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Re: [PATCH v6 0/4] memory: prevent dma-reentracy issues
From: |
Alexander Bulekov |
Subject: |
Re: [PATCH v6 0/4] memory: prevent dma-reentracy issues |
Date: |
Sun, 12 Feb 2023 21:11:41 -0500 |
ping
On 230204 2307, Alexander Bulekov wrote:
> These patches aim to solve two types of DMA-reentrancy issues:
>
> 1.) mmio -> dma -> mmio case
> To solve this, we track whether the device is engaged in io by
> checking/setting a reentrancy-guard within APIs used for MMIO access.
>
> 2.) bh -> dma write -> mmio case
> This case is trickier, since we dont have a generic way to associate a
> bh with the underlying Device/DeviceState. Thus, this version allows a
> device to associate a reentrancy-guard with a bh, when creating it.
> (Instead of calling qemu_bh_new, you call qemu_bh_new_guarded)
>
> I replaced most of the qemu_bh_new invocations with the guarded analog,
> except for the ones where the DeviceState was not trivially accessible.
>
> v5 -> v6:
> - Only apply checkpatch checks to code in paths containing "/hw/"
> (/hw/ and include/hw/)
> - Fix a bug in a _guarded call added to hw/block/virtio-blk.c
> v4-> v5:
> - Add corresponding checkpatch checks
> - Save/restore reentrancy-flag when entering/exiting BHs
> - Improve documentation
> - Check object_dynamic_cast return value
>
> v3 -> v4: Instead of changing all of the DMA APIs, instead add an
> optional reentrancy guard to the BH API.
>
> v2 -> v3: Bite the bullet and modify the DMA APIs, rather than
> attempting to guess DeviceStates in BHs.
>
> Alexander Bulekov (4):
> memory: prevent dma-reentracy issues
> async: Add an optional reentrancy guard to the BH API
> checkpatch: add qemu_bh_new/aio_bh_new checks
> hw: replace most qemu_bh_new calls with qemu_bh_new_guarded
>
> docs/devel/multiple-iothreads.txt | 7 +++++++
> hw/9pfs/xen-9p-backend.c | 4 +++-
> hw/block/dataplane/virtio-blk.c | 3 ++-
> hw/block/dataplane/xen-block.c | 5 +++--
> hw/char/virtio-serial-bus.c | 3 ++-
> hw/display/qxl.c | 9 ++++++---
> hw/display/virtio-gpu.c | 6 ++++--
> hw/ide/ahci.c | 3 ++-
> hw/ide/core.c | 3 ++-
> hw/misc/imx_rngc.c | 6 ++++--
> hw/misc/macio/mac_dbdma.c | 2 +-
> hw/net/virtio-net.c | 3 ++-
> hw/nvme/ctrl.c | 6 ++++--
> hw/scsi/mptsas.c | 3 ++-
> hw/scsi/scsi-bus.c | 3 ++-
> hw/scsi/vmw_pvscsi.c | 3 ++-
> hw/usb/dev-uas.c | 3 ++-
> hw/usb/hcd-dwc2.c | 3 ++-
> hw/usb/hcd-ehci.c | 3 ++-
> hw/usb/hcd-uhci.c | 2 +-
> hw/usb/host-libusb.c | 6 ++++--
> hw/usb/redirect.c | 6 ++++--
> hw/usb/xen-usb.c | 3 ++-
> hw/virtio/virtio-balloon.c | 5 +++--
> hw/virtio/virtio-crypto.c | 3 ++-
> include/block/aio.h | 18 ++++++++++++++++--
> include/hw/qdev-core.h | 7 +++++++
> include/qemu/main-loop.h | 7 +++++--
> scripts/checkpatch.pl | 8 ++++++++
> softmmu/memory.c | 17 +++++++++++++++++
> softmmu/trace-events | 1 +
> tests/unit/ptimer-test-stubs.c | 3 ++-
> util/async.c | 18 +++++++++++++++++-
> util/main-loop.c | 5 +++--
> util/trace-events | 1 +
> 35 files changed, 147 insertions(+), 41 deletions(-)
>
> --
> 2.39.0
>