From: Kirti Wankhede <kwankhede@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: cohuck@redhat.com, cjia@nvidia.com, aik@ozlabs.ru,
Zhengxiao.zx@Alibaba-inc.com, shuangtai.tst@alibaba-inc.com,
qemu-devel@nongnu.org, peterx@redhat.com, eauger@redhat.com,
yi.l.liu@intel.com, quintela@redhat.com, ziye.yang@intel.com,
armbru@redhat.com, mlevitsk@redhat.com, pasic@linux.ibm.com,
felipe@nutanix.com, zhi.a.wang@intel.com, kevin.tian@intel.com,
yan.y.zhao@intel.com, dgilbert@redhat.com,
changpeng.liu@intel.com, eskultet@redhat.com, Ken.Xue@amd.com,
jonathan.davies@nutanix.com, pbonzini@redhat.com
Subject: Re: [PATCH v26 13/17] vfio: create mapped iova list when vIOMMU is enabled
Date: Mon, 19 Oct 2020 11:31:03 +0530 [thread overview]
Message-ID: <d7337283-72b6-3047-3c91-580697a63715@nvidia.com> (raw)
In-Reply-To: <20200925162316.53dbd2b0@x1.home>
On 9/26/2020 3:53 AM, Alex Williamson wrote:
> On Wed, 23 Sep 2020 04:54:15 +0530
> Kirti Wankhede <kwankhede@nvidia.com> wrote:
>
>> Create mapped iova list when vIOMMU is enabled. For each mapped iova
>> save translated address. Add node to list on MAP and remove node from
>> list on UNMAP.
>> This list is used to track dirty pages during migration.
>>
>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
>> ---
>> hw/vfio/common.c | 58 ++++++++++++++++++++++++++++++++++++++-----
>> include/hw/vfio/vfio-common.h | 8 ++++++
>> 2 files changed, 60 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index d4959c036dd1..dc56cded2d95 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -407,8 +407,8 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
>> }
>>
>> /* Called with rcu_read_lock held. */
>> -static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
>> - bool *read_only)
>> +static bool vfio_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
>> + ram_addr_t *ram_addr, bool *read_only)
>> {
>> MemoryRegion *mr;
>> hwaddr xlat;
>> @@ -439,8 +439,17 @@ static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
>> return false;
>> }
>>
>> - *vaddr = memory_region_get_ram_ptr(mr) + xlat;
>> - *read_only = !writable || mr->readonly;
>> + if (vaddr) {
>> + *vaddr = memory_region_get_ram_ptr(mr) + xlat;
>> + }
>> +
>> + if (ram_addr) {
>> + *ram_addr = memory_region_get_ram_addr(mr) + xlat;
>> + }
>> +
>> + if (read_only) {
>> + *read_only = !writable || mr->readonly;
>> + }
>>
>> return true;
>> }
>> @@ -450,7 +459,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>> VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
>> VFIOContainer *container = giommu->container;
>> hwaddr iova = iotlb->iova + giommu->iommu_offset;
>> - bool read_only;
>> void *vaddr;
>> int ret;
>>
>> @@ -466,7 +474,10 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>> rcu_read_lock();
>>
>> if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
>> - if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
>> + ram_addr_t ram_addr;
>> + bool read_only;
>> +
>> + if (!vfio_get_xlat_addr(iotlb, &vaddr, &ram_addr, &read_only)) {
>> goto out;
>> }
>> /*
>> @@ -484,8 +495,28 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>> "0x%"HWADDR_PRIx", %p) = %d (%m)",
>> container, iova,
>> iotlb->addr_mask + 1, vaddr, ret);
>> + } else {
>> + VFIOIovaRange *iova_range;
>> +
>> + iova_range = g_malloc0(sizeof(*iova_range));
>> + iova_range->iova = iova;
>> + iova_range->size = iotlb->addr_mask + 1;
>> + iova_range->ram_addr = ram_addr;
>> +
>> + QLIST_INSERT_HEAD(&giommu->iova_list, iova_range, next);
>> }
>> } else {
>> + VFIOIovaRange *iova_range, *tmp;
>> +
>> + QLIST_FOREACH_SAFE(iova_range, &giommu->iova_list, next, tmp) {
>> + if (iova_range->iova >= iova &&
>> + iova_range->iova + iova_range->size <= iova +
>> + iotlb->addr_mask + 1) {
>> + QLIST_REMOVE(iova_range, next);
>> + g_free(iova_range);
>> + }
>> + }
>> +
>
>
> This is some pretty serious overhead... can't we trigger a replay when
> migration is enabled to build this information then?
Are you suggesting to call memory_region_iommu_replay() before
vfio_sync_dirty_bitmap(), which would call vfio_iommu_map_notify() where
iova list of mapping is maintained? Then in the notifer check if
migration_is_running() and container->dirty_pages_supported == true,
then only create iova mapping tree? In this case how would we know that
this is triggered by
vfio_sync_dirty_bitmap()
-> memory_region_iommu_replay()
and we don't have to call vfio_dma_map()?
> We're looking at
> potentially thousands of entries, so a list is probably also not a good
> choice.
Changing it to tree.
Thanks,
Kirti
I don't think it's acceptable to incur this even when not
> migrating (ie. the vast majority of the time). Thanks,
>
> Alex
>
>> ret = vfio_dma_unmap(container, iova, iotlb->addr_mask + 1);
>> if (ret) {
>> error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
>> @@ -642,6 +673,7 @@ static void vfio_listener_region_add(MemoryListener *listener,
>> g_free(giommu);
>> goto fail;
>> }
>> + QLIST_INIT(&giommu->iova_list);
>> QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
>> memory_region_iommu_replay(giommu->iommu, &giommu->n);
>>
>> @@ -740,6 +772,13 @@ static void vfio_listener_region_del(MemoryListener *listener,
>> QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
>> if (MEMORY_REGION(giommu->iommu) == section->mr &&
>> giommu->n.start == section->offset_within_region) {
>> + VFIOIovaRange *iova_range, *tmp;
>> +
>> + QLIST_FOREACH_SAFE(iova_range, &giommu->iova_list, next, tmp) {
>> + QLIST_REMOVE(iova_range, next);
>> + g_free(iova_range);
>> + }
>> +
>> memory_region_unregister_iommu_notifier(section->mr,
>> &giommu->n);
>> QLIST_REMOVE(giommu, giommu_next);
>> @@ -1541,6 +1580,13 @@ static void vfio_disconnect_container(VFIOGroup *group)
>> QLIST_REMOVE(container, next);
>>
>> QLIST_FOREACH_SAFE(giommu, &container->giommu_list, giommu_next, tmp) {
>> + VFIOIovaRange *iova_range, *itmp;
>> +
>> + QLIST_FOREACH_SAFE(iova_range, &giommu->iova_list, next, itmp) {
>> + QLIST_REMOVE(iova_range, next);
>> + g_free(iova_range);
>> + }
>> +
>> memory_region_unregister_iommu_notifier(
>> MEMORY_REGION(giommu->iommu), &giommu->n);
>> QLIST_REMOVE(giommu, giommu_next);
>> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
>> index 0a1651eda2d0..aa7524fe2cc5 100644
>> --- a/include/hw/vfio/vfio-common.h
>> +++ b/include/hw/vfio/vfio-common.h
>> @@ -89,11 +89,19 @@ typedef struct VFIOContainer {
>> QLIST_ENTRY(VFIOContainer) next;
>> } VFIOContainer;
>>
>> +typedef struct VFIOIovaRange {
>> + hwaddr iova;
>> + size_t size;
>> + ram_addr_t ram_addr;
>> + QLIST_ENTRY(VFIOIovaRange) next;
>> +} VFIOIovaRange;
>> +
>> typedef struct VFIOGuestIOMMU {
>> VFIOContainer *container;
>> IOMMUMemoryRegion *iommu;
>> hwaddr iommu_offset;
>> IOMMUNotifier n;
>> + QLIST_HEAD(, VFIOIovaRange) iova_list;
>> QLIST_ENTRY(VFIOGuestIOMMU) giommu_next;
>> } VFIOGuestIOMMU;
>>
>
next prev parent reply other threads:[~2020-10-19 6:03 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 23:24 [PATCH QEMU v25 00/17] Add migration support for VFIO devices Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 01/17] vfio: Add function to unmap VFIO region Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 02/17] vfio: Add vfio_get_object callback to VFIODeviceOps Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 03/17] vfio: Add save and load functions for VFIO PCI devices Kirti Wankhede
2020-09-23 6:38 ` Zenghui Yu
2020-09-24 22:49 ` Alex Williamson
2020-10-21 9:30 ` Zenghui Yu
2020-10-21 19:03 ` Alex Williamson
2020-09-22 23:24 ` [PATCH v26 04/17] vfio: Add migration region initialization and finalize function Kirti Wankhede
2020-09-24 14:08 ` Cornelia Huck
2020-10-17 20:14 ` Kirti Wankhede
2020-09-25 20:20 ` Alex Williamson
2020-09-28 9:39 ` Cornelia Huck
2020-10-17 20:17 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 05/17] vfio: Add VM state change handler to know state of VM Kirti Wankhede
2020-09-24 15:02 ` Cornelia Huck
2020-09-29 11:03 ` Dr. David Alan Gilbert
2020-10-17 20:24 ` Kirti Wankhede
2020-10-20 10:51 ` Cornelia Huck
2020-10-21 5:33 ` Kirti Wankhede
2020-10-22 7:51 ` Cornelia Huck
2020-10-22 15:42 ` Kirti Wankhede
2020-10-22 15:49 ` Cornelia Huck
2020-09-25 20:20 ` Alex Williamson
2020-10-17 20:30 ` Kirti Wankhede
2020-10-17 23:44 ` Alex Williamson
2020-10-18 17:43 ` Kirti Wankhede
2020-10-19 17:51 ` Alex Williamson
2020-10-20 10:23 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 06/17] vfio: Add migration state change notifier Kirti Wankhede
2020-09-25 20:20 ` Alex Williamson
2020-10-17 20:35 ` Kirti Wankhede
2020-10-19 17:57 ` Alex Williamson
2020-10-20 10:55 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 07/17] vfio: Register SaveVMHandlers for VFIO device Kirti Wankhede
2020-09-24 15:15 ` Philippe Mathieu-Daudé
2020-09-29 10:19 ` Dr. David Alan Gilbert
2020-10-17 20:36 ` Kirti Wankhede
2020-09-25 11:53 ` Cornelia Huck
2020-10-18 20:55 ` Kirti Wankhede
2020-10-20 15:51 ` Cornelia Huck
2020-09-25 20:20 ` Alex Williamson
2020-10-18 17:40 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 08/17] vfio: Add save state functions to SaveVMHandlers Kirti Wankhede
2020-09-23 11:42 ` Wang, Zhi A
2020-10-21 14:30 ` Kirti Wankhede
2020-09-25 21:02 ` Alex Williamson
2020-10-18 18:00 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 09/17] vfio: Add load " Kirti Wankhede
2020-10-01 10:07 ` Cornelia Huck
2020-10-18 20:47 ` Kirti Wankhede
2020-10-20 16:25 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 10/17] memory: Set DIRTY_MEMORY_MIGRATION when IOMMU is enabled Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 11/17] vfio: Get migration capability flags for container Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 12/17] vfio: Add function to start and stop dirty pages tracking Kirti Wankhede
2020-09-25 21:55 ` Alex Williamson
2020-10-18 20:52 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 13/17] vfio: create mapped iova list when vIOMMU is enabled Kirti Wankhede
2020-09-25 22:23 ` Alex Williamson
2020-10-19 6:01 ` Kirti Wankhede [this message]
2020-10-19 17:24 ` Alex Williamson
2020-10-19 19:15 ` Kirti Wankhede
2020-10-19 20:07 ` Alex Williamson
2020-09-22 23:24 ` [PATCH v26 14/17] vfio: Add vfio_listener_log_sync to mark dirty pages Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 15/17] vfio: Add ioctl to get dirty pages bitmap during dma unmap Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 16/17] vfio: Make vfio-pci device migration capable Kirti Wankhede
2020-09-25 12:17 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 17/17] qapi: Add VFIO devices migration stats in Migration stats Kirti Wankhede
2020-09-24 15:14 ` Eric Blake
2020-09-25 22:55 ` Alex Williamson
2020-09-29 10:40 ` Dr. David Alan Gilbert
2020-09-23 7:06 ` [PATCH QEMU v25 00/17] Add migration support for VFIO devices Zenghui Yu
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