Re: [PATCH v5 0/8] s390: virtio: support protected virtualization

Michael Mueller
2019-06-13T11:17:59Z

Sure.

On 13.06.19 13:14, Halil Pasic wrote:
> On Thu, 13 Jun 2019 11:11:13 +0200
> Michael Mueller <mimu@linux.ibm.com> wrote:
>
>> Halil,
>>
>> I just ran my toleration tests successfully on current HW for
>> this series.
>>
>> Michael
> Thanks Michael! May I add a
> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> for each patch?
>
>> On 12.06.19 13:12, Halil Pasic wrote:
>>> Enhanced virtualization protection technology may require the use of
>>> bounce buffers for I/O. While support for this was built into the virtio
>>> core, virtio-ccw wasn't changed accordingly.
>>>
>>> Some background on technology (not part of this series) and the
>>> terminology used.
>>>
>>> * Protected Virtualization (PV):
>>>
>>> Protected Virtualization guarantees, that non-shared memory of a guest
>>> that operates in PV mode private to that guest. I.e. any attempts by the
>>> hypervisor or other guests to access it will result in an exception. If
>>> supported by the environment (machine, KVM, guest VM) a guest can decide
>>> to change into PV mode by doing the appropriate ultravisor calls.
>>>
>>> * Ultravisor:
>>>
>>> A hardware/firmware entity that manages PV guests, and polices access to
>>> their memory. A PV guest prospect needs to interact with the ultravisor,
>>> to enter PV mode, and potentially to share pages (for I/O which should
>>> be encrypted by the guest). A guest interacts with the ultravisor via so
>>> called ultravisor calls. A hypervisor needs to interact with the
>>> ultravisor to facilitate interpretation, emulation and swapping. A
>>> hypervisor interacts with the ultravisor via ultravisor calls and via
>>> the SIE state description. Generally the ultravisor sanitizes hypervisor
>>> inputs so that the guest can not be corrupted (except for denial of
>>> service.
>>>
>>>
>>> What needs to be done
>>> =====================
>>>
>>> Thus what needs to be done to bring virtio-ccw up to speed with respect
>>> to protected virtualization is:
>>> * use some 'new' common virtio stuff
>>> * make sure that virtio-ccw specific stuff uses shared memory when
>>> talking to the hypervisor (except control/communication blocks like ORB,
>>> these are handled by the ultravisor)
>>> * make sure the DMA API does what is necessary to talk through shared
>>> memory if we are a protected virtualization guest.
>>> * make sure the common IO layer plays along as well (airqs, sense).
>>>
>>>
>>> Important notes
>>> ================
>>>
>>> * This patch set is based on Martins features branch
>>> (git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git branch
>>> 'features').
>>>
>>> * Documentation is still very sketchy. I'm committed to improving this,
>>> but I'm currently hampered by some dependencies currently.
>>>
>>> * The existing naming in the common infrastructure (kernel internal
>>> interfaces) is pretty much based on the AMD SEV terminology. Thus the
>>> names aren't always perfect. There might be merit to changing these
>>> names to more abstract ones. I did not put much thought into that at
>>> the current stage.
>>>
>>> * Testing: Please use iommu_platform=on for any virtio devices you are
>>> going to test this code with (so virtio actually uses the DMA API).
>>>
>>> @Sebastian: I kept your r-b on patch 2 "s390/cio: introduce DMA pools to
>>> cio" despite the small changes pointed out below. Please do complain if
>>> it ain't OK for you!
>>>
>>> Change log
>>> ==========
>>>
>>> v4 --> v5:
>>> * work around dma_pool API not tolerating NULL dma pool (patch 4)
>>> * make the genpool based dma pools API tolerate NULL genpool (patch 2)
>>> * fix typo (patch 2)
>>> * fix unintended code move (patch 7)
>>> * add more r-b's
>>>
>>>
>>>
>>> v3 --> v4
>>> * fixed cleanup in css_bus_init() (Connie)
>>> * made cio.h include genalloc.h instead of a forward declaration
>>> (Connie)
>>> * added comments about dma_mask/coherent_dma_mask values (Connie)
>>> * fixed error handling in virtio_ccw_init() (Connie)
>>> * got rid of the *vc_dma* wrappers (Connie)
>>> * added some Reviewed-bys
>>> * rebased on top of current master, no changes were necessary
>>>
>>> v2 --> v3:
>>> * patch 2/8
>>> potential cio_dma_pool_init() returning NULL issue fixed
>>> potential cio_gp_dma_create() returning NULL issue fixed
>>> warning issues with doc type comments fixed
>>> unused define statement removed
>>> * patch 3/8
>>> potential cio_gp_dma_create() returning NULL issue fixed
>>> whitespace issue fixed
>>> warning issues with doc type comments fixed
>>> * patch 8/8
>>> potential cio_dma_zalloc() returning NULL issue fixed
>>>
>>> v1 --> v2:
>>> * patch "virtio/s390: use vring_create_virtqueue" went already upstream
>>> * patch "virtio/s390: DMA support for virtio-ccw" went already upstream
>>> * patch "virtio/s390: enable packed ring" went already upstream
>>> * Made dev.dma_mask point to dev.coherent_dma_mask for css, subchannel
>>> and ccw devices.
>>> * While rebasing 's390/airq: use DMA memory for adapter interrupts' the
>>> newly introduced kmem_cache was replaced with an equivalent dma_pool;
>>> the kalloc() allocations are now replaced with cio_dma_zalloc()
>>> allocations to avoid wasting almost a full page.
>>> * Made virtio-ccw use the new AIRQ_IV_CACHELINE flag.
>>> * fixed all remaining checkpatch issues
>>>
>>> RFC --> v1:
>>> * Fixed bugs found by Connie (may_reduce and handling reduced, warning,
>>> split move -- thanks Connie!).
>>> * Fixed console bug found by Sebastian (thanks Sebastian!).
>>> * Removed the completely useless duplicate of dma-mapping.h spotted by
>>> Christoph (thanks Christoph!).
>>> * Don't use the global DMA pool for subchannel and ccw device
>>> owned memory as requested by Sebastian. Consequences:
>>> * Both subchannel and ccw devices have their dma masks
>>> now (both specifying 31 bit addressable)
>>> * We require at least 2 DMA pages per ccw device now, most of
>>> this memory is wasted though.
>>> * DMA memory allocated by virtio is also 31 bit addressable now
>>> as virtio uses the parent (which is the ccw device).
>>> * Enabled packed ring.
>>> * Rebased onto Martins feature branch; using the actual uv (ultravisor)
>>> interface instead of TODO comments.
>>> * Added some explanations to the cover letter (Connie, David).
>>> * Squashed a couple of patches together and fixed some text stuff.
>>>
>>> Halil Pasic (8):
>>> s390/mm: force swiotlb for protected virtualization
>>> s390/cio: introduce DMA pools to cio
>>> s390/cio: add basic protected virtualization support
>>> s390/airq: use DMA memory for adapter interrupts
>>> virtio/s390: use cacheline aligned airq bit vectors
>>> virtio/s390: add indirection to indicators access
>>> virtio/s390: use DMA memory for ccw I/O and classic notifiers
>>> virtio/s390: make airq summary indicators DMA
>>>
>>> arch/s390/Kconfig | 5 +
>>> arch/s390/include/asm/airq.h | 2 +
>>> arch/s390/include/asm/ccwdev.h | 4 +
>>> arch/s390/include/asm/cio.h | 11 ++
>>> arch/s390/include/asm/mem_encrypt.h | 18 ++
>>> arch/s390/mm/init.c | 47 ++++++
>>> drivers/s390/cio/airq.c | 37 +++--
>>> drivers/s390/cio/ccwreq.c | 9 +-
>>> drivers/s390/cio/cio.h | 2 +
>>> drivers/s390/cio/css.c | 134 ++++++++++++++-
>>> drivers/s390/cio/device.c | 68 ++++++--
>>> drivers/s390/cio/device_fsm.c | 49 +++---
>>> drivers/s390/cio/device_id.c | 20 ++-
>>> drivers/s390/cio/device_ops.c | 21 ++-
>>> drivers/s390/cio/device_pgid.c | 22 +--
>>> drivers/s390/cio/device_status.c | 24 +--
>>> drivers/s390/cio/io_sch.h | 20 ++-
>>> drivers/s390/virtio/virtio_ccw.c | 246 +++++++++++++++-------------
>>> 18 files changed, 538 insertions(+), 201 deletions(-)
>>> create mode 100644 arch/s390/include/asm/mem_encrypt.h
>>>
--
Mit freundlichen Grüßen / Kind regards
Michael Müller

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