This is a note to let you know that I've just added the patch titled
powerpc/pseries/iommu: enable_ddw incorrectly returns direct mapping for SR-IOV device
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-pseries-iommu-enable_ddw-incorrectly-returns.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e8c5af5c56f6481c9f6b7141b8a934242cc0b36c
Author: Gaurav Batra <gbatra@xxxxxxxxxxxxxxxxxx>
Date: Mon Oct 2 22:08:02 2023 -0500
powerpc/pseries/iommu: enable_ddw incorrectly returns direct mapping for SR-IOV device
[ Upstream commit 3bf983e4e93ce8e6d69e9d63f52a66ec0856672e ]
When a device is initialized, the driver invokes dma_supported() twice -
first for streaming mappings followed by coherent mappings. For an
SR-IOV device, default window is deleted and DDW created. With vPMEM
enabled, TCE mappings are dynamically created for both vPMEM and SR-IOV
device. There are no direct mappings.
First time when dma_supported() is called with 64 bit mask, DDW is created
and marked as dynamic window. The second time dma_supported() is called,
enable_ddw() finds existing window for the device and incorrectly returns
it as "direct mapping".
This only happens when size of DDW is big enough to map max LPAR memory.
This results in streaming TCEs to not get dynamically mapped, since code
incorrently assumes these are already pre-mapped. The adapter initially
comes up but goes down due to EEH.
Fixes: 381ceda88c4c ("powerpc/pseries/iommu: Make use of DDW for indirect mapping")
Cc: stable@xxxxxxxxxxxxxxx # v5.15+
Signed-off-by: Gaurav Batra <gbatra@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20231003030802.47914-1-gbatra@xxxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index aa5f8074e9b10..bee61292de23b 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -891,7 +891,8 @@ static int remove_ddw(struct device_node *np, bool remove_prop, const char *win_
return 0;
}
-static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, int *window_shift)
+static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, int *window_shift,
+ bool *direct_mapping)
{
struct dma_win *window;
const struct dynamic_dma_window_prop *dma64;
@@ -904,6 +905,7 @@ static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, int *windo
dma64 = window->prop;
*dma_addr = be64_to_cpu(dma64->dma_base);
*window_shift = be32_to_cpu(dma64->window_shift);
+ *direct_mapping = window->direct;
found = true;
break;
}
@@ -1253,10 +1255,8 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
mutex_lock(&dma_win_init_mutex);
- if (find_existing_ddw(pdn, &dev->dev.archdata.dma_offset, &len)) {
- direct_mapping = (len >= max_ram_len);
+ if (find_existing_ddw(pdn, &dev->dev.archdata.dma_offset, &len, &direct_mapping))
goto out_unlock;
- }
/*
* If we already went through this for a previous function of
