From: Sebastian Ott sebott@linux.vnet.ibm.com
[ Upstream commit 725708349172f00b86e2bac5c03de360b79aaf65 ]
DMA tables are freed in zpci_dma_exit_device regardless of the return code of zpci_unregister_ioat. This could lead to a use after free. On the other hand during function hot-unplug, zpci_unregister_ioat will always fail since the function is already gone.
So let zpci_unregister_ioat report success when the function is gone but don't cleanup the dma table when a function could still have it in access.
Signed-off-by: Sebastian Ott sebott@linux.vnet.ibm.com Reviewed-by: Gerald Schaefer gerald.schaefer@de.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- arch/s390/pci/pci.c | 19 ++++++++++++++----- arch/s390/pci/pci_dma.c | 4 +++- 2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 17f81991ee9b..c22b4734fc12 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -169,19 +169,28 @@ static int mod_pci(struct zpci_dev *zdev, int fn, u8 dmaas, struct mod_pci_args int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas, u64 base, u64 limit, u64 iota) { - struct mod_pci_args args = { base, limit, iota, 0 }; + u64 req = ZPCI_CREATE_REQ(zdev->fh, dmaas, ZPCI_MOD_FC_REG_IOAT); + struct zpci_fib fib = {0}; + u8 status;
WARN_ON_ONCE(iota & 0x3fff); - args.iota |= ZPCI_IOTA_RTTO_FLAG; - return mod_pci(zdev, ZPCI_MOD_FC_REG_IOAT, dmaas, &args); + fib.pba = base; + fib.pal = limit; + fib.iota = iota | ZPCI_IOTA_RTTO_FLAG; + return zpci_mod_fc(req, &fib, &status) ? -EIO : 0; }
/* Modify PCI: Unregister I/O address translation parameters */ int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas) { - struct mod_pci_args args = { 0, 0, 0, 0 }; + u64 req = ZPCI_CREATE_REQ(zdev->fh, dmaas, ZPCI_MOD_FC_DEREG_IOAT); + struct zpci_fib fib = {0}; + u8 cc, status;
- return mod_pci(zdev, ZPCI_MOD_FC_DEREG_IOAT, dmaas, &args); + cc = zpci_mod_fc(req, &fib, &status); + if (cc == 3) /* Function already gone. */ + cc = 0; + return cc ? -EIO : 0; }
/* Modify PCI: Set PCI function measurement parameters */ diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c index 049e3860ac54..be17f05f645e 100644 --- a/arch/s390/pci/pci_dma.c +++ b/arch/s390/pci/pci_dma.c @@ -600,7 +600,9 @@ void zpci_dma_exit_device(struct zpci_dev *zdev) */ WARN_ON(zdev->s390_domain);
- zpci_unregister_ioat(zdev, 0); + if (zpci_unregister_ioat(zdev, 0)) + return; + dma_cleanup_tables(zdev->dma_table); zdev->dma_table = NULL; vfree(zdev->iommu_bitmap);