Hello Michael,

Here are the changes in v2 of the patch

1. added some wording to change log to specify why we are seeing the issue now. Also added "CC: sta...@vger.kernel.org"

2. changed "limit" to unsigned long. I have kept "rpages" as "long"

Thanks,

Gaurav

On 5/25/23 9:34 AM, Gaurav Batra wrote:
As of now, in tce_freemulti_pSeriesLP(), there is no limit on how many TCEs
are passed to H_STUFF_TCE hcall. This was not an issue until now. Newer
firmware releases have started enforcing this requirement.

The interface has been in it's current form since the beginning.

Cc: sta...@vger.kernel.org

Signed-off-by: Gaurav Batra <gba...@linux.vnet.ibm.com>
Reviewed-by: Brian King <brk...@linux.vnet.ibm.com>
---
  arch/powerpc/platforms/pseries/iommu.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c 
b/arch/powerpc/platforms/pseries/iommu.c
index c74b71d4733d..f159a195101d 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -306,13 +306,22 @@ static void tce_free_pSeriesLP(unsigned long liobn, long 
tcenum, long tceshift,
  static void tce_freemulti_pSeriesLP(struct iommu_table *tbl, long tcenum, 
long npages)
  {
        u64 rc;
+       long rpages = npages;
+       unsigned long limit;

        if (!firmware_has_feature(FW_FEATURE_STUFF_TCE))
                return tce_free_pSeriesLP(tbl->it_index, tcenum,
                                          tbl->it_page_shift, npages);

-       rc = plpar_tce_stuff((u64)tbl->it_index,
-                            (u64)tcenum << tbl->it_page_shift, 0, npages);
+       do {
+               limit = min_t(unsigned long, rpages, 512);
+
+               rc = plpar_tce_stuff((u64)tbl->it_index,
+                               (u64)tcenum << tbl->it_page_shift, 0, limit);
+
+               rpages -= limit;
+               tcenum += limit;
+       } while (rpages > 0 && !rc);

        if (rc && printk_ratelimit()) {
                printk("tce_freemulti_pSeriesLP: plpar_tce_stuff failed\n");

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