From: Sebastian Ott <seb...@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 <seb...@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schae...@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidef...@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.le...@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);
--
2.15.1
