xemu/hw
Michael S. Tsirkin 110c477c2e pcie: work around for racy guest init
During boot, linux guests tend to clear all bits in pcie slot status
register which is used for hotplug.
If they clear bits that weren't set this is racy and will lose events:
not a big problem for manual hotplug on bare-metal, but a problem for us.

For example, the following is broken ATM:

/x86_64-softmmu/qemu-system-x86_64 -enable-kvm -S -machine q35  \
    -device pcie-root-port,id=pcie_root_port_0,slot=2,chassis=2,addr=0x2,bus=pcie.0 \
    -device virtio-balloon-pci,id=balloon,bus=pcie_root_port_0 \
    -monitor stdio disk.qcow2
(qemu)device_del balloon
(qemu)cont

Balloon isn't deleted as it should.

As a work-around, detect this attempt to clear slot status and revert
status to what it was before the write.

Note: in theory this can be detected as a duplicate button press
which cancels the previous press. Does not seem to happen in
practice as guests seem to only have this bug during init.

Note2: the right thing to do is probably to fix Linux to
read status before clearing it, and act on the bits that are set.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
2019-07-01 09:17:30 -04:00
..
9pfs Supply missing header guards 2019-06-12 13:20:21 +02:00
acpi hw/acpi: extract acpi_add_rom_blob() 2019-06-16 16:16:52 -04:00
adc Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
alpha Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
arm hw/arm: Correctly disable FPU/DSP for some ARMSSE-based boards 2019-06-17 15:12:25 +01:00
audio Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
block nvme: do not advertise support for unsupported arbitration mechanism 2019-06-24 15:53:01 +02:00
bt Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
char Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
core hw: Nuke hw_compat_4_0_1 and pc_compat_4_0_1 2019-06-21 13:25:29 +02:00
cpu Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
cris Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
display edid: flip the default to enabled 2019-06-13 09:34:50 +02:00
dma Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
gpio Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
hppa Supply missing header guards 2019-06-12 13:20:21 +02:00
hyperv Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
i2c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
i386 hw: Nuke hw_compat_4_0_1 and pc_compat_4_0_1 2019-06-21 13:25:29 +02:00
ide Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
input Supply missing header guards 2019-06-12 13:20:21 +02:00
intc hw/intc/arm_gicv3: GICD_TYPER.SecurityExtn is RAZ if GICD_CTLR.DS == 1 2019-06-17 15:13:19 +01:00
ipack Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
ipmi Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
isa Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
lm32 Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
m68k Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
mem Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
microblaze Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
mips Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
misc Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
moxie Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
net Supply missing header guards 2019-06-12 13:20:21 +02:00
nios2 Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
nvram Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
openrisc Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
pci pcie: work around for racy guest init 2019-07-01 09:17:30 -04:00
pci-bridge pcie: check that slt ctrl changed before deleting 2019-07-01 09:17:30 -04:00
pci-host q35: fix mmconfig and PCI0._CRS 2019-06-16 16:16:52 -04:00
pcmcia Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
ppc ppc patch queue 2019-06-12 2019-06-12 14:43:47 +01:00
rdma Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
riscv Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
s390x Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
scsi Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
sd sd: Fix out-of-bounds assertions 2019-06-21 13:25:29 +02:00
semihosting semihosting: split console_out into string and char versions 2019-06-12 17:53:22 +01:00
sh4 Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
smbios Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
sparc Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
sparc64 Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
ssi Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
timer Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
tpm Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
tricore Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
unicore32 target/unicore32: Use env_cpu, env_archcpu 2019-06-10 07:03:42 -07:00
usb Supply missing header guards 2019-06-12 13:20:21 +02:00
vfio vfio/common: Introduce vfio_set_irq_signaling helper 2019-06-13 09:57:37 -06:00
virtio vhost: fix vhost_log size overflow during migration 2019-06-16 16:16:52 -04:00
watchdog Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
xen Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
xenpv xen: Replace few mentions of xend by libxl 2019-01-14 13:45:40 +00:00
xtensa Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
Kconfig semihosting: introduce CONFIG_SEMIHOSTING 2019-05-28 10:28:50 +01:00
Makefile.objs semihosting: move semihosting configuration into its own directory 2019-05-28 10:28:50 +01:00