Messages in this thread | | | Subject | Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support | From | Vlad Zolotarov <> | Date | Mon, 5 Oct 2015 10:41:39 +0300 |
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On 10/05/15 06:11, Greg KH wrote: > On Sun, Oct 04, 2015 at 11:43:17PM +0300, Vlad Zolotarov wrote: >> Add support for MSI and MSI-X interrupt modes: >> - Interrupt mode selection order is: >> INT#X (for backward compatibility) -> MSI-X -> MSI. >> - Add ioctl() commands: >> - UIO_PCI_GENERIC_INT_MODE_GET: query the current interrupt mode. >> - UIO_PCI_GENERIC_IRQ_NUM_GET: query the maximum number of IRQs. >> - UIO_PCI_GENERIC_IRQ_SET: bind the IRQ to eventfd (similar to vfio). >> - Add mappings to all bars (memory and portio): some devices have >> registers related to MSI/MSI-X handling outside BAR0. >> >> Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com> >> --- >> New in v3: >> - Add __iomem qualifier to temp buffer receiving ioremap value. >> >> New in v2: >> - Added #include <linux/uaccess.h> to uio_pci_generic.c >> >> Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com> >> --- >> drivers/uio/uio_pci_generic.c | 410 +++++++++++++++++++++++++++++++++++++--- >> include/linux/uio_pci_generic.h | 36 ++++ >> 2 files changed, 423 insertions(+), 23 deletions(-) >> create mode 100644 include/linux/uio_pci_generic.h >> >> diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c >> index d0b508b..6b8b1789 100644 >> --- a/drivers/uio/uio_pci_generic.c >> +++ b/drivers/uio/uio_pci_generic.c >> @@ -22,16 +22,32 @@ >> #include <linux/device.h> >> #include <linux/module.h> >> #include <linux/pci.h> >> +#include <linux/msi.h> >> #include <linux/slab.h> >> #include <linux/uio_driver.h> >> +#include <linux/uio_pci_generic.h> >> +#include <linux/eventfd.h> >> +#include <linux/uaccess.h> >> >> #define DRIVER_VERSION "0.01.0" >> #define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>" >> #define DRIVER_DESC "Generic UIO driver for PCI 2.3 devices" >> >> +struct msix_info { >> + int num_irqs; >> + struct msix_entry *table; >> + struct uio_msix_irq_ctx { >> + struct eventfd_ctx *trigger; /* MSI-x vector to eventfd */ > Why are you using eventfd for msi vectors? What's the reason for > needing this?
A small correction - for MSI-X vectors. There may be only one MSI vector per PCI function and if it's used it would use the same interface as a legacy INT#x interrupt uses at the moment. So, for MSI-X case the reason is that there may be (in most cases there will be) more than one interrupt vector. Thus, as I've explained in a PATCH1 thread we need a way to indicated each of them separately. eventfd seems like a good way of doing so. If u have better ideas, pls., share.
> > You haven't documented how this api works at all, you are going to have > to a lot more work to justify this, as this greatly increases the > complexity of the user/kernel api in unknown ways.
I actually do documented it a bit. Pls., check PATCH3 out. I admit that I could do a better job by for instance providing a code example. I'll improve this in v4 once we agree on all other details.
thanks, vlad
> > greg k-h
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