On Thu, Jun 14, 2012 at 05:55:18PM +0200, Jan Kiszka wrote:
> On 2012-06-14 17:49, Michael S. Tsirkin wrote:
> > On Wed, Jun 13, 2012 at 10:51:19PM -0600, Alex Williamson wrote:
> >> msi_init() takes over a BAR without really specifying or allowing
> >> specification of how it does so. Instead, let's split it into
> >> two interfaces, one fully specified, and one trivially easy. This
> >> implements the latter. msix_init_exclusive_bar() takes over
> >> allocating and filling a PCI BAR _exclusively_ for the use of MSIX.
> >> When used, the matching msi_uninit_exclusive_bar() should be used
> >> to tear it down.
> >>
> >> Signed-off-by: Alex Williamson <alex.william...@redhat.com>
> >> ---
> >>
> >> hw/msix.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> >> hw/msix.h | 3 +++
> >> hw/pci.h | 2 ++
> >> 3 files changed, 48 insertions(+)
> >>
> >> diff --git a/hw/msix.c b/hw/msix.c
> >> index b64f109..a4cdfb0 100644
> >> --- a/hw/msix.c
> >> +++ b/hw/msix.c
> >> @@ -299,6 +299,41 @@ err_config:
> >> return ret;
> >> }
> >>
> >> +int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries,
> >> + uint8_t bar_nr)
> >> +{
> >> + int ret;
> >> + char *name;
> >> +
> >> + /*
> >> + * Migration compatibility dictates that this remains a 4k
> >> + * BAR with the vector table in the lower half and PBA in
> >> + * the upper half.
> >> + */
> >> + if (nentries * PCI_MSIX_ENTRY_SIZE > 2048) {
> >> + return -EINVAL;
> >> + }
> >> +
> >> + if (asprintf(&name, "%s MSIX BAR", dev->name) == -1) {
> >> + return -ENOMEM;
> >> + }
> >> +
> >> + memory_region_init(&dev->msix_exclusive_bar, name, 4096);
> >> +
> >> + free(name);
> >> +
> >> + ret = msix_init(dev, nentries, &dev->msix_exclusive_bar, bar_nr,
> >> 4096);
> >> + if (ret) {
> >> + memory_region_destroy(&dev->msix_exclusive_bar);
> >> + return ret;
> >> + }
> >> +
> >> + pci_register_bar(dev, bar_nr, PCI_BASE_ADDRESS_SPACE_MEMORY,
> >> + &dev->msix_exclusive_bar);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> static void msix_free_irq_entries(PCIDevice *dev)
> >> {
> >> int vector;
> >> @@ -329,6 +364,14 @@ int msix_uninit(PCIDevice *dev, MemoryRegion *bar)
> >> return 0;
> >> }
> >>
> >> +void msix_uninit_exclusive_bar(PCIDevice *dev)
> >> +{
> >> + if (msix_present(dev)) {
> >> + msix_uninit(dev, &dev->msix_exclusive_bar);
> >> + memory_region_destroy(&dev->msix_exclusive_bar);
> >> + }
> >> +}
> >> +
> >> void msix_save(PCIDevice *dev, QEMUFile *f)
> >> {
> >> unsigned n = dev->msix_entries_nr;
> >> diff --git a/hw/msix.h b/hw/msix.h
> >> index e5a488d..bed6bfb 100644
> >> --- a/hw/msix.h
> >> +++ b/hw/msix.h
> >> @@ -7,11 +7,14 @@
> >> int msix_init(PCIDevice *pdev, unsigned short nentries,
> >> MemoryRegion *bar,
> >> unsigned bar_nr, unsigned bar_size);
> >> +int msix_init_exclusive_bar(PCIDevice *dev, unsigned short nentries,
> >> + uint8_t bar_nr);
> >>
> >> void msix_write_config(PCIDevice *pci_dev, uint32_t address,
> >> uint32_t val, int len);
> >>
> >> int msix_uninit(PCIDevice *d, MemoryRegion *bar);
> >> +void msix_uninit_exclusive_bar(PCIDevice *dev);
> >>
> >> unsigned int msix_nr_vectors_allocated(const PCIDevice *dev);
> >>
> >> diff --git a/hw/pci.h b/hw/pci.h
> >> index 4c96268..d517a54 100644
> >> --- a/hw/pci.h
> >> +++ b/hw/pci.h
> >> @@ -226,6 +226,8 @@ struct PCIDevice {
> >>
> >> /* Space to store MSIX table */
> >> uint8_t *msix_table_page;
> >> + /* MemoryRegion container for msix exclusive BAR setup */
> >> + MemoryRegion msix_exclusive_bar;
> >
> > Wrappers are good but this doesn't belong in PCIDevice IMO.
> > E.g. when I debug and look at data structure I don't want to dig into
> > code and go "oh this device uses an exclusive bar to it's here, that one
> > uses a non exlcusive so the field is invalid, the real bar is over
> > there.
> >
> > Keep the region in devices where it was, pass to msix_init_exclusive_bar
> > by parameter.
>
> I disagree. There are plenty of fields in PCIDevice that are only used
> under certain circumstances. This is just +1, and it makes the interface
> usage much easier.
>
> Jan
*Much* easier? It's one parameter less.
> --
> Siemens AG, Corporate Technology, CT T DE IT 1
> Corporate Competence Center Embedded Linux
