[tip:,x86/tdx] x86/virt/tdx: Allocate and set up PAMTs for TDMRs

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2c69ef8..e255d8a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1972,6 +1972,7 @@  config INTEL_TDX_HOST
 	depends on KVM_INTEL
 	depends on X86_X2APIC
 	select ARCH_KEEP_MEMBLOCK
+	depends on CONTIG_ALLOC
 	help
 	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
 	  host and certain physical attacks.  This option enables necessary TDX
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index d7f9287..c2bff81 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -173,7 +173,7 @@  EXPORT_SYMBOL_GPL(tdx_cpu_enable);
  * overlap.
  */
 static int add_tdx_memblock(struct list_head *tmb_list, unsigned long start_pfn,
-			    unsigned long end_pfn)
+			    unsigned long end_pfn, int nid)
 {
 	struct tdx_memblock *tmb;
 
@@ -184,6 +184,7 @@  static int add_tdx_memblock(struct list_head *tmb_list, unsigned long start_pfn,
 	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);
@@ -211,9 +212,9 @@  static void free_tdx_memlist(struct list_head *tmb_list)
 static int build_tdx_memlist(struct list_head *tmb_list)
 {
 	unsigned long start_pfn, end_pfn;
-	int i, ret;
+	int i, nid, ret;
 
-	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
+	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
@@ -229,7 +230,7 @@  static int build_tdx_memlist(struct list_head *tmb_list)
 		 * memblock has already guaranteed they are in address
 		 * ascending order and don't overlap.
 		 */
-		ret = add_tdx_memblock(tmb_list, start_pfn, end_pfn);
+		ret = add_tdx_memblock(tmb_list, start_pfn, end_pfn, nid);
 		if (ret)
 			goto err;
 	}
@@ -466,6 +467,202 @@  static int fill_out_tdmrs(struct list_head *tmb_list,
 }
 
 /*
+ * 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_free_pamt(struct tdmr_info *tdmr)
+{
+	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;
+
+	free_contig_range(pamt_base >> PAGE_SHIFT, pamt_size >> PAGE_SHIFT);
+}
+
+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;
+}
+
+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;
+}
+
+/*
  * 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.
@@ -480,10 +677,13 @@  static int construct_tdmrs(struct list_head *tmb_list,
 	if (ret)
 		return ret;
 
+	ret = tdmrs_set_up_pamt_all(tdmr_list, tmb_list,
+			tdmr_sysinfo->pamt_entry_size);
+	if (ret)
+		return ret;
 	/*
 	 * TODO:
 	 *
-	 *  - Allocate and set up PAMTs for each TDMR.
 	 *  - Designate reserved areas for each TDMR.
 	 *
 	 * Return -EINVAL until constructing TDMRs is done
@@ -537,7 +737,10 @@  static int init_tdx_module(void)
 	 */
 	ret = -EINVAL;
 	if (ret)
-		goto err_free_tdmrs;
+		goto err_free_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.
@@ -546,6 +749,8 @@  out_put_tdxmem:
 	put_online_mems();
 	return ret;
 
+err_free_pamts:
+	tdmrs_free_pamt_all(&tdx_tdmr_list);
 err_free_tdmrs:
 	free_tdmr_list(&tdx_tdmr_list);
 err_free_tdxmem:
diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
index f18ce1b..1b04efe 100644
--- a/arch/x86/virt/vmx/tdx/tdx.h
+++ b/arch/x86/virt/vmx/tdx/tdx.h
@@ -87,6 +87,7 @@  struct tdx_memblock {
 	struct list_head list;
 	unsigned long start_pfn;
 	unsigned long end_pfn;
+	int nid;
 };
 
 /* "TDMR info" part of "Global Scope Metadata" for constructing TDMRs */