Hi Jason,
On 2022/4/17 22:56, Yi Liu wrote:
On 2022/4/13 22:49, Yi Liu wrote:
On 2022/4/13 22:36, Jason Gunthorpe wrote:
On Wed, Apr 13, 2022 at 10:02:58PM +0800, Yi Liu wrote:
+/**
+ * iopt_unmap_iova() - Remove a range of iova
+ * @iopt: io_pagetable to act on
+ * @iova: Starting iova to unmap
+ * @length: Number of bytes to unmap
+ *
+ * The requested range must exactly match an existing range.
+ * Splitting/truncating IOVA mappings is not allowed.
+ */
+int iopt_unmap_iova(struct io_pagetable *iopt, unsigned long iova,
+ unsigned long length)
+{
+ struct iopt_pages *pages;
+ struct iopt_area *area;
+ unsigned long iova_end;
+ int rc;
+
+ if (!length)
+ return -EINVAL;
+
+ if (check_add_overflow(iova, length - 1, &iova_end))
+ return -EOVERFLOW;
+
+ down_read(&iopt->domains_rwsem);
+ down_write(&iopt->iova_rwsem);
+ area = iopt_find_exact_area(iopt, iova, iova_end);
when testing vIOMMU with Qemu using iommufd, I hit a problem as log #3
shows. Qemu failed when trying to do map due to an IOVA still in use.
After debugging, the 0xfffff000 IOVA is mapped but not unmapped. But
per log
#2, Qemu has issued unmap with a larger range (0xff000000 -
0x100000000) which includes the 0xfffff000. But iopt_find_exact_area()
doesn't find any area. So 0xfffff000 is not unmapped. Is this correct?
Same
test passed with vfio iommu type1 driver. any idea?
There are a couple of good reasons why the iopt_unmap_iova() should
proccess any contiguous range of fully contained areas, so I would
consider this something worth fixing. can you send a small patch and
test case and I'll fold it in?
sure. just spotted it, so haven't got fix patch yet. I may work on
it tomorrow.
Hi Jason,
Got below patch for it. Also pushed to the exploration branch.
https://github.com/luxis1999/iommufd/commit/d764f3288de0fd52c578684788a437701ec31b2d
0-day reports a use without initialization to me. So updated it. Please get
the change in below commit. Sorry for the noise.
https://github.com/luxis1999/iommufd/commit/10674417c235cb4a4caf2202fffb078611441da2
--
Regards,
Yi Liu
