vfio/pci: Replace vfio_pci_core_setup_barmap() with vfio_pci_core_get_iomap()

Since "vfio/pci: Set up barmap in vfio_pci_core_enable()", the
resource request and iomap for the BARs was performed early, and
vfio_pci_core_setup_barmap() just checks those actions succeeded.

Move this logic to a new helper that checks success and returns the
iomap address, replacing the various bare vdev->barmap[] lookups.
This maintains the error behaviour of the previous on-demand
vfio_pci_core_setup_barmap() scheme.

Signed-off-by: Matt Evans <mattev@meta.com>
Link: https://lore.kernel.org/r/20260511145829.2993601-4-mattev@meta.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

diff --git a/drivers/vfio/pci/nvgrace-gpu/main.c b/drivers/vfio/pci/nvgrace-gpu/main.c
index fa056b69f899a4bf214bb4902fd02f1068049330..15e2f03c6cd44d058c01868d444f90cbb9de5aa7 100644 (file)
--- a/drivers/vfio/pci/nvgrace-gpu/main.c
+++ b/drivers/vfio/pci/nvgrace-gpu/main.c
@@ -61,6 +61,7 @@ struct nvgrace_gpu_pci_core_device {
        struct mem_region resmem;
        /* Lock to control device memory kernel mapping */
        struct mutex remap_lock;
+       void __iomem *bar0_base;
        bool has_mig_hw_bug;
        /* GPU has just been reset */
        bool reset_done;
@@ -171,6 +172,7 @@ static int nvgrace_gpu_open_device(struct vfio_device *core_vdev)
        struct nvgrace_gpu_pci_core_device *nvdev =
                container_of(core_vdev, struct nvgrace_gpu_pci_core_device,
                             core_device.vdev);
+       void __iomem *io;
        int ret;
 
        ret = vfio_pci_core_enable(vdev);
@@ -184,14 +186,14 @@ static int nvgrace_gpu_open_device(struct vfio_device *core_vdev)
 
        /*
         * GPU readiness is checked by reading the BAR0 registers.
-        *
-        * ioremap BAR0 to ensure that the BAR0 mapping is present before
-        * register reads on first fault before establishing any GPU
-        * memory mapping.
+        * The BAR map was just set up by vfio_pci_core_enable(), so
+        * bail early if that wasn't successful:
         */
-       ret = vfio_pci_core_setup_barmap(vdev, 0);
-       if (ret)
+       io = vfio_pci_core_get_iomap(vdev, 0);
+       if (IS_ERR(io)) {
+               ret = PTR_ERR(io);
                goto error_exit;
+       }
 
        if (nvdev->resmem.memlength) {
                ret = nvgrace_gpu_vfio_pci_register_pfn_range(core_vdev, &nvdev->resmem);
@@ -204,6 +206,8 @@ static int nvgrace_gpu_open_device(struct vfio_device *core_vdev)
                goto register_mem_failed;
 
        vfio_pci_core_finish_enable(vdev);
+       nvdev->bar0_base = io;
+
        return 0;
 
 register_mem_failed:
@@ -220,6 +224,8 @@ static void nvgrace_gpu_close_device(struct vfio_device *core_vdev)
                container_of(core_vdev, struct nvgrace_gpu_pci_core_device,
                             core_device.vdev);
 
+       nvdev->bar0_base = NULL;
+
        if (nvdev->resmem.memlength)
                unregister_pfn_address_space(&nvdev->resmem.pfn_address_space);
 
@@ -275,7 +281,7 @@ nvgrace_gpu_check_device_ready(struct nvgrace_gpu_pci_core_device *nvdev)
        if (!__vfio_pci_memory_enabled(vdev))
                return -EIO;
 
-       ret = nvgrace_gpu_wait_device_ready(vdev->barmap[0]);
+       ret = nvgrace_gpu_wait_device_ready(nvdev->bar0_base);
        if (ret)
                return ret;
 

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 050e7542952ed150023d7e1c408d957efb288999..041243a84d8171271d47544f317b883501493ed6 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1762,7 +1762,7 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
        struct pci_dev *pdev = vdev->pdev;
        unsigned int index;
        u64 phys_len, req_len, pgoff, req_start;
-       int ret;
+       void __iomem *bar_io;
 
        index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);
 
@@ -1796,12 +1796,11 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
                return -EINVAL;
 
        /*
-        * Even though we don't make use of the barmap for the mmap,
-        * we need to request the region and the barmap tracks that.
+        * Ensure the BAR resource region is reserved for use.
         */
-       ret = vfio_pci_core_setup_barmap(vdev, index);
-       if (ret)
-               return ret;
+       bar_io = vfio_pci_core_get_iomap(vdev, index);
+       if (IS_ERR(bar_io))
+               return PTR_ERR(bar_io);
 
        vma->vm_private_data = vdev;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
index 1a177ce7de546aa388783f7100f78cefd5365f86..c16f460c01d681200809ca45742ab8102aa5664b 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_dmabuf.c
+++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
@@ -248,7 +248,7 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
         * else.  Check that PCI resources have been claimed for it.
         */
        if (get_dma_buf.region_index >= VFIO_PCI_ROM_REGION_INDEX ||
-           vfio_pci_core_setup_barmap(vdev, get_dma_buf.region_index))
+           IS_ERR(vfio_pci_core_get_iomap(vdev, get_dma_buf.region_index)))
                return -ENODEV;
 
        dma_ranges = memdup_array_user(&arg->dma_ranges, get_dma_buf.nr_ranges,

diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index 3bfbb879a00513c7a9539f5f0fda1ce6f74aa157..7f14dd46de17a072be8722a12a39945113d6b25e 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -198,19 +198,6 @@ ssize_t vfio_pci_core_do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
 }
 EXPORT_SYMBOL_GPL(vfio_pci_core_do_io_rw);
 
-/*
- * The barmap is set up in vfio_pci_core_enable().  Callers use this
- * function to check that the BAR resources are requested or that the
- * pci_iomap() was done.
- */
-int vfio_pci_core_setup_barmap(struct vfio_pci_core_device *vdev, int bar)
-{
-       if (IS_ERR(vdev->barmap[bar]))
-               return PTR_ERR(vdev->barmap[bar]);
-       return 0;
-}
-EXPORT_SYMBOL_GPL(vfio_pci_core_setup_barmap);
-
 ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
                        size_t count, loff_t *ppos, bool iswrite)
 {
@@ -262,13 +249,11 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
                 */
                max_width = VFIO_PCI_IO_WIDTH_4;
        } else {
-               int ret = vfio_pci_core_setup_barmap(vdev, bar);
-               if (ret) {
-                       done = ret;
+               io = vfio_pci_core_get_iomap(vdev, bar);
+               if (IS_ERR(io)) {
+                       done = PTR_ERR(io);
                        goto out;
                }
-
-               io = vdev->barmap[bar];
        }
 
        if (bar == vdev->msix_bar) {
@@ -423,6 +408,7 @@ int vfio_pci_ioeventfd(struct vfio_pci_core_device *vdev, loff_t offset,
        loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
        int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
        struct vfio_pci_ioeventfd *ioeventfd;
+       void __iomem *io;
 
        /* Only support ioeventfds into BARs */
        if (bar > VFIO_PCI_BAR5_REGION_INDEX)
@@ -440,9 +426,9 @@ int vfio_pci_ioeventfd(struct vfio_pci_core_device *vdev, loff_t offset,
        if (count == 8)
                return -EINVAL;
 
-       ret = vfio_pci_core_setup_barmap(vdev, bar);
-       if (ret)
-               return ret;
+       io = vfio_pci_core_get_iomap(vdev, bar);
+       if (IS_ERR(io))
+               return PTR_ERR(io);
 
        mutex_lock(&vdev->ioeventfds_lock);
 
@@ -479,7 +465,7 @@ int vfio_pci_ioeventfd(struct vfio_pci_core_device *vdev, loff_t offset,
        }
 
        ioeventfd->vdev = vdev;
-       ioeventfd->addr = vdev->barmap[bar] + pos;
+       ioeventfd->addr = io + pos;
        ioeventfd->data = data;
        ioeventfd->pos = pos;
        ioeventfd->bar = bar;

diff --git a/drivers/vfio/pci/virtio/legacy_io.c b/drivers/vfio/pci/virtio/legacy_io.c
index f022301e60d6e888d5cc4dcd2fad46bb81391b66..74ff302edc9f0384889d4f8b6675fcba29b0fab0 100644 (file)
--- a/drivers/vfio/pci/virtio/legacy_io.c
+++ b/drivers/vfio/pci/virtio/legacy_io.c
@@ -298,19 +298,18 @@ int virtiovf_pci_ioctl_get_region_info(struct vfio_device *core_vdev,
 static int virtiovf_set_notify_addr(struct virtiovf_pci_core_device *virtvdev)
 {
        struct vfio_pci_core_device *core_device = &virtvdev->core_device;
-       int ret;
+       void __iomem *io;
 
        /*
         * Setup the BAR where the 'notify' exists to be used by vfio as well
         * This will let us mmap it only once and use it when needed.
         */
-       ret = vfio_pci_core_setup_barmap(core_device,
-                                        virtvdev->notify_bar);
-       if (ret)
-               return ret;
+       io = vfio_pci_core_get_iomap(core_device,
+                                    virtvdev->notify_bar);
+       if (IS_ERR(io))
+               return PTR_ERR(io);
 
-       virtvdev->notify_addr = core_device->barmap[virtvdev->notify_bar] +
-                       virtvdev->notify_offset;
+       virtvdev->notify_addr = io + virtvdev->notify_offset;
        return 0;
 }
 

diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 89165b769e5c168a043bece8b995702627067002..7accd0eac457d354d47b8eef707da3faacc38de1 100644 (file)
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -188,7 +188,6 @@ int vfio_pci_core_match_token_uuid(struct vfio_device *core_vdev,
 int vfio_pci_core_enable(struct vfio_pci_core_device *vdev);
 void vfio_pci_core_disable(struct vfio_pci_core_device *vdev);
 void vfio_pci_core_finish_enable(struct vfio_pci_core_device *vdev);
-int vfio_pci_core_setup_barmap(struct vfio_pci_core_device *vdev, int bar);
 pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
                                                pci_channel_state_t state);
 ssize_t vfio_pci_core_do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
@@ -234,6 +233,25 @@ static inline bool is_aligned_for_order(struct vm_area_struct *vma,
                           !IS_ALIGNED(pfn, 1 << order)));
 }
 
+/*
+ * Returns a BAR's iomap base or an ERR_PTR() if, for example, the
+ * BAR isn't valid, its resource wasn't acquired, or its iomap
+ * failed.  This shall only be used after vfio_pci_core_enable()
+ * has set up the BAR maps and before vfio_pci_core_disable()
+ * tears them down.
+ */
+static inline void __iomem __must_check *
+vfio_pci_core_get_iomap(struct vfio_pci_core_device *vdev, unsigned int bar)
+{
+       if (WARN_ON_ONCE(bar >= PCI_STD_NUM_BARS))
+               return ERR_PTR(-EINVAL);
+
+       if (WARN_ON_ONCE(!vdev->barmap[bar]))
+               return ERR_PTR(-ENODEV);
+
+       return vdev->barmap[bar];
+}
+
 int vfio_pci_dma_buf_iommufd_map(struct dma_buf_attachment *attachment,
                                 struct phys_vec *phys);