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From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Peter Xu <peterx@redhat.com>
Cc: "jean-philippe@linaro.org" <jean-philippe@linaro.org>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	Jacob Pan <jacob.jun.pan@linux.intel.com>,
	Yi Sun <yi.y.sun@linux.intel.com>,
	Eduardo Habkost <ehabkost@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"mst@redhat.com" <mst@redhat.com>,
	"Tian, Jun J" <jun.j.tian@intel.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"eric.auger@redhat.com" <eric.auger@redhat.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"Wu, Hao" <hao.wu@intel.com>, "Sun, Yi Y" <yi.y.sun@intel.com>,
	Richard Henderson <rth@twiddle.net>,
	"david@gibson.dropbear.id.au" <david@gibson.dropbear.id.au>
Subject: RE: [PATCH v1 20/22] intel_iommu: propagate PASID-based iotlb invalidation to host
Date: Thu, 26 Mar 2020 05:41:39 +0000	[thread overview]
Message-ID: <A2975661238FB949B60364EF0F2C25743A203E63@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <A2975661238FB949B60364EF0F2C25743A2022C5@SHSMSX104.ccr.corp.intel.com>

> From: Liu, Yi L
> Sent: Wednesday, March 25, 2020 9:22 PM
> To: 'Peter Xu' <peterx@redhat.com>
> Subject: RE: [PATCH v1 20/22] intel_iommu: propagate PASID-based iotlb
> invalidation to host
> 
> > From: Peter Xu <peterx@redhat.com>
> > Sent: Wednesday, March 25, 2020 2:34 AM
> > To: Liu, Yi L <yi.l.liu@intel.com>
> > Subject: Re: [PATCH v1 20/22] intel_iommu: propagate PASID-based iotlb
> > invalidation to host
> >
> > On Sun, Mar 22, 2020 at 05:36:17AM -0700, Liu Yi L wrote:
> > > This patch propagates PASID-based iotlb invalidation to host.
> > >
> > > Intel VT-d 3.0 supports nested translation in PASID granular.
> > > Guest SVA support could be implemented by configuring nested
> > > translation on specific PASID. This is also known as dual stage DMA
> > > translation.
> > >
> > > Under such configuration, guest owns the GVA->GPA translation which
> > > is configured as first level page table in host side for a specific
> > > pasid, and host owns GPA->HPA translation. As guest owns first level
> > > translation table, piotlb invalidation should be propagated to host
> > > since host IOMMU will cache first level page table related mappings
> > > during DMA address translation.
> > >
> > > This patch traps the guest PASID-based iotlb flush and propagate it
> > > to host.
> > >
> > > Cc: Kevin Tian <kevin.tian@intel.com>
> > > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > > Cc: Peter Xu <peterx@redhat.com>
> > > Cc: Yi Sun <yi.y.sun@linux.intel.com>
> > > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > > Cc: Richard Henderson <rth@twiddle.net>
> > > Cc: Eduardo Habkost <ehabkost@redhat.com>
> > > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> > > ---
> > >  hw/i386/intel_iommu.c          | 139
> > +++++++++++++++++++++++++++++++++++++++++
> > >  hw/i386/intel_iommu_internal.h |   7 +++
> > >  2 files changed, 146 insertions(+)
> > >
> > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index
> > > b9ac07d..10d314d 100644
> > > --- a/hw/i386/intel_iommu.c
> > > +++ b/hw/i386/intel_iommu.c
> > > @@ -3134,15 +3134,154 @@ static bool
> > vtd_process_pasid_desc(IntelIOMMUState *s,
> > >      return (ret == 0) ? true : false;  }
> > >
> > > +/**
> > > + * Caller of this function should hold iommu_lock.
> > > + */
> > > +static void vtd_invalidate_piotlb(IntelIOMMUState *s,
> > > +                                  VTDBus *vtd_bus,
> > > +                                  int devfn,
> > > +                                  DualIOMMUStage1Cache
> > > +*stage1_cache) {
> > > +    VTDHostIOMMUContext *vtd_dev_icx;
> > > +    HostIOMMUContext *host_icx;
> > > +
> > > +    vtd_dev_icx = vtd_bus->dev_icx[devfn];
> > > +    if (!vtd_dev_icx) {
> > > +        goto out;
> > > +    }
> > > +    host_icx = vtd_dev_icx->host_icx;
> > > +    if (!host_icx) {
> > > +        goto out;
> > > +    }
> > > +    if (host_iommu_ctx_flush_stage1_cache(host_icx, stage1_cache)) {
> > > +        error_report("Cache flush failed");
> >
> > I think this should not easily be triggered by the guest, but just in
> > case... Let's use
> > error_report_once() to be safe.
> 
> Agreed.
> 
> > > +    }
> > > +out:
> > > +    return;
> > > +}
> > > +
> > > +static inline bool vtd_pasid_cache_valid(
> > > +                          VTDPASIDAddressSpace *vtd_pasid_as) {
> > > +    return vtd_pasid_as->iommu_state &&
> >
> > This check can be dropped because always true?
> >
> > If you agree with both the changes, please add:
> >
> > Reviewed-by: Peter Xu <peterx@redhat.com>
> 
> I think the code should ensure all the pasid_as in hash table is valid. And we can
> since all the operations are under protection of iommu_lock.
> 
Peter,

I think my reply was wrong. pasid_as in has table may be stale since
the per pasid_as cache_gen may be not identical with the cache_gen
in iommu_state. e.g. vtd_pasid_cache_reset() only increases the
cache_gen in iommu_state. So there will be pasid_as in hash table
which has cached pasid entry but its cache_gen is not equal to the
one in iommu_state. For such pasid_as, we should treat it as stale.
So I guess the vtd_pasid_cache_valid() is still necessary.

Regards,
Yi Liu


  reply	other threads:[~2020-03-26  5:43 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-22 12:35 [PATCH v1 00/22] intel_iommu: expose Shared Virtual Addressing to VMs Liu Yi L
2020-03-22 12:35 ` [PATCH v1 01/22] scripts/update-linux-headers: Import iommu.h Liu Yi L
2020-03-22 12:35 ` [PATCH v1 02/22] header file update VFIO/IOMMU vSVA APIs Liu Yi L
2020-03-29 16:32   ` Auger Eric
2020-03-30  7:06     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 03/22] vfio: check VFIO_TYPE1_NESTING_IOMMU support Liu Yi L
2020-03-22 12:36 ` [PATCH v1 04/22] hw/iommu: introduce HostIOMMUContext Liu Yi L
2020-03-23 20:58   ` Peter Xu
2020-03-24 10:00     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 05/22] hw/pci: modify pci_setup_iommu() to set PCIIOMMUOps Liu Yi L
2020-03-22 12:36 ` [PATCH v1 06/22] hw/pci: introduce pci_device_set/unset_iommu_context() Liu Yi L
2020-03-23 21:15   ` Peter Xu
2020-03-24 10:02     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 07/22] intel_iommu: add set/unset_iommu_context callback Liu Yi L
2020-03-23 21:29   ` Peter Xu
2020-03-24 11:15     ` Liu, Yi L
2020-03-24 15:24       ` Peter Xu
2020-03-25  9:37         ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 08/22] vfio: init HostIOMMUContext per-container Liu Yi L
     [not found]   ` <20200323213943.GR127076@xz-x1>
2020-03-24 13:03     ` Liu, Yi L
2020-03-24 14:45       ` Peter Xu
2020-03-25  9:30         ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 09/22] vfio/common: check PASID alloc/free availability Liu Yi L
2020-03-23 22:06   ` Peter Xu
2020-03-24 11:18     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 10/22] intel_iommu: add virtual command capability support Liu Yi L
2020-03-22 12:36 ` [PATCH v1 11/22] intel_iommu: process PASID cache invalidation Liu Yi L
2020-03-22 12:36 ` [PATCH v1 12/22] intel_iommu: add PASID cache management infrastructure Liu Yi L
2020-03-24 17:32   ` Peter Xu
2020-03-25 12:20     ` Liu, Yi L
2020-03-25 14:52       ` Peter Xu
2020-03-26  6:15         ` Liu, Yi L
2020-03-26 13:57           ` Liu, Yi L
2020-03-26 15:53             ` Peter Xu
2020-03-27  1:33               ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 13/22] vfio: add bind stage-1 page table support Liu Yi L
2020-03-24 17:41   ` Peter Xu
2020-03-25  9:49     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 14/22] intel_iommu: bind/unbind guest page table to host Liu Yi L
2020-03-24 17:46   ` Peter Xu
2020-03-25 12:42     ` Liu, Yi L
2020-03-25 14:56       ` Peter Xu
2020-03-26  3:04         ` Liu, Yi L
2020-03-25 12:47     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 15/22] intel_iommu: replay guest pasid bindings " Liu Yi L
2020-03-24 18:00   ` Peter Xu
2020-03-25 13:14     ` Liu, Yi L
2020-03-25 15:06       ` Peter Xu
2020-03-26  3:17         ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 16/22] intel_iommu: replay pasid binds after context cache invalidation Liu Yi L
2020-03-24 18:07   ` Peter Xu
2020-03-25 13:18     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 17/22] intel_iommu: do not pass down pasid bind for PASID #0 Liu Yi L
2020-03-24 18:13   ` Peter Xu
2020-03-25 10:42     ` Liu, Yi L
2020-03-25 15:12       ` Peter Xu
2020-03-26  2:42         ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 18/22] vfio: add support for flush iommu stage-1 cache Liu Yi L
2020-03-24 18:19   ` Peter Xu
2020-03-25 10:40     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 19/22] intel_iommu: process PASID-based iotlb invalidation Liu Yi L
2020-03-24 18:26   ` Peter Xu
2020-03-25 13:36     ` Liu, Yi L
2020-03-25 15:15       ` Peter Xu
2020-03-29 11:17         ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 20/22] intel_iommu: propagate PASID-based iotlb invalidation to host Liu Yi L
2020-03-24 18:34   ` Peter Xu
2020-03-25 13:21     ` Liu, Yi L
2020-03-26  5:41       ` Liu, Yi L [this message]
2020-03-26 13:02         ` Peter Xu
2020-03-26 13:22           ` Peter Xu
2020-03-26 13:33             ` Liu, Yi L
2020-03-26 13:23           ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 21/22] intel_iommu: process PASID-based Device-TLB invalidation Liu Yi L
2020-03-24 18:36   ` Peter Xu
2020-03-25  9:19     ` Liu, Yi L
2020-03-22 12:36 ` [PATCH v1 22/22] intel_iommu: modify x-scalable-mode to be string option Liu Yi L
2020-03-24 18:39   ` Peter Xu
2020-03-25 13:22     ` Liu, Yi L
2020-03-22 13:25 ` [PATCH v1 00/22] intel_iommu: expose Shared Virtual Addressing to VMs no-reply

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