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The current implementation of hv_compose_msi_msg() is incompatible with the new functionality that allows changing the vCPU a VMBus channel will interrupt: if this function always calls hv_pci_onchannelcallback() in the polling loop, the interrupt going to a different CPU could cause hv_pci_onchannelcallback() to be running simultaneously in a tasklet, which will break. The current code also has a problem in that it is not synchronized with vmbus_reset_channel_cb(): hv_compose_msi_msg() could be accessing the ring buffer via the call of hv_pci_onchannelcallback() well after the time that vmbus_reset_channel_cb() has finished. Fix these issues as follows. Disable the channel tasklet before entering the polling loop in hv_compose_msi_msg() and re-enable it when done. This will prevent hv_pci_onchannelcallback() from running in a tasklet on a different CPU. Moreover, poll by always calling hv_pci_onchannelcallback(), but check the channel callback function for NULL and invoke the callback within a sched_lock critical section. This will prevent hv_compose_msi_msg() from accessing the ring buffer after vmbus_reset_channel_cb() has acquired the sched_lock spinlock. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Andrew Murray <amurray@thegoodpenguin.co.uk> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: <linux-pci@vger.kernel.org> Link: https://lore.kernel.org/r/20200406001514.19876-8-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org> |
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| .. | ||
| controller | ||
| endpoint | ||
| hotplug | ||
| pcie | ||
| switch | ||
| access.c | ||
| ats.c | ||
| bus.c | ||
| ecam.c | ||
| host-bridge.c | ||
| iov.c | ||
| irq.c | ||
| Kconfig | ||
| Makefile | ||
| mmap.c | ||
| msi.c | ||
| of.c | ||
| p2pdma.c | ||
| pci-acpi.c | ||
| pci-bridge-emul.c | ||
| pci-bridge-emul.h | ||
| pci-driver.c | ||
| pci-label.c | ||
| pci-mid.c | ||
| pci-pf-stub.c | ||
| pci-stub.c | ||
| pci-sysfs.c | ||
| pci.c | ||
| pci.h | ||
| probe.c | ||
| proc.c | ||
| quirks.c | ||
| remove.c | ||
| rom.c | ||
| search.c | ||
| setup-bus.c | ||
| setup-irq.c | ||
| setup-res.c | ||
| slot.c | ||
| syscall.c | ||
| vc.c | ||
| vpd.c | ||
| xen-pcifront.c | ||