| Message ID | 20231025202344.581132-12-sunilvl@ventanamicro.com |
|---|---|
| State | New |
| Headers | show |
| Series | RISC-V: ACPI: Add external interrupt controller support | expand |
On Thu, Oct 26 2023 at 01:53, Sunil V. L. wrote: > Like pci_no_msi() used to disable MSI support, add a function to enable > system wide MSI support. Why? int pci_msi_enable = 1; So this function makes it more one or what am I missing here? Thanks, tglx
On Mon, Oct 30, 2023 at 03:28:53PM +0100, Thomas Gleixner wrote: > On Thu, Oct 26 2023 at 01:53, Sunil V. L. wrote: > > Like pci_no_msi() used to disable MSI support, add a function to enable > > system wide MSI support. > > Why? > > int pci_msi_enable = 1; > > So this function makes it more one or what am I missing here? > Hi Thomas, Just noting related discussion : https://www.spinics.net/lists/linux-serial/msg57616.html The MSI controller on RISC-V (IMSIC) is optional for the platform. So, when by default pci_msi_enable = 1 and the MSI controller is not discovered, we get stack trace like below. [ 0.608941] [<ffffffff804d0400>] pci_msi_setup_msi_irqs+0x18/0x34 [ 0.608991] [<ffffffff804cfe04>] msix_capability_init+0x228/0x406 [ 0.609001] [<ffffffff804cfbc6>] __pci_enable_msix_range+0x1b4/0x1ca [ 0.609011] [<ffffffff804ce8c2>] pci_alloc_irq_vectors_affinity+0x6e/0xee [ 0.609020] [<ffffffff8055015c>] vp_find_vqs_msix+0xfa/0x350 [ 0.609031] [<ffffffff8054ff54>] vp_find_vqs+0x36/0x144 [ 0.609040] [<ffffffff8054f7b8>] vp_modern_find_vqs+0x14/0x48 [ 0.609049] [<ffffffff8064d3fc>] init_vqs+0x362/0x4ee [ 0.609058] [<ffffffff8064c8be>] virtnet_probe+0x672/0xa70 [ 0.609067] [<ffffffff80549d38>] virtio_dev_probe+0x194/0x200 [ 0.609075] [<ffffffff805afb52>] really_probe+0x106/0x28a [ 0.609083] [<ffffffff805aefda>] __driver_probe_device+0x62/0xdc [ 0.609091] [<ffffffff805af920>] driver_probe_device+0x38/0x164 [ 0.609098] [<ffffffff805af146>] __driver_attach+0xd0/0x17c [ 0.609106] [<ffffffff805ac6e2>] bus_for_each_dev+0xd0/0x11c [ 0.609116] [<ffffffff805af06e>] driver_attach+0x1a/0x22 [ 0.609123] [<ffffffff805ace06>] bus_add_driver+0x136/0x208 [ 0.609132] [<ffffffff805b044e>] driver_register+0x48/0xda [ 0.609140] [<ffffffff80549594>] register_virtio_driver+0x20/0x2a [ 0.609157] [<ffffffff80a3060e>] virtio_net_driver_init+0x76/0xa6 [ 0.609168] [<ffffffff800020ec>] do_one_initcall+0xc0/0x21e [ 0.609176] [<ffffffff80a00f68>] do_initcall_level+0x7c/0x8e [ 0.609186] [<ffffffff80a00eb6>] do_initcalls+0x52/0x88 [ 0.609195] [<ffffffff80a00e5c>] do_basic_setup+0x1c/0x24 [ 0.609204] [<ffffffff80a00e00>] kernel_init_freeable+0xe2/0x122 [ 0.609213] [<ffffffff8090beb4>] kernel_init+0x1a/0x18e [ 0.609223] [<ffffffff8000383e>] ret_from_fork+0xa/0x1c So, what I did was, by default call pci_no_msi() to disable MSI and then call pci_set_msi() to enable when MSI controller is probed. But I think Bjorn's suggestion to depend on PCI_BUS_FLAGS_NO_MSI may be better idea. In that case, we need to set bridge->msi_domain to true in pci_create_root_bus(). Let me know what do you prefer or if I am completely missing something here. Thanks, Sunil
On Mon, Oct 30 2023 at 23:24, Sunil V. L. wrote: > On Mon, Oct 30, 2023 at 03:28:53PM +0100, Thomas Gleixner wrote: > Just noting related discussion : > https://www.spinics.net/lists/linux-serial/msg57616.html > > The MSI controller on RISC-V (IMSIC) is optional for the platform. So, > when by default pci_msi_enable = 1 and the MSI controller is not > discovered, we get stack trace like below. <SNIP> > So, what I did was, by default call pci_no_msi() to disable MSI and then > call pci_set_msi() to enable when MSI controller is probed. Your taste sensors should have gone out of range ... > But I think Bjorn's suggestion to depend on PCI_BUS_FLAGS_NO_MSI may be > better idea. In that case, we need to set bridge->msi_domain to true in > pci_create_root_bus(). Let me know what do you prefer or if I am > completely missing something here. That's definitely more sensible, but as I said in the other thread, Marc is the one who did the PCI core/bridge setup magic and he is definitely in a better position to answer that bridge->msi_domain question. Thanks, tglx
On Mon, Oct 30, 2023 at 08:29:13PM +0100, Thomas Gleixner wrote: > On Mon, Oct 30 2023 at 23:24, Sunil V. L. wrote: > > On Mon, Oct 30, 2023 at 03:28:53PM +0100, Thomas Gleixner wrote: > > Just noting related discussion : > > https://www.spinics.net/lists/linux-serial/msg57616.html > > > > The MSI controller on RISC-V (IMSIC) is optional for the platform. So, > > when by default pci_msi_enable = 1 and the MSI controller is not > > discovered, we get stack trace like below. > > <SNIP> > > > So, what I did was, by default call pci_no_msi() to disable MSI and then > > call pci_set_msi() to enable when MSI controller is probed. > > Your taste sensors should have gone out of range ... > > > But I think Bjorn's suggestion to depend on PCI_BUS_FLAGS_NO_MSI may be > > better idea. In that case, we need to set bridge->msi_domain to true in > > pci_create_root_bus(). Let me know what do you prefer or if I am > > completely missing something here. > > That's definitely more sensible, but as I said in the other thread, Marc > is the one who did the PCI core/bridge setup magic and he is definitely > in a better position to answer that bridge->msi_domain question. > Thanks!. It looks like Marc introduced bridge->msi_domain in [1] for exactly the same problem we have with RISC-V + ACPI. Let me remove this hack and do similar to pci_host_common_probe() in next revision unless I get objections to that approach. Sorry, somehow my script didn't copy Marc in the series. Will make sure I copy him explicitly in next revision. [1] - https://lore.kernel.org/all/20210330151145.997953-12-maz@kernel.org/ Thanks! Sunil
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c index ef1d8857a51b..e76ccb8b5f0b 100644 --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -913,3 +913,8 @@ void pci_no_msi(void) { pci_msi_enable = 0; } + +void pci_set_msi(void) +{ + pci_msi_enable = 1; +} diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 39a8932dc340..2f876c29f75c 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -167,8 +167,10 @@ extern unsigned int pci_pm_d3hot_delay; #ifdef CONFIG_PCI_MSI void pci_no_msi(void); +void pci_set_msi(void); #else static inline void pci_no_msi(void) { } +static inline void pci_set_msi(void) { } #endif void pci_realloc_get_opt(char *);
Like pci_no_msi() used to disable MSI support, add a function to enable system wide MSI support. Signed-off-by: Sunil V L <sunilvl@ventanamicro.com> --- drivers/pci/msi/msi.c | 5 +++++ drivers/pci/pci.h | 2 ++ 2 files changed, 7 insertions(+)