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Re: [PATCH v6 0/4] memory: prevent dma-reentracy issues
From: |
Michael S. Tsirkin |
Subject: |
Re: [PATCH v6 0/4] memory: prevent dma-reentracy issues |
Date: |
Mon, 13 Feb 2023 15:26:49 -0500 |
On Sun, Feb 12, 2023 at 09:11:41PM -0500, Alexander Bulekov wrote:
> 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.
As long as we are adding the new APIs virtio things look ok to me.
Pls merge with rest of patches.
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> > 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
> >
- [PATCH v6 0/4] memory: prevent dma-reentracy issues, Alexander Bulekov, 2023/02/04
- [PATCH v6 1/4] memory: prevent dma-reentracy issues, Alexander Bulekov, 2023/02/04
- [PATCH v6 2/4] async: Add an optional reentrancy guard to the BH API, Alexander Bulekov, 2023/02/04
- [PATCH v6 3/4] checkpatch: add qemu_bh_new/aio_bh_new checks, Alexander Bulekov, 2023/02/04
- [PATCH v6 4/4] hw: replace most qemu_bh_new calls with qemu_bh_new_guarded, Alexander Bulekov, 2023/02/04
- Re: [PATCH v6 0/4] memory: prevent dma-reentracy issues, Alexander Bulekov, 2023/02/12
- Re: [PATCH v6 0/4] memory: prevent dma-reentracy issues, Darren Kenny, 2023/02/13
- Re: [PATCH v6 0/4] memory: prevent dma-reentracy issues, Stefan Hajnoczi, 2023/02/22