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240ad77cb5
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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| .. | ||
| cadence | ||
| dwc | ||
| mobiveil | ||
| Kconfig | ||
| Makefile | ||
| pci-aardvark.c | ||
| pci-ftpci100.c | ||
| pci-host-common.c | ||
| pci-host-generic.c | ||
| pci-hyperv-intf.c | ||
| pci-hyperv.c | ||
| pci-mvebu.c | ||
| pci-rcar-gen2.c | ||
| pci-tegra.c | ||
| pci-thunder-ecam.c | ||
| pci-thunder-pem.c | ||
| pci-v3-semi.c | ||
| pci-versatile.c | ||
| pci-xgene-msi.c | ||
| pci-xgene.c | ||
| pcie-altera-msi.c | ||
| pcie-altera.c | ||
| pcie-brcmstb.c | ||
| pcie-iproc-bcma.c | ||
| pcie-iproc-msi.c | ||
| pcie-iproc-platform.c | ||
| pcie-iproc.c | ||
| pcie-iproc.h | ||
| pcie-mediatek.c | ||
| pcie-rcar.c | ||
| pcie-rockchip-ep.c | ||
| pcie-rockchip-host.c | ||
| pcie-rockchip.c | ||
| pcie-rockchip.h | ||
| pcie-tango.c | ||
| pcie-xilinx-nwl.c | ||
| pcie-xilinx.c | ||
| vmd.c | ||