Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 298 insertions, 0 deletions

diff --git a/drivers/iommu/amd/nested.c b/drivers/iommu/amd/nested.c
new file mode 100644
index 000000000..63b53b29e
--- /dev/null
+++ b/drivers/iommu/amd/nested.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 Advanced Micro Devices, Inc.
+ */
+
+#define dev_fmt(fmt)	"AMD-Vi: " fmt
+
+#include <linux/iommu.h>
+#include <linux/refcount.h>
+#include <uapi/linux/iommufd.h>
+
+#include "amd_iommu.h"
+
+static const struct iommu_domain_ops nested_domain_ops;
+
+static inline struct nested_domain *to_ndomain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct nested_domain, domain);
+}
+
+/*
+ * Validate guest DTE to make sure that configuration for host (v1)
+ * and guest (v2) page tables are valid when allocating nested domain.
+ */
+static int validate_gdte_nested(struct iommu_hwpt_amd_guest *gdte)
+{
+	u32 gpt_level = FIELD_GET(DTE_GPT_LEVEL_MASK, gdte->dte[2]);
+
+	/* Must be zero: Mode, Host-TPR */
+	if (FIELD_GET(DTE_MODE_MASK, gdte->dte[0]) != 0 ||
+	    FIELD_GET(DTE_HOST_TRP, gdte->dte[0]) != 0)
+		return -EINVAL;
+
+	/* GCR3 TRP must be non-zero if V, GV is set */
+	if (FIELD_GET(DTE_FLAG_V, gdte->dte[0]) == 1 &&
+	    FIELD_GET(DTE_FLAG_GV, gdte->dte[0]) == 1 &&
+	    FIELD_GET(DTE_GCR3_14_12, gdte->dte[0]) == 0 &&
+	    FIELD_GET(DTE_GCR3_30_15, gdte->dte[1]) == 0 &&
+	    FIELD_GET(DTE_GCR3_51_31, gdte->dte[1]) == 0)
+		return -EINVAL;
+
+	/* Valid Guest Paging Mode values are 0 and 1 */
+	if (gpt_level != GUEST_PGTABLE_4_LEVEL &&
+	    gpt_level != GUEST_PGTABLE_5_LEVEL)
+		return -EINVAL;
+
+	/* GLX = 3 is reserved */
+	if (FIELD_GET(DTE_GLX, gdte->dte[0]) == 3)
+		return -EINVAL;
+
+	/*
+	 * We need to check host capability before setting
+	 * the Guest Paging Mode
+	 */
+	if (gpt_level == GUEST_PGTABLE_5_LEVEL &&
+	    amd_iommu_gpt_level < PAGE_MODE_5_LEVEL)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static void *gdom_info_load_or_alloc_locked(struct xarray *xa,
+					    unsigned long index,
+					    unsigned long *flags)
+{
+	struct guest_domain_mapping_info *elm, *res;
+
+	elm = xa_load(xa, index);
+	if (elm)
+		return elm;
+
+	xa_unlock_irqrestore(xa, *flags);
+	elm = kzalloc_obj(struct guest_domain_mapping_info);
+	xa_lock_irqsave(xa, *flags);
+	if (!elm)
+		return ERR_PTR(-ENOMEM);
+
+	res = __xa_cmpxchg(xa, index, NULL, elm, GFP_ATOMIC);
+	if (xa_is_err(res))
+		res = ERR_PTR(xa_err(res));
+
+	if (res) {
+		kfree(elm);
+		return res;
+	}
+
+	refcount_set(&elm->users, 0);
+	return elm;
+}
+
+/*
+ * This function is assigned to struct iommufd_viommu_ops.alloc_domain_nested()
+ * during the call to struct iommu_ops.viommu_init().
+ */
+struct iommu_domain *
+amd_iommu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
+			      const struct iommu_user_data *user_data)
+{
+	int ret;
+	unsigned long irqflags;
+	struct nested_domain *ndom;
+	struct guest_domain_mapping_info *gdom_info;
+	struct amd_iommu_viommu *aviommu = container_of(viommu, struct amd_iommu_viommu, core);
+
+	if (user_data->type != IOMMU_HWPT_DATA_AMD_GUEST)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	ndom = kzalloc_obj(*ndom);
+	if (!ndom)
+		return ERR_PTR(-ENOMEM);
+
+	ret = iommu_copy_struct_from_user(&ndom->gdte, user_data,
+					  IOMMU_HWPT_DATA_AMD_GUEST,
+					  dte);
+	if (ret)
+		goto out_err;
+
+	ret = validate_gdte_nested(&ndom->gdte);
+	if (ret)
+		goto out_err;
+
+	ndom->gdom_id = FIELD_GET(DTE_DOMID_MASK, ndom->gdte.dte[1]);
+	ndom->domain.ops = &nested_domain_ops;
+	ndom->domain.type = IOMMU_DOMAIN_NESTED;
+	ndom->viommu = aviommu;
+
+	/*
+	 * Normally, when a guest has multiple pass-through devices,
+	 * the IOMMU driver setup DTEs with the same stage-2 table and
+	 * use the same host domain ID (hDomId). In case of nested translation,
+	 * if the guest setup different stage-1 tables with same PASID,
+	 * IOMMU would use the same TLB tag. This will results in TLB
+	 * aliasing issue.
+	 *
+	 * The guest is assigning gDomIDs based on its own algorithm for managing
+	 * cache tags of (DomID, PASID). Within a single viommu, the nest parent domain
+	 * (w/ S2 table) is used by all DTEs. But we need to consistently map the gDomID
+	 * to a single hDomID. This is done using an xarray in the vIOMMU to
+	 * keep track of the gDomID mapping. When the S2 is changed, the INVALIDATE_IOMMU_PAGES
+	 * command must be issued for each hDomID in the xarray.
+	 */
+	xa_lock_irqsave(&aviommu->gdomid_array, irqflags);
+
+	gdom_info = gdom_info_load_or_alloc_locked(&aviommu->gdomid_array,
+						   ndom->gdom_id, &irqflags);
+	if (IS_ERR(gdom_info)) {
+		xa_unlock_irqrestore(&aviommu->gdomid_array, irqflags);
+		ret = PTR_ERR(gdom_info);
+		goto out_err;
+	}
+
+	/* Check if gDomID exist */
+	if (refcount_inc_not_zero(&gdom_info->users)) {
+		ndom->gdom_info = gdom_info;
+		xa_unlock_irqrestore(&aviommu->gdomid_array, irqflags);
+
+		pr_debug("%s: Found gdom_id=%#x, hdom_id=%#x\n",
+			  __func__, ndom->gdom_id, gdom_info->hdom_id);
+
+		return &ndom->domain;
+	}
+
+	/* The gDomID does not exist. We allocate new hdom_id */
+	gdom_info->hdom_id = amd_iommu_pdom_id_alloc();
+	if (gdom_info->hdom_id <= 0) {
+		__xa_cmpxchg(&aviommu->gdomid_array,
+			     ndom->gdom_id, gdom_info, NULL, GFP_ATOMIC);
+		xa_unlock_irqrestore(&aviommu->gdomid_array, irqflags);
+		ret = -ENOSPC;
+		goto out_err_gdom_info;
+	}
+
+	ndom->gdom_info = gdom_info;
+	refcount_set(&gdom_info->users, 1);
+
+	xa_unlock_irqrestore(&aviommu->gdomid_array, irqflags);
+
+	pr_debug("%s: Allocate gdom_id=%#x, hdom_id=%#x\n",
+		 __func__, ndom->gdom_id, gdom_info->hdom_id);
+
+	return &ndom->domain;
+
+out_err_gdom_info:
+	kfree(gdom_info);
+out_err:
+	kfree(ndom);
+	return ERR_PTR(ret);
+}
+
+static void set_dte_nested(struct amd_iommu *iommu, struct iommu_domain *dom,
+			   struct iommu_dev_data *dev_data, struct dev_table_entry *new)
+{
+	struct protection_domain *parent;
+	struct nested_domain *ndom = to_ndomain(dom);
+	struct iommu_hwpt_amd_guest *gdte = &ndom->gdte;
+	struct pt_iommu_amdv1_hw_info pt_info;
+
+	/*
+	 * The nest parent domain is attached during the call to the
+	 * struct iommu_ops.viommu_init(), which will be stored as part
+	 * of the struct amd_iommu_viommu.parent.
+	 */
+	if (WARN_ON(!ndom->viommu || !ndom->viommu->parent))
+		return;
+
+	parent = ndom->viommu->parent;
+	amd_iommu_make_clear_dte(dev_data, new);
+
+	/* Retrieve the current pagetable info via the IOMMU PT API. */
+	pt_iommu_amdv1_hw_info(&parent->amdv1, &pt_info);
+
+	/*
+	 * Use domain ID from nested domain to program DTE.
+	 * See amd_iommu_alloc_domain_nested().
+	 */
+	amd_iommu_set_dte_v1(dev_data, parent, ndom->gdom_info->hdom_id,
+			     &pt_info, new);
+
+	/* GV is required for nested page table */
+	new->data[0] |= DTE_FLAG_GV;
+
+	/* Guest PPR */
+	new->data[0] |= gdte->dte[0] & DTE_FLAG_PPR;
+
+	/* Guest translation stuff */
+	new->data[0] |= gdte->dte[0] & (DTE_GLX | DTE_FLAG_GIOV);
+
+	/* GCR3 table */
+	new->data[0] |= gdte->dte[0] & DTE_GCR3_14_12;
+	new->data[1] |= gdte->dte[1] & (DTE_GCR3_30_15 | DTE_GCR3_51_31);
+
+	/* Guest paging mode */
+	new->data[2] |= gdte->dte[2] & DTE_GPT_LEVEL_MASK;
+}
+
+static int nested_attach_device(struct iommu_domain *dom, struct device *dev,
+				struct iommu_domain *old)
+{
+	struct dev_table_entry new = {0};
+	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
+	struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data);
+	int ret = 0;
+
+	/*
+	 * Needs to make sure PASID is not enabled
+	 * for this attach path.
+	 */
+	if (WARN_ON(dev_data->pasid_enabled))
+		return -EINVAL;
+
+	mutex_lock(&dev_data->mutex);
+
+	set_dte_nested(iommu, dom, dev_data, &new);
+
+	amd_iommu_update_dte(iommu, dev_data, &new);
+
+	mutex_unlock(&dev_data->mutex);
+
+	return ret;
+}
+
+static void nested_domain_free(struct iommu_domain *dom)
+{
+	unsigned long irqflags;
+	struct guest_domain_mapping_info *curr;
+	struct nested_domain *ndom __free(kfree) = to_ndomain(dom);
+	struct amd_iommu_viommu *aviommu = ndom->viommu;
+
+	xa_lock_irqsave(&aviommu->gdomid_array, irqflags);
+
+	if (!refcount_dec_and_test(&ndom->gdom_info->users)) {
+		xa_unlock_irqrestore(&aviommu->gdomid_array, irqflags);
+		return;
+	}
+
+	/*
+	 * The refcount for the gdom_id to hdom_id mapping is zero.
+	 * It is now safe to remove the mapping.
+	 */
+	curr = __xa_cmpxchg(&aviommu->gdomid_array, ndom->gdom_id,
+			    ndom->gdom_info, NULL, GFP_ATOMIC);
+
+	xa_unlock_irqrestore(&aviommu->gdomid_array, irqflags);
+	if (WARN_ON(!curr || xa_err(curr)))
+		return;
+
+	/* success */
+	pr_debug("%s: Free gdom_id=%#x, hdom_id=%#x\n",
+		__func__, ndom->gdom_id, curr->hdom_id);
+
+	amd_iommu_pdom_id_free(ndom->gdom_info->hdom_id);
+	kfree(curr);
+}
+
+static const struct iommu_domain_ops nested_domain_ops = {
+	.attach_dev = nested_attach_device,
+	.free = nested_domain_free,
+};