Re:[PATCH v1] powerpc/powernv/pci: fix PE in re-used pci_dn for pnv_pci_enable_device_hook

[虞陆铭]

Hi,

Looks like the latest upstream kernel has sovled the problem:
echo 1 >  /sys/bus/pci/devices/0001:0d:00.0/remove
 echo 1 >  /sys/bus/pci/rescan

[  230.399969] pci_bus 0001:0d: Configuring PE for bus
[  230.399974] pci 0001:0d     : [PE# fb] Secondary bus 0x000000000000000d associated with PE#fb
[  230.400084] pci 0001:0d:00.0: Configured PE#fb
[  230.400086] pci 0001:0d     : [PE# fb] Setting up 32-bit TCE table at 0..80000000
[  230.400698] pci 0001:0d     : [PE# fb] Setting up window#0 0..3fffffffff pg=10000
[  230.400703] pci 0001:0d     : [PE# fb] Enabling 64-bit DMA bypass
[  230.400716] pci 0001:0d:00.0: Adding to iommu group 1
[  230.400917] mmiotrace: ioremap_*(0x3fe080800000, 0x2000) = 00000000ecf53fa1
[  230.401088] nvme nvme0: pci function 0001:0d:00.0
[  230.401098] nvme 0001:0d:00.0: enabling device (0140 -> 0142)
[  230.401146] mmiotrace: ioremap_*(0x3fe080804000, 0x400) = 000000003e6b2e5b
[  230.429600] nvme nvme0: D3 entry latency set to 10 seconds
[  230.429896] mmiotrace: ioremap_*(0x3fe080804000, 0x400) = 000000006f3fd92d
[  230.439138] nvme nvme0: 63/0/0 default/read/poll queues

the original problem in pci rescan path after hot remove like below is gone!
pci 0020:0e:00.0: BAR 0: assigned [mem 0x3fe801820000-0x3fe80182ffff 64bit]
    nvme nvme1: pci function 0020:0e:00.0
    nvme 0020:0e:00.0 pci_enable_device() blocked, no PE assigned.

Probably fixed by the commit:
5ac129cdb50b4efda59ee5ea7c711996a3637b34
Author: Joel Stanley <joel@xxxxxxxxx>
Date:   Tue Jun 13 14:22:00 2023 +0930
powerpc/powernv/pci: Remove ioda1 support

that was merged mainline later than the upstream kernel I saw the problem last time I came
up with the patch.

Given the facts changed,  the patch proposal became even more trivial now.
I won't push it for upstream inclusion now. Instead, I will keep it in my local test queue for a while.   

Cheers!
Luming

------------------ Original ------------------
From:  "虞陆铭"<luming.yu@xxxxxxxxxxxx>;
Date:  Tue, Nov 28, 2023 02:43 PM
To:  "linuxppc-dev"<linuxppc-dev@xxxxxxxxxxxxxxxx>; "linux-kernel"<linux-kernel@xxxxxxxxxxxxxxx>; "mpe"<mpe@xxxxxxxxxxxxxx>; "npiggin"<npiggin@xxxxxxxxx>; "christophe.leroy"<christophe.leroy@xxxxxxxxxx>; 
Cc:  "luming.yu"<luming.yu@xxxxxxxxx>; "ke.zhao"<ke.zhao@xxxxxxxxxxxx>; "dawei.li"<dawei.li@xxxxxxxxxxxx>; "shenghui.qu"<shenghui.qu@xxxxxxxxxxxx>; "虞陆铭"<luming.yu@xxxxxxxxxxxx>; 
Subject:  [PATCH v1] powerpc/powernv/pci: fix PE in re-used pci_dn for pnv_pci_enable_device_hook

 

after hot remove a pcie deivce with pci_dn having pnp_php driver attached,
pci rescan with echo 1 > /sys/bus/pci/rescan could fail with error
message like:
pci 0020:0e:00.0: BAR 0: assigned [mem 0x3fe801820000-0x3fe80182ffff
64bit]
nvme nvme1: pci function 0020:0e:00.0
nvme 0020:0e:00.0 pci_enable_device() blocked, no PE assigned.

It appears that the pci_dn object is reused with only pe_number
clobbered in the case. And a simple call to pnv_ioda_setup_dev_PE should
get PE number back and solve the problem.

Signed-off-by: Luming Yu <luming.yu@xxxxxxxxxxxx>
---
v0 -> v1:
-clean up garbage leaked in git format patch that stems from git clone and checkout 
-conflicts of files in local windows filesystem with weird cases and names quriks.
---
 arch/powerpc/platforms/powernv/pci-ioda.c     |  11 +-
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 28fac4770073..9d7add79ee3d 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2325,11 +2325,18 @@ static resource_size_t pnv_pci_default_alignment(void)
 static bool pnv_pci_enable_device_hook(struct pci_dev *dev)
 {
 	struct pci_dn *pdn;
+	struct pnv_ioda_pe *pe;
 
 	pdn = pci_get_pdn(dev);
-	if (!pdn || pdn->pe_number == IODA_INVALID_PE) {
-		pci_err(dev, "pci_enable_device() blocked, no PE assigned.\n");
+	if (!pdn)
 		return false;
+
+	if (pdn->pe_number == IODA_INVALID_PE) {
+		pe = pnv_ioda_setup_dev_PE(dev);
+		if (!pe) {
+			pci_err(dev, "pci_enable_device() blocked, no PE assigned.\n");
+			return false;
+		}
 	}
 
 	return true;