tmb_list) and PAMTs (via @tdmr_list). + */ +static int tdmr_populate_rsvd_areas(struct tdmr_info *tdmr, + struct list_head *tmb_list, + struct tdmr_info_list *tdmr_list, + u16 max_reserved_per_tdmr) +{ + int ret, rsvd_idx = 0; + + ret = tdmr_populate_rsvd_holes(tmb_list, tdmr, &rsvd_idx, + max_reserved_per_tdmr); + if (ret) + return ret; + + ret = tdmr_populate_rsvd_pamts(tdmr_list, tdmr, &rsvd_idx, + max_reserved_per_tdmr); + if (ret) + return ret; + + /* TDX requires reserved areas listed in address ascending order */ + sort(tdmr->reserved_areas, rsvd_idx, sizeof(struct tdmr_reserved_area), + rsvd_area_cmp_func, NULL); + + return 0; +} + +/* + * Populate reserved areas for all TDMRs in @tdmr_list, including memory + * holes (via @tmb_list) and PAMTs. + */ +static int tdmrs_populate_rsvd_areas_all(struct tdmr_info_list *tdmr_list, + struct list_head *tmb_list, + u16 max_reserved_per_tdmr) +{ + int i; + + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) { + int ret; + + ret = tdmr_populate_rsvd_areas(tdmr_entry(tdmr_list, i), + tmb_list, tdmr_list, max_reserved_per_tdmr); + if (ret) + return ret; + } + + return 0; +} + +/* + * Construct a list of TDMRs on the preallocated space in @tdmr_list + * to cover all TDX memory regions in @tmb_list based on the TDX module + * TDMR global information in @tdmr_sysinfo. + */ +static int construct_tdmrs(struct list_head *tmb_list, + struct tdmr_info_list *tdmr_list, + struct tdx_tdmr_sysinfo *tdmr_sysinfo) +{ + int ret; + + ret = fill_out_tdmrs(tmb_list, tdmr_list); + if (ret) + return ret; + + ret = tdmrs_set_up_pamt_all(tdmr_list, tmb_list, + tdmr_sysinfo->pamt_entry_size); + if (ret) + return ret; + + ret = tdmrs_populate_rsvd_areas_all(tdmr_list, tmb_list, + tdmr_sysinfo->max_reserved_per_tdmr); + if (ret) + tdmrs_free_pamt_all(tdmr_list); + + /* + * The tdmr_info_list is read-only from here on out. + * Ensure that these writes are seen by other CPUs. + * Pairs with a smp_rmb() in is_pamt_page(). + */ + smp_wmb(); + + return ret; +} + +static int config_tdx_module(struct tdmr_info_list *tdmr_list, u64 global_keyid) +{ + struct tdx_module_args args = {}; + u64 *tdmr_pa_array; + size_t array_sz; + int i, ret; + + /* + * TDMRs are passed to the TDX module via an array of physical + * addresses of each TDMR. The array itself also has certain + * alignment requirement. + */ + array_sz = tdmr_list->nr_consumed_tdmrs * sizeof(u64); + array_sz = roundup_pow_of_two(array_sz); + if (array_sz < TDMR_INFO_PA_ARRAY_ALIGNMENT) + array_sz = TDMR_INFO_PA_ARRAY_ALIGNMENT; + + tdmr_pa_array = kzalloc(array_sz, GFP_KERNEL); + if (!tdmr_pa_array) + return -ENOMEM; + + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) + tdmr_pa_array[i] = __pa(tdmr_entry(tdmr_list, i)); + + args.rcx = __pa(tdmr_pa_array); + args.rdx = tdmr_list->nr_consumed_tdmrs; + args.r8 = global_keyid; + ret = seamcall_prerr(TDH_SYS_CONFIG, &args); + + /* Free the array as it is not required anymore. */ + kfree(tdmr_pa_array); + + return ret; +} + +static int do_global_key_config(void *unused) +{ + struct tdx_module_args args = {}; + + return seamcall_prerr(TDH_SYS_KEY_CONFIG, &args); +} + +/* + * Attempt to configure the global KeyID on all physical packages. + * + * This requires running code on at least one CPU in each package. + * TDMR initialization) will fail will fail if any package in the + * system has no online CPUs. + * + * This code takes no affirmative steps to online CPUs. Callers (aka. + * KVM) can ensure success by ensuring sufficient CPUs are online and + * can run SEAMCALLs. + */ +static int config_global_keyid(void) +{ + cpumask_var_t packages; + int cpu, ret = -EINVAL; + + if (!zalloc_cpumask_var(&packages, GFP_KERNEL)) + return -ENOMEM; + + /* + * Hardware doesn't guarantee cache coherency across different + * KeyIDs. The kernel needs to flush PAMT's dirty cachelines + * (associated with KeyID 0) before the TDX module can use the + * global KeyID to access the PAMT. Given PAMTs are potentially + * large (~1/256th of system RAM), just use WBINVD. + */ + wbinvd_on_all_cpus(); + + for_each_online_cpu(cpu) { + /* + * The key configuration only needs to be done once per + * package and will return an error if configured more + * than once. Avoid doing it multiple times per package. + */ + if (cpumask_test_and_set_cpu(topology_physical_package_id(cpu), + packages)) + continue; + + /* + * TDH.SYS.KEY.CONFIG cannot run concurrently on + * different cpus. Do it one by one. + */ + ret = smp_call_on_cpu(cpu, do_global_key_config, NULL, true); + if (ret) + break; + } + + free_cpumask_var(packages); + return ret; +} + +static int init_tdmr(struct tdmr_info *tdmr) +{ + u64 next; + + /* + * Initializing a TDMR can be time consuming. To avoid long + * SEAMCALLs, the TDX module may only initialize a part of the + * TDMR in each call. + */ + do { + struct tdx_module_args args = { + .rcx = tdmr->base, + }; + int ret; + + ret = seamcall_prerr_ret(TDH_SYS_TDMR_INIT, &args); + if (ret) + return ret; + /* + * RDX contains 'next-to-initialize' address if + * TDH.SYS.TDMR.INIT did not fully complete and + * should be retried. + */ + next = args.rdx; + cond_resched(); + /* Keep making SEAMCALLs until the TDMR is done */ + } while (next < tdmr->base + tdmr->size); + + return 0; +} + +static int init_tdmrs(struct tdmr_info_list *tdmr_list) +{ + int i; + + /* + * This operation is costly. It can be parallelized, + * but keep it simple for now. + */ + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) { + int ret; + + ret = init_tdmr(tdmr_entry(tdmr_list, i)); + if (ret) + return ret; + } + + return 0; +} + +static int init_tdx_module(void) +{ + struct tdx_tdmr_sysinfo tdmr_sysinfo; + int ret; + + /* + * To keep things simple, assume that all TDX-protected memory + * will come from the page allocator. Make sure all pages in the + * page allocator are TDX-usable memory. + * + * Build the list of "TDX-usable" memory regions which cover all + * pages in the page allocator to guarantee that. Do it while + * holding mem_hotplug_lock read-lock as the memory hotplug code + * path reads the @tdx_memlist to reject any new memory. + */ + get_online_mems(); + + ret = build_tdx_memlist(&tdx_memlist); + if (ret) + goto out_put_tdxmem; + + ret = get_tdx_tdmr_sysinfo(&tdmr_sysinfo); + if (ret) + goto err_free_tdxmem; + + /* Allocate enough space for constructing TDMRs */ + ret = alloc_tdmr_list(&tdx_tdmr_list, &tdmr_sysinfo); + if (ret) + goto err_free_tdxmem; + + /* Cover all TDX-usable memory regions in TDMRs */ + ret = construct_tdmrs(&tdx_memlist, &tdx_tdmr_list, &tdmr_sysinfo); + if (ret) + goto err_free_tdmrs; + + /* Pass the TDMRs and the global KeyID to the TDX module */ + ret = config_tdx_module(&tdx_tdmr_list, tdx_global_keyid); + if (ret) + goto err_free_pamts; + + /* Config the key of global KeyID on all packages */ + ret = config_global_keyid(); + if (ret) + goto err_reset_pamts; + + /* Initialize TDMRs to complete the TDX module initialization */ + ret = init_tdmrs(&tdx_tdmr_list); + if (ret) + goto err_reset_pamts; + + pr_info("%lu KB allocated for PAMT\n", tdmrs_count_pamt_kb(&tdx_tdmr_list)); + +out_put_tdxmem: + /* + * @tdx_memlist is written here and read at memory hotplug time. + * Lock out memory hotplug code while building it. + */ + put_online_mems(); + return ret; + +err_reset_pamts: + /* + * Part of PAMTs may already have been initialized by the + * TDX module. Flush cache before returning PAMTs back + * to the kernel. + */ + wbinvd_on_all_cpus(); + /* + * According to the TDX hardware spec, if the platform + * doesn't have the "partial write machine check" + * erratum, any kernel read/write will never cause #MC + * in kernel space, thus it's OK to not convert PAMTs + * back to normal. But do the conversion anyway here + * as suggested by the TDX spec. + */ + tdmrs_reset_pamt_all(&tdx_tdmr_list); +err_free_pamts: + tdmrs_free_pamt_all(&tdx_tdmr_list); +err_free_tdmrs: + free_tdmr_list(&tdx_tdmr_list); +err_free_tdxmem: + free_tdx_memlist(&tdx_memlist); + goto out_put_tdxmem; +} + +static int __tdx_enable(void) +{ + int ret; + + ret = init_tdx_module(); + if (ret) { + pr_err("module initialization failed (%d)\n", ret); + tdx_module_status = TDX_MODULE_ERROR; + return ret; + } + + pr_info("module initialized\n"); + tdx_module_status = TDX_MODULE_INITIALIZED; + + return 0; +} + +/** + * tdx_enable - Enable TDX module to make it ready to run TDX guests + * + * This function assumes the caller has: 1) held read lock of CPU hotplug + * lock to prevent any new cpu from becoming online; 2) done both VMXON + * and tdx_cpu_enable() on all online cpus. + * + * This function requires there's at least one online cpu for each CPU + * package to succeed. + * + * This function can be called in parallel by multiple callers. + * + * Return 0 if TDX is enabled successfully, otherwise error. + */ +int tdx_enable(void) +{ + int ret; + + if (!boot_cpu_has(X86_FEATURE_TDX_HOST_PLATFORM)) + return -ENODEV; + + lockdep_assert_cpus_held(); + + mutex_lock(&tdx_module_lock); + + switch (tdx_module_status) { + case TDX_MODULE_UNINITIALIZED: + ret = __tdx_enable(); + break; + case TDX_MODULE_INITIALIZED: + /* Already initialized, great, tell the caller. */ + ret = 0; + break; + default: + /* Failed to initialize in the previous attempts */ + ret = -EINVAL; + break; + } + + mutex_unlock(&tdx_module_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(tdx_enable); + +static bool is_pamt_page(unsigned long phys) +{ + struct tdmr_info_list *tdmr_list = &tdx_tdmr_list; + int i; + + /* Ensure that all remote 'tdmr_list' writes are visible: */ + smp_rmb(); + + /* + * The TDX module is no longer returning TDX_SYS_NOT_READY and + * is initialized. The 'tdmr_list' was initialized long ago + * and is now read-only. + */ + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) { + unsigned long base, size; + + tdmr_get_pamt(tdmr_entry(tdmr_list, i), &base, &size); + + if (phys >= base && phys < (base + size)) + return true; + } + + return false; +} + +/* + * Return whether the memory page at the given physical address is TDX + * private memory or not. + * + * This can be imprecise for two known reasons: + * 1. PAMTs are private memory and exist before the TDX module is + * ready and TDH_PHYMEM_PAGE_RDMD works. This is a relatively + * short window that occurs once per boot. + * 2. TDH_PHYMEM_PAGE_RDMD reflects the TDX module's knowledge of the + * page. However, the page can still cause #MC until it has been + * fully converted to shared using 64-byte writes like MOVDIR64B. + * Buggy hosts might still leave #MC-causing memory in place which + * this function can not detect. + */ +static bool paddr_is_tdx_private(unsigned long phys) +{ + struct tdx_module_args args = { + .rcx = phys & PAGE_MASK, + }; + u64 sret; + + if (!boot_cpu_has(X86_FEATURE_TDX_HOST_PLATFORM)) + return false; + + /* Get page type from the TDX module */ + sret = __seamcall_ret(TDH_PHYMEM_PAGE_RDMD, &args); + + /* + * The SEAMCALL will not return success unless there is a + * working, "ready" TDX module. Assume an absence of TDX + * private pages until SEAMCALL is working. + */ + if (sret) + return false; + + /* + * SEAMCALL was successful -- read page type (via RCX): + * + * - PT_NDA: Page is not used by the TDX module + * - PT_RSVD: Reserved for Non-TDX use + * - Others: Page is used by the TDX module + * + * Note PAMT pages are marked as PT_RSVD but they are also TDX + * private memory. + */ + switch (args.rcx) { + case PT_NDA: + return false; + case PT_RSVD: + return is_pamt_page(phys); + default: + return true; + } +} + +/* + * Some TDX-capable CPUs have an erratum. A write to TDX private + * memory poisons that memory, and a subsequent read of that memory + * triggers #MC. + * + * Help distinguish erratum-triggered #MCs from a normal hardware one. + * Just print additional message to show such #MC may be result of the + * erratum. + */ +const char *tdx_dump_mce_info(struct mce *m) +{ + if (!m || !mce_is_memory_error(m) || !mce_usable_address(m)) + return NULL; + + if (!paddr_is_tdx_private(m->addr)) + return NULL; + + return "TDX private memory error. Possible kernel bug."; +} + +static __init int record_keyid_partitioning(u32 *tdx_keyid_start, + u32 *nr_tdx_keyids) +{ + u32 _nr_mktme_keyids, _tdx_keyid_start, _nr_tdx_keyids; + int ret; + + /* + * IA32_MKTME_KEYID_PARTIONING: + * Bit [31:0]: Number of MKTME KeyIDs. + * Bit [63:32]: Number of TDX private KeyIDs. + */ + ret = rdmsr_safe(MSR_IA32_MKTME_KEYID_PARTITIONING, &_nr_mktme_keyids, + &_nr_tdx_keyids); + if (ret || !_nr_tdx_keyids) + return -EINVAL; + + /* TDX KeyIDs start after the last MKTME KeyID. */ + _tdx_keyid_start = _nr_mktme_keyids + 1; + + *tdx_keyid_start = _tdx_keyid_start; + *nr_tdx_keyids = _nr_tdx_keyids; + + return 0; +} + +static bool is_tdx_memory(unsigned long start_pfn, unsigned long end_pfn) +{ + struct tdx_memblock *tmb; + + /* + * This check assumes that the start_pfn<->end_pfn range does not + * cross multiple @tdx_memlist entries. A single memory online + * event across multiple memblocks (from which @tdx_memlist + * entries are derived at the time of module initialization) is + * not possible. This is because memory offline/online is done + * on granularity of 'struct memory_block', and the hotpluggable + * memory region (one memblock) must be multiple of memory_block. + */ + list_for_each_entry(tmb, &tdx_memlist, list) { + if (start_pfn >= tmb->start_pfn && end_pfn <= tmb->end_pfn) + return true; + } + return false; +} + +static int tdx_memory_notifier(struct notifier_block *nb, unsigned long action, + void *v) +{ + struct memory_notify *mn = v; + + if (action != MEM_GOING_ONLINE) + return NOTIFY_OK; + + /* + * Empty list means TDX isn't enabled. Allow any memory + * to go online. + */ + if (list_empty(&tdx_memlist)) + return NOTIFY_OK; + + /* + * The TDX memory configuration is static and can not be + * changed. Reject onlining any memory which is outside of + * the static configuration whether it supports TDX or not. + */ + if (is_tdx_memory(mn->start_pfn, mn->start_pfn + mn->nr_pages)) + return NOTIFY_OK; + + return NOTIFY_BAD; +} + +static struct notifier_block tdx_memory_nb = { + .notifier_call = tdx_memory_notifier, +}; + +static void __init check_tdx_erratum(void) +{ + /* + * These CPUs have an erratum. A partial write from non-TD + * software (e.g. via MOVNTI variants or UC/WC mapping) to TDX + * private memory poisons that memory, and a subsequent read of + * that memory triggers #MC. + */ + switch (boot_cpu_data.x86_model) { + case INTEL_FAM6_SAPPHIRERAPIDS_X: + case INTEL_FAM6_EMERALDRAPIDS_X: + setup_force_cpu_bug(X86_BUG_TDX_PW_MCE); + } +} + +void __init tdx_init(void) +{ + u32 tdx_keyid_start, nr_tdx_keyids; + int err; + + err = record_keyid_partitioning(&tdx_keyid_start, &nr_tdx_keyids); + if (err) + return; + + pr_info("BIOS enabled: private KeyID range [%u, %u)\n", + tdx_keyid_start, tdx_keyid_start + nr_tdx_keyids); + + /* + * The TDX module itself requires one 'global KeyID' to protect + * its metadata. If there's only one TDX KeyID, there won't be + * any left for TDX guests thus there's no point to enable TDX + * at all. + */ + if (nr_tdx_keyids < 2) { + pr_err("initialization failed: too few private KeyIDs available.\n"); + return; + } + + /* + * At this point, hibernation_available() indicates whether or + * not hibernation support has been permanently disabled. + */ + if (hibernation_available()) { + pr_err("initialization failed: Hibernation support is enabled\n"); + return; + } + + err = register_memory_notifier(&tdx_memory_nb); + if (err) { + pr_err("initialization failed: register_memory_notifier() failed (%d)\n", + err); + return; + } + +#if defined(CONFIG_ACPI) && defined(CONFIG_SUSPEND) + pr_info("Disable ACPI S3. Turn off TDX in the BIOS to use ACPI S3.\n"); + acpi_suspend_lowlevel = NULL; +#endif + + /* + * Just use the first TDX KeyID as the 'global KeyID' and + * leave the rest for TDX guests. + */ + tdx_global_keyid = tdx_keyid_start; + tdx_guest_keyid_start = tdx_keyid_start + 1; + tdx_nr_guest_keyids = nr_tdx_keyids - 1; + + setup_force_cpu_cap(X86_FEATURE_TDX_HOST_PLATFORM); + + check_tdx_erratum(); +} |