freebsd-dev/sys/amd64
John Baldwin 254e4e5b77 Simplify swi for bus_dma.
When a DMA request using bounce pages completes, a swi is triggered to
schedule pending DMA requests using the just-freed bounce pages.  For
a long time this bus_dma swi has been tied to a "virtual memory" swi
(swi_vm).  However, all of the swi_vm implementations are the same and
consist of checking a flag (busdma_swi_pending) which is always true
and if set calling busdma_swi.  I suspect this dates back to the
pre-SMPng days and that the intention was for swi_vm to serve as a
mux.  However, in the current scheme there's no need for the mux.

Instead, remove swi_vm and vm_ih.  Each bus_dma implementation that
uses bounce pages is responsible for creating its own swi (busdma_ih)
which it now schedules directly.  This swi invokes busdma_swi directly
removing the need for busdma_swi_pending.

One consequence is that the swi now works on RISC-V which had previously
failed to invoke busdma_swi from swi_vm.

Reviewed by:	imp, kib
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D33447
2021-12-28 13:51:25 -08:00
..
acpica amd64 wakeup: rework trampoline page allocation 2021-09-14 00:23:15 +03:00
amd64 Simplify swi for bus_dma. 2021-12-28 13:51:25 -08:00
conf Remove references to PCMCIA 2021-12-14 15:27:47 -07:00
ia32 amd64 ia32 vdso: add unwind annotations to the signal trampoline 2021-12-06 20:47:24 +02:00
include Simplify swi for bus_dma. 2021-12-28 13:51:25 -08:00
linux sysent: regenerate 2021-12-16 20:56:28 -06:00
linux32 sysent: regenerate 2021-12-16 20:56:28 -06:00
pci
sgx
vmm vlapic: Schedule callouts on the local CPU 2021-10-19 21:22:57 -04:00
Makefile Bring the tags and links entries for amd64 up to date. 2021-09-27 20:04:51 -07:00