Messages in this thread | | | From | Thomas Gleixner <> | Subject | [patch 00/10] genirq/msi, PCI/MSI: Support for dynamic MSI-X vector expansion - Part 4 | Date | Sat, 27 Nov 2021 02:24:30 +0100 (CET) |
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This is finally the point where dynamically expanding MSI-X vectors after enabling MSI-X is implemented.
The first three parts of this work can be found here:
https://lore.kernel.org/r/20211126222700.862407977@linutronix.de https://lore.kernel.org/r/20211126224100.303046749@linutronix.de https://lore.kernel.org/r/20211126230957.239391799@linutronix.de
This last and smallest part of the overall series contains the following changes:
1) Prepare the core MSI irq domain code to handle range based allocation and free
2) Prepare the PCI/MSI code to handle range based allocation and free
3) Implement a new interface which allows to expand the MSI-X vector space after initialization
4) Enable support for the X86 PCI/MSI irq domains
This is unfortunate, but some PCI/MSI irq domain implementations, e.g. powerpc and the x86/XEN irqdomain wrappers are not really ready to support this out of the box.
I looked at the 30 places which implement PCI/MSI irq domains and many of them look like they could support it out of the box, but as we have two which definitely don't, making this opt-in is the only safe option.
I've tested this by hacking up the XHCI driver and it works like a charm.
There is certainly some more room for consolidating the PCI/MSI-X usage in drivers, i.e. getting rid of pci_enable_msix*(), but this would have made this overall series even larger and is an orthogonal issue.
This fourth series is based on:
git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-3
and also available from git:
git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-4
Thanks,
tglx --- arch/powerpc/platforms/pseries/msi.c | 6 +- arch/x86/kernel/apic/msi.c | 4 - arch/x86/pci/xen.c | 10 +-- drivers/base/platform-msi.c | 3 - drivers/pci/msi/irqdomain.c | 39 ++++++++++---- drivers/pci/msi/msi.c | 97 +++++++++++++++++++++++++++-------- drivers/pci/msi/msi.h | 4 - include/linux/msi.h | 46 +++++++++++----- include/linux/pci.h | 13 ++++ kernel/irq/msi.c | 75 +++++++++++++++------------ 10 files changed, 208 insertions(+), 89 deletions(-)
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