[PULL 10/16] backends/iommufd: Add a helper to invalidate user-managed HWPT

["Cédric Le Goater" <clg@redhat.com>]

From: Zhenzhong Duan <zhenzhong.duan@intel.com>

This helper passes cache invalidation request from guest to invalidate
stage-1 page table cache in host hardware.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250604062115.4004200-2-zhenzhong.duan@intel.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 include/system/iommufd.h |  4 ++++
 backends/iommufd.c       | 36 ++++++++++++++++++++++++++++++++++++
 backends/trace-events    |  1 +
 3 files changed, 41 insertions(+)

diff --git a/include/system/iommufd.h b/include/system/iommufd.h
index cbab75bfbf67fe75e97dffbbbd2d98caca7f7c5e..83ab8e1e4ca034ecad07e08d55ef3cb5183b1fe2 100644
--- a/include/system/iommufd.h
+++ b/include/system/iommufd.h
@@ -61,6 +61,10 @@ bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,
                                       uint64_t iova, ram_addr_t size,
                                       uint64_t page_size, uint64_t *data,
                                       Error **errp);
+bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
+                                      uint32_t data_type, uint32_t entry_len,
+                                      uint32_t *entry_num, void *data,
+                                      Error **errp);
 
 #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
 #endif
diff --git a/backends/iommufd.c b/backends/iommufd.c
index b73f75cd0bca694267e8c54af9750f08cd305a50..8bcdb60fe7ee439503f0fcc4d65d50c5916dcf1f 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -311,6 +311,42 @@ bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
     return true;
 }
 
+bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
+                                      uint32_t data_type, uint32_t entry_len,
+                                      uint32_t *entry_num, void *data,
+                                      Error **errp)
+{
+    int ret, fd = be->fd;
+    uint32_t total_entries = *entry_num;
+    struct iommu_hwpt_invalidate cache = {
+        .size = sizeof(cache),
+        .hwpt_id = id,
+        .data_type = data_type,
+        .entry_len = entry_len,
+        .entry_num = total_entries,
+        .data_uptr = (uintptr_t)data,
+    };
+
+    ret = ioctl(fd, IOMMU_HWPT_INVALIDATE, &cache);
+    trace_iommufd_backend_invalidate_cache(fd, id, data_type, entry_len,
+                                           total_entries, cache.entry_num,
+                                           (uintptr_t)data, ret ? errno : 0);
+    *entry_num = cache.entry_num;
+
+    if (ret) {
+        error_setg_errno(errp, errno, "IOMMU_HWPT_INVALIDATE failed:"
+                         " total %d entries, processed %d entries",
+                         total_entries, cache.entry_num);
+    } else if (total_entries != cache.entry_num) {
+        error_setg(errp, "IOMMU_HWPT_INVALIDATE succeed but with unprocessed"
+                         " entries: total %d entries, processed %d entries."
+                         " Kernel BUG?!", total_entries, cache.entry_num);
+        return false;
+    }
+
+    return !ret;
+}
+
 static int hiod_iommufd_get_cap(HostIOMMUDevice *hiod, int cap, Error **errp)
 {
     HostIOMMUDeviceCaps *caps = &hiod->caps;
diff --git a/backends/trace-events b/backends/trace-events
index 40811a316215bad7b8554cedf3b8ba1968a6fbfe..7278214ea51144b7d7b36d64908567c9467036e8 100644
--- a/backends/trace-events
+++ b/backends/trace-events
@@ -18,3 +18,4 @@ iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id, uint32_t pt_id, uint32_
 iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d id=%d (%d)"
 iommufd_backend_set_dirty(int iommufd, uint32_t hwpt_id, bool start, int ret) " iommufd=%d hwpt=%u enable=%d (%d)"
 iommufd_backend_get_dirty_bitmap(int iommufd, uint32_t hwpt_id, uint64_t iova, uint64_t size, uint64_t page_size, int ret) " iommufd=%d hwpt=%u iova=0x%"PRIx64" size=0x%"PRIx64" page_size=0x%"PRIx64" (%d)"
+iommufd_backend_invalidate_cache(int iommufd, uint32_t id, uint32_t data_type, uint32_t entry_len, uint32_t entry_num, uint32_t done_num, uint64_t data_ptr, int ret) " iommufd=%d id=%u data_type=%u entry_len=%u entry_num=%u done_num=%u data_ptr=0x%"PRIx64" (%d)"
-- 
2.49.0