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path: root/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
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Diffstat (limited to 'drivers/gpu/drm/vmwgfx/vmwgfx_msg.c')
-rw-r--r--drivers/gpu/drm/vmwgfx/vmwgfx_msg.c579
1 files changed, 579 insertions, 0 deletions
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
index 3d08f5700bdb..4218fe00e3b1 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
@@ -31,10 +31,12 @@
#include <linux/mem_encrypt.h>
#include <asm/hypervisor.h>
+#include <drm/drm_ioctl.h>
#include "vmwgfx_drv.h"
#include "vmwgfx_msg_x86.h"
#include "vmwgfx_msg_arm64.h"
+#include "vmwgfx_mksstat.h"
#define MESSAGE_STATUS_SUCCESS 0x0001
#define MESSAGE_STATUS_DORECV 0x0002
@@ -56,6 +58,11 @@
#define VMW_PORT_CMD_RECVSIZE (MSG_TYPE_RECVSIZE << 16 | VMW_PORT_CMD_MSG)
#define VMW_PORT_CMD_RECVSTATUS (MSG_TYPE_RECVSTATUS << 16 | VMW_PORT_CMD_MSG)
+#define VMW_PORT_CMD_MKS_GUEST_STATS 85
+#define VMW_PORT_CMD_MKSGS_RESET (0 << 16 | VMW_PORT_CMD_MKS_GUEST_STATS)
+#define VMW_PORT_CMD_MKSGS_ADD_PPN (1 << 16 | VMW_PORT_CMD_MKS_GUEST_STATS)
+#define VMW_PORT_CMD_MKSGS_REMOVE_PPN (2 << 16 | VMW_PORT_CMD_MKS_GUEST_STATS)
+
#define HIGH_WORD(X) ((X & 0xFFFF0000) >> 16)
#define MAX_USER_MSG_LENGTH PAGE_SIZE
@@ -612,3 +619,575 @@ out_open:
return -EINVAL;
}
+
+/**
+ * reset_ppn_array: Resets a PPN64 array to INVALID_PPN64 content
+ *
+ * @arr: Array to reset.
+ * @size: Array length.
+ */
+static inline void reset_ppn_array(PPN64 *arr, size_t size)
+{
+ size_t i;
+
+ BUG_ON(!arr || size == 0);
+
+ for (i = 0; i < size; ++i)
+ arr[i] = INVALID_PPN64;
+}
+
+/**
+ * hypervisor_ppn_reset_all: Removes all mksGuestStat instance descriptors from
+ * the hypervisor. All related pages should be subsequently unpinned or freed.
+ *
+ */
+static inline void hypervisor_ppn_reset_all(void)
+{
+ unsigned long eax, ebx, ecx, edx, si = 0, di = 0;
+
+ VMW_PORT(VMW_PORT_CMD_MKSGS_RESET,
+ 0, si, di,
+ 0,
+ VMW_HYPERVISOR_MAGIC,
+ eax, ebx, ecx, edx, si, di);
+}
+
+/**
+ * hypervisor_ppn_add: Adds a single mksGuestStat instance descriptor to the
+ * hypervisor. Any related userspace pages should be pinned in advance.
+ *
+ * @pfn: Physical page number of the instance descriptor
+ */
+static inline void hypervisor_ppn_add(PPN64 pfn)
+{
+ unsigned long eax, ebx, ecx, edx, si = 0, di = 0;
+
+ VMW_PORT(VMW_PORT_CMD_MKSGS_ADD_PPN,
+ pfn, si, di,
+ 0,
+ VMW_HYPERVISOR_MAGIC,
+ eax, ebx, ecx, edx, si, di);
+}
+
+/**
+ * hypervisor_ppn_remove: Removes a single mksGuestStat instance descriptor from
+ * the hypervisor. All related pages should be subsequently unpinned or freed.
+ *
+ * @pfn: Physical page number of the instance descriptor
+ */
+static inline void hypervisor_ppn_remove(PPN64 pfn)
+{
+ unsigned long eax, ebx, ecx, edx, si = 0, di = 0;
+
+ VMW_PORT(VMW_PORT_CMD_MKSGS_REMOVE_PPN,
+ pfn, si, di,
+ 0,
+ VMW_HYPERVISOR_MAGIC,
+ eax, ebx, ecx, edx, si, di);
+}
+
+#if IS_ENABLED(CONFIG_DRM_VMWGFX_MKSSTATS)
+
+/* Order of the total number of pages used for kernel-internal mksGuestStat; at least 2 */
+#define MKSSTAT_KERNEL_PAGES_ORDER 2
+/* Header to the text description of mksGuestStat instance descriptor */
+#define MKSSTAT_KERNEL_DESCRIPTION "vmwgfx"
+
+/* Kernel mksGuestStats counter names and desciptions; same order as enum mksstat_kern_stats_t */
+static const char* const mksstat_kern_name_desc[MKSSTAT_KERN_COUNT][2] =
+{
+ { "vmw_execbuf_ioctl", "vmw_execbuf_ioctl" },
+};
+
+/**
+ * mksstat_init_record: Initializes an MKSGuestStatCounter-based record
+ * for the respective mksGuestStat index.
+ *
+ * @stat_idx: Index of the MKSGuestStatCounter-based mksGuestStat record.
+ * @pstat: Pointer to array of MKSGuestStatCounterTime.
+ * @pinfo: Pointer to array of MKSGuestStatInfoEntry.
+ * @pstrs: Pointer to current end of the name/description sequence.
+ * Return: Pointer to the new end of the names/description sequence.
+ */
+
+static inline char *mksstat_init_record(mksstat_kern_stats_t stat_idx,
+ MKSGuestStatCounterTime *pstat, MKSGuestStatInfoEntry *pinfo, char *pstrs)
+{
+ char *const pstrd = pstrs + strlen(mksstat_kern_name_desc[stat_idx][0]) + 1;
+ strcpy(pstrs, mksstat_kern_name_desc[stat_idx][0]);
+ strcpy(pstrd, mksstat_kern_name_desc[stat_idx][1]);
+
+ pinfo[stat_idx].name.s = pstrs;
+ pinfo[stat_idx].description.s = pstrd;
+ pinfo[stat_idx].flags = MKS_GUEST_STAT_FLAG_NONE;
+ pinfo[stat_idx].stat.counter = (MKSGuestStatCounter *)&pstat[stat_idx];
+
+ return pstrd + strlen(mksstat_kern_name_desc[stat_idx][1]) + 1;
+}
+
+/**
+ * mksstat_init_record_time: Initializes an MKSGuestStatCounterTime-based record
+ * for the respective mksGuestStat index.
+ *
+ * @stat_idx: Index of the MKSGuestStatCounterTime-based mksGuestStat record.
+ * @pstat: Pointer to array of MKSGuestStatCounterTime.
+ * @pinfo: Pointer to array of MKSGuestStatInfoEntry.
+ * @pstrs: Pointer to current end of the name/description sequence.
+ * Return: Pointer to the new end of the names/description sequence.
+ */
+
+static inline char *mksstat_init_record_time(mksstat_kern_stats_t stat_idx,
+ MKSGuestStatCounterTime *pstat, MKSGuestStatInfoEntry *pinfo, char *pstrs)
+{
+ char *const pstrd = pstrs + strlen(mksstat_kern_name_desc[stat_idx][0]) + 1;
+ strcpy(pstrs, mksstat_kern_name_desc[stat_idx][0]);
+ strcpy(pstrd, mksstat_kern_name_desc[stat_idx][1]);
+
+ pinfo[stat_idx].name.s = pstrs;
+ pinfo[stat_idx].description.s = pstrd;
+ pinfo[stat_idx].flags = MKS_GUEST_STAT_FLAG_TIME;
+ pinfo[stat_idx].stat.counterTime = &pstat[stat_idx];
+
+ return pstrd + strlen(mksstat_kern_name_desc[stat_idx][1]) + 1;
+}
+
+/**
+ * mksstat_init_kern_id: Creates a single mksGuestStat instance descriptor and
+ * kernel-internal counters. Adds PFN mapping to the hypervisor.
+ *
+ * Create a single mksGuestStat instance descriptor and corresponding structures
+ * for all kernel-internal counters. The corresponding PFNs are mapped with the
+ * hypervisor.
+ *
+ * @ppage: Output pointer to page containing the instance descriptor.
+ * Return: Zero on success, negative error code on error.
+ */
+
+static int mksstat_init_kern_id(struct page **ppage)
+{
+ MKSGuestStatInstanceDescriptor *pdesc;
+ MKSGuestStatCounterTime *pstat;
+ MKSGuestStatInfoEntry *pinfo;
+ char *pstrs, *pstrs_acc;
+
+ /* Allocate pages for the kernel-internal instance descriptor */
+ struct page *page = alloc_pages(GFP_KERNEL | __GFP_ZERO, MKSSTAT_KERNEL_PAGES_ORDER);
+
+ if (!page)
+ return -ENOMEM;
+
+ pdesc = page_address(page);
+ pstat = vmw_mksstat_get_kern_pstat(pdesc);
+ pinfo = vmw_mksstat_get_kern_pinfo(pdesc);
+ pstrs = vmw_mksstat_get_kern_pstrs(pdesc);
+
+ /* Set up all kernel-internal counters and corresponding structures */
+ pstrs_acc = pstrs;
+ pstrs_acc = mksstat_init_record_time(MKSSTAT_KERN_EXECBUF, pstat, pinfo, pstrs_acc);
+
+ /* Add new counters above, in their order of appearance in mksstat_kern_stats_t */
+
+ BUG_ON(pstrs_acc - pstrs > PAGE_SIZE);
+
+ /* Set up the kernel-internal instance descriptor */
+ pdesc->reservedMBZ = 0;
+ pdesc->statStartVA = (uintptr_t)pstat;
+ pdesc->strsStartVA = (uintptr_t)pstrs;
+ pdesc->statLength = sizeof(*pstat) * MKSSTAT_KERN_COUNT;
+ pdesc->infoLength = sizeof(*pinfo) * MKSSTAT_KERN_COUNT;
+ pdesc->strsLength = pstrs_acc - pstrs;
+ snprintf(pdesc->description, ARRAY_SIZE(pdesc->description) - 1, "%s pid=%d",
+ MKSSTAT_KERNEL_DESCRIPTION, current->pid);
+
+ pdesc->statPPNs[0] = page_to_pfn(virt_to_page(pstat));
+ reset_ppn_array(pdesc->statPPNs + 1, ARRAY_SIZE(pdesc->statPPNs) - 1);
+
+ pdesc->infoPPNs[0] = page_to_pfn(virt_to_page(pinfo));
+ reset_ppn_array(pdesc->infoPPNs + 1, ARRAY_SIZE(pdesc->infoPPNs) - 1);
+
+ pdesc->strsPPNs[0] = page_to_pfn(virt_to_page(pstrs));
+ reset_ppn_array(pdesc->strsPPNs + 1, ARRAY_SIZE(pdesc->strsPPNs) - 1);
+
+ *ppage = page;
+
+ hypervisor_ppn_add((PPN64)page_to_pfn(page));
+
+ return 0;
+}
+
+/**
+ * vmw_mksstat_get_kern_slot: Acquires a slot for a single kernel-internal
+ * mksGuestStat instance descriptor.
+ *
+ * Find a slot for a single kernel-internal mksGuestStat instance descriptor.
+ * In case no such was already present, allocate a new one and set up a kernel-
+ * internal mksGuestStat instance descriptor for the former.
+ *
+ * @pid: Process for which a slot is sought.
+ * @dev_priv: Identifies the drm private device.
+ * Return: Non-negative slot on success, negative error code on error.
+ */
+
+int vmw_mksstat_get_kern_slot(pid_t pid, struct vmw_private *dev_priv)
+{
+ const size_t base = (u32)hash_32(pid, MKSSTAT_CAPACITY_LOG2);
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(dev_priv->mksstat_kern_pids); ++i) {
+ const size_t slot = (i + base) % ARRAY_SIZE(dev_priv->mksstat_kern_pids);
+
+ /* Check if an instance descriptor for this pid is already present */
+ if (pid == (pid_t)atomic_read(&dev_priv->mksstat_kern_pids[slot]))
+ return (int)slot;
+
+ /* Set up a new instance descriptor for this pid */
+ if (!atomic_cmpxchg(&dev_priv->mksstat_kern_pids[slot], 0, MKSSTAT_PID_RESERVED)) {
+ const int ret = mksstat_init_kern_id(&dev_priv->mksstat_kern_pages[slot]);
+
+ if (!ret) {
+ /* Reset top-timer tracking for this slot */
+ dev_priv->mksstat_kern_top_timer[slot] = MKSSTAT_KERN_COUNT;
+
+ atomic_set(&dev_priv->mksstat_kern_pids[slot], pid);
+ return (int)slot;
+ }
+
+ atomic_set(&dev_priv->mksstat_kern_pids[slot], 0);
+ return ret;
+ }
+ }
+
+ return -ENOSPC;
+}
+
+#endif
+
+/**
+ * vmw_mksstat_cleanup_descriptor: Frees a single userspace-originating
+ * mksGuestStat instance-descriptor page and unpins all related user pages.
+ *
+ * Unpin all user pages realated to this instance descriptor and free
+ * the instance-descriptor page itself.
+ *
+ * @page: Page of the instance descriptor.
+ */
+
+static void vmw_mksstat_cleanup_descriptor(struct page *page)
+{
+ MKSGuestStatInstanceDescriptor *pdesc = page_address(page);
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(pdesc->statPPNs) && pdesc->statPPNs[i] != INVALID_PPN64; ++i)
+ unpin_user_page(pfn_to_page(pdesc->statPPNs[i]));
+
+ for (i = 0; i < ARRAY_SIZE(pdesc->infoPPNs) && pdesc->infoPPNs[i] != INVALID_PPN64; ++i)
+ unpin_user_page(pfn_to_page(pdesc->infoPPNs[i]));
+
+ for (i = 0; i < ARRAY_SIZE(pdesc->strsPPNs) && pdesc->strsPPNs[i] != INVALID_PPN64; ++i)
+ unpin_user_page(pfn_to_page(pdesc->strsPPNs[i]));
+
+ __free_page(page);
+}
+
+/**
+ * vmw_mksstat_remove_all: Resets all mksGuestStat instance descriptors
+ * from the hypervisor.
+ *
+ * Discard all hypervisor PFN mappings, containing active mksGuestState instance
+ * descriptors, unpin the related userspace pages and free the related kernel pages.
+ *
+ * @dev_priv: Identifies the drm private device.
+ * Return: Zero on success, negative error code on error.
+ */
+
+int vmw_mksstat_remove_all(struct vmw_private *dev_priv)
+{
+ int ret = 0;
+ size_t i;
+
+ /* Discard all PFN mappings with the hypervisor */
+ hypervisor_ppn_reset_all();
+
+ /* Discard all userspace-originating instance descriptors and unpin all related pages */
+ for (i = 0; i < ARRAY_SIZE(dev_priv->mksstat_user_pids); ++i) {
+ const pid_t pid0 = (pid_t)atomic_read(&dev_priv->mksstat_user_pids[i]);
+
+ if (!pid0)
+ continue;
+
+ if (pid0 != MKSSTAT_PID_RESERVED) {
+ const pid_t pid1 = atomic_cmpxchg(&dev_priv->mksstat_user_pids[i], pid0, MKSSTAT_PID_RESERVED);
+
+ if (!pid1)
+ continue;
+
+ if (pid1 == pid0) {
+ struct page *const page = dev_priv->mksstat_user_pages[i];
+
+ BUG_ON(!page);
+
+ dev_priv->mksstat_user_pages[i] = NULL;
+ atomic_set(&dev_priv->mksstat_user_pids[i], 0);
+
+ vmw_mksstat_cleanup_descriptor(page);
+ continue;
+ }
+ }
+
+ ret = -EAGAIN;
+ }
+
+#if IS_ENABLED(CONFIG_DRM_VMWGFX_MKSSTATS)
+ /* Discard all kernel-internal instance descriptors and free all related pages */
+ for (i = 0; i < ARRAY_SIZE(dev_priv->mksstat_kern_pids); ++i) {
+ const pid_t pid0 = (pid_t)atomic_read(&dev_priv->mksstat_kern_pids[i]);
+
+ if (!pid0)
+ continue;
+
+ if (pid0 != MKSSTAT_PID_RESERVED) {
+ const pid_t pid1 = atomic_cmpxchg(&dev_priv->mksstat_kern_pids[i], pid0, MKSSTAT_PID_RESERVED);
+
+ if (!pid1)
+ continue;
+
+ if (pid1 == pid0) {
+ struct page *const page = dev_priv->mksstat_kern_pages[i];
+
+ BUG_ON(!page);
+
+ dev_priv->mksstat_kern_pages[i] = NULL;
+ atomic_set(&dev_priv->mksstat_kern_pids[i], 0);
+
+ __free_pages(page, MKSSTAT_KERNEL_PAGES_ORDER);
+ continue;
+ }
+ }
+
+ ret = -EAGAIN;
+ }
+
+#endif
+ return ret;
+}
+
+/**
+ * vmw_mksstat_reset_ioctl: Resets all mksGuestStat instance descriptors
+ * from the hypervisor.
+ *
+ * Discard all hypervisor PFN mappings, containing active mksGuestStat instance
+ * descriptors, unpin the related userspace pages and free the related kernel pages.
+ *
+ * @dev: Identifies the drm device.
+ * @data: Pointer to the ioctl argument.
+ * @file_priv: Identifies the caller; unused.
+ * Return: Zero on success, negative error code on error.
+ */
+
+int vmw_mksstat_reset_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct vmw_private *const dev_priv = vmw_priv(dev);
+ return vmw_mksstat_remove_all(dev_priv);
+}
+
+/**
+ * vmw_mksstat_add_ioctl: Creates a single userspace-originating mksGuestStat
+ * instance descriptor and registers that with the hypervisor.
+ *
+ * Create a hypervisor PFN mapping, containing a single mksGuestStat instance
+ * descriptor and pin the corresponding userspace pages.
+ *
+ * @dev: Identifies the drm device.
+ * @data: Pointer to the ioctl argument.
+ * @file_priv: Identifies the caller; unused.
+ * Return: Zero on success, negative error code on error.
+ */
+
+int vmw_mksstat_add_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_vmw_mksstat_add_arg *arg =
+ (struct drm_vmw_mksstat_add_arg *) data;
+
+ struct vmw_private *const dev_priv = vmw_priv(dev);
+
+ struct page *page;
+ MKSGuestStatInstanceDescriptor *pdesc;
+ const size_t num_pages_stat = vmw_num_pages(arg->stat_len);
+ const size_t num_pages_info = vmw_num_pages(arg->info_len);
+ const size_t num_pages_strs = vmw_num_pages(arg->strs_len);
+ long desc_len;
+ long nr_pinned_stat;
+ long nr_pinned_info;
+ long nr_pinned_strs;
+ struct page *pages_stat[ARRAY_SIZE(pdesc->statPPNs)];
+ struct page *pages_info[ARRAY_SIZE(pdesc->infoPPNs)];
+ struct page *pages_strs[ARRAY_SIZE(pdesc->strsPPNs)];
+ size_t i, slot;
+
+ arg->id = -1;
+
+ if (!arg->stat || !arg->info || !arg->strs)
+ return -EINVAL;
+
+ if (!arg->stat_len || !arg->info_len || !arg->strs_len)
+ return -EINVAL;
+
+ if (!arg->description)
+ return -EINVAL;
+
+ if (num_pages_stat > ARRAY_SIZE(pdesc->statPPNs) ||
+ num_pages_info > ARRAY_SIZE(pdesc->infoPPNs) ||
+ num_pages_strs > ARRAY_SIZE(pdesc->strsPPNs))
+ return -EINVAL;
+
+ /* Find an available slot in the mksGuestStats user array and reserve it */
+ for (slot = 0; slot < ARRAY_SIZE(dev_priv->mksstat_user_pids); ++slot)
+ if (!atomic_cmpxchg(&dev_priv->mksstat_user_pids[slot], 0, MKSSTAT_PID_RESERVED))
+ break;
+
+ if (slot == ARRAY_SIZE(dev_priv->mksstat_user_pids))
+ return -ENOSPC;
+
+ BUG_ON(dev_priv->mksstat_user_pages[slot]);
+
+ /* Allocate a page for the instance descriptor */
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+
+ if (!page) {
+ atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
+ return -ENOMEM;
+ }
+
+ /* Set up the instance descriptor */
+ pdesc = page_address(page);
+
+ pdesc->reservedMBZ = 0;
+ pdesc->statStartVA = arg->stat;
+ pdesc->strsStartVA = arg->strs;
+ pdesc->statLength = arg->stat_len;
+ pdesc->infoLength = arg->info_len;
+ pdesc->strsLength = arg->strs_len;
+ desc_len = strncpy_from_user(pdesc->description, u64_to_user_ptr(arg->description),
+ ARRAY_SIZE(pdesc->description) - 1);
+
+ if (desc_len < 0) {
+ atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
+ return -EFAULT;
+ }
+
+ reset_ppn_array(pdesc->statPPNs, ARRAY_SIZE(pdesc->statPPNs));
+ reset_ppn_array(pdesc->infoPPNs, ARRAY_SIZE(pdesc->infoPPNs));
+ reset_ppn_array(pdesc->strsPPNs, ARRAY_SIZE(pdesc->strsPPNs));
+
+ /* Pin mksGuestStat user pages and store those in the instance descriptor */
+ nr_pinned_stat = pin_user_pages(arg->stat, num_pages_stat, FOLL_LONGTERM, pages_stat, NULL);
+ if (num_pages_stat != nr_pinned_stat)
+ goto err_pin_stat;
+
+ for (i = 0; i < num_pages_stat; ++i)
+ pdesc->statPPNs[i] = page_to_pfn(pages_stat[i]);
+
+ nr_pinned_info = pin_user_pages(arg->info, num_pages_info, FOLL_LONGTERM, pages_info, NULL);
+ if (num_pages_info != nr_pinned_info)
+ goto err_pin_info;
+
+ for (i = 0; i < num_pages_info; ++i)
+ pdesc->infoPPNs[i] = page_to_pfn(pages_info[i]);
+
+ nr_pinned_strs = pin_user_pages(arg->strs, num_pages_strs, FOLL_LONGTERM, pages_strs, NULL);
+ if (num_pages_strs != nr_pinned_strs)
+ goto err_pin_strs;
+
+ for (i = 0; i < num_pages_strs; ++i)
+ pdesc->strsPPNs[i] = page_to_pfn(pages_strs[i]);
+
+ /* Send the descriptor to the host via a hypervisor call. The mksGuestStat
+ pages will remain in use until the user requests a matching remove stats
+ or a stats reset occurs. */
+ hypervisor_ppn_add((PPN64)page_to_pfn(page));
+
+ dev_priv->mksstat_user_pages[slot] = page;
+ atomic_set(&dev_priv->mksstat_user_pids[slot], current->pid);
+
+ arg->id = slot;
+
+ DRM_DEV_INFO(dev->dev, "pid=%d arg.description='%.*s' id=%lu\n", current->pid, (int)desc_len, pdesc->description, slot);
+
+ return 0;
+
+err_pin_strs:
+ if (nr_pinned_strs > 0)
+ unpin_user_pages(pages_strs, nr_pinned_strs);
+
+err_pin_info:
+ if (nr_pinned_info > 0)
+ unpin_user_pages(pages_info, nr_pinned_info);
+
+err_pin_stat:
+ if (nr_pinned_stat > 0)
+ unpin_user_pages(pages_stat, nr_pinned_stat);
+
+ atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
+ __free_page(page);
+ return -ENOMEM;
+}
+
+/**
+ * vmw_mksstat_remove_ioctl: Removes a single userspace-originating mksGuestStat
+ * instance descriptor from the hypervisor.
+ *
+ * Discard a hypervisor PFN mapping, containing a single mksGuestStat instance
+ * descriptor and unpin the corresponding userspace pages.
+ *
+ * @dev: Identifies the drm device.
+ * @data: Pointer to the ioctl argument.
+ * @file_priv: Identifies the caller; unused.
+ * Return: Zero on success, negative error code on error.
+ */
+
+int vmw_mksstat_remove_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_vmw_mksstat_remove_arg *arg =
+ (struct drm_vmw_mksstat_remove_arg *) data;
+
+ struct vmw_private *const dev_priv = vmw_priv(dev);
+
+ const size_t slot = arg->id;
+ pid_t pid0;
+
+ if (slot >= ARRAY_SIZE(dev_priv->mksstat_user_pids))
+ return -EINVAL;
+
+ DRM_DEV_INFO(dev->dev, "pid=%d arg.id=%lu\n", current->pid, slot);
+
+ pid0 = atomic_read(&dev_priv->mksstat_user_pids[slot]);
+
+ if (!pid0)
+ return 0;
+
+ if (pid0 != MKSSTAT_PID_RESERVED) {
+ const pid_t pid1 = atomic_cmpxchg(&dev_priv->mksstat_user_pids[slot], pid0, MKSSTAT_PID_RESERVED);
+
+ if (!pid1)
+ return 0;
+
+ if (pid1 == pid0) {
+ struct page *const page = dev_priv->mksstat_user_pages[slot];
+
+ BUG_ON(!page);
+
+ dev_priv->mksstat_user_pages[slot] = NULL;
+ atomic_set(&dev_priv->mksstat_user_pids[slot], 0);
+
+ hypervisor_ppn_remove((PPN64)page_to_pfn(page));
+
+ vmw_mksstat_cleanup_descriptor(page);
+ return 0;
+ }
+ }
+
+ return -EAGAIN;
+}