hw/pci/pcie.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-)
PCI hotplug for downstream endpoints on arm fails because Linux'
PCIe hotplug driver doesn't like the QEMU provided LNKSTA:
pcieport 0000:08:01.0: pciehp: Slot(2): Card present
pcieport 0000:08:01.0: pciehp: Slot(2): Link Up
pcieport 0000:08:01.0: pciehp: Slot(2): Cannot train link: status 0x2000
There's 2 cases where LNKSTA isn't setup properly:
* the downstream device has no express capability
* max link width of the bridge is 0
Fix these by making the LNKSTA modifications independent of each other.
Signed-off-by: Sebastian Ott <sebott@redhat.com>
---
hw/pci/pcie.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 0b455c8654..f714f4fb7c 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -1109,20 +1109,20 @@ void pcie_sync_bridge_lnk(PCIDevice *bridge_dev)
lnksta = target->config_read(target,
target->exp.exp_cap + PCI_EXP_LNKSTA,
sizeof(lnksta));
-
- if ((lnksta & PCI_EXP_LNKSTA_NLW) > (lnkcap & PCI_EXP_LNKCAP_MLW)) {
- lnksta &= ~PCI_EXP_LNKSTA_NLW;
- lnksta |= lnkcap & PCI_EXP_LNKCAP_MLW;
- } else if (!(lnksta & PCI_EXP_LNKSTA_NLW)) {
- lnksta |= QEMU_PCI_EXP_LNKSTA_NLW(QEMU_PCI_EXP_LNK_X1);
- }
-
- if ((lnksta & PCI_EXP_LNKSTA_CLS) > (lnkcap & PCI_EXP_LNKCAP_SLS)) {
- lnksta &= ~PCI_EXP_LNKSTA_CLS;
- lnksta |= lnkcap & PCI_EXP_LNKCAP_SLS;
- } else if (!(lnksta & PCI_EXP_LNKSTA_CLS)) {
- lnksta |= QEMU_PCI_EXP_LNKSTA_CLS(QEMU_PCI_EXP_LNK_2_5GT);
- }
+ }
+ if ((lnksta & PCI_EXP_LNKSTA_NLW) > (lnkcap & PCI_EXP_LNKCAP_MLW)) {
+ lnksta &= ~PCI_EXP_LNKSTA_NLW;
+ lnksta |= lnkcap & PCI_EXP_LNKCAP_MLW;
+ }
+ if (!(lnksta & PCI_EXP_LNKSTA_NLW)) {
+ lnksta |= QEMU_PCI_EXP_LNKSTA_NLW(QEMU_PCI_EXP_LNK_X1);
+ }
+ if ((lnksta & PCI_EXP_LNKSTA_CLS) > (lnkcap & PCI_EXP_LNKCAP_SLS)) {
+ lnksta &= ~PCI_EXP_LNKSTA_CLS;
+ lnksta |= lnkcap & PCI_EXP_LNKCAP_SLS;
+ }
+ if (!(lnksta & PCI_EXP_LNKSTA_CLS)) {
+ lnksta |= QEMU_PCI_EXP_LNKSTA_CLS(QEMU_PCI_EXP_LNK_2_5GT);
}
pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA,
--
2.42.0On Mon, 11 Nov 2024, Sebastian Ott wrote: > PCI hotplug for downstream endpoints on arm fails because Linux' > PCIe hotplug driver doesn't like the QEMU provided LNKSTA: > > pcieport 0000:08:01.0: pciehp: Slot(2): Card present > pcieport 0000:08:01.0: pciehp: Slot(2): Link Up > pcieport 0000:08:01.0: pciehp: Slot(2): Cannot train link: status 0x2000 > > There's 2 cases where LNKSTA isn't setup properly: > * the downstream device has no express capability > * max link width of the bridge is 0 > > Fix these by making the LNKSTA modifications independent of each other. > > Signed-off-by: Sebastian Ott <sebott@redhat.com> Friendly ping. This fixes PCI hotplug to a downstream port on ARM. Thanks, Sebastian
On 2024/11/11 20:37, Sebastian Ott wrote:
> PCI hotplug for downstream endpoints on arm fails because Linux'
> PCIe hotplug driver doesn't like the QEMU provided LNKSTA:
>
> pcieport 0000:08:01.0: pciehp: Slot(2): Card present
> pcieport 0000:08:01.0: pciehp: Slot(2): Link Up
> pcieport 0000:08:01.0: pciehp: Slot(2): Cannot train link: status 0x2000
>
> There's 2 cases where LNKSTA isn't setup properly:
> * the downstream device has no express capability
> * max link width of the bridge is 0
>
> Fix these by making the LNKSTA modifications independent of each other.
>
> Signed-off-by: Sebastian Ott<sebott@redhat.com>
> ---
> hw/pci/pcie.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index 0b455c8654..f714f4fb7c 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -1109,20 +1109,20 @@ void pcie_sync_bridge_lnk(PCIDevice *bridge_dev)
> lnksta = target->config_read(target,
> target->exp.exp_cap + PCI_EXP_LNKSTA,
> sizeof(lnksta));
> -
> - if ((lnksta & PCI_EXP_LNKSTA_NLW) > (lnkcap & PCI_EXP_LNKCAP_MLW)) {
> - lnksta &= ~PCI_EXP_LNKSTA_NLW;
> - lnksta |= lnkcap & PCI_EXP_LNKCAP_MLW;
> - } else if (!(lnksta & PCI_EXP_LNKSTA_NLW)) {
> - lnksta |= QEMU_PCI_EXP_LNKSTA_NLW(QEMU_PCI_EXP_LNK_X1);
> - }
> -
> - if ((lnksta & PCI_EXP_LNKSTA_CLS) > (lnkcap & PCI_EXP_LNKCAP_SLS)) {
> - lnksta &= ~PCI_EXP_LNKSTA_CLS;
> - lnksta |= lnkcap & PCI_EXP_LNKCAP_SLS;
> - } else if (!(lnksta & PCI_EXP_LNKSTA_CLS)) {
> - lnksta |= QEMU_PCI_EXP_LNKSTA_CLS(QEMU_PCI_EXP_LNK_2_5GT);
> - }
> + }
> + if ((lnksta & PCI_EXP_LNKSTA_NLW) > (lnkcap & PCI_EXP_LNKCAP_MLW)) {
> + lnksta &= ~PCI_EXP_LNKSTA_NLW;
> + lnksta |= lnkcap & PCI_EXP_LNKCAP_MLW;
> + }
> + if (!(lnksta & PCI_EXP_LNKSTA_NLW)) {
> + lnksta |= QEMU_PCI_EXP_LNKSTA_NLW(QEMU_PCI_EXP_LNK_X1);
> + }
> + if ((lnksta & PCI_EXP_LNKSTA_CLS) > (lnkcap & PCI_EXP_LNKCAP_SLS)) {
> + lnksta &= ~PCI_EXP_LNKSTA_CLS;
> + lnksta |= lnkcap & PCI_EXP_LNKCAP_SLS;
> + }
> + if (!(lnksta & PCI_EXP_LNKSTA_CLS)) {
> + lnksta |= QEMU_PCI_EXP_LNKSTA_CLS(QEMU_PCI_EXP_LNK_2_5GT);
> }
>
> pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA,
|[PATCH] pci: ensure valid link status bits for downstream ports
Test on aarch64 host(v9.2.0-rc0-1-gbde0d70333)
PCI hotplug for downstream endpoints on arm succeed
The test results are as expected.
|
|Tested-by: Zhenyu Zhang <zhenyzha@redhat.com> |
On Mon, 11 Nov 2024, Sebastian Ott wrote: > PCI hotplug for downstream endpoints on arm fails because Linux' > PCIe hotplug driver doesn't like the QEMU provided LNKSTA: > > pcieport 0000:08:01.0: pciehp: Slot(2): Card present > pcieport 0000:08:01.0: pciehp: Slot(2): Link Up > pcieport 0000:08:01.0: pciehp: Slot(2): Cannot train link: status 0x2000 > > There's 2 cases where LNKSTA isn't setup properly: > * the downstream device has no express capability I stumbled over this while debugging - is a pci device attached to a pcie downstream even a valid usecase? > * max link width of the bridge is 0 MLW for the downstream is initialized with defaults but gets overwritten later because speed and width properties are 0. Dunno if that's the issue we should address? Sebastian
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