Re: [PATCH 00/10] MdeModulePkg, OvmfPkg: unmap DMA buffers at ExitBootServices

["Zeng, Star" <star.zeng@intel.com>]

Reviewed-by: Star Zeng <star.zeng@intel.com> to MdeModulePkg changes.

-----Original Message-----
From: Laszlo Ersek [mailto:lersek@redhat.com] 
Sent: Friday, September 8, 2017 6:41 AM
To: edk2-devel-01 <edk2-devel@lists.01.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>; Brijesh Singh <brijesh.singh@amd.com>; Dong, Eric <eric.dong@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>; Justen, Jordan L <jordan.l.justen@intel.com>; Zeng, Star <star.zeng@intel.com>
Subject: [PATCH 00/10] MdeModulePkg, OvmfPkg: unmap DMA buffers at ExitBootServices

Repo:   https://github.com/lersek/edk2.git
Branch: iommu_exit_boot

This series is the result of the discussion under

  [edk2] [PATCH 0/4] MdeModulePkg: some PCI HC drivers: unmap common
                     buffers at ExitBootServices()
  https://lists.01.org/pipermail/edk2-devel/2017-September/014099.html

At ExitBootServices(), PCI and VirtIo drivers should only care about aborting pending DMA on the devices. Cleaning up PciIo mappings (which ultimately boil down to IOMMU mappings) for those aborted DMA operations should be the job of the IOMMU driver.

Patches 01 through 03 clean up the AtaAtapiPassThru driver in MdeModulePkg a little bit, because at present, (a) it unmaps the buffers and disables BMDMA in the wrong order in its DriverBindingStop() function, (b) it doesn't abort pending DMA at ExitBootServices().

This subset can be treated separately from the rest of the series, but I thought they belonged loosely together (given that AtaAtapiPassThru is used on QEMU's Q35 machine type).

Patches 04 through 07 remove VIRTIO_DEVICE_PROTOCOL.UnmapSharedBuffer()
calls from the VirtIo drivers' ExitBootServices() handlers.

(The conversion of VirtioNetDxe to device addresses is still in progress
-- Brijesh, when you submit v2 of that, under this approach, there is no need to change VirtioNetExitBoot() relative to current upstream, and you can use VirtioOperationBusMasterRead to map outgoing packets.)

Patches 08 through 10 make OvmfPkg/IoMmuDxe track all mappings, and unmap all mappings (Read, Write, CommonBuffer) that are in effect when
ExitBootServices() is called. It is ensured that PCI and VirtIo drivers abort pending DMA first, and IoMmuDxe clean up the mappings last.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Star Zeng <star.zeng@intel.com>

Thanks
Laszlo

Laszlo Ersek (10):
  MdeModulePkg/AtaAtapiPassThru: cache EnabledPciAttributes
  MdeModulePkg/AtaAtapiPassThru: unmap DMA buffers after disabling BM
    DMA
  MdeModulePkg/AtaAtapiPassThru: disable the device at
    ExitBootServices()
  OvmfPkg/VirtioBlkDxe: don't unmap VRING at ExitBootServices()
  OvmfPkg/VirtioGpuDxe: don't unmap VRING & BackingStore at
    ExitBootServices
  OvmfPkg/VirtioRngDxe: don't unmap VRING at ExitBootServices()
  OvmfPkg/VirtioScsiDxe: don't unmap VRING at ExitBootServices()
  OvmfPkg/IoMmuDxe: track all mappings
  OvmfPkg/IoMmuDxe: generalize IoMmuUnmap() to IoMmuUnmapWorker()
  OvmfPkg/IoMmuDxe: unmap all IOMMU mappings at ExitBootServices()

 MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c | 103 +++++---
 MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h |   7 +
 OvmfPkg/IoMmuDxe/AmdSevIoMmu.c                           | 246 +++++++++++++++++---
 OvmfPkg/VirtioBlkDxe/VirtioBlk.c                         |   7 +-
 OvmfPkg/VirtioGpuDxe/Commands.c                          |  23 +-
 OvmfPkg/VirtioRngDxe/VirtioRng.c                         |   7 +-
 OvmfPkg/VirtioScsiDxe/VirtioScsi.c                       |   7 +-
 7 files changed, 299 insertions(+), 101 deletions(-)

--
2.14.1.3.gb7cf6e02401b