This is a note to let you know that I've just added the patch titled
powerpc/iommu: Limit number of TCEs to 512 for H_STUFF_TCE hcall
to the 6.3-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-iommu-limit-number-of-tces-to-512-for-h_stuff_tce-hcall.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9d2ccf00bddc268045e3d65a8108d61ada0e4b4e Mon Sep 17 00:00:00 2001
From: Gaurav Batra <gbatra@xxxxxxxxxxxxxxxxxx>
Date: Thu, 25 May 2023 09:34:54 -0500
Subject: powerpc/iommu: Limit number of TCEs to 512 for H_STUFF_TCE hcall
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From: Gaurav Batra <gbatra@xxxxxxxxxxxxxxxxxx>
commit 9d2ccf00bddc268045e3d65a8108d61ada0e4b4e upstream.
Currently in tce_freemulti_pSeriesLP() there is no limit on how many
TCEs are passed to the H_STUFF_TCE hcall. This has not caused an issue
until now, but newer firmware releases have started enforcing a limit of
512 TCEs per call.
The limit is correct per the specification (PAPR v2.12 § 14.5.4.2.3).
The code has been in it's current form since it was initially merged.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Gaurav Batra <gbatra@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
[mpe: Tweak change log wording & add PAPR reference]
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20230525143454.56878-1-gbatra@xxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/platforms/pseries/iommu.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -311,13 +311,22 @@ static void tce_free_pSeriesLP(unsigned
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");
Patches currently in stable-queue which might be from gbatra@xxxxxxxxxxxxxxxxxx are
queue-6.3/powerpc-iommu-limit-number-of-tces-to-512-for-h_stuff_tce-hcall.patch
