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Date: Wed, 5 Apr 2023 11:01:34 -0700
From: <ankita@...dia.com>
To: <ankita@...dia.com>, <jgg@...dia.com>,
<alex.williamson@...hat.com>, <naoya.horiguchi@....com>,
<maz@...nel.org>, <oliver.upton@...ux.dev>
CC: <aniketa@...dia.com>, <cjia@...dia.com>, <kwankhede@...dia.com>,
<targupta@...dia.com>, <vsethi@...dia.com>, <acurrid@...dia.com>,
<apopple@...dia.com>, <jhubbard@...dia.com>, <danw@...dia.com>,
<kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <linux-mm@...ck.org>
Subject: [PATCH v3 6/6] vfio/nvgpu: register device memory for poison handling
From: Ankit Agrawal <ankita@...dia.com>
The nvgpu-vfio-pci module maps QEMU VMA to device memory through
remap_pfn_range(). The new mechanism to handle poison on memory not backed
by struct page is leveraged here.
nvgpu-vfio-pci defines a function pfn_memory_failure() to get the ECC PFN
from the MM. The function is registered with kernel MM along with the
address space and PFN range through register_pfn_address_space().
Track poisoned PFN in the nvgpu-vfio-pci module as bitmap with a bit per
PFN. The PFN is communicated by the kernel MM to the module through the
failure function, which sets the appropriate bit in the bitmap.
Register a VMA fault ops for the module. It returns VM_FAULT_HWPOISON
in case the bit for the PFN is set in the bitmap.
Clear bitmap on reset to reflect the clean state of the device memory
after reset.
Signed-off-by: Ankit Agrawal <ankita@...dia.com>
---
drivers/vfio/pci/nvgpu/main.c | 116 ++++++++++++++++++++++++++++++++--
1 file changed, 110 insertions(+), 6 deletions(-)
diff --git a/drivers/vfio/pci/nvgpu/main.c b/drivers/vfio/pci/nvgpu/main.c
index 2dd8cc6e0145..8ccd3fe33a0f 100644
--- a/drivers/vfio/pci/nvgpu/main.c
+++ b/drivers/vfio/pci/nvgpu/main.c
@@ -5,6 +5,8 @@
#include <linux/pci.h>
#include <linux/vfio_pci_core.h>
+#include <linux/bitmap.h>
+#include <linux/memory-failure.h>
#define DUMMY_PFN \
(((nvdev->mem_prop.hpa + nvdev->mem_prop.mem_length) >> PAGE_SHIFT) - 1)
@@ -12,12 +14,78 @@
struct dev_mem_properties {
uint64_t hpa;
uint64_t mem_length;
+ unsigned long *pfn_bitmap;
int bar1_start_offset;
};
struct nvgpu_vfio_pci_core_device {
struct vfio_pci_core_device core_device;
struct dev_mem_properties mem_prop;
+ struct pfn_address_space pfn_address_space;
+};
+
+void nvgpu_vfio_pci_pfn_memory_failure(struct pfn_address_space *pfn_space,
+ unsigned long pfn)
+{
+ struct nvgpu_vfio_pci_core_device *nvdev = container_of(
+ pfn_space, struct nvgpu_vfio_pci_core_device, pfn_address_space);
+
+ /*
+ * MM has called to notify a poisoned page. Track that in the bitmap.
+ */
+ __set_bit(pfn - (pfn_space->node.start), nvdev->mem_prop.pfn_bitmap);
+}
+
+struct pfn_address_space_ops nvgpu_vfio_pci_pas_ops = {
+ .failure = nvgpu_vfio_pci_pfn_memory_failure,
+};
+
+static int
+nvgpu_vfio_pci_register_pfn_range(struct nvgpu_vfio_pci_core_device *nvdev,
+ struct vm_area_struct *vma)
+{
+ unsigned long nr_pages;
+ int ret = 0;
+
+ nr_pages = nvdev->mem_prop.mem_length >> PAGE_SHIFT;
+
+ nvdev->pfn_address_space.node.start = vma->vm_pgoff;
+ nvdev->pfn_address_space.node.last = vma->vm_pgoff + nr_pages - 1;
+ nvdev->pfn_address_space.ops = &nvgpu_vfio_pci_pas_ops;
+ nvdev->pfn_address_space.mapping = vma->vm_file->f_mapping;
+
+ ret = register_pfn_address_space(&(nvdev->pfn_address_space));
+
+ return ret;
+}
+
+static vm_fault_t nvgpu_vfio_pci_fault(struct vm_fault *vmf)
+{
+ unsigned long mem_offset = vmf->pgoff - vmf->vma->vm_pgoff;
+ struct nvgpu_vfio_pci_core_device *nvdev = container_of(
+ vmf->vma->vm_file->private_data,
+ struct nvgpu_vfio_pci_core_device, core_device.vdev);
+ int ret;
+
+ /*
+ * Check if the page is poisoned.
+ */
+ if (mem_offset < (nvdev->mem_prop.mem_length >> PAGE_SHIFT) &&
+ test_bit(mem_offset, nvdev->mem_prop.pfn_bitmap))
+ return VM_FAULT_HWPOISON;
+
+ ret = remap_pfn_range(vmf->vma,
+ vmf->vma->vm_start + (mem_offset << PAGE_SHIFT),
+ DUMMY_PFN, PAGE_SIZE,
+ vmf->vma->vm_page_prot);
+ if (ret)
+ return VM_FAULT_ERROR;
+
+ return VM_FAULT_NOPAGE;
+}
+
+static const struct vm_operations_struct nvgpu_vfio_pci_mmap_ops = {
+ .fault = nvgpu_vfio_pci_fault,
};
static int vfio_get_bar1_start_offset(struct vfio_pci_core_device *vdev)
@@ -26,8 +94,9 @@ static int vfio_get_bar1_start_offset(struct vfio_pci_core_device *vdev)
pci_read_config_byte(vdev->pdev, 0x10, &val);
/*
- * The BAR1 start offset in the PCI config space depends on the BAR0size.
- * Check if the BAR0 is 64b and return the approproiate BAR1 offset.
+ * The BAR1 start offset in the PCI config space depends on the BAR0
+ * size. Check if the BAR0 is 64b and return the approproiate BAR1
+ * offset.
*/
if (val & PCI_BASE_ADDRESS_MEM_TYPE_64)
return VFIO_PCI_BAR2_REGION_INDEX;
@@ -54,6 +123,16 @@ static int nvgpu_vfio_pci_open_device(struct vfio_device *core_vdev)
return ret;
}
+void nvgpu_vfio_pci_close_device(struct vfio_device *core_vdev)
+{
+ struct nvgpu_vfio_pci_core_device *nvdev = container_of(
+ core_vdev, struct nvgpu_vfio_pci_core_device, core_device.vdev);
+
+ unregister_pfn_address_space(&(nvdev->pfn_address_space));
+
+ vfio_pci_core_close_device(core_vdev);
+}
+
int nvgpu_vfio_pci_mmap(struct vfio_device *core_vdev,
struct vm_area_struct *vma)
{
@@ -93,8 +172,11 @@ int nvgpu_vfio_pci_mmap(struct vfio_device *core_vdev,
return ret;
vma->vm_pgoff = start_pfn + pgoff;
+ vma->vm_ops = &nvgpu_vfio_pci_mmap_ops;
- return 0;
+ ret = nvgpu_vfio_pci_register_pfn_range(nvdev, vma);
+
+ return ret;
}
long nvgpu_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
@@ -140,7 +222,14 @@ long nvgpu_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
}
return vfio_pci_core_ioctl(core_vdev, cmd, arg);
-
+ case VFIO_DEVICE_RESET:
+ /*
+ * Resetting the GPU clears up the poisoned page. Reset the
+ * poisoned page bitmap.
+ */
+ memset(nvdev->mem_prop.pfn_bitmap, 0,
+ nvdev->mem_prop.mem_length >> (PAGE_SHIFT + 3));
+ return vfio_pci_core_ioctl(core_vdev, cmd, arg);
default:
return vfio_pci_core_ioctl(core_vdev, cmd, arg);
}
@@ -151,7 +240,7 @@ static const struct vfio_device_ops nvgpu_vfio_pci_ops = {
.init = vfio_pci_core_init_dev,
.release = vfio_pci_core_release_dev,
.open_device = nvgpu_vfio_pci_open_device,
- .close_device = vfio_pci_core_close_device,
+ .close_device = nvgpu_vfio_pci_close_device,
.ioctl = nvgpu_vfio_pci_ioctl,
.read = vfio_pci_core_read,
.write = vfio_pci_core_write,
@@ -188,7 +277,20 @@ nvgpu_vfio_pci_fetch_memory_property(struct pci_dev *pdev,
ret = device_property_read_u64(&(pdev->dev), "nvidia,gpu-mem-size",
&(nvdev->mem_prop.mem_length));
- return ret;
+ if (ret)
+ return ret;
+
+ /*
+ * A bitmap is maintained to teack the pages that are poisoned. Each
+ * page is represented by a bit. Allocation size in bytes is
+ * determined by shifting the device memory size by PAGE_SHIFT to
+ * determine the number of pages; and further shifted by 3 as each
+ * byte could track 8 pages.
+ */
+ nvdev->mem_prop.pfn_bitmap
+ = vzalloc(nvdev->mem_prop.mem_length >> (PAGE_SHIFT + 3));
+
+ return 0;
}
static int nvgpu_vfio_pci_probe(struct pci_dev *pdev,
@@ -224,6 +326,8 @@ static void nvgpu_vfio_pci_remove(struct pci_dev *pdev)
struct nvgpu_vfio_pci_core_device *nvdev = nvgpu_drvdata(pdev);
struct vfio_pci_core_device *vdev = &nvdev->core_device;
+ vfree(nvdev->mem_prop.pfn_bitmap);
+
vfio_pci_core_unregister_device(vdev);
vfio_put_device(&vdev->vdev);
}
--
2.17.1
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