2023-10-04 08:56:50

by Niklas Schnelle

[permalink] [raw]
Subject: [PATCH] s390/pci: Fix reset of IOMMU software counters

Together with enabling the Function Measurement Block
zpci_fmb_enable_device() also resets the software counters. This allows
to use "echo 0 > /sys/kernel/debug/pci/<dev>/statistics" followed by
echo "1 > /../statistics" to reset all counters. In commit c76c067e488c
("s390/pci: Use dma-iommu layer") this use of the now obsolete counters
in struct zpci_device was missed as was their removal. Fix this by
resetting the new counters and removing the old ones.

Fixes: c76c067e488c ("s390/pci: Use dma-iommu layer")
Signed-off-by: Niklas Schnelle <[email protected]>
---
Note: This is based on and references commit IDs from Joerg Roedel's
iommu/next branch and should go in via the iommu tree.
---
arch/s390/include/asm/pci.h | 4 ----
arch/s390/pci/pci.c | 13 ++++++++++---
2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 3f74f1cf37df..e91cd6bbc330 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -173,10 +173,6 @@ struct zpci_dev {
struct zpci_fmb *fmb;
u16 fmb_update; /* update interval */
u16 fmb_length;
- /* software counters */
- atomic64_t allocated_pages;
- atomic64_t mapped_pages;
- atomic64_t unmapped_pages;

u8 version;
enum pci_bus_speed max_bus_speed;
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 563cb72d9ed0..63fd9e1d9f22 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -157,6 +157,7 @@ int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas)
int zpci_fmb_enable_device(struct zpci_dev *zdev)
{
u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_SET_MEASURE);
+ struct zpci_iommu_ctrs *ctrs;
struct zpci_fib fib = {0};
u8 cc, status;

@@ -169,9 +170,15 @@ int zpci_fmb_enable_device(struct zpci_dev *zdev)
WARN_ON((u64) zdev->fmb & 0xf);

/* reset software counters */
- atomic64_set(&zdev->allocated_pages, 0);
- atomic64_set(&zdev->mapped_pages, 0);
- atomic64_set(&zdev->unmapped_pages, 0);
+ ctrs = zpci_get_iommu_ctrs(zdev);
+ if (ctrs) {
+ atomic64_set(&ctrs->mapped_pages, 0);
+ atomic64_set(&ctrs->unmapped_pages, 0);
+ atomic64_set(&ctrs->global_rpcits, 0);
+ atomic64_set(&ctrs->sync_map_rpcits, 0);
+ atomic64_set(&ctrs->sync_rpcits, 0);
+ }
+

fib.fmb_addr = virt_to_phys(zdev->fmb);
fib.gd = zdev->gisa;

---
base-commit: 8e5ab3f54a1061c2be3e1fbcda01fbe604c3450e
change-id: 20231002-dma_iommu_fix-0a5397992f15

Best regards,
--
Niklas Schnelle
Linux on Z Development

IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Gregor Pillen
Geschäftsführung: David Faller
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294
IBM Data Privacy Statement - https://www.ibm.com/privacy


2023-10-04 15:24:53

by Matthew Rosato

[permalink] [raw]
Subject: Re: [PATCH] s390/pci: Fix reset of IOMMU software counters

On 10/4/23 4:56 AM, Niklas Schnelle wrote:
> Together with enabling the Function Measurement Block
> zpci_fmb_enable_device() also resets the software counters. This allows
> to use "echo 0 > /sys/kernel/debug/pci/<dev>/statistics" followed by
> echo "1 > /../statistics" to reset all counters. In commit c76c067e488c
> ("s390/pci: Use dma-iommu layer") this use of the now obsolete counters
> in struct zpci_device was missed as was their removal. Fix this by
> resetting the new counters and removing the old ones.
>
> Fixes: c76c067e488c ("s390/pci: Use dma-iommu layer")
> Signed-off-by: Niklas Schnelle <[email protected]>

Reviewed-by: Matthew Rosato <[email protected]>

Verified that I could reproduce the initial issue + tested the fix using NVMe and mlx devices

> ---
> Note: This is based on and references commit IDs from Joerg Roedel's
> iommu/next branch and should go in via the iommu tree.
> ---
> arch/s390/include/asm/pci.h | 4 ----
> arch/s390/pci/pci.c | 13 ++++++++++---
> 2 files changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 3f74f1cf37df..e91cd6bbc330 100644
> --- a/arch/s390/include/asm/pci.h
> +++ b/arch/s390/include/asm/pci.h
> @@ -173,10 +173,6 @@ struct zpci_dev {
> struct zpci_fmb *fmb;
> u16 fmb_update; /* update interval */
> u16 fmb_length;
> - /* software counters */
> - atomic64_t allocated_pages;
> - atomic64_t mapped_pages;
> - atomic64_t unmapped_pages;
>
> u8 version;
> enum pci_bus_speed max_bus_speed;
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index 563cb72d9ed0..63fd9e1d9f22 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -157,6 +157,7 @@ int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas)
> int zpci_fmb_enable_device(struct zpci_dev *zdev)
> {
> u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_SET_MEASURE);
> + struct zpci_iommu_ctrs *ctrs;
> struct zpci_fib fib = {0};
> u8 cc, status;
>
> @@ -169,9 +170,15 @@ int zpci_fmb_enable_device(struct zpci_dev *zdev)
> WARN_ON((u64) zdev->fmb & 0xf);
>
> /* reset software counters */
> - atomic64_set(&zdev->allocated_pages, 0);
> - atomic64_set(&zdev->mapped_pages, 0);
> - atomic64_set(&zdev->unmapped_pages, 0);
> + ctrs = zpci_get_iommu_ctrs(zdev);
> + if (ctrs) {
> + atomic64_set(&ctrs->mapped_pages, 0);
> + atomic64_set(&ctrs->unmapped_pages, 0);
> + atomic64_set(&ctrs->global_rpcits, 0);
> + atomic64_set(&ctrs->sync_map_rpcits, 0);
> + atomic64_set(&ctrs->sync_rpcits, 0);
> + }
> +
>
> fib.fmb_addr = virt_to_phys(zdev->fmb);
> fib.gd = zdev->gisa;
>
> ---
> base-commit: 8e5ab3f54a1061c2be3e1fbcda01fbe604c3450e
> change-id: 20231002-dma_iommu_fix-0a5397992f15
>
> Best regards,

2023-10-05 14:35:11

by Joerg Roedel

[permalink] [raw]
Subject: Re: [PATCH] s390/pci: Fix reset of IOMMU software counters

On Wed, Oct 04, 2023 at 10:56:12AM +0200, Niklas Schnelle wrote:
> arch/s390/include/asm/pci.h | 4 ----
> arch/s390/pci/pci.c | 13 ++++++++++---
> 2 files changed, 10 insertions(+), 7 deletions(-)

Applied, thanks.

--
J?rg R?del
[email protected]

SUSE Software Solutions Germany GmbH
Frankenstra?e 146
90461 N?rnberg
Germany

(HRB 36809, AG N?rnberg)
Gesch?ftsf?hrer: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman