qemu-e2k/hw
Alexey Kardashevskiy 5f36666722 spapr_iommu: Do not replay mappings from just created DMA window
On sPAPR vfio_listener_region_add() is called in 2 situations:
1. a new listener is registered from vfio_connect_container();
2. a new IOMMU Memory Region is added from rtas_ibm_create_pe_dma_window().

In both cases vfio_listener_region_add() calls
memory_region_iommu_replay() to notify newly registered IOMMU notifiers
about existing mappings which is totally desirable for case 1.

However for case 2 it is nothing but noop as the window has just been
created and has no valid mappings so replaying those does not do anything.
It is barely noticeable with usual guests but if the window happens to be
really big, such no-op replay might take minutes and trigger RCU stall
warnings in the guest.

For example, a upcoming GPU RAM memory region mapped at 64TiB (right
after SPAPR_PCI_LIMIT) causes a 64bit DMA window to be at least 128TiB
which is (128<<40)/0x10000=2.147.483.648 TCEs to replay.

This mitigates the problem by adding an "skipping_replay" flag to
sPAPRTCETable and defining sPAPR own IOMMU MR replay() hook which does
exactly the same thing as the generic one except it returns early if
@skipping_replay==true.

Another way of fixing this would be delaying replay till the very first
H_PUT_TCE but this does not work if in-kernel H_PUT_TCE handler is
enabled (a likely case).

When "ibm,create-pe-dma-window" is complete, the guest will map only
required regions of the huge DMA window.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20190307050518.64968-2-aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2019-03-12 14:33:04 +11:00
..
9pfs virtio: express virtio dependencies with Kconfig 2019-03-07 21:45:53 +01:00
acpi i386-softmmu.mak: remove all CONFIG_* except boards definitions 2019-03-07 21:45:53 +01:00
adc kconfig: introduce kconfig files 2019-03-07 21:45:53 +01:00
alpha - qtest fixes 2019-03-08 16:31:34 +00:00
arm - qtest fixes 2019-03-08 16:31:34 +00:00
audio i2c: express dependencies with Kconfig 2019-03-07 21:45:53 +01:00
block Pull request 2019-03-09 17:35:48 +00:00
bt kconfig: introduce kconfig files 2019-03-07 21:45:53 +01:00
char virtio: express virtio dependencies with Kconfig 2019-03-07 21:45:53 +01:00
core kconfig: introduce kconfig files 2019-03-07 21:45:53 +01:00
cpu kconfig: introduce kconfig files 2019-03-07 21:45:53 +01:00
cris cris-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
display hw/display: Add basic ATI VGA emulation 2019-03-11 08:04:55 +01:00
dma isa: express dependencies with kconfig 2019-03-07 21:45:53 +01:00
gpio i2c: express dependencies with Kconfig 2019-03-07 21:45:53 +01:00
hppa - qtest fixes 2019-03-08 16:31:34 +00:00
hyperv hyperv: express dependencies with kconfig 2019-03-07 21:45:53 +01:00
i2c PPC: E500: Add FSL I2C controller and integrate RTC with it 2019-03-12 14:33:04 +11:00
i386 update copyright notice 2019-03-11 16:33:49 +01:00
ide isa: express dependencies with kconfig 2019-03-07 21:45:53 +01:00
input virtio: express virtio dependencies with Kconfig 2019-03-07 21:45:53 +01:00
intc ppc/xive: activate HV support 2019-03-12 14:33:04 +11:00
ipack build: convert pci.mak to Kconfig 2019-03-07 21:45:53 +01:00
ipmi ipmi: express dependencies with kconfig 2019-03-07 21:45:53 +01:00
isa isa: express SuperIO dependencies with Kconfig 2019-03-07 21:45:53 +01:00
lm32 - qtest fixes 2019-03-08 16:31:34 +00:00
m68k m68k-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
mem ppc64: Express dependencies of 'pseries' and 'powernv' machines with kconfig 2019-03-07 21:45:53 +01:00
microblaze - qtest fixes 2019-03-08 16:31:34 +00:00
mips mips_fulong2e: Add on-board graphics chip 2019-03-11 08:04:55 +01:00
misc sparc-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
moxie moxie-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
net - qtest fixes 2019-03-08 16:31:34 +00:00
nios2 nios2-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
nvram i2c: express dependencies with Kconfig 2019-03-07 21:45:53 +01:00
openrisc or1k-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
pci build: convert pci.mak to Kconfig 2019-03-07 21:45:53 +01:00
pci-bridge i386-softmmu.mak: remove all CONFIG_* except boards definitions 2019-03-07 21:45:53 +01:00
pci-host ppc: Express dependencies of the Mac machines with kconfig 2019-03-07 21:46:19 +01:00
pcmcia kconfig: introduce kconfig files 2019-03-07 21:45:53 +01:00
ppc spapr_iommu: Do not replay mappings from just created DMA window 2019-03-12 14:33:04 +11:00
rdma hw/rdma: modify struct initialization 2019-01-19 11:01:33 +02:00
riscv riscv/Kconfig: enable PCI_DEVICES 2019-03-11 16:33:49 +01:00
s390x s390x: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
scsi lsi: 810/895A are always little endian 2019-03-11 16:33:49 +01:00
sd sd: express dependencies with kconfig 2019-03-07 21:45:53 +01:00
sh4 - qtest fixes 2019-03-08 16:31:34 +00:00
smbios kconfig: introduce kconfig files 2019-03-07 21:45:53 +01:00
sparc sparc-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
sparc64 sparc64-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
ssi ssi: express dependencies with kconfig 2019-03-07 21:45:53 +01:00
timer i386-softmmu.mak: remove all CONFIG_* except boards definitions 2019-03-07 21:45:53 +01:00
tpm tpm: express dependencies with Kconfig 2019-03-07 21:45:53 +01:00
tricore - qtest fixes 2019-03-08 16:31:34 +00:00
unicore32 unicore32-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
usb - qtest fixes 2019-03-08 16:31:34 +00:00
vfio vfio/spapr: Rename local systempagesize variable 2019-03-12 10:50:59 +11:00
virtio virtio: add class_size to VirtioPCIDeviceTypeInfo 2019-03-11 08:04:12 +01:00
watchdog ptimer: express dependencies with Kconfig 2019-03-07 21:45:53 +01:00
xen xen: fix xen-bus state model to allow frontend re-connection 2019-02-04 11:04:49 +00:00
xenpv xen: Replace few mentions of xend by libxl 2019-01-14 13:45:40 +00:00
xtensa xtensa-softmmu.mak: express dependencies with Kconfig 2019-03-07 21:46:19 +01:00
Kconfig ptimer: express dependencies with Kconfig 2019-03-07 21:45:53 +01:00
Makefile.objs i2c: express dependencies with Kconfig 2019-03-07 21:45:53 +01:00