I need to rework the layout of IRQ values to be more dynamic (per a thread on current@) as I've seen at least a few systems now that have more than 256 I/O APIC pins. Currently we kind of depend on interrupt_sources[] being statically sized, but I could rework this to support dynamic sizing as a result and probably provide a tunable to control the limit on MSI interrupts (and possibly derive the default limit from the number of CPUs).
On Thursday, April 19, 2018 08:59:32 AM Eric Joyner wrote: > Is the limit going to be increased at some point? Is there a true limit > somewhere? > > On Wed, Apr 18, 2018 at 11:45 AM, John Baldwin <j...@freebsd.org> wrote: > > > Author: jhb > > Date: Wed Apr 18 18:45:34 2018 > > New Revision: 332735 > > URL: https://svnweb.freebsd.org/changeset/base/332735 > > > > Log: > > Fix two off-by-one errors when allocating MSI and MSI-X interrupts. > > > > x86 enforces an (arbitray) limit on the number of available MSI and > > MSI-X interrupts to simplify code (in particular, interrupt_source[] > > is statically sized). This means that an attempt to allocate an MSI > > vector needs to fail if it would go beyond the limit, but the checks > > for exceeding the limit had an off-by-one error. In the case of MSI-X > > which allocates interrupts one at a time this meant that IRQ 768 kept > > getting handed out multiple times for msix_alloc() instead of failing > > because all MSI IRQs were in use. > > > > Tested by: lidl > > MFC after: 1 week > > > > Modified: > > head/sys/x86/x86/msi.c > > > > Modified: head/sys/x86/x86/msi.c > > ============================================================ > > ================== > > --- head/sys/x86/x86/msi.c Wed Apr 18 18:45:04 2018 (r332734) > > +++ head/sys/x86/x86/msi.c Wed Apr 18 18:45:34 2018 (r332735) > > @@ -404,7 +404,7 @@ again: > > /* Do we need to create some new sources? */ > > if (cnt < count) { > > /* If we would exceed the max, give up. */ > > - if (i + (count - cnt) > FIRST_MSI_INT + NUM_MSI_INTS) { > > + if (i + (count - cnt) >= FIRST_MSI_INT + NUM_MSI_INTS) { > > mtx_unlock(&msi_lock); > > free(mirqs, M_MSI); > > return (ENXIO); > > @@ -645,7 +645,7 @@ again: > > /* Do we need to create a new source? */ > > if (msi == NULL) { > > /* If we would exceed the max, give up. */ > > - if (i + 1 > FIRST_MSI_INT + NUM_MSI_INTS) { > > + if (i + 1 >= FIRST_MSI_INT + NUM_MSI_INTS) { > > mtx_unlock(&msi_lock); > > return (ENXIO); > > } > > > > -- John Baldwin _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
