From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44928) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1akO0F-0001ia-0c for qemu-devel@nongnu.org; Sun, 27 Mar 2016 23:38:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1akO09-0005zR-KZ for qemu-devel@nongnu.org; Sun, 27 Mar 2016 23:38:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38228) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1akO09-0005zE-DT for qemu-devel@nongnu.org; Sun, 27 Mar 2016 23:38:01 -0400 Date: Mon, 28 Mar 2016 11:37:53 +0800 From: Peter Xu Message-ID: <20160328033753.GK28183@pxdev.xzpeter.org> References: <1458872009-13342-1-git-send-email-jasowang@redhat.com> <1458872009-13342-7-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1458872009-13342-7-git-send-email-jasowang@redhat.com> Subject: Re: [Qemu-devel] [RFC PATCH 6/8] intel_iommu: support device iotlb descriptor List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: Eduardo Habkost , mst@redhat.com, qemu-devel@nongnu.org, cornelia.huck@de.ibm.com, pbonzini@redhat.com, Richard Henderson On Fri, Mar 25, 2016 at 10:13:27AM +0800, Jason Wang wrote: > This patch enables device IOTLB support for intel iommu. The major > work is to implement QI device IOTLB descriptor processing and notify > the device through iommu notifier. > > Cc: Paolo Bonzini > Cc: Richard Henderson > Cc: Eduardo Habkost > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang > --- > hw/i386/intel_iommu.c | 81 ++++++++++++++++++++++++++++++++++++++---- > hw/i386/intel_iommu_internal.h | 13 +++++-- > 2 files changed, 86 insertions(+), 8 deletions(-) > [...] > +static bool vtd_process_device_iotlb_desc(IntelIOMMUState *s, > + VTDInvDesc *inv_desc) > +{ > + VTDAddressSpace *vtd_dev_as; > + IOMMUTLBEntry entry; > + struct VTDBus *vtd_bus; > + hwaddr addr; > + uint64_t sz; > + uint16_t sid; > + uint8_t devfn; > + bool size; > + uint8_t bus_num; > + > + addr = VTD_INV_DESC_DEVICE_IOTLB_ADDR(inv_desc->hi); > + sid = VTD_INV_DESC_DEVICE_IOTLB_SID(inv_desc->lo); > + devfn = sid & 0xff; > + bus_num = sid >> 8; > + size = VTD_INV_DESC_DEVICE_IOTLB_SIZE(inv_desc->hi); > + > + if ((inv_desc->lo & VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO) || > + (inv_desc->hi & VTD_INV_DESC_DEVICE_IOTLB_RSVD_HI)) { > + VTD_DPRINTF(GENERAL, "error: non-zero reserved field in Device " > + "IOTLB Invalidate Descriptor hi 0x%"PRIx64 " lo 0x%"PRIx64, > + inv_desc->hi, inv_desc->lo); > + return false; > + } > + > + vtd_bus = vtd_find_as_from_bus_num(s, bus_num); > + if (!vtd_bus) { > + goto done; > + } > + > + vtd_dev_as = vtd_bus->dev_as[devfn]; > + if (!vtd_dev_as) { > + goto done; > + } > + > + if (size) { > + sz = ffsll(~(addr >> VTD_PAGE_SHIFT)); > + addr = addr & ~((1 << (sz + VTD_PAGE_SHIFT)) - 1); > + sz = VTD_PAGE_SIZE << sz; For these three lines, could it be shorter like: sz = 1 << ffsll(~addr); addr &= ~(sz - 1); It seems that we can avoid using VTD_PAGE_*. > + } else { > + sz = VTD_PAGE_SIZE; > + } > + > + entry.target_as = &vtd_dev_as->as; > + entry.addr_mask = sz - 1; > + entry.iova = addr; > + memory_region_notify_iommu(entry.target_as->root, entry); Here, we seems to be posting this invalidation to all registered notifiers. Since this is a device-tlb invalidation, and we should know which device (BDF) that we should invalidate, is there any way that we can directly route this info to that specific device? E.g., if we enable VFIO with current patch, this notify will possibly be passed to VFIO devices as well, even it's actually for vhost devices. Not sure whether there would be problem. Another thing totally not related to this patch: I see that the second parameter for memory_region_notify_iommu() is IOMMUTLBEntry, rather than its pointer. While inside of the funccall, it only passes in the pointer directly: void memory_region_notify_iommu(MemoryRegion *mr, IOMMUTLBEntry entry) { assert(memory_region_is_iommu(mr)); notifier_list_notify(&mr->iommu_notify, &entry); } Shall we change "entry" into a pointer as well? I found no reason why we need to keep this IOMMUTLBEntry in stack twice... Thanks. -- peterx