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Violators will be prosecuted for from ; Thu, 13 Jun 2019 10:11:20 +0100 Reply-To: mimu@linux.ibm.com Subject: Re: [PATCH v5 0/8] s390: virtio: support protected virtualization References: <20190612111236.99538-1-pasic@linux.ibm.com> From: Michael Mueller Date: Thu, 13 Jun 2019 11:11:13 +0200 MIME-Version: 1.0 In-Reply-To: <20190612111236.99538-1-pasic@linux.ibm.com> Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 8bit Message-Id: <4d10d4f8-aeb0-a5bc-6900-ab7901c01cf2@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Halil Pasic , kvm@vger.kernel.org, linux-s390@vger.kernel.org, Cornelia Huck , Sebastian Ott , Heiko Carstens Cc: virtualization@lists.linux-foundation.org, "Michael S. Tsirkin" , Christoph Hellwig , Thomas Huth , Christian Borntraeger , Viktor Mihajlovski , Vasily Gorbik , Janosch Frank , Claudio Imbrenda , Farhan Ali , Eric Farman , "Jason J. Herne" Halil, I just ran my toleration tests successfully on current HW for this series. Michael 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 IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Matthias Hartmann Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294