[Qemu-devel] [PATCH v5 00/18] VT-d: vfio enablement and misc enhances

[Qemu-devel] [PATCH v5 00/18] VT-d: vfio enablement and misc enhances

[Peter Xu]

This is v5 of vt-d vfio enablement series.

Most of the changes in v5 is not functionally, but related to
comments, error_report()s, debugging, squashing patches, etc. (which
are confirmed changes in v4), besides a tiny tweak when unmapping a
whole address space (please see below changelog). There are still
discussions in v4 thread, we can just continue there (or here), and
from this version I'll remove RFC tag.

I didn't rebase to master since current master failed to build on my
laptop (with a "vl.c/hax..." error), however this series should be
okay to be applied cleanly upon it.

v5:
- fix patch 4 subject too long, and error spelling [Eric]
- add ack-by for alex in patch 1 [Alex]
- squashing patch 19/20 into patch 18 [Jason]
- fix comments in vtd_page_walk() [Jason]
- remove all error_report() [Jason]
- add comment for patch 18, mention about that enabled vhost without
  ATS as well [Jason]
- remove skipped debug thing during page walk [Jason]
- remove duplicated page walk trace [Jason]
- some tunings in vtd_address_space_unmap(), to provide correct iova
  and addr_mask. For this, I tuned this patch as well a bit:
  "memory: add section range info for IOMMU notifier"
  to loosen the range check

v4:
- convert all error_report()s into traces (in the two patches that did
  that)
- rebased to Jason's DMAR series (master + one more patch:
  "[PATCH V4 net-next] vhost_net: device IOTLB support")
- let vhost use the new api iommu_notifier_init() so it won't break
  vhost dmar [Jason]
- touch commit message of the patch:
  "intel_iommu: provide its own replay() callback"
  old replay is not a dead loop, but it will just consume lots of time
  [Jason]
- add comment for patch:
  "intel_iommu: do replay when context invalidate"
  telling why replay won't be a problem even without CM=1 [Jason]
- remove a useless comment line [Jason]
- remove dmar_enabled parameter for vtd_switch_address_space() and
  vtd_switch_address_space_all() [Mst, Jason]
- merged the vfio patches in, to support unmap of big ranges at the
  beginning ("[PATCH RFC 0/3] vfio: allow to notify unmap for very big
  region")
- using caching_mode instead of cache_mode_enabled, and "caching-mode"
  instead of "cache-mode" [Kevin]
- when receive context entry invalidation, we unmap the entire region
  first, then replay [Alex]
- fix commit message for patch:
  "intel_iommu: simplify irq region translation" [Kevin]
- handle domain/global invalidation, and notify where proper [Jason,
  Kevin]

v3:
- fix style error reported by patchew
- fix comment in domain switch patch: use "IOMMU address space" rather
  than "IOMMU region" [Kevin]
- add ack-by for Paolo in patch:
  "memory: add section range info for IOMMU notifier"
  (this is seperately collected besides this thread)
- remove 3 patches which are merged already (from Jason)
- rebase to master b6c0897

v2:
- change comment for "end" parameter in vtd_page_walk() [Tianyu]
- change comment for "a iova" to "an iova" [Yi]
- fix fault printed val for GPA address in vtd_page_walk_level (debug
  only)
- rebased to master (rather than Aviv's v6 series) and merged Aviv's
  series v6: picked patch 1 (as patch 1 in this series), dropped patch
  2, re-wrote patch 3 (as patch 17 of this series).
- picked up two more bugfix patches from Jason's DMAR series
- picked up the following patch as well:
  "[PATCH v3] intel_iommu: allow dynamic switch of IOMMU region"

This RFC series is a re-work for Aviv B.D.'s vfio enablement series
with vt-d:

  https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg01452.html

Aviv has done a great job there, and what we still lack there are
mostly the following:

(1) VFIO got duplicated IOTLB notifications due to splitted VT-d IOMMU
    memory region.

(2) VT-d still haven't provide a correct replay() mechanism (e.g.,
    when IOMMU domain switches, things will broke).

This series should have solved the above two issues.

Online repo:

  https://github.com/xzpeter/qemu/tree/vtd-vfio-enablement-v5

I would be glad to hear about any review comments for above patches.

=========
Test Done
=========

Build test passed for x86_64/arm/ppc64.

Simply tested with x86_64, assigning two PCI devices to a single VM,
boot the VM using:

bin=x86_64-softmmu/qemu-system-x86_64
$bin -M q35,accel=kvm,kernel-irqchip=split -m 1G \
     -device intel-iommu,intremap=on,eim=off,caching-mode=on \
     -netdev user,id=net0,hostfwd=tcp::5555-:22 \
     -device virtio-net-pci,netdev=net0 \
     -device vfio-pci,host=03:00.0 \
     -device vfio-pci,host=02:00.0 \
     -trace events=".trace.vfio" \
     /var/lib/libvirt/images/vm1.qcow2

pxdev:bin [vtd-vfio-enablement]# cat .trace.vfio
vtd_page_walk*
vtd_replay*
vtd_inv_desc*

Then, in the guest, run the following tool:

  https://github.com/xzpeter/clibs/blob/master/gpl/userspace/vfio-bind-group/vfio-bind-group.c

With parameter:

  ./vfio-bind-group 00:03.0 00:04.0

Check host side trace log, I can see pages are replayed and mapped in
00:04.0 device address space, like:

...
vtd_replay_ce_valid replay valid context device 00:04.00 hi 0x401 lo 0x38fe1001
vtd_page_walk Page walk for ce (0x401, 0x38fe1001) iova range 0x0 - 0x8000000000
vtd_page_walk_level Page walk (base=0x38fe1000, level=3) iova range 0x0 - 0x8000000000
vtd_page_walk_level Page walk (base=0x35d31000, level=2) iova range 0x0 - 0x40000000
vtd_page_walk_level Page walk (base=0x34979000, level=1) iova range 0x0 - 0x200000
vtd_page_walk_one Page walk detected map level 0x1 iova 0x0 -> gpa 0x22dc3000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x1000 -> gpa 0x22e25000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x2000 -> gpa 0x22e12000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x3000 -> gpa 0x22e2d000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x4000 -> gpa 0x12a49000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x5000 -> gpa 0x129bb000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x6000 -> gpa 0x128db000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x7000 -> gpa 0x12a80000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x8000 -> gpa 0x12a7e000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0x9000 -> gpa 0x12b22000 mask 0xfff perm 3
vtd_page_walk_one Page walk detected map level 0x1 iova 0xa000 -> gpa 0x12b41000 mask 0xfff perm 3
...

=========
Todo List
=========

- error reporting for the assigned devices (as Tianyu has mentioned)

- per-domain address-space: A better solution in the future may be -
  we maintain one address space per IOMMU domain in the guest (so
  multiple devices can share a same address space if they are sharing
  the same IOMMU domains in the guest), rather than one address space
  per device (which is current implementation of vt-d). However that's
  a step further than this series, and let's see whether we can first
  provide a workable version of device assignment with vt-d
  protection.

- more to come...

Thanks,

Aviv Ben-David (1):
  intel_iommu: add "caching-mode" option

Peter Xu (17):
  vfio: trace map/unmap for notify as well
  vfio: introduce vfio_get_vaddr()
  vfio: allow to notify unmap for very large region
  intel_iommu: simplify irq region translation
  intel_iommu: renaming gpa to iova where proper
  intel_iommu: fix trace for inv desc handling
  intel_iommu: fix trace for addr translation
  intel_iommu: vtd_slpt_level_shift check level
  memory: add section range info for IOMMU notifier
  memory: provide IOMMU_NOTIFIER_FOREACH macro
  memory: provide iommu_replay_all()
  memory: introduce memory_region_notify_one()
  memory: add MemoryRegionIOMMUOps.replay() callback
  intel_iommu: provide its own replay() callback
  intel_iommu: do replay when context invalidate
  intel_iommu: allow dynamic switch of IOMMU region
  intel_iommu: enable vfio devices

 hw/i386/intel_iommu.c          | 645 +++++++++++++++++++++++++++++++----------
 hw/i386/intel_iommu_internal.h |   2 +
 hw/i386/trace-events           |  30 ++
 hw/vfio/common.c               |  68 +++--
 hw/vfio/trace-events           |   2 +-
 hw/virtio/vhost.c              |   4 +-
 include/exec/memory.h          |  49 +++-
 include/hw/i386/intel_iommu.h  |  12 +
 memory.c                       |  52 +++-
 9 files changed, 673 insertions(+), 191 deletions(-)

-- 
2.7.4

[Qemu-devel] [PATCH v5 01/18] vfio: trace map/unmap for notify as well

[Peter Xu]

We traces its range, but we don't know whether it's a MAP/UNMAP. Let's
dump it as well.

Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/vfio/common.c     | 3 ++-
 hw/vfio/trace-events | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 801578b..174f351 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -305,7 +305,8 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     void *vaddr;
     int ret;
 
-    trace_vfio_iommu_map_notify(iova, iova + iotlb->addr_mask);
+    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
+                                iova, iova + iotlb->addr_mask);
 
     if (iotlb->target_as != &address_space_memory) {
         error_report("Wrong target AS \"%s\", only system memory is allowed",
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index ef81609..7ae8233 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -84,7 +84,7 @@ vfio_pci_igd_lpc_bridge_enabled(const char *name) "%s"
 # hw/vfio/common.c
 vfio_region_write(const char *name, int index, uint64_t addr, uint64_t data, unsigned size) " (%s:region%d+0x%"PRIx64", 0x%"PRIx64 ", %d)"
 vfio_region_read(char *name, int index, uint64_t addr, unsigned size, uint64_t data) " (%s:region%d+0x%"PRIx64", %d) = 0x%"PRIx64
-vfio_iommu_map_notify(uint64_t iova_start, uint64_t iova_end) "iommu map @ %"PRIx64" - %"PRIx64
+vfio_iommu_map_notify(const char *op, uint64_t iova_start, uint64_t iova_end) "iommu %s @ %"PRIx64" - %"PRIx64
 vfio_listener_region_add_skip(uint64_t start, uint64_t end) "SKIPPING region_add %"PRIx64" - %"PRIx64
 vfio_listener_region_add_iommu(uint64_t start, uint64_t end) "region_add [iommu] %"PRIx64" - %"PRIx64
 vfio_listener_region_add_ram(uint64_t iova_start, uint64_t iova_end, void *vaddr) "region_add [ram] %"PRIx64" - %"PRIx64" [%p]"
-- 
2.7.4

[Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Peter Xu]

A cleanup for vfio_iommu_map_notify(). Should have no functional change,
just to make the function shorter and easier to understand.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/vfio/common.c | 58 +++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 38 insertions(+), 20 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 174f351..ce55dff 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -294,25 +294,14 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
            section->offset_within_address_space & (1ULL << 63);
 }
 
-static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
+static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
+                           bool *read_only)
 {
-    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
-    VFIOContainer *container = giommu->container;
-    hwaddr iova = iotlb->iova + giommu->iommu_offset;
     MemoryRegion *mr;
     hwaddr xlat;
     hwaddr len = iotlb->addr_mask + 1;
-    void *vaddr;
-    int ret;
-
-    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
-                                iova, iova + iotlb->addr_mask);
-
-    if (iotlb->target_as != &address_space_memory) {
-        error_report("Wrong target AS \"%s\", only system memory is allowed",
-                     iotlb->target_as->name ? iotlb->target_as->name : "none");
-        return;
-    }
+    bool ret = false;
+    bool writable = iotlb->perm & IOMMU_WO;
 
     /*
      * The IOMMU TLB entry we have just covers translation through
@@ -322,12 +311,13 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
     rcu_read_lock();
     mr = address_space_translate(&address_space_memory,
                                  iotlb->translated_addr,
-                                 &xlat, &len, iotlb->perm & IOMMU_WO);
+                                 &xlat, &len, writable);
     if (!memory_region_is_ram(mr)) {
         error_report("iommu map to non memory area %"HWADDR_PRIx"",
                      xlat);
         goto out;
     }
+
     /*
      * Translation truncates length to the IOMMU page size,
      * check that it did not truncate too much.
@@ -337,11 +327,41 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
         goto out;
     }
 
+    *vaddr = memory_region_get_ram_ptr(mr) + xlat;
+    *read_only = !writable || mr->readonly;
+    ret = true;
+
+out:
+    rcu_read_unlock();
+    return ret;
+}
+
+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;
+
+    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
+                                iova, iova + iotlb->addr_mask);
+
+    if (iotlb->target_as != &address_space_memory) {
+        error_report("Wrong target AS \"%s\", only system memory is allowed",
+                     iotlb->target_as->name ? iotlb->target_as->name : "none");
+        return;
+    }
+
+    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
+        return;
+    }
+
     if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
-        vaddr = memory_region_get_ram_ptr(mr) + xlat;
         ret = vfio_dma_map(container, iova,
                            iotlb->addr_mask + 1, vaddr,
-                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
+                           read_only);
         if (ret) {
             error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
                          "0x%"HWADDR_PRIx", %p) = %d (%m)",
@@ -357,8 +377,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
                          iotlb->addr_mask + 1, ret);
         }
     }
-out:
-    rcu_read_unlock();
 }
 
 static void vfio_listener_region_add(MemoryListener *listener,
-- 
2.7.4

[Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very large region

[Peter Xu]

Linux vfio driver supports to do VFIO_IOMMU_UNMAP_DMA for a very big
region. This can be leveraged by QEMU IOMMU implementation to cleanup
existing page mappings for an entire iova address space (by notifying
with an IOTLB with extremely huge addr_mask). However current
vfio_iommu_map_notify() does not allow that. It make sure that all the
translated address in IOTLB is falling into RAM range.

The check makes sense, but it should only be a sensible checker for
mapping operations, and mean little for unmap operations.

This patch moves this check into map logic only, so that we'll get
faster unmap handling (no need to translate again), and also we can then
better support unmapping a very big region when it covers non-ram ranges
or even not-existing ranges.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/vfio/common.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index ce55dff..4d90844 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -354,11 +354,10 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
         return;
     }
 
-    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
-        return;
-    }
-
     if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
+        if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
+            return;
+        }
         ret = vfio_dma_map(container, iova,
                            iotlb->addr_mask + 1, vaddr,
                            read_only);
-- 
2.7.4

[Qemu-devel] [PATCH v5 04/18] intel_iommu: add "caching-mode" option

[Peter Xu]

From: Aviv Ben-David <bd.aviv@gmail.com>

This capability asks the guest to invalidate cache before each map operation.
We can use this invalidation to trap map operations in the hypervisor.

Signed-off-by: Aviv Ben-David <bd.aviv@gmail.com>
[peterx: using "caching-mode" instead of "cache-mode" to align with spec]
[peterx: re-write the subject to make it short and clear]
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c          | 5 +++++
 hw/i386/intel_iommu_internal.h | 1 +
 include/hw/i386/intel_iommu.h  | 2 ++
 3 files changed, 8 insertions(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index ec62239..e58f1de 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -2107,6 +2107,7 @@ static Property vtd_properties[] = {
     DEFINE_PROP_ON_OFF_AUTO("eim", IntelIOMMUState, intr_eim,
                             ON_OFF_AUTO_AUTO),
     DEFINE_PROP_BOOL("x-buggy-eim", IntelIOMMUState, buggy_eim, false),
+    DEFINE_PROP_BOOL("caching-mode", IntelIOMMUState, caching_mode, FALSE),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -2488,6 +2489,10 @@ static void vtd_init(IntelIOMMUState *s)
         s->ecap |= VTD_ECAP_DT;
     }
 
+    if (s->caching_mode) {
+        s->cap |= VTD_CAP_CM;
+    }
+
     vtd_reset_context_cache(s);
     vtd_reset_iotlb(s);
 
diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index 356f188..4104121 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -202,6 +202,7 @@
 #define VTD_CAP_MAMV                (VTD_MAMV << 48)
 #define VTD_CAP_PSI                 (1ULL << 39)
 #define VTD_CAP_SLLPS               ((1ULL << 34) | (1ULL << 35))
+#define VTD_CAP_CM                  (1ULL << 7)
 
 /* Supported Adjusted Guest Address Widths */
 #define VTD_CAP_SAGAW_SHIFT         8
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 405c9d1..fe645aa 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -257,6 +257,8 @@ struct IntelIOMMUState {
     uint8_t womask[DMAR_REG_SIZE];  /* WO (write only - read returns 0) */
     uint32_t version;
 
+    bool caching_mode;          /* RO - is cap CM enabled? */
+
     dma_addr_t root;                /* Current root table pointer */
     bool root_extended;             /* Type of root table (extended or not) */
     bool dmar_enabled;              /* Set if DMA remapping is enabled */
-- 
2.7.4

[Qemu-devel] [PATCH v5 05/18] intel_iommu: simplify irq region translation

[Peter Xu]

Now we have a standalone memory region for MSI, all the irq region
requests should be redirected there. Cleaning up the block with an
assertion instead.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c | 28 ++++++----------------------
 1 file changed, 6 insertions(+), 22 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index e58f1de..55b8ff4 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -818,28 +818,12 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
     bool writes = true;
     VTDIOTLBEntry *iotlb_entry;
 
-    /* Check if the request is in interrupt address range */
-    if (vtd_is_interrupt_addr(addr)) {
-        if (is_write) {
-            /* FIXME: since we don't know the length of the access here, we
-             * treat Non-DWORD length write requests without PASID as
-             * interrupt requests, too. Withoud interrupt remapping support,
-             * we just use 1:1 mapping.
-             */
-            VTD_DPRINTF(MMU, "write request to interrupt address "
-                        "gpa 0x%"PRIx64, addr);
-            entry->iova = addr & VTD_PAGE_MASK_4K;
-            entry->translated_addr = addr & VTD_PAGE_MASK_4K;
-            entry->addr_mask = ~VTD_PAGE_MASK_4K;
-            entry->perm = IOMMU_WO;
-            return;
-        } else {
-            VTD_DPRINTF(GENERAL, "error: read request from interrupt address "
-                        "gpa 0x%"PRIx64, addr);
-            vtd_report_dmar_fault(s, source_id, addr, VTD_FR_READ, is_write);
-            return;
-        }
-    }
+    /*
+     * We have standalone memory region for interrupt addresses, we
+     * should never receive translation requests in this region.
+     */
+    assert(!vtd_is_interrupt_addr(addr));
+
     /* Try to fetch slpte form IOTLB */
     iotlb_entry = vtd_lookup_iotlb(s, source_id, addr);
     if (iotlb_entry) {
-- 
2.7.4

[Qemu-devel] [PATCH v5 06/18] intel_iommu: renaming gpa to iova where proper

[Peter Xu]

There are lots of places in current intel_iommu.c codes that named
"iova" as "gpa". It is really confusing to use a name "gpa" in these
places (which is very easily to be understood as "Guest Physical
Address", while it's not). To make the codes (much) easier to be read, I
decided to do this once and for all.

No functional change is made. Only literal ones.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 55b8ff4..b934b56 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -259,7 +259,7 @@ static void vtd_update_iotlb(IntelIOMMUState *s, uint16_t source_id,
     uint64_t *key = g_malloc(sizeof(*key));
     uint64_t gfn = vtd_get_iotlb_gfn(addr, level);
 
-    VTD_DPRINTF(CACHE, "update iotlb sid 0x%"PRIx16 " gpa 0x%"PRIx64
+    VTD_DPRINTF(CACHE, "update iotlb sid 0x%"PRIx16 " iova 0x%"PRIx64
                 " slpte 0x%"PRIx64 " did 0x%"PRIx16, source_id, addr, slpte,
                 domain_id);
     if (g_hash_table_size(s->iotlb) >= VTD_IOTLB_MAX_SIZE) {
@@ -575,12 +575,12 @@ static uint64_t vtd_get_slpte(dma_addr_t base_addr, uint32_t index)
     return slpte;
 }
 
-/* Given a gpa and the level of paging structure, return the offset of current
- * level.
+/* Given an iova and the level of paging structure, return the offset
+ * of current level.
  */
-static inline uint32_t vtd_gpa_level_offset(uint64_t gpa, uint32_t level)
+static inline uint32_t vtd_iova_level_offset(uint64_t iova, uint32_t level)
 {
-    return (gpa >> vtd_slpt_level_shift(level)) &
+    return (iova >> vtd_slpt_level_shift(level)) &
             ((1ULL << VTD_SL_LEVEL_BITS) - 1);
 }
 
@@ -628,10 +628,10 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte, uint32_t level)
     }
 }
 
-/* Given the @gpa, get relevant @slptep. @slpte_level will be the last level
+/* Given the @iova, get relevant @slptep. @slpte_level will be the last level
  * of the translation, can be used for deciding the size of large page.
  */
-static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t gpa, bool is_write,
+static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write,
                             uint64_t *slptep, uint32_t *slpte_level,
                             bool *reads, bool *writes)
 {
@@ -642,11 +642,11 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t gpa, bool is_write,
     uint32_t ce_agaw = vtd_get_agaw_from_context_entry(ce);
     uint64_t access_right_check;
 
-    /* Check if @gpa is above 2^X-1, where X is the minimum of MGAW in CAP_REG
-     * and AW in context-entry.
+    /* Check if @iova is above 2^X-1, where X is the minimum of MGAW
+     * in CAP_REG and AW in context-entry.
      */
-    if (gpa & ~((1ULL << MIN(ce_agaw, VTD_MGAW)) - 1)) {
-        VTD_DPRINTF(GENERAL, "error: gpa 0x%"PRIx64 " exceeds limits", gpa);
+    if (iova & ~((1ULL << MIN(ce_agaw, VTD_MGAW)) - 1)) {
+        VTD_DPRINTF(GENERAL, "error: iova 0x%"PRIx64 " exceeds limits", iova);
         return -VTD_FR_ADDR_BEYOND_MGAW;
     }
 
@@ -654,13 +654,13 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t gpa, bool is_write,
     access_right_check = is_write ? VTD_SL_W : VTD_SL_R;
 
     while (true) {
-        offset = vtd_gpa_level_offset(gpa, level);
+        offset = vtd_iova_level_offset(iova, level);
         slpte = vtd_get_slpte(addr, offset);
 
         if (slpte == (uint64_t)-1) {
             VTD_DPRINTF(GENERAL, "error: fail to access second-level paging "
-                        "entry at level %"PRIu32 " for gpa 0x%"PRIx64,
-                        level, gpa);
+                        "entry at level %"PRIu32 " for iova 0x%"PRIx64,
+                        level, iova);
             if (level == vtd_get_level_from_context_entry(ce)) {
                 /* Invalid programming of context-entry */
                 return -VTD_FR_CONTEXT_ENTRY_INV;
@@ -672,8 +672,8 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t gpa, bool is_write,
         *writes = (*writes) && (slpte & VTD_SL_W);
         if (!(slpte & access_right_check)) {
             VTD_DPRINTF(GENERAL, "error: lack of %s permission for "
-                        "gpa 0x%"PRIx64 " slpte 0x%"PRIx64,
-                        (is_write ? "write" : "read"), gpa, slpte);
+                        "iova 0x%"PRIx64 " slpte 0x%"PRIx64,
+                        (is_write ? "write" : "read"), iova, slpte);
             return is_write ? -VTD_FR_WRITE : -VTD_FR_READ;
         }
         if (vtd_slpte_nonzero_rsvd(slpte, level)) {
@@ -827,7 +827,7 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
     /* Try to fetch slpte form IOTLB */
     iotlb_entry = vtd_lookup_iotlb(s, source_id, addr);
     if (iotlb_entry) {
-        VTD_DPRINTF(CACHE, "hit iotlb sid 0x%"PRIx16 " gpa 0x%"PRIx64
+        VTD_DPRINTF(CACHE, "hit iotlb sid 0x%"PRIx16 " iova 0x%"PRIx64
                     " slpte 0x%"PRIx64 " did 0x%"PRIx16, source_id, addr,
                     iotlb_entry->slpte, iotlb_entry->domain_id);
         slpte = iotlb_entry->slpte;
@@ -2025,7 +2025,7 @@ static IOMMUTLBEntry vtd_iommu_translate(MemoryRegion *iommu, hwaddr addr,
                            is_write, &ret);
     VTD_DPRINTF(MMU,
                 "bus %"PRIu8 " slot %"PRIu8 " func %"PRIu8 " devfn %"PRIu8
-                " gpa 0x%"PRIx64 " hpa 0x%"PRIx64, pci_bus_num(vtd_as->bus),
+                " iova 0x%"PRIx64 " hpa 0x%"PRIx64, pci_bus_num(vtd_as->bus),
                 VTD_PCI_SLOT(vtd_as->devfn), VTD_PCI_FUNC(vtd_as->devfn),
                 vtd_as->devfn, addr, ret.translated_addr);
     return ret;
-- 
2.7.4

[Qemu-devel] [PATCH v5 07/18] intel_iommu: fix trace for inv desc handling

[Peter Xu]

VT-d codes are still using static DEBUG_INTEL_IOMMU macro. That's not
good, and we should end the day when we need to recompile the code
before getting useful debugging information for vt-d. Time to switch to
the trace system.

This is the first patch to do it.

Generally, the rule of mine is:

- for the old GENERAL typed message, I use trace_vtd_err*() in general.

- for the non-GENERAL typed messages, convert into specified trace_*().

- for useless DPRINTFs, I removed them.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c | 97 +++++++++++++++++++++------------------------------
 hw/i386/trace-events  | 15 ++++++++
 2 files changed, 54 insertions(+), 58 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index b934b56..343a2ad 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -35,6 +35,7 @@
 #include "sysemu/kvm.h"
 #include "hw/i386/apic_internal.h"
 #include "kvm_i386.h"
+#include "trace.h"
 
 /*#define DEBUG_INTEL_IOMMU*/
 #ifdef DEBUG_INTEL_IOMMU
@@ -474,22 +475,19 @@ static void vtd_handle_inv_queue_error(IntelIOMMUState *s)
 /* Set the IWC field and try to generate an invalidation completion interrupt */
 static void vtd_generate_completion_event(IntelIOMMUState *s)
 {
-    VTD_DPRINTF(INV, "completes an invalidation wait command with "
-                "Interrupt Flag");
     if (vtd_get_long_raw(s, DMAR_ICS_REG) & VTD_ICS_IWC) {
-        VTD_DPRINTF(INV, "there is a previous interrupt condition to be "
-                    "serviced by software, "
-                    "new invalidation event is not generated");
+        trace_vtd_inv_desc_wait_irq("One pending, skip current");
         return;
     }
     vtd_set_clear_mask_long(s, DMAR_ICS_REG, 0, VTD_ICS_IWC);
     vtd_set_clear_mask_long(s, DMAR_IECTL_REG, 0, VTD_IECTL_IP);
     if (vtd_get_long_raw(s, DMAR_IECTL_REG) & VTD_IECTL_IM) {
-        VTD_DPRINTF(INV, "IM filed in IECTL_REG is set, new invalidation "
-                    "event is not generated");
+        trace_vtd_inv_desc_wait_irq("IM in IECTL_REG is set, "
+                                    "new event not generated");
         return;
     } else {
         /* Generate the interrupt event */
+        trace_vtd_inv_desc_wait_irq("Generating complete event");
         vtd_generate_interrupt(s, DMAR_IEADDR_REG, DMAR_IEDATA_REG);
         vtd_set_clear_mask_long(s, DMAR_IECTL_REG, VTD_IECTL_IP, 0);
     }
@@ -923,6 +921,7 @@ static void vtd_interrupt_remap_table_setup(IntelIOMMUState *s)
 
 static void vtd_context_global_invalidate(IntelIOMMUState *s)
 {
+    trace_vtd_inv_desc_cc_global();
     s->context_cache_gen++;
     if (s->context_cache_gen == VTD_CONTEXT_CACHE_GEN_MAX) {
         vtd_reset_context_cache(s);
@@ -962,9 +961,11 @@ static void vtd_context_device_invalidate(IntelIOMMUState *s,
     uint16_t mask;
     VTDBus *vtd_bus;
     VTDAddressSpace *vtd_as;
-    uint16_t devfn;
+    uint8_t bus_n, devfn;
     uint16_t devfn_it;
 
+    trace_vtd_inv_desc_cc_devices(source_id, func_mask);
+
     switch (func_mask & 3) {
     case 0:
         mask = 0;   /* No bits in the SID field masked */
@@ -980,16 +981,16 @@ static void vtd_context_device_invalidate(IntelIOMMUState *s,
         break;
     }
     mask = ~mask;
-    VTD_DPRINTF(INV, "device-selective invalidation source 0x%"PRIx16
-                    " mask %"PRIu16, source_id, mask);
-    vtd_bus = vtd_find_as_from_bus_num(s, VTD_SID_TO_BUS(source_id));
+
+    bus_n = VTD_SID_TO_BUS(source_id);
+    vtd_bus = vtd_find_as_from_bus_num(s, bus_n);
     if (vtd_bus) {
         devfn = VTD_SID_TO_DEVFN(source_id);
         for (devfn_it = 0; devfn_it < X86_IOMMU_PCI_DEVFN_MAX; ++devfn_it) {
             vtd_as = vtd_bus->dev_as[devfn_it];
             if (vtd_as && ((devfn_it & mask) == (devfn & mask))) {
-                VTD_DPRINTF(INV, "invalidate context-cahce of devfn 0x%"PRIx16,
-                            devfn_it);
+                trace_vtd_inv_desc_cc_device(bus_n, VTD_PCI_SLOT(devfn_it),
+                                             VTD_PCI_FUNC(devfn_it));
                 vtd_as->context_cache_entry.context_cache_gen = 0;
             }
         }
@@ -1302,9 +1303,7 @@ static bool vtd_process_wait_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
 {
     if ((inv_desc->hi & VTD_INV_DESC_WAIT_RSVD_HI) ||
         (inv_desc->lo & VTD_INV_DESC_WAIT_RSVD_LO)) {
-        VTD_DPRINTF(GENERAL, "error: non-zero reserved field in Invalidation "
-                    "Wait Descriptor hi 0x%"PRIx64 " lo 0x%"PRIx64,
-                    inv_desc->hi, inv_desc->lo);
+        trace_vtd_err_nonzero_reserved("invalidation wait desc");
         return false;
     }
     if (inv_desc->lo & VTD_INV_DESC_WAIT_SW) {
@@ -1316,21 +1315,18 @@ static bool vtd_process_wait_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
 
         /* FIXME: need to be masked with HAW? */
         dma_addr_t status_addr = inv_desc->hi;
-        VTD_DPRINTF(INV, "status data 0x%x, status addr 0x%"PRIx64,
-                    status_data, status_addr);
+        trace_vtd_inv_desc_wait_sw(status_addr, status_data);
         status_data = cpu_to_le32(status_data);
         if (dma_memory_write(&address_space_memory, status_addr, &status_data,
                              sizeof(status_data))) {
-            VTD_DPRINTF(GENERAL, "error: fail to perform a coherent write");
+            trace_vtd_err("Invalidate Desc Wait status write failed");
             return false;
         }
     } else if (inv_desc->lo & VTD_INV_DESC_WAIT_IF) {
         /* Interrupt flag */
-        VTD_DPRINTF(INV, "Invalidation Wait Descriptor interrupt completion");
         vtd_generate_completion_event(s);
     } else {
-        VTD_DPRINTF(GENERAL, "error: invalid Invalidation Wait Descriptor: "
-                    "hi 0x%"PRIx64 " lo 0x%"PRIx64, inv_desc->hi, inv_desc->lo);
+        trace_vtd_err("invalid Invalidation Wait Descriptor");
         return false;
     }
     return true;
@@ -1339,30 +1335,30 @@ static bool vtd_process_wait_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
 static bool vtd_process_context_cache_desc(IntelIOMMUState *s,
                                            VTDInvDesc *inv_desc)
 {
+    uint16_t sid, fmask;
+
     if ((inv_desc->lo & VTD_INV_DESC_CC_RSVD) || inv_desc->hi) {
-        VTD_DPRINTF(GENERAL, "error: non-zero reserved field in Context-cache "
-                    "Invalidate Descriptor");
+        trace_vtd_err_nonzero_reserved("Context-cache invalidation desc");
         return false;
     }
     switch (inv_desc->lo & VTD_INV_DESC_CC_G) {
     case VTD_INV_DESC_CC_DOMAIN:
-        VTD_DPRINTF(INV, "domain-selective invalidation domain 0x%"PRIx16,
-                    (uint16_t)VTD_INV_DESC_CC_DID(inv_desc->lo));
+        trace_vtd_inv_desc_cc_domain(
+            (uint16_t)VTD_INV_DESC_CC_DID(inv_desc->lo));
         /* Fall through */
     case VTD_INV_DESC_CC_GLOBAL:
-        VTD_DPRINTF(INV, "global invalidation");
         vtd_context_global_invalidate(s);
         break;
 
     case VTD_INV_DESC_CC_DEVICE:
-        vtd_context_device_invalidate(s, VTD_INV_DESC_CC_SID(inv_desc->lo),
-                                      VTD_INV_DESC_CC_FM(inv_desc->lo));
+        sid = VTD_INV_DESC_CC_SID(inv_desc->lo);
+        fmask = VTD_INV_DESC_CC_FM(inv_desc->lo);
+        vtd_context_device_invalidate(s, sid, fmask);
         break;
 
     default:
-        VTD_DPRINTF(GENERAL, "error: invalid granularity in Context-cache "
-                    "Invalidate Descriptor hi 0x%"PRIx64  " lo 0x%"PRIx64,
-                    inv_desc->hi, inv_desc->lo);
+        trace_vtd_err("invalid granularity in Context-cache "
+                      "Invalidate Descriptor");
         return false;
     }
     return true;
@@ -1376,22 +1372,19 @@ static bool vtd_process_iotlb_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
 
     if ((inv_desc->lo & VTD_INV_DESC_IOTLB_RSVD_LO) ||
         (inv_desc->hi & VTD_INV_DESC_IOTLB_RSVD_HI)) {
-        VTD_DPRINTF(GENERAL, "error: non-zero reserved field in IOTLB "
-                    "Invalidate Descriptor hi 0x%"PRIx64 " lo 0x%"PRIx64,
-                    inv_desc->hi, inv_desc->lo);
+        trace_vtd_err_nonzero_reserved("IOTLB invalidation desc");
         return false;
     }
 
     switch (inv_desc->lo & VTD_INV_DESC_IOTLB_G) {
     case VTD_INV_DESC_IOTLB_GLOBAL:
-        VTD_DPRINTF(INV, "global invalidation");
+        trace_vtd_inv_desc_iotlb_global();
         vtd_iotlb_global_invalidate(s);
         break;
 
     case VTD_INV_DESC_IOTLB_DOMAIN:
         domain_id = VTD_INV_DESC_IOTLB_DID(inv_desc->lo);
-        VTD_DPRINTF(INV, "domain-selective invalidation domain 0x%"PRIx16,
-                    domain_id);
+        trace_vtd_inv_desc_iotlb_domain(domain_id);
         vtd_iotlb_domain_invalidate(s, domain_id);
         break;
 
@@ -1399,20 +1392,16 @@ static bool vtd_process_iotlb_desc(IntelIOMMUState *s, VTDInvDesc *inv_desc)
         domain_id = VTD_INV_DESC_IOTLB_DID(inv_desc->lo);
         addr = VTD_INV_DESC_IOTLB_ADDR(inv_desc->hi);
         am = VTD_INV_DESC_IOTLB_AM(inv_desc->hi);
-        VTD_DPRINTF(INV, "page-selective invalidation domain 0x%"PRIx16
-                    " addr 0x%"PRIx64 " mask %"PRIu8, domain_id, addr, am);
+        trace_vtd_inv_desc_iotlb_pages(domain_id, addr, am);
         if (am > VTD_MAMV) {
-            VTD_DPRINTF(GENERAL, "error: supported max address mask value is "
-                        "%"PRIu8, (uint8_t)VTD_MAMV);
+            trace_vtd_err("IOTLB page inv desc addr mask overflow");
             return false;
         }
         vtd_iotlb_page_invalidate(s, domain_id, addr, am);
         break;
 
     default:
-        VTD_DPRINTF(GENERAL, "error: invalid granularity in IOTLB Invalidate "
-                    "Descriptor hi 0x%"PRIx64 " lo 0x%"PRIx64,
-                    inv_desc->hi, inv_desc->lo);
+        trace_vtd_err("invalid granularity in IOTLB inv desc");
         return false;
     }
     return true;
@@ -1492,7 +1481,6 @@ static bool vtd_process_inv_desc(IntelIOMMUState *s)
     VTDInvDesc inv_desc;
     uint8_t desc_type;
 
-    VTD_DPRINTF(INV, "iq head %"PRIu16, s->iq_head);
     if (!vtd_get_inv_desc(s->iq, s->iq_head, &inv_desc)) {
         s->iq_last_desc_type = VTD_INV_DESC_NONE;
         return false;
@@ -1503,33 +1491,28 @@ static bool vtd_process_inv_desc(IntelIOMMUState *s)
 
     switch (desc_type) {
     case VTD_INV_DESC_CC:
-        VTD_DPRINTF(INV, "Context-cache Invalidate Descriptor hi 0x%"PRIx64
-                    " lo 0x%"PRIx64, inv_desc.hi, inv_desc.lo);
+        trace_vtd_inv_desc("context-cache", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_context_cache_desc(s, &inv_desc)) {
             return false;
         }
         break;
 
     case VTD_INV_DESC_IOTLB:
-        VTD_DPRINTF(INV, "IOTLB Invalidate Descriptor hi 0x%"PRIx64
-                    " lo 0x%"PRIx64, inv_desc.hi, inv_desc.lo);
+        trace_vtd_inv_desc("iotlb", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_iotlb_desc(s, &inv_desc)) {
             return false;
         }
         break;
 
     case VTD_INV_DESC_WAIT:
-        VTD_DPRINTF(INV, "Invalidation Wait Descriptor hi 0x%"PRIx64
-                    " lo 0x%"PRIx64, inv_desc.hi, inv_desc.lo);
+        trace_vtd_inv_desc("wait", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_wait_desc(s, &inv_desc)) {
             return false;
         }
         break;
 
     case VTD_INV_DESC_IEC:
-        VTD_DPRINTF(INV, "Invalidation Interrupt Entry Cache "
-                    "Descriptor hi 0x%"PRIx64 " lo 0x%"PRIx64,
-                    inv_desc.hi, inv_desc.lo);
+        trace_vtd_inv_desc("iec", inv_desc.hi, inv_desc.lo);
         if (!vtd_process_inv_iec_desc(s, &inv_desc)) {
             return false;
         }
@@ -1544,9 +1527,7 @@ static bool vtd_process_inv_desc(IntelIOMMUState *s)
         break;
 
     default:
-        VTD_DPRINTF(GENERAL, "error: unkonw Invalidation Descriptor type "
-                    "hi 0x%"PRIx64 " lo 0x%"PRIx64 " type %"PRIu8,
-                    inv_desc.hi, inv_desc.lo, desc_type);
+        trace_vtd_err("Unkonw Invalidation Descriptor type");
         return false;
     }
     s->iq_head++;
diff --git a/hw/i386/trace-events b/hw/i386/trace-events
index d2b4973..eea3e84 100644
--- a/hw/i386/trace-events
+++ b/hw/i386/trace-events
@@ -10,6 +10,21 @@ xen_pv_mmio_write(uint64_t addr) "WARNING: write to Xen PV Device MMIO space (ad
 # hw/i386/x86-iommu.c
 x86_iommu_iec_notify(bool global, uint32_t index, uint32_t mask) "Notify IEC invalidation: global=%d index=%" PRIu32 " mask=%" PRIu32
 
+# hw/i386/intel_iommu.c
+vtd_switch_address_space(uint8_t bus, uint8_t slot, uint8_t fn, bool on) "Device %02x:%02x.%x switching address space (iommu enabled=%d)"
+vtd_inv_desc(const char *type, uint64_t hi, uint64_t lo) "invalidate desc type %s high 0x%"PRIx64" low 0x%"PRIx64
+vtd_inv_desc_cc_domain(uint16_t domain) "context invalidate domain 0x%"PRIx16
+vtd_inv_desc_cc_global(void) "context invalidate globally"
+vtd_inv_desc_cc_device(uint8_t bus, uint8_t dev, uint8_t fn) "context invalidate device %02"PRIx8":%02"PRIx8".%02"PRIx8
+vtd_inv_desc_cc_devices(uint16_t sid, uint16_t fmask) "context invalidate devices sid 0x%"PRIx16" fmask 0x%"PRIx16
+vtd_inv_desc_iotlb_global(void) "iotlb invalidate global"
+vtd_inv_desc_iotlb_domain(uint16_t domain) "iotlb invalidate whole domain 0x%"PRIx16
+vtd_inv_desc_iotlb_pages(uint16_t domain, uint64_t addr, uint8_t mask) "iotlb invalidate domain 0x%"PRIx16" addr 0x%"PRIx64" mask 0x%"PRIx8
+vtd_inv_desc_wait_sw(uint64_t addr, uint32_t data) "wait invalidate status write addr 0x%"PRIx64" data 0x%"PRIx32
+vtd_inv_desc_wait_irq(const char *msg) "%s"
+vtd_err_nonzero_reserved(const char *msg) "Non-zero reserved field in %s"
+vtd_err(const char *msg) "%s"
+
 # hw/i386/amd_iommu.c
 amdvi_evntlog_fail(uint64_t addr, uint32_t head) "error: fail to write at addr 0x%"PRIx64" +  offset 0x%"PRIx32
 amdvi_cache_update(uint16_t domid, uint8_t bus, uint8_t slot, uint8_t func, uint64_t gpa, uint64_t txaddr) " update iotlb domid 0x%"PRIx16" devid: %02x:%02x.%x gpa 0x%"PRIx64" hpa 0x%"PRIx64
-- 
2.7.4

[Qemu-devel] [PATCH v5 08/18] intel_iommu: fix trace for addr translation

[Peter Xu]

Another patch to convert the DPRINTF() stuffs. This patch focuses on the
address translation path and caching.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c | 84 ++++++++++++++++++++-------------------------------
 hw/i386/trace-events  |  7 +++++
 2 files changed, 39 insertions(+), 52 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 343a2ad..2c13b7b 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -260,11 +260,9 @@ static void vtd_update_iotlb(IntelIOMMUState *s, uint16_t source_id,
     uint64_t *key = g_malloc(sizeof(*key));
     uint64_t gfn = vtd_get_iotlb_gfn(addr, level);
 
-    VTD_DPRINTF(CACHE, "update iotlb sid 0x%"PRIx16 " iova 0x%"PRIx64
-                " slpte 0x%"PRIx64 " did 0x%"PRIx16, source_id, addr, slpte,
-                domain_id);
+    trace_vtd_iotlb_page_update(source_id, addr, slpte, domain_id);
     if (g_hash_table_size(s->iotlb) >= VTD_IOTLB_MAX_SIZE) {
-        VTD_DPRINTF(CACHE, "iotlb exceeds size limit, forced to reset");
+        trace_vtd_iotlb_reset("iotlb exceeds size limit");
         vtd_reset_iotlb(s);
     }
 
@@ -505,8 +503,7 @@ static int vtd_get_root_entry(IntelIOMMUState *s, uint8_t index,
 
     addr = s->root + index * sizeof(*re);
     if (dma_memory_read(&address_space_memory, addr, re, sizeof(*re))) {
-        VTD_DPRINTF(GENERAL, "error: fail to access root-entry at 0x%"PRIx64
-                    " + %"PRIu8, s->root, index);
+        trace_vtd_err("Fail to access root-entry");
         re->val = 0;
         return -VTD_FR_ROOT_TABLE_INV;
     }
@@ -525,14 +522,12 @@ static int vtd_get_context_entry_from_root(VTDRootEntry *root, uint8_t index,
     dma_addr_t addr;
 
     if (!vtd_root_entry_present(root)) {
-        VTD_DPRINTF(GENERAL, "error: root-entry is not present");
+        trace_vtd_err("Root-entry is not present");
         return -VTD_FR_ROOT_ENTRY_P;
     }
     addr = (root->val & VTD_ROOT_ENTRY_CTP) + index * sizeof(*ce);
     if (dma_memory_read(&address_space_memory, addr, ce, sizeof(*ce))) {
-        VTD_DPRINTF(GENERAL, "error: fail to access context-entry at 0x%"PRIx64
-                    " + %"PRIu8,
-                    (uint64_t)(root->val & VTD_ROOT_ENTRY_CTP), index);
+        trace_vtd_err("Fail to access context-entry");
         return -VTD_FR_CONTEXT_TABLE_INV;
     }
     ce->lo = le64_to_cpu(ce->lo);
@@ -644,7 +639,7 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write,
      * in CAP_REG and AW in context-entry.
      */
     if (iova & ~((1ULL << MIN(ce_agaw, VTD_MGAW)) - 1)) {
-        VTD_DPRINTF(GENERAL, "error: iova 0x%"PRIx64 " exceeds limits", iova);
+        trace_vtd_err("IOVA exceeds limits");
         return -VTD_FR_ADDR_BEYOND_MGAW;
     }
 
@@ -656,9 +651,7 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write,
         slpte = vtd_get_slpte(addr, offset);
 
         if (slpte == (uint64_t)-1) {
-            VTD_DPRINTF(GENERAL, "error: fail to access second-level paging "
-                        "entry at level %"PRIu32 " for iova 0x%"PRIx64,
-                        level, iova);
+            trace_vtd_err("Fail to access second-level paging entry");
             if (level == vtd_get_level_from_context_entry(ce)) {
                 /* Invalid programming of context-entry */
                 return -VTD_FR_CONTEXT_ENTRY_INV;
@@ -669,15 +662,11 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write,
         *reads = (*reads) && (slpte & VTD_SL_R);
         *writes = (*writes) && (slpte & VTD_SL_W);
         if (!(slpte & access_right_check)) {
-            VTD_DPRINTF(GENERAL, "error: lack of %s permission for "
-                        "iova 0x%"PRIx64 " slpte 0x%"PRIx64,
-                        (is_write ? "write" : "read"), iova, slpte);
+            trace_vtd_err("Lack of permission for page");
             return is_write ? -VTD_FR_WRITE : -VTD_FR_READ;
         }
         if (vtd_slpte_nonzero_rsvd(slpte, level)) {
-            VTD_DPRINTF(GENERAL, "error: non-zero reserved field in second "
-                        "level paging entry level %"PRIu32 " slpte 0x%"PRIx64,
-                        level, slpte);
+            trace_vtd_err_nonzero_reserved("second level paging entry");
             return -VTD_FR_PAGING_ENTRY_RSVD;
         }
 
@@ -704,12 +693,11 @@ static int vtd_dev_to_context_entry(IntelIOMMUState *s, uint8_t bus_num,
     }
 
     if (!vtd_root_entry_present(&re)) {
-        VTD_DPRINTF(GENERAL, "error: root-entry #%"PRIu8 " is not present",
-                    bus_num);
+        /* Not error - it's okay we don't have root entry. */
+        trace_vtd_re_not_present(bus_num);
         return -VTD_FR_ROOT_ENTRY_P;
     } else if (re.rsvd || (re.val & VTD_ROOT_ENTRY_RSVD)) {
-        VTD_DPRINTF(GENERAL, "error: non-zero reserved field in root-entry "
-                    "hi 0x%"PRIx64 " lo 0x%"PRIx64, re.rsvd, re.val);
+        trace_vtd_err_nonzero_reserved("Root entry");
         return -VTD_FR_ROOT_ENTRY_RSVD;
     }
 
@@ -719,22 +707,17 @@ static int vtd_dev_to_context_entry(IntelIOMMUState *s, uint8_t bus_num,
     }
 
     if (!vtd_context_entry_present(ce)) {
-        VTD_DPRINTF(GENERAL,
-                    "error: context-entry #%"PRIu8 "(bus #%"PRIu8 ") "
-                    "is not present", devfn, bus_num);
+        /* Not error - it's okay we don't have context entry. */
+        trace_vtd_ce_not_present(bus_num, devfn);
         return -VTD_FR_CONTEXT_ENTRY_P;
     } else if ((ce->hi & VTD_CONTEXT_ENTRY_RSVD_HI) ||
                (ce->lo & VTD_CONTEXT_ENTRY_RSVD_LO)) {
-        VTD_DPRINTF(GENERAL,
-                    "error: non-zero reserved field in context-entry "
-                    "hi 0x%"PRIx64 " lo 0x%"PRIx64, ce->hi, ce->lo);
+        trace_vtd_err_nonzero_reserved("Context entry");
         return -VTD_FR_CONTEXT_ENTRY_RSVD;
     }
     /* Check if the programming of context-entry is valid */
     if (!vtd_is_level_supported(s, vtd_get_level_from_context_entry(ce))) {
-        VTD_DPRINTF(GENERAL, "error: unsupported Address Width value in "
-                    "context-entry hi 0x%"PRIx64 " lo 0x%"PRIx64,
-                    ce->hi, ce->lo);
+        trace_vtd_err("Unsupported Address Width value in context-entry");
         return -VTD_FR_CONTEXT_ENTRY_INV;
     } else {
         switch (ce->lo & VTD_CONTEXT_ENTRY_TT) {
@@ -743,9 +726,7 @@ static int vtd_dev_to_context_entry(IntelIOMMUState *s, uint8_t bus_num,
         case VTD_CONTEXT_TT_DEV_IOTLB:
             break;
         default:
-            VTD_DPRINTF(GENERAL, "error: unsupported Translation Type in "
-                        "context-entry hi 0x%"PRIx64 " lo 0x%"PRIx64,
-                        ce->hi, ce->lo);
+            trace_vtd_err("Unsupported Translation Type in context-entry");
             return -VTD_FR_CONTEXT_ENTRY_INV;
         }
     }
@@ -825,9 +806,8 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
     /* Try to fetch slpte form IOTLB */
     iotlb_entry = vtd_lookup_iotlb(s, source_id, addr);
     if (iotlb_entry) {
-        VTD_DPRINTF(CACHE, "hit iotlb sid 0x%"PRIx16 " iova 0x%"PRIx64
-                    " slpte 0x%"PRIx64 " did 0x%"PRIx16, source_id, addr,
-                    iotlb_entry->slpte, iotlb_entry->domain_id);
+        trace_vtd_iotlb_page_hit(source_id, addr, iotlb_entry->slpte,
+                                 iotlb_entry->domain_id);
         slpte = iotlb_entry->slpte;
         reads = iotlb_entry->read_flags;
         writes = iotlb_entry->write_flags;
@@ -836,10 +816,9 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
     }
     /* Try to fetch context-entry from cache first */
     if (cc_entry->context_cache_gen == s->context_cache_gen) {
-        VTD_DPRINTF(CACHE, "hit context-cache bus %d devfn %d "
-                    "(hi %"PRIx64 " lo %"PRIx64 " gen %"PRIu32 ")",
-                    bus_num, devfn, cc_entry->context_entry.hi,
-                    cc_entry->context_entry.lo, cc_entry->context_cache_gen);
+        trace_vtd_iotlb_cc_hit(bus_num, devfn, cc_entry->context_entry.hi,
+                               cc_entry->context_entry.lo,
+                               cc_entry->context_cache_gen);
         ce = cc_entry->context_entry;
         is_fpd_set = ce.lo & VTD_CONTEXT_ENTRY_FPD;
     } else {
@@ -848,19 +827,18 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
         if (ret_fr) {
             ret_fr = -ret_fr;
             if (is_fpd_set && vtd_is_qualified_fault(ret_fr)) {
-                VTD_DPRINTF(FLOG, "fault processing is disabled for DMA "
-                            "requests through this context-entry "
-                            "(with FPD Set)");
+                trace_vtd_err("Fault processing is disabled for DMA "
+                              "requests through this context-entry "
+                              "(with FPD Set)");
             } else {
                 vtd_report_dmar_fault(s, source_id, addr, ret_fr, is_write);
             }
             return;
         }
         /* Update context-cache */
-        VTD_DPRINTF(CACHE, "update context-cache bus %d devfn %d "
-                    "(hi %"PRIx64 " lo %"PRIx64 " gen %"PRIu32 "->%"PRIu32 ")",
-                    bus_num, devfn, ce.hi, ce.lo,
-                    cc_entry->context_cache_gen, s->context_cache_gen);
+        trace_vtd_iotlb_cc_update(bus_num, devfn, ce.hi, ce.lo,
+                                  cc_entry->context_cache_gen,
+                                  s->context_cache_gen);
         cc_entry->context_entry = ce;
         cc_entry->context_cache_gen = s->context_cache_gen;
     }
@@ -870,8 +848,9 @@ static void vtd_do_iommu_translate(VTDAddressSpace *vtd_as, PCIBus *bus,
     if (ret_fr) {
         ret_fr = -ret_fr;
         if (is_fpd_set && vtd_is_qualified_fault(ret_fr)) {
-            VTD_DPRINTF(FLOG, "fault processing is disabled for DMA requests "
-                        "through this context-entry (with FPD Set)");
+            trace_vtd_err("Fault processing is disabled for DMA "
+                          "requests through this context-entry "
+                          "(with FPD Set)");
         } else {
             vtd_report_dmar_fault(s, source_id, addr, ret_fr, is_write);
         }
@@ -1031,6 +1010,7 @@ static uint64_t vtd_context_cache_invalidate(IntelIOMMUState *s, uint64_t val)
 
 static void vtd_iotlb_global_invalidate(IntelIOMMUState *s)
 {
+    trace_vtd_iotlb_reset("global invalidation recved");
     vtd_reset_iotlb(s);
 }
 
diff --git a/hw/i386/trace-events b/hw/i386/trace-events
index eea3e84..a273980 100644
--- a/hw/i386/trace-events
+++ b/hw/i386/trace-events
@@ -24,6 +24,13 @@ vtd_inv_desc_wait_sw(uint64_t addr, uint32_t data) "wait invalidate status write
 vtd_inv_desc_wait_irq(const char *msg) "%s"
 vtd_err_nonzero_reserved(const char *msg) "Non-zero reserved field in %s"
 vtd_err(const char *msg) "%s"
+vtd_re_not_present(uint8_t bus) "Root entry bus %"PRIu8" not present"
+vtd_ce_not_present(uint8_t bus, uint8_t devfn) "Context entry bus %"PRIu8" devfn %"PRIu8" not present"
+vtd_iotlb_page_hit(uint16_t sid, uint64_t addr, uint64_t slpte, uint16_t domain) "IOTLB page hit sid 0x%"PRIx16" iova 0x%"PRIx64" slpte 0x%"PRIx64" domain 0x%"PRIx16
+vtd_iotlb_page_update(uint16_t sid, uint64_t addr, uint64_t slpte, uint16_t domain) "IOTLB page update sid 0x%"PRIx16" iova 0x%"PRIx64" slpte 0x%"PRIx64" domain 0x%"PRIx16
+vtd_iotlb_cc_hit(uint8_t bus, uint8_t devfn, uint64_t high, uint64_t low, uint32_t gen) "IOTLB context hit bus 0x%"PRIx8" devfn 0x%"PRIx8" high 0x%"PRIx64" low 0x%"PRIx64" gen %"PRIu32
+vtd_iotlb_cc_update(uint8_t bus, uint8_t devfn, uint64_t high, uint64_t low, uint32_t gen1, uint32_t gen2) "IOTLB context update bus 0x%"PRIx8" devfn 0x%"PRIx8" high 0x%"PRIx64" low 0x%"PRIx64" gen %"PRIu32" -> gen %"PRIu32
+vtd_iotlb_reset(const char *reason) "IOTLB reset (reason: %s)"
 
 # hw/i386/amd_iommu.c
 amdvi_evntlog_fail(uint64_t addr, uint32_t head) "error: fail to write at addr 0x%"PRIx64" +  offset 0x%"PRIx32
-- 
2.7.4

[Qemu-devel] [PATCH v5 09/18] intel_iommu: vtd_slpt_level_shift check level

[Peter Xu]

This helps in debugging incorrect level passed in.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 2c13b7b..6f5f68a 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -168,6 +168,7 @@ static gboolean vtd_hash_remove_by_domain(gpointer key, gpointer value,
 /* The shift of an addr for a certain level of paging structure */
 static inline uint32_t vtd_slpt_level_shift(uint32_t level)
 {
+    assert(level != 0);
     return VTD_PAGE_SHIFT_4K + (level - 1) * VTD_SL_LEVEL_BITS;
 }
 
-- 
2.7.4

[Qemu-devel] [PATCH v5 10/18] memory: add section range info for IOMMU notifier

[Peter Xu]

In this patch, IOMMUNotifier.{start|end} are introduced to store section
information for a specific notifier. When notification occurs, we not
only check the notification type (MAP|UNMAP), but also check whether the
notified iova range overlaps with the range of specific IOMMU notifier,
and skip those notifiers if not in the listened range.

When removing an region, we need to make sure we removed the correct
VFIOGuestIOMMU by checking the IOMMUNotifier.start address as well.

Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/vfio/common.c      | 12 +++++++++---
 hw/virtio/vhost.c     |  4 ++--
 include/exec/memory.h | 19 ++++++++++++++++++-
 memory.c              |  9 +++++++++
 4 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 4d90844..49dc035 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -471,8 +471,13 @@ static void vfio_listener_region_add(MemoryListener *listener,
         giommu->iommu_offset = section->offset_within_address_space -
                                section->offset_within_region;
         giommu->container = container;
-        giommu->n.notify = vfio_iommu_map_notify;
-        giommu->n.notifier_flags = IOMMU_NOTIFIER_ALL;
+        llend = int128_add(int128_make64(section->offset_within_region),
+                           section->size);
+        llend = int128_sub(llend, int128_one());
+        iommu_notifier_init(&giommu->n, vfio_iommu_map_notify,
+                            IOMMU_NOTIFIER_ALL,
+                            section->offset_within_region,
+                            int128_get64(llend));
         QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
 
         memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
@@ -543,7 +548,8 @@ static void vfio_listener_region_del(MemoryListener *listener,
         VFIOGuestIOMMU *giommu;
 
         QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
-            if (giommu->iommu == section->mr) {
+            if (giommu->iommu == section->mr &&
+                giommu->n.start == section->offset_within_region) {
                 memory_region_unregister_iommu_notifier(giommu->iommu,
                                                         &giommu->n);
                 QLIST_REMOVE(giommu, giommu_next);
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 9cacf55..cc99c6a 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1242,8 +1242,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
         .priority = 10
     };
 
-    hdev->n.notify = vhost_iommu_unmap_notify;
-    hdev->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
+    iommu_notifier_init(&hdev->n, vhost_iommu_unmap_notify,
+                        IOMMU_NOTIFIER_UNMAP, 0, ~0ULL);
 
     if (hdev->migration_blocker == NULL) {
         if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) {
diff --git a/include/exec/memory.h b/include/exec/memory.h
index bec9756..ae4c9a9 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -81,13 +81,30 @@ typedef enum {
 
 #define IOMMU_NOTIFIER_ALL (IOMMU_NOTIFIER_MAP | IOMMU_NOTIFIER_UNMAP)
 
+struct IOMMUNotifier;
+typedef void (*IOMMUNotify)(struct IOMMUNotifier *notifier,
+                            IOMMUTLBEntry *data);
+
 struct IOMMUNotifier {
-    void (*notify)(struct IOMMUNotifier *notifier, IOMMUTLBEntry *data);
+    IOMMUNotify notify;
     IOMMUNotifierFlag notifier_flags;
+    /* Notify for address space range start <= addr <= end */
+    hwaddr start;
+    hwaddr end;
     QLIST_ENTRY(IOMMUNotifier) node;
 };
 typedef struct IOMMUNotifier IOMMUNotifier;
 
+static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
+                                       IOMMUNotifierFlag flags,
+                                       hwaddr start, hwaddr end)
+{
+    n->notify = fn;
+    n->notifier_flags = flags;
+    n->start = start;
+    n->end = end;
+}
+
 /* New-style MMIO accessors can indicate that the transaction failed.
  * A zero (MEMTX_OK) response means success; anything else is a failure
  * of some kind. The memory subsystem will bitwise-OR together results
diff --git a/memory.c b/memory.c
index 2bfc37f..80ab3c1 100644
--- a/memory.c
+++ b/memory.c
@@ -1610,6 +1610,7 @@ void memory_region_register_iommu_notifier(MemoryRegion *mr,
 
     /* We need to register for at least one bitfield */
     assert(n->notifier_flags != IOMMU_NOTIFIER_NONE);
+    assert(n->start <= n->end);
     QLIST_INSERT_HEAD(&mr->iommu_notify, n, node);
     memory_region_update_iommu_notify_flags(mr);
 }
@@ -1671,6 +1672,14 @@ void memory_region_notify_iommu(MemoryRegion *mr,
     }
 
     QLIST_FOREACH(iommu_notifier, &mr->iommu_notify, node) {
+        /*
+         * Skip the notification if the notification does not overlap
+         * with registered range.
+         */
+        if (iommu_notifier->start > entry.iova + entry.addr_mask + 1 ||
+            iommu_notifier->end < entry.iova) {
+            continue;
+        }
         if (iommu_notifier->notifier_flags & request_flags) {
             iommu_notifier->notify(iommu_notifier, &entry);
         }
-- 
2.7.4

[Qemu-devel] [PATCH v5 11/18] memory: provide IOMMU_NOTIFIER_FOREACH macro

[Peter Xu]

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/exec/memory.h | 3 +++
 memory.c              | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index ae4c9a9..f0cb631 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -243,6 +243,9 @@ struct MemoryRegion {
     IOMMUNotifierFlag iommu_notify_flags;
 };
 
+#define IOMMU_NOTIFIER_FOREACH(n, mr) \
+    QLIST_FOREACH((n), &(mr)->iommu_notify, node)
+
 /**
  * MemoryListener: callbacks structure for updates to the physical memory map
  *
diff --git a/memory.c b/memory.c
index 80ab3c1..3a94656 100644
--- a/memory.c
+++ b/memory.c
@@ -1587,7 +1587,7 @@ static void memory_region_update_iommu_notify_flags(MemoryRegion *mr)
     IOMMUNotifierFlag flags = IOMMU_NOTIFIER_NONE;
     IOMMUNotifier *iommu_notifier;
 
-    QLIST_FOREACH(iommu_notifier, &mr->iommu_notify, node) {
+    IOMMU_NOTIFIER_FOREACH(iommu_notifier, mr) {
         flags |= iommu_notifier->notifier_flags;
     }
 
@@ -1671,7 +1671,7 @@ void memory_region_notify_iommu(MemoryRegion *mr,
         request_flags = IOMMU_NOTIFIER_UNMAP;
     }
 
-    QLIST_FOREACH(iommu_notifier, &mr->iommu_notify, node) {
+    IOMMU_NOTIFIER_FOREACH(iommu_notifier, mr) {
         /*
          * Skip the notification if the notification does not overlap
          * with registered range.
-- 
2.7.4

[Qemu-devel] [PATCH v5 12/18] memory: provide iommu_replay_all()

[Peter Xu]

This is an "global" version of exising memory_region_iommu_replay() - we
announce the translations to all the registered notifiers, instead of a
specific one.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/exec/memory.h | 8 ++++++++
 memory.c              | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index f0cb631..885c05f 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -711,6 +711,14 @@ void memory_region_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n,
                                 bool is_write);
 
 /**
+ * memory_region_iommu_replay_all: replay existing IOMMU translations
+ * to all the notifiers registered.
+ *
+ * @mr: the memory region to observe
+ */
+void memory_region_iommu_replay_all(MemoryRegion *mr);
+
+/**
  * memory_region_unregister_iommu_notifier: unregister a notifier for
  * changes to IOMMU translation entries.
  *
diff --git a/memory.c b/memory.c
index 3a94656..85cdcd1 100644
--- a/memory.c
+++ b/memory.c
@@ -1646,6 +1646,15 @@ void memory_region_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n,
     }
 }
 
+void memory_region_iommu_replay_all(MemoryRegion *mr)
+{
+    IOMMUNotifier *notifier;
+
+    IOMMU_NOTIFIER_FOREACH(notifier, mr) {
+        memory_region_iommu_replay(mr, notifier, false);
+    }
+}
+
 void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
                                              IOMMUNotifier *n)
 {
-- 
2.7.4

[Qemu-devel] [PATCH v5 13/18] memory: introduce memory_region_notify_one()

[Peter Xu]

Generalizing the notify logic in memory_region_notify_iommu() into a
single function. This can be further used in customized replay()
functions for IOMMUs.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/exec/memory.h | 15 +++++++++++++++
 memory.c              | 40 ++++++++++++++++++++++++----------------
 2 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 885c05f..75371e9 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -686,6 +686,21 @@ void memory_region_notify_iommu(MemoryRegion *mr,
                                 IOMMUTLBEntry entry);
 
 /**
+ * memory_region_notify_one: notify a change in an IOMMU translation
+ *                           entry to a single notifier
+ *
+ * This works just like memory_region_notify_iommu(), but it only
+ * notifies a specific notifier, not all of them.
+ *
+ * @notifier: the notifier to be notified
+ * @entry: the new entry in the IOMMU translation table.  The entry
+ *         replaces all old entries for the same virtual I/O address range.
+ *         Deleted entries have .@perm == 0.
+ */
+void memory_region_notify_one(IOMMUNotifier *notifier,
+                              IOMMUTLBEntry *entry);
+
+/**
  * memory_region_register_iommu_notifier: register a notifier for changes to
  * IOMMU translation entries.
  *
diff --git a/memory.c b/memory.c
index 85cdcd1..d0a5f01 100644
--- a/memory.c
+++ b/memory.c
@@ -1666,32 +1666,40 @@ void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
     memory_region_update_iommu_notify_flags(mr);
 }
 
-void memory_region_notify_iommu(MemoryRegion *mr,
-                                IOMMUTLBEntry entry)
+void memory_region_notify_one(IOMMUNotifier *notifier,
+                              IOMMUTLBEntry *entry)
 {
-    IOMMUNotifier *iommu_notifier;
     IOMMUNotifierFlag request_flags;
 
-    assert(memory_region_is_iommu(mr));
+    /*
+     * Skip the notification if the notification does not overlap
+     * with registered range.
+     */
+    if (notifier->start > entry->iova + entry->addr_mask + 1 ||
+        notifier->end < entry->iova) {
+        return;
+    }
 
-    if (entry.perm & IOMMU_RW) {
+    if (entry->perm & IOMMU_RW) {
         request_flags = IOMMU_NOTIFIER_MAP;
     } else {
         request_flags = IOMMU_NOTIFIER_UNMAP;
     }
 
+    if (notifier->notifier_flags & request_flags) {
+        notifier->notify(notifier, entry);
+    }
+}
+
+void memory_region_notify_iommu(MemoryRegion *mr,
+                                IOMMUTLBEntry entry)
+{
+    IOMMUNotifier *iommu_notifier;
+
+    assert(memory_region_is_iommu(mr));
+
     IOMMU_NOTIFIER_FOREACH(iommu_notifier, mr) {
-        /*
-         * Skip the notification if the notification does not overlap
-         * with registered range.
-         */
-        if (iommu_notifier->start > entry.iova + entry.addr_mask + 1 ||
-            iommu_notifier->end < entry.iova) {
-            continue;
-        }
-        if (iommu_notifier->notifier_flags & request_flags) {
-            iommu_notifier->notify(iommu_notifier, &entry);
-        }
+        memory_region_notify_one(iommu_notifier, &entry);
     }
 }
 
-- 
2.7.4

[Qemu-devel] [PATCH v5 14/18] memory: add MemoryRegionIOMMUOps.replay() callback

[Peter Xu]

Originally we have one memory_region_iommu_replay() function, which is
the default behavior to replay the translations of the whole IOMMU
region. However, on some platform like x86, we may want our own replay
logic for IOMMU regions. This patch add one more hook for IOMMUOps for
the callback, and it'll override the default if set.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/exec/memory.h | 2 ++
 memory.c              | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 75371e9..bb4e654 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -195,6 +195,8 @@ struct MemoryRegionIOMMUOps {
     void (*notify_flag_changed)(MemoryRegion *iommu,
                                 IOMMUNotifierFlag old_flags,
                                 IOMMUNotifierFlag new_flags);
+    /* Set this up to provide customized IOMMU replay function */
+    void (*replay)(MemoryRegion *iommu, IOMMUNotifier *notifier);
 };
 
 typedef struct CoalescedMemoryRange CoalescedMemoryRange;
diff --git a/memory.c b/memory.c
index d0a5f01..1715ae8 100644
--- a/memory.c
+++ b/memory.c
@@ -1630,6 +1630,12 @@ void memory_region_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n,
     hwaddr addr, granularity;
     IOMMUTLBEntry iotlb;
 
+    /* If the IOMMU has its own replay callback, override */
+    if (mr->iommu_ops->replay) {
+        mr->iommu_ops->replay(mr, n);
+        return;
+    }
+
     granularity = memory_region_iommu_get_min_page_size(mr);
 
     for (addr = 0; addr < memory_region_size(mr); addr += granularity) {
-- 
2.7.4

[Qemu-devel] [PATCH v5 15/18] intel_iommu: provide its own replay() callback

[Peter Xu]

The default replay() don't work for VT-d since vt-d will have a huge
default memory region which covers address range 0-(2^64-1). This will
normally consumes a lot of time (which looks like a dead loop).

The solution is simple - we don't walk over all the regions. Instead, we
jump over the regions when we found that the page directories are empty.
It'll greatly reduce the time to walk the whole region.

To achieve this, we provided a page walk helper to do that, invoking
corresponding hook function when we found an page we are interested in.
vtd_page_walk_level() is the core logic for the page walking. It's
interface is designed to suite further use case, e.g., to invalidate a
range of addresses.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++--
 hw/i386/trace-events  |   7 ++
 include/exec/memory.h |   2 +
 3 files changed, 189 insertions(+), 5 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 6f5f68a..a79250b 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -598,6 +598,22 @@ static inline uint32_t vtd_get_agaw_from_context_entry(VTDContextEntry *ce)
     return 30 + (ce->hi & VTD_CONTEXT_ENTRY_AW) * 9;
 }
 
+static inline uint64_t vtd_iova_limit(VTDContextEntry *ce)
+{
+    uint32_t ce_agaw = vtd_get_agaw_from_context_entry(ce);
+    return 1ULL << MIN(ce_agaw, VTD_MGAW);
+}
+
+/* Return true if IOVA passes range check, otherwise false. */
+static inline bool vtd_iova_range_check(uint64_t iova, VTDContextEntry *ce)
+{
+    /*
+     * Check if @iova is above 2^X-1, where X is the minimum of MGAW
+     * in CAP_REG and AW in context-entry.
+     */
+    return !(iova & ~(vtd_iova_limit(ce) - 1));
+}
+
 static const uint64_t vtd_paging_entry_rsvd_field[] = {
     [0] = ~0ULL,
     /* For not large page */
@@ -633,13 +649,9 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write,
     uint32_t level = vtd_get_level_from_context_entry(ce);
     uint32_t offset;
     uint64_t slpte;
-    uint32_t ce_agaw = vtd_get_agaw_from_context_entry(ce);
     uint64_t access_right_check;
 
-    /* Check if @iova is above 2^X-1, where X is the minimum of MGAW
-     * in CAP_REG and AW in context-entry.
-     */
-    if (iova & ~((1ULL << MIN(ce_agaw, VTD_MGAW)) - 1)) {
+    if (!vtd_iova_range_check(iova, ce)) {
         trace_vtd_err("IOVA exceeds limits");
         return -VTD_FR_ADDR_BEYOND_MGAW;
     }
@@ -681,6 +693,137 @@ static int vtd_gpa_to_slpte(VTDContextEntry *ce, uint64_t iova, bool is_write,
     }
 }
 
+typedef int (*vtd_page_walk_hook)(IOMMUTLBEntry *entry, void *private);
+
+/**
+ * vtd_page_walk_level - walk over specific level for IOVA range
+ *
+ * @addr: base GPA addr to start the walk
+ * @start: IOVA range start address
+ * @end: IOVA range end address (start <= addr < end)
+ * @hook_fn: hook func to be called when detected page
+ * @private: private data to be passed into hook func
+ * @read: whether parent level has read permission
+ * @write: whether parent level has write permission
+ * @notify_unmap: whether we should notify invalid entries
+ */
+static int vtd_page_walk_level(dma_addr_t addr, uint64_t start,
+                               uint64_t end, vtd_page_walk_hook hook_fn,
+                               void *private, uint32_t level,
+                               bool read, bool write, bool notify_unmap)
+{
+    bool read_cur, write_cur, entry_valid;
+    uint32_t offset;
+    uint64_t slpte;
+    uint64_t subpage_size, subpage_mask;
+    IOMMUTLBEntry entry;
+    uint64_t iova = start;
+    uint64_t iova_next;
+    int ret = 0;
+
+    trace_vtd_page_walk_level(addr, level, start, end);
+
+    subpage_size = 1ULL << vtd_slpt_level_shift(level);
+    subpage_mask = vtd_slpt_level_page_mask(level);
+
+    while (iova < end) {
+        iova_next = (iova & subpage_mask) + subpage_size;
+
+        offset = vtd_iova_level_offset(iova, level);
+        slpte = vtd_get_slpte(addr, offset);
+
+        if (slpte == (uint64_t)-1) {
+            trace_vtd_page_walk_skip_read(iova, iova_next);
+            goto next;
+        }
+
+        if (vtd_slpte_nonzero_rsvd(slpte, level)) {
+            trace_vtd_page_walk_skip_reserve(iova, iova_next);
+            goto next;
+        }
+
+        /* Permissions are stacked with parents' */
+        read_cur = read && (slpte & VTD_SL_R);
+        write_cur = write && (slpte & VTD_SL_W);
+
+        /*
+         * As long as we have either read/write permission, this is a
+         * valid entry. The rule works for both page entries and page
+         * table entries.
+         */
+        entry_valid = read_cur | write_cur;
+
+        if (vtd_is_last_slpte(slpte, level)) {
+            entry.target_as = &address_space_memory;
+            entry.iova = iova & subpage_mask;
+            /* NOTE: this is only meaningful if entry_valid == true */
+            entry.translated_addr = vtd_get_slpte_addr(slpte);
+            entry.addr_mask = ~subpage_mask;
+            entry.perm = IOMMU_ACCESS_FLAG(read_cur, write_cur);
+            if (!entry_valid && !notify_unmap) {
+                trace_vtd_page_walk_skip_perm(iova, iova_next);
+                goto next;
+            }
+            trace_vtd_page_walk_one(level, entry.iova, entry.translated_addr,
+                                    entry.addr_mask, entry.perm);
+            if (hook_fn) {
+                ret = hook_fn(&entry, private);
+                if (ret < 0) {
+                    trace_vtd_err("Detected error in page walk hook "
+                                  "function, stop walk.");
+                    return ret;
+                }
+            }
+        } else {
+            if (!entry_valid) {
+                trace_vtd_page_walk_skip_perm(iova, iova_next);
+                goto next;
+            }
+            ret = vtd_page_walk_level(vtd_get_slpte_addr(slpte), iova,
+                                      MIN(iova_next, end), hook_fn, private,
+                                      level - 1, read_cur, write_cur,
+                                      notify_unmap);
+            if (ret < 0) {
+                return ret;
+            }
+        }
+
+next:
+        iova = iova_next;
+    }
+
+    return 0;
+}
+
+/**
+ * vtd_page_walk - walk specific IOVA range, and call the hook
+ *
+ * @ce: context entry to walk upon
+ * @start: IOVA address to start the walk
+ * @end: IOVA range end address (start <= addr < end)
+ * @hook_fn: the hook that to be called for each detected area
+ * @private: private data for the hook function
+ */
+static int vtd_page_walk(VTDContextEntry *ce, uint64_t start, uint64_t end,
+                         vtd_page_walk_hook hook_fn, void *private)
+{
+    dma_addr_t addr = vtd_get_slpt_base_from_context(ce);
+    uint32_t level = vtd_get_level_from_context_entry(ce);
+
+    if (!vtd_iova_range_check(start, ce)) {
+        trace_vtd_err("Detected IOVA exceeds limits");
+        return -VTD_FR_ADDR_BEYOND_MGAW;
+    }
+
+    if (!vtd_iova_range_check(end, ce)) {
+        /* Fix end so that it reaches the maximum */
+        end = vtd_iova_limit(ce);
+    }
+
+    return vtd_page_walk_level(addr, start, end, hook_fn, private,
+                               level, true, true, false);
+}
+
 /* Map a device to its corresponding domain (context-entry) */
 static int vtd_dev_to_context_entry(IntelIOMMUState *s, uint8_t bus_num,
                                     uint8_t devfn, VTDContextEntry *ce)
@@ -2395,6 +2538,37 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn)
     return vtd_dev_as;
 }
 
+static int vtd_replay_hook(IOMMUTLBEntry *entry, void *private)
+{
+    memory_region_notify_one((IOMMUNotifier *)private, entry);
+    return 0;
+}
+
+static void vtd_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n)
+{
+    VTDAddressSpace *vtd_as = container_of(mr, VTDAddressSpace, iommu);
+    IntelIOMMUState *s = vtd_as->iommu_state;
+    uint8_t bus_n = pci_bus_num(vtd_as->bus);
+    VTDContextEntry ce;
+
+    if (vtd_dev_to_context_entry(s, bus_n, vtd_as->devfn, &ce) == 0) {
+        /*
+         * Scanned a valid context entry, walk over the pages and
+         * notify when needed.
+         */
+        trace_vtd_replay_ce_valid(bus_n, PCI_SLOT(vtd_as->devfn),
+                                  PCI_FUNC(vtd_as->devfn),
+                                  VTD_CONTEXT_ENTRY_DID(ce.hi),
+                                  ce.hi, ce.lo);
+        vtd_page_walk(&ce, 0, ~0, vtd_replay_hook, (void *)n);
+    } else {
+        trace_vtd_replay_ce_invalid(bus_n, PCI_SLOT(vtd_as->devfn),
+                                    PCI_FUNC(vtd_as->devfn));
+    }
+
+    return;
+}
+
 /* Do the initialization. It will also be called when reset, so pay
  * attention when adding new initialization stuff.
  */
@@ -2409,6 +2583,7 @@ static void vtd_init(IntelIOMMUState *s)
 
     s->iommu_ops.translate = vtd_iommu_translate;
     s->iommu_ops.notify_flag_changed = vtd_iommu_notify_flag_changed;
+    s->iommu_ops.replay = vtd_iommu_replay;
     s->root = 0;
     s->root_extended = false;
     s->dmar_enabled = false;
diff --git a/hw/i386/trace-events b/hw/i386/trace-events
index a273980..a3e1a9d 100644
--- a/hw/i386/trace-events
+++ b/hw/i386/trace-events
@@ -31,6 +31,13 @@ vtd_iotlb_page_update(uint16_t sid, uint64_t addr, uint64_t slpte, uint16_t doma
 vtd_iotlb_cc_hit(uint8_t bus, uint8_t devfn, uint64_t high, uint64_t low, uint32_t gen) "IOTLB context hit bus 0x%"PRIx8" devfn 0x%"PRIx8" high 0x%"PRIx64" low 0x%"PRIx64" gen %"PRIu32
 vtd_iotlb_cc_update(uint8_t bus, uint8_t devfn, uint64_t high, uint64_t low, uint32_t gen1, uint32_t gen2) "IOTLB context update bus 0x%"PRIx8" devfn 0x%"PRIx8" high 0x%"PRIx64" low 0x%"PRIx64" gen %"PRIu32" -> gen %"PRIu32
 vtd_iotlb_reset(const char *reason) "IOTLB reset (reason: %s)"
+vtd_replay_ce_valid(uint8_t bus, uint8_t dev, uint8_t fn, uint16_t domain, uint64_t hi, uint64_t lo) "replay valid context device %02"PRIx8":%02"PRIx8".%02"PRIx8" domain 0x%"PRIx16" hi 0x%"PRIx64" lo 0x%"PRIx64
+vtd_replay_ce_invalid(uint8_t bus, uint8_t dev, uint8_t fn) "replay invalid context device %02"PRIx8":%02"PRIx8".%02"PRIx8
+vtd_page_walk_level(uint64_t addr, uint32_t level, uint64_t start, uint64_t end) "walk (base=0x%"PRIx64", level=%"PRIu32") iova range 0x%"PRIx64" - 0x%"PRIx64
+vtd_page_walk_one(uint32_t level, uint64_t iova, uint64_t gpa, uint64_t mask, int perm) "detected page level 0x%"PRIx32" iova 0x%"PRIx64" -> gpa 0x%"PRIx64" mask 0x%"PRIx64" perm %d"
+vtd_page_walk_skip_read(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to unable to read"
+vtd_page_walk_skip_perm(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to perm empty"
+vtd_page_walk_skip_reserve(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to rsrv set"
 
 # hw/i386/amd_iommu.c
 amdvi_evntlog_fail(uint64_t addr, uint32_t head) "error: fail to write at addr 0x%"PRIx64" +  offset 0x%"PRIx32
diff --git a/include/exec/memory.h b/include/exec/memory.h
index bb4e654..9fd3232 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -59,6 +59,8 @@ typedef enum {
     IOMMU_RW   = 3,
 } IOMMUAccessFlags;
 
+#define IOMMU_ACCESS_FLAG(r, w) (((r) ? IOMMU_RO : 0) | ((w) ? IOMMU_WO : 0))
+
 struct IOMMUTLBEntry {
     AddressSpace    *target_as;
     hwaddr           iova;
-- 
2.7.4

[Qemu-devel] [PATCH v5 16/18] intel_iommu: do replay when context invalidate

[Peter Xu]

Before this one we only invalidate context cache when we receive context
entry invalidations. However it's possible that the invalidation also
contains a domain switch (only if cache-mode is enabled for vIOMMU). In
that case we need to notify all the registered components about the new
mapping.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index a79250b..9d9a38d 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -1115,6 +1115,16 @@ static void vtd_context_device_invalidate(IntelIOMMUState *s,
                 trace_vtd_inv_desc_cc_device(bus_n, VTD_PCI_SLOT(devfn_it),
                                              VTD_PCI_FUNC(devfn_it));
                 vtd_as->context_cache_entry.context_cache_gen = 0;
+                /*
+                 * So a device is moving out of (or moving into) a
+                 * domain, a replay() suites here to notify all the
+                 * IOMMU_NOTIFIER_MAP registers about this change.
+                 * This won't bring bad even if we have no such
+                 * notifier registered - the IOMMU notification
+                 * framework will skip MAP notifications if that
+                 * happened.
+                 */
+                memory_region_iommu_replay_all(&vtd_as->iommu);
             }
         }
     }
-- 
2.7.4

[Qemu-devel] [PATCH v5 17/18] intel_iommu: allow dynamic switch of IOMMU region

[Peter Xu]

This is preparation work to finally enabled dynamic switching ON/OFF for
VT-d protection. The old VT-d codes is using static IOMMU address space,
and that won't satisfy vfio-pci device listeners.

Let me explain.

vfio-pci devices depend on the memory region listener and IOMMU replay
mechanism to make sure the device mapping is coherent with the guest
even if there are domain switches. And there are two kinds of domain
switches:

  (1) switch from domain A -> B
  (2) switch from domain A -> no domain (e.g., turn DMAR off)

Case (1) is handled by the context entry invalidation handling by the
VT-d replay logic. What the replay function should do here is to replay
the existing page mappings in domain B.

However for case (2), we don't want to replay any domain mappings - we
just need the default GPA->HPA mappings (the address_space_memory
mapping). And this patch helps on case (2) to build up the mapping
automatically by leveraging the vfio-pci memory listeners.

Another important thing that this patch does is to seperate
IR (Interrupt Remapping) from DMAR (DMA Remapping). IR region should not
depend on the DMAR region (like before this patch). It should be a
standalone region, and it should be able to be activated without
DMAR (which is a common behavior of Linux kernel - by default it enables
IR while disabled DMAR).

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c         | 78 ++++++++++++++++++++++++++++++++++++++++---
 hw/i386/trace-events          |  2 +-
 include/hw/i386/intel_iommu.h |  2 ++
 3 files changed, 77 insertions(+), 5 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 9d9a38d..0c43745 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -1305,9 +1305,49 @@ static void vtd_handle_gcmd_sirtp(IntelIOMMUState *s)
     vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_IRTPS);
 }
 
+static void vtd_switch_address_space(VTDAddressSpace *as)
+{
+    assert(as);
+
+    trace_vtd_switch_address_space(pci_bus_num(as->bus),
+                                   VTD_PCI_SLOT(as->devfn),
+                                   VTD_PCI_FUNC(as->devfn),
+                                   as->iommu_state->dmar_enabled);
+
+    /* Turn off first then on the other */
+    if (as->iommu_state->dmar_enabled) {
+        memory_region_set_enabled(&as->sys_alias, false);
+        memory_region_set_enabled(&as->iommu, true);
+    } else {
+        memory_region_set_enabled(&as->iommu, false);
+        memory_region_set_enabled(&as->sys_alias, true);
+    }
+}
+
+static void vtd_switch_address_space_all(IntelIOMMUState *s)
+{
+    GHashTableIter iter;
+    VTDBus *vtd_bus;
+    int i;
+
+    g_hash_table_iter_init(&iter, s->vtd_as_by_busptr);
+    while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) {
+        for (i = 0; i < X86_IOMMU_PCI_DEVFN_MAX; i++) {
+            if (!vtd_bus->dev_as[i]) {
+                continue;
+            }
+            vtd_switch_address_space(vtd_bus->dev_as[i]);
+        }
+    }
+}
+
 /* Handle Translation Enable/Disable */
 static void vtd_handle_gcmd_te(IntelIOMMUState *s, bool en)
 {
+    if (s->dmar_enabled == en) {
+        return;
+    }
+
     VTD_DPRINTF(CSR, "Translation Enable %s", (en ? "on" : "off"));
 
     if (en) {
@@ -1322,6 +1362,8 @@ static void vtd_handle_gcmd_te(IntelIOMMUState *s, bool en)
         /* Ok - report back to driver */
         vtd_set_clear_mask_long(s, DMAR_GSTS_REG, VTD_GSTS_TES, 0);
     }
+
+    vtd_switch_address_space_all(s);
 }
 
 /* Handle Interrupt Remap Enable/Disable */
@@ -2535,15 +2577,43 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn)
         vtd_dev_as->devfn = (uint8_t)devfn;
         vtd_dev_as->iommu_state = s;
         vtd_dev_as->context_cache_entry.context_cache_gen = 0;
+
+        /*
+         * Memory region relationships looks like (Address range shows
+         * only lower 32 bits to make it short in length...):
+         *
+         * |-----------------+-------------------+----------|
+         * | Name            | Address range     | Priority |
+         * |-----------------+-------------------+----------+
+         * | vtd_root        | 00000000-ffffffff |        0 |
+         * |  intel_iommu    | 00000000-ffffffff |        1 |
+         * |  vtd_sys_alias  | 00000000-ffffffff |        1 |
+         * |  intel_iommu_ir | fee00000-feefffff |       64 |
+         * |-----------------+-------------------+----------|
+         *
+         * We enable/disable DMAR by switching enablement for
+         * vtd_sys_alias and intel_iommu regions. IR region is always
+         * enabled.
+         */
         memory_region_init_iommu(&vtd_dev_as->iommu, OBJECT(s),
                                  &s->iommu_ops, "intel_iommu", UINT64_MAX);
+        memory_region_init_alias(&vtd_dev_as->sys_alias, OBJECT(s),
+                                 "vtd_sys_alias", get_system_memory(),
+                                 0, memory_region_size(get_system_memory()));
         memory_region_init_io(&vtd_dev_as->iommu_ir, OBJECT(s),
                               &vtd_mem_ir_ops, s, "intel_iommu_ir",
                               VTD_INTERRUPT_ADDR_SIZE);
-        memory_region_add_subregion(&vtd_dev_as->iommu, VTD_INTERRUPT_ADDR_FIRST,
-                                    &vtd_dev_as->iommu_ir);
-        address_space_init(&vtd_dev_as->as,
-                           &vtd_dev_as->iommu, name);
+        memory_region_init(&vtd_dev_as->root, OBJECT(s),
+                           "vtd_root", UINT64_MAX);
+        memory_region_add_subregion_overlap(&vtd_dev_as->root,
+                                            VTD_INTERRUPT_ADDR_FIRST,
+                                            &vtd_dev_as->iommu_ir, 64);
+        address_space_init(&vtd_dev_as->as, &vtd_dev_as->root, name);
+        memory_region_add_subregion_overlap(&vtd_dev_as->root, 0,
+                                            &vtd_dev_as->sys_alias, 1);
+        memory_region_add_subregion_overlap(&vtd_dev_as->root, 0,
+                                            &vtd_dev_as->iommu, 1);
+        vtd_switch_address_space(vtd_dev_as);
     }
     return vtd_dev_as;
 }
diff --git a/hw/i386/trace-events b/hw/i386/trace-events
index a3e1a9d..bd57b0a 100644
--- a/hw/i386/trace-events
+++ b/hw/i386/trace-events
@@ -11,7 +11,6 @@ xen_pv_mmio_write(uint64_t addr) "WARNING: write to Xen PV Device MMIO space (ad
 x86_iommu_iec_notify(bool global, uint32_t index, uint32_t mask) "Notify IEC invalidation: global=%d index=%" PRIu32 " mask=%" PRIu32
 
 # hw/i386/intel_iommu.c
-vtd_switch_address_space(uint8_t bus, uint8_t slot, uint8_t fn, bool on) "Device %02x:%02x.%x switching address space (iommu enabled=%d)"
 vtd_inv_desc(const char *type, uint64_t hi, uint64_t lo) "invalidate desc type %s high 0x%"PRIx64" low 0x%"PRIx64
 vtd_inv_desc_cc_domain(uint16_t domain) "context invalidate domain 0x%"PRIx16
 vtd_inv_desc_cc_global(void) "context invalidate globally"
@@ -38,6 +37,7 @@ vtd_page_walk_one(uint32_t level, uint64_t iova, uint64_t gpa, uint64_t mask, in
 vtd_page_walk_skip_read(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to unable to read"
 vtd_page_walk_skip_perm(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to perm empty"
 vtd_page_walk_skip_reserve(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to rsrv set"
+vtd_switch_address_space(uint8_t bus, uint8_t slot, uint8_t fn, bool on) "Device %02x:%02x.%x switching address space (iommu enabled=%d)"
 
 # hw/i386/amd_iommu.c
 amdvi_evntlog_fail(uint64_t addr, uint32_t head) "error: fail to write at addr 0x%"PRIx64" +  offset 0x%"PRIx32
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index fe645aa..8f212a1 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -83,6 +83,8 @@ struct VTDAddressSpace {
     uint8_t devfn;
     AddressSpace as;
     MemoryRegion iommu;
+    MemoryRegion root;
+    MemoryRegion sys_alias;
     MemoryRegion iommu_ir;      /* Interrupt region: 0xfeeXXXXX */
     IntelIOMMUState *iommu_state;
     VTDContextCacheEntry context_cache_entry;
-- 
2.7.4

[Qemu-devel] [PATCH v5 18/18] intel_iommu: enable vfio devices

[Peter Xu]

This patch is based on Aviv Ben-David (<bd.aviv@gmail.com>)'s patch
upstream:

  "IOMMU: enable intel_iommu map and unmap notifiers"
  https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg01453.html

However I removed/fixed some content, and added my own codes.

Instead of translate() every page for iotlb invalidations (which is
slower), we walk the pages when needed and notify in a hook function.

This patch enables vfio devices for VT-d emulation.

And, since we already have vhost DMAR support via device-iotlb, a
natural benefit that this patch brings is that vt-d enabled vhost can
live even without ATS capability now. Though more tests are needed.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/intel_iommu.c          | 151 ++++++++++++++++++++++++++++++++++++++---
 hw/i386/intel_iommu_internal.h |   1 +
 hw/i386/trace-events           |   1 +
 include/hw/i386/intel_iommu.h  |   8 +++
 4 files changed, 150 insertions(+), 11 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 0c43745..60dbe56 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -805,7 +805,8 @@ next:
  * @private: private data for the hook function
  */
 static int vtd_page_walk(VTDContextEntry *ce, uint64_t start, uint64_t end,
-                         vtd_page_walk_hook hook_fn, void *private)
+                         vtd_page_walk_hook hook_fn, void *private,
+                         bool notify_unmap)
 {
     dma_addr_t addr = vtd_get_slpt_base_from_context(ce);
     uint32_t level = vtd_get_level_from_context_entry(ce);
@@ -821,7 +822,7 @@ static int vtd_page_walk(VTDContextEntry *ce, uint64_t start, uint64_t end,
     }
 
     return vtd_page_walk_level(addr, start, end, hook_fn, private,
-                               level, true, true, false);
+                               level, true, true, notify_unmap);
 }
 
 /* Map a device to its corresponding domain (context-entry) */
@@ -1164,14 +1165,60 @@ static uint64_t vtd_context_cache_invalidate(IntelIOMMUState *s, uint64_t val)
 
 static void vtd_iotlb_global_invalidate(IntelIOMMUState *s)
 {
+    IntelIOMMUNotifierNode *node;
+
     trace_vtd_iotlb_reset("global invalidation recved");
     vtd_reset_iotlb(s);
+
+    QLIST_FOREACH(node, &s->notifiers_list, next) {
+        memory_region_iommu_replay_all(&node->vtd_as->iommu);
+    }
 }
 
 static void vtd_iotlb_domain_invalidate(IntelIOMMUState *s, uint16_t domain_id)
 {
+    IntelIOMMUNotifierNode *node;
+    VTDContextEntry ce;
+    VTDAddressSpace *vtd_as;
+
     g_hash_table_foreach_remove(s->iotlb, vtd_hash_remove_by_domain,
                                 &domain_id);
+
+    QLIST_FOREACH(node, &s->notifiers_list, next) {
+        vtd_as = node->vtd_as;
+        if (!vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus),
+                                      vtd_as->devfn, &ce) &&
+            domain_id == VTD_CONTEXT_ENTRY_DID(ce.hi)) {
+            memory_region_iommu_replay_all(&vtd_as->iommu);
+        }
+    }
+}
+
+static int vtd_page_invalidate_notify_hook(IOMMUTLBEntry *entry,
+                                           void *private)
+{
+    memory_region_notify_iommu((MemoryRegion *)private, *entry);
+    return 0;
+}
+
+static void vtd_iotlb_page_invalidate_notify(IntelIOMMUState *s,
+                                           uint16_t domain_id, hwaddr addr,
+                                           uint8_t am)
+{
+    IntelIOMMUNotifierNode *node;
+    VTDContextEntry ce;
+    int ret;
+
+    QLIST_FOREACH(node, &(s->notifiers_list), next) {
+        VTDAddressSpace *vtd_as = node->vtd_as;
+        ret = vtd_dev_to_context_entry(s, pci_bus_num(vtd_as->bus),
+                                       vtd_as->devfn, &ce);
+        if (!ret && domain_id == VTD_CONTEXT_ENTRY_DID(ce.hi)) {
+            vtd_page_walk(&ce, addr, addr + (1 << am) * VTD_PAGE_SIZE,
+                          vtd_page_invalidate_notify_hook,
+                          (void *)&vtd_as->iommu, true);
+        }
+    }
 }
 
 static void vtd_iotlb_page_invalidate(IntelIOMMUState *s, uint16_t domain_id,
@@ -1184,6 +1231,7 @@ static void vtd_iotlb_page_invalidate(IntelIOMMUState *s, uint16_t domain_id,
     info.addr = addr;
     info.mask = ~((1 << am) - 1);
     g_hash_table_foreach_remove(s->iotlb, vtd_hash_remove_by_page, &info);
+    vtd_iotlb_page_invalidate_notify(s, domain_id, addr, am);
 }
 
 /* Flush IOTLB
@@ -2193,15 +2241,33 @@ static void vtd_iommu_notify_flag_changed(MemoryRegion *iommu,
                                           IOMMUNotifierFlag new)
 {
     VTDAddressSpace *vtd_as = container_of(iommu, VTDAddressSpace, iommu);
+    IntelIOMMUState *s = vtd_as->iommu_state;
+    IntelIOMMUNotifierNode *node = NULL;
+    IntelIOMMUNotifierNode *next_node = NULL;
 
-    if (new & IOMMU_NOTIFIER_MAP) {
-        error_report("Device at bus %s addr %02x.%d requires iommu "
-                     "notifier which is currently not supported by "
-                     "intel-iommu emulation",
-                     vtd_as->bus->qbus.name, PCI_SLOT(vtd_as->devfn),
-                     PCI_FUNC(vtd_as->devfn));
+    if (!s->caching_mode && new & IOMMU_NOTIFIER_MAP) {
+        error_report("We need to set cache_mode=1 for intel-iommu to enable "
+                     "device assignment with IOMMU protection.");
         exit(1);
     }
+
+    if (old == IOMMU_NOTIFIER_NONE) {
+        node = g_malloc0(sizeof(*node));
+        node->vtd_as = vtd_as;
+        QLIST_INSERT_HEAD(&s->notifiers_list, node, next);
+        return;
+    }
+
+    /* update notifier node with new flags */
+    QLIST_FOREACH_SAFE(node, &s->notifiers_list, next, next_node) {
+        if (node->vtd_as == vtd_as) {
+            if (new == IOMMU_NOTIFIER_NONE) {
+                QLIST_REMOVE(node, next);
+                g_free(node);
+            }
+            return;
+        }
+    }
 }
 
 static const VMStateDescription vtd_vmstate = {
@@ -2618,6 +2684,65 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn)
     return vtd_dev_as;
 }
 
+/*
+ * Unmap the whole range in the notifier's scope. If we have recorded
+ * any high watermark (VTDAddressSpace.iova_max), we use it to limit
+ * the n->end as well.
+ */
+static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
+{
+    IOMMUTLBEntry entry;
+    hwaddr size;
+    hwaddr start = n->start;
+    hwaddr end = n->end;
+
+    /*
+     * Note: all the codes in this function has a assumption that IOVA
+     * bits are no more than VTD_MGAW bits (which is restricted by
+     * VT-d spec), otherwise we need to consider overflow of 64 bits.
+     */
+
+    if (end > VTD_ADDRESS_SIZE) {
+        /*
+         * Don't need to unmap regions that is bigger than the whole
+         * VT-d supported address space size
+         */
+        end = VTD_ADDRESS_SIZE;
+    }
+
+    assert(start <= end);
+    size = end - start;
+
+    if (ctpop64(size) != 1) {
+        /*
+         * This size cannot format a correct mask. Let's enlarge it to
+         * suite the minimum available mask.
+         */
+        int n = 64 - clz64(size);
+        if (n > VTD_MGAW) {
+            /* should not happen, but in case it happens, limit it */
+            trace_vtd_err("Address space unmap found size too big");
+            n = VTD_MGAW;
+        }
+        size = 1ULL << n;
+    }
+
+    entry.target_as = &address_space_memory;
+    /* Adjust iova for the size */
+    entry.iova = n->start & ~(size - 1);
+    /* This field is meaningless for unmap */
+    entry.translated_addr = 0;
+    entry.perm = IOMMU_NONE;
+    entry.addr_mask = size - 1;
+
+    trace_vtd_as_unmap_whole(pci_bus_num(as->bus),
+                             VTD_PCI_SLOT(as->devfn),
+                             VTD_PCI_FUNC(as->devfn),
+                             entry.iova, size);
+
+    memory_region_notify_one(n, &entry);
+}
+
 static int vtd_replay_hook(IOMMUTLBEntry *entry, void *private)
 {
     memory_region_notify_one((IOMMUNotifier *)private, entry);
@@ -2633,14 +2758,17 @@ static void vtd_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n)
 
     if (vtd_dev_to_context_entry(s, bus_n, vtd_as->devfn, &ce) == 0) {
         /*
-         * Scanned a valid context entry, walk over the pages and
-         * notify when needed.
+         * Scanned a valid context entry, we first make sure to remove
+         * all existing mappings in old domain, by sending UNMAP to
+         * all the notifiers. Then, we walk over the pages and notify
+         * with existing mapped new entries in the new domain.
          */
         trace_vtd_replay_ce_valid(bus_n, PCI_SLOT(vtd_as->devfn),
                                   PCI_FUNC(vtd_as->devfn),
                                   VTD_CONTEXT_ENTRY_DID(ce.hi),
                                   ce.hi, ce.lo);
-        vtd_page_walk(&ce, 0, ~0, vtd_replay_hook, (void *)n);
+        vtd_address_space_unmap(vtd_as, n);
+        vtd_page_walk(&ce, 0, ~0, vtd_replay_hook, (void *)n, false);
     } else {
         trace_vtd_replay_ce_invalid(bus_n, PCI_SLOT(vtd_as->devfn),
                                     PCI_FUNC(vtd_as->devfn));
@@ -2822,6 +2950,7 @@ static void vtd_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    QLIST_INIT(&s->notifiers_list);
     memset(s->vtd_as_by_bus_num, 0, sizeof(s->vtd_as_by_bus_num));
     memory_region_init_io(&s->csrmem, OBJECT(s), &vtd_mem_ops, s,
                           "intel_iommu", DMAR_REG_SIZE);
diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index 4104121..29d6707 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -197,6 +197,7 @@
 #define VTD_DOMAIN_ID_MASK          ((1UL << VTD_DOMAIN_ID_SHIFT) - 1)
 #define VTD_CAP_ND                  (((VTD_DOMAIN_ID_SHIFT - 4) / 2) & 7ULL)
 #define VTD_MGAW                    39  /* Maximum Guest Address Width */
+#define VTD_ADDRESS_SIZE            (1ULL << VTD_MGAW)
 #define VTD_CAP_MGAW                (((VTD_MGAW - 1) & 0x3fULL) << 16)
 #define VTD_MAMV                    18ULL
 #define VTD_CAP_MAMV                (VTD_MAMV << 48)
diff --git a/hw/i386/trace-events b/hw/i386/trace-events
index bd57b0a..ef725ca 100644
--- a/hw/i386/trace-events
+++ b/hw/i386/trace-events
@@ -38,6 +38,7 @@ vtd_page_walk_skip_read(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"P
 vtd_page_walk_skip_perm(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to perm empty"
 vtd_page_walk_skip_reserve(uint64_t iova, uint64_t next) "Page walk skip iova 0x%"PRIx64" - 0x%"PRIx64" due to rsrv set"
 vtd_switch_address_space(uint8_t bus, uint8_t slot, uint8_t fn, bool on) "Device %02x:%02x.%x switching address space (iommu enabled=%d)"
+vtd_as_unmap_whole(uint8_t bus, uint8_t slot, uint8_t fn, uint64_t iova, uint64_t size) "Device %02x:%02x.%x start 0x%"PRIx64" size 0x%"PRIx64
 
 # hw/i386/amd_iommu.c
 amdvi_evntlog_fail(uint64_t addr, uint32_t head) "error: fail to write at addr 0x%"PRIx64" +  offset 0x%"PRIx32
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 8f212a1..3e51876 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -63,6 +63,7 @@ typedef union VTD_IR_TableEntry VTD_IR_TableEntry;
 typedef union VTD_IR_MSIAddress VTD_IR_MSIAddress;
 typedef struct VTDIrq VTDIrq;
 typedef struct VTD_MSIMessage VTD_MSIMessage;
+typedef struct IntelIOMMUNotifierNode IntelIOMMUNotifierNode;
 
 /* Context-Entry */
 struct VTDContextEntry {
@@ -249,6 +250,11 @@ struct VTD_MSIMessage {
 /* When IR is enabled, all MSI/MSI-X data bits should be zero */
 #define VTD_IR_MSI_DATA          (0)
 
+struct IntelIOMMUNotifierNode {
+    VTDAddressSpace *vtd_as;
+    QLIST_ENTRY(IntelIOMMUNotifierNode) next;
+};
+
 /* The iommu (DMAR) device state struct */
 struct IntelIOMMUState {
     X86IOMMUState x86_iommu;
@@ -286,6 +292,8 @@ struct IntelIOMMUState {
     MemoryRegionIOMMUOps iommu_ops;
     GHashTable *vtd_as_by_busptr;   /* VTDBus objects indexed by PCIBus* reference */
     VTDBus *vtd_as_by_bus_num[VTD_PCI_BUS_MAX]; /* VTDBus objects indexed by bus number */
+    /* list of registered notifiers */
+    QLIST_HEAD(, IntelIOMMUNotifierNode) notifiers_list;
 
     /* interrupt remapping */
     bool intr_enabled;              /* Whether guest enabled IR */
-- 
2.7.4

Re: [Qemu-devel] [PATCH v5 00/18] VT-d: vfio enablement and misc enhances

[Peter Xu]

On Tue, Jan 24, 2017 at 06:25:53PM +0800, Peter Xu wrote:
> This is v5 of vt-d vfio enablement series.
> 
> Most of the changes in v5 is not functionally, but related to
> comments, error_report()s, debugging, squashing patches, etc. (which
> are confirmed changes in v4), besides a tiny tweak when unmapping a
> whole address space (please see below changelog). There are still
> discussions in v4 thread, we can just continue there (or here), and
> from this version I'll remove RFC tag.
> 
> I didn't rebase to master since current master failed to build on my
> laptop (with a "vl.c/hax..." error), however this series should be
> okay to be applied cleanly upon it.

Sorry I forgot to append the todo list (please help adding in in case
I missed anything):

- don't need to notify IOTLB (psi/gsi/global) invalidations to devices
  that with ATS enabled
- investigate when guest map page while mask contains existing mapped
  pages (e.g. map 12k-16k first, then map 0-12k)
- coalesce unmap during page walk (currently, we send it once per
  page)
- when do PSI for unmap, whether we can send one notify directly
  instead of walking over the page table?

Above does not contain those that are still during discussion. And,
some of the entries still need tests to further prove it's
feasibility.

Thanks,

-- peterx

Re: [Qemu-devel] [PATCH v5 00/18] VT-d: vfio enablement and misc enhances

[Michael S. Tsirkin]

On Tue, Jan 24, 2017 at 07:49:10PM +0800, Peter Xu wrote:
> On Tue, Jan 24, 2017 at 06:25:53PM +0800, Peter Xu wrote:
> > This is v5 of vt-d vfio enablement series.
> > 
> > Most of the changes in v5 is not functionally, but related to
> > comments, error_report()s, debugging, squashing patches, etc. (which
> > are confirmed changes in v4), besides a tiny tweak when unmapping a
> > whole address space (please see below changelog). There are still
> > discussions in v4 thread, we can just continue there (or here), and
> > from this version I'll remove RFC tag.
> > 
> > I didn't rebase to master since current master failed to build on my
> > laptop (with a "vl.c/hax..." error), however this series should be
> > okay to be applied cleanly upon it.
> 
> Sorry I forgot to append the todo list (please help adding in in case
> I missed anything):
> 
> - don't need to notify IOTLB (psi/gsi/global) invalidations to devices
>   that with ATS enabled
> - investigate when guest map page while mask contains existing mapped
>   pages (e.g. map 12k-16k first, then map 0-12k)
> - coalesce unmap during page walk (currently, we send it once per
>   page)
> - when do PSI for unmap, whether we can send one notify directly
>   instead of walking over the page table?
> 
> Above does not contain those that are still during discussion. And,
> some of the entries still need tests to further prove it's
> feasibility.
> 
> Thanks,
> 
> -- peterx

While valid I don't think above need to block merging.

-- 
MST

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Alex Williamson]

On Tue, 24 Jan 2017 18:25:55 +0800
Peter Xu <peterx@redhat.com> wrote:

> A cleanup for vfio_iommu_map_notify(). Should have no functional change,
> just to make the function shorter and easier to understand.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  hw/vfio/common.c | 58 +++++++++++++++++++++++++++++++++++++-------------------
>  1 file changed, 38 insertions(+), 20 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 174f351..ce55dff 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -294,25 +294,14 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
>             section->offset_within_address_space & (1ULL << 63);
>  }
>  
> -static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> +static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
> +                           bool *read_only)
>  {
> -    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
> -    VFIOContainer *container = giommu->container;
> -    hwaddr iova = iotlb->iova + giommu->iommu_offset;
>      MemoryRegion *mr;
>      hwaddr xlat;
>      hwaddr len = iotlb->addr_mask + 1;
> -    void *vaddr;
> -    int ret;
> -
> -    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> -                                iova, iova + iotlb->addr_mask);
> -
> -    if (iotlb->target_as != &address_space_memory) {
> -        error_report("Wrong target AS \"%s\", only system memory is allowed",
> -                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> -        return;
> -    }
> +    bool ret = false;
> +    bool writable = iotlb->perm & IOMMU_WO;
>  
>      /*
>       * The IOMMU TLB entry we have just covers translation through
> @@ -322,12 +311,13 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>      rcu_read_lock();
>      mr = address_space_translate(&address_space_memory,
>                                   iotlb->translated_addr,
> -                                 &xlat, &len, iotlb->perm & IOMMU_WO);
> +                                 &xlat, &len, writable);
>      if (!memory_region_is_ram(mr)) {
>          error_report("iommu map to non memory area %"HWADDR_PRIx"",
>                       xlat);
>          goto out;
>      }
> +
>      /*
>       * Translation truncates length to the IOMMU page size,
>       * check that it did not truncate too much.
> @@ -337,11 +327,41 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>          goto out;
>      }
>  
> +    *vaddr = memory_region_get_ram_ptr(mr) + xlat;
> +    *read_only = !writable || mr->readonly;
> +    ret = true;
> +
> +out:
> +    rcu_read_unlock();
> +    return ret;
> +}
> +
> +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;
> +
> +    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> +                                iova, iova + iotlb->addr_mask);
> +
> +    if (iotlb->target_as != &address_space_memory) {
> +        error_report("Wrong target AS \"%s\", only system memory is allowed",
> +                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> +        return;
> +    }
> +
> +    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> +        return;
> +    }
> +
>      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> -        vaddr = memory_region_get_ram_ptr(mr) + xlat;
>          ret = vfio_dma_map(container, iova,
>                             iotlb->addr_mask + 1, vaddr,
> -                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
> +                           read_only);
>          if (ret) {
>              error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
>                           "0x%"HWADDR_PRIx", %p) = %d (%m)",
> @@ -357,8 +377,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>                           iotlb->addr_mask + 1, ret);
>          }
>      }
> -out:
> -    rcu_read_unlock();

The comment from v4 still needs input from Paolo, is it valid to make
use of vaddr (based on address_space_translate ->
memory_region_get_ram_ptr) outside of the rcu read lock or could future
BQL reduction efforts allow this to race?

>  }
>  
>  static void vfio_listener_region_add(MemoryListener *listener,

Re: [Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very large region

[Alex Williamson]

On Tue, 24 Jan 2017 18:25:56 +0800
Peter Xu <peterx@redhat.com> wrote:

> Linux vfio driver supports to do VFIO_IOMMU_UNMAP_DMA for a very big
> region. This can be leveraged by QEMU IOMMU implementation to cleanup
> existing page mappings for an entire iova address space (by notifying
> with an IOTLB with extremely huge addr_mask). However current
> vfio_iommu_map_notify() does not allow that. It make sure that all the
> translated address in IOTLB is falling into RAM range.
> 
> The check makes sense, but it should only be a sensible checker for
> mapping operations, and mean little for unmap operations.
> 
> This patch moves this check into map logic only, so that we'll get
> faster unmap handling (no need to translate again), and also we can then
> better support unmapping a very big region when it covers non-ram ranges
> or even not-existing ranges.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  hw/vfio/common.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index ce55dff..4d90844 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -354,11 +354,10 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>          return;
>      }
>  
> -    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> -        return;
> -    }
> -
>      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> +        if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> +            return;
> +        }


David, is SPAPR going to freak out if it sees unmaps to ranges that
extend beyond individual mappings, or perhaps include no mappings?
This effectively allows unmapping the entire address space of the iommu
in one pass, without validating or translating the backing.

>          ret = vfio_dma_map(container, iova,
>                             iotlb->addr_mask + 1, vaddr,
>                             read_only);

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Peter Xu]

On Tue, Jan 24, 2017 at 09:29:05AM -0700, Alex Williamson wrote:
> On Tue, 24 Jan 2017 18:25:55 +0800
> Peter Xu <peterx@redhat.com> wrote:
> 
> > A cleanup for vfio_iommu_map_notify(). Should have no functional change,
> > just to make the function shorter and easier to understand.
> > 
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  hw/vfio/common.c | 58 +++++++++++++++++++++++++++++++++++++-------------------
> >  1 file changed, 38 insertions(+), 20 deletions(-)
> > 
> > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > index 174f351..ce55dff 100644
> > --- a/hw/vfio/common.c
> > +++ b/hw/vfio/common.c
> > @@ -294,25 +294,14 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> >             section->offset_within_address_space & (1ULL << 63);
> >  }
> >  
> > -static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> > +static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
> > +                           bool *read_only)
> >  {
> > -    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
> > -    VFIOContainer *container = giommu->container;
> > -    hwaddr iova = iotlb->iova + giommu->iommu_offset;
> >      MemoryRegion *mr;
> >      hwaddr xlat;
> >      hwaddr len = iotlb->addr_mask + 1;
> > -    void *vaddr;
> > -    int ret;
> > -
> > -    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> > -                                iova, iova + iotlb->addr_mask);
> > -
> > -    if (iotlb->target_as != &address_space_memory) {
> > -        error_report("Wrong target AS \"%s\", only system memory is allowed",
> > -                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> > -        return;
> > -    }
> > +    bool ret = false;
> > +    bool writable = iotlb->perm & IOMMU_WO;
> >  
> >      /*
> >       * The IOMMU TLB entry we have just covers translation through
> > @@ -322,12 +311,13 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >      rcu_read_lock();
> >      mr = address_space_translate(&address_space_memory,
> >                                   iotlb->translated_addr,
> > -                                 &xlat, &len, iotlb->perm & IOMMU_WO);
> > +                                 &xlat, &len, writable);
> >      if (!memory_region_is_ram(mr)) {
> >          error_report("iommu map to non memory area %"HWADDR_PRIx"",
> >                       xlat);
> >          goto out;
> >      }
> > +
> >      /*
> >       * Translation truncates length to the IOMMU page size,
> >       * check that it did not truncate too much.
> > @@ -337,11 +327,41 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >          goto out;
> >      }
> >  
> > +    *vaddr = memory_region_get_ram_ptr(mr) + xlat;
> > +    *read_only = !writable || mr->readonly;
> > +    ret = true;
> > +
> > +out:
> > +    rcu_read_unlock();
> > +    return ret;
> > +}
> > +
> > +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;
> > +
> > +    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> > +                                iova, iova + iotlb->addr_mask);
> > +
> > +    if (iotlb->target_as != &address_space_memory) {
> > +        error_report("Wrong target AS \"%s\", only system memory is allowed",
> > +                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> > +        return;
> > +    }
> > +
> > +    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> > +        return;
> > +    }
> > +
> >      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> > -        vaddr = memory_region_get_ram_ptr(mr) + xlat;
> >          ret = vfio_dma_map(container, iova,
> >                             iotlb->addr_mask + 1, vaddr,
> > -                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
> > +                           read_only);
> >          if (ret) {
> >              error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
> >                           "0x%"HWADDR_PRIx", %p) = %d (%m)",
> > @@ -357,8 +377,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >                           iotlb->addr_mask + 1, ret);
> >          }
> >      }
> > -out:
> > -    rcu_read_unlock();
> 
> The comment from v4 still needs input from Paolo, is it valid to make
> use of vaddr (based on address_space_translate ->
> memory_region_get_ram_ptr) outside of the rcu read lock or could future
> BQL reduction efforts allow this to race?

Yes we should continue the discussion. Sorry for the inconvenient and
misunderstanding (I was only trying to provide a non-rfc version of
the series, in case Michael would like to pick up some cleanup any of
the patches).

I have similar question as well above - IIUC the RCU read lock
protects us from not losing the references of memory objects, however
in our case even after we release the lock, we are still using the
backend ram (vaddr) since we have set it up inside kernel to build up
the IO page table. After that, the kernel/device should be able to
write to addresses of that backend ram any time. Is there possibly a
window that kernel/device may write to that backend ram even after
guest destroyed the memory objects (e.g., by memory unplug?) and its
backend ram?

Thanks,

-- peterx

Re: [Qemu-devel] [PATCH v5 00/18] VT-d: vfio enablement and misc enhances

[Peter Xu]

On Tue, Jan 24, 2017 at 04:48:49PM +0200, Michael S. Tsirkin wrote:
> On Tue, Jan 24, 2017 at 07:49:10PM +0800, Peter Xu wrote:
> > On Tue, Jan 24, 2017 at 06:25:53PM +0800, Peter Xu wrote:
> > > This is v5 of vt-d vfio enablement series.
> > > 
> > > Most of the changes in v5 is not functionally, but related to
> > > comments, error_report()s, debugging, squashing patches, etc. (which
> > > are confirmed changes in v4), besides a tiny tweak when unmapping a
> > > whole address space (please see below changelog). There are still
> > > discussions in v4 thread, we can just continue there (or here), and
> > > from this version I'll remove RFC tag.
> > > 
> > > I didn't rebase to master since current master failed to build on my
> > > laptop (with a "vl.c/hax..." error), however this series should be
> > > okay to be applied cleanly upon it.
> > 
> > Sorry I forgot to append the todo list (please help adding in in case
> > I missed anything):
> > 
> > - don't need to notify IOTLB (psi/gsi/global) invalidations to devices
> >   that with ATS enabled
> > - investigate when guest map page while mask contains existing mapped
> >   pages (e.g. map 12k-16k first, then map 0-12k)
> > - coalesce unmap during page walk (currently, we send it once per
> >   page)
> > - when do PSI for unmap, whether we can send one notify directly
> >   instead of walking over the page table?
> > 
> > Above does not contain those that are still during discussion. And,
> > some of the entries still need tests to further prove it's
> > feasibility.
> > 
> > Thanks,
> > 
> > -- peterx
> 
> While valid I don't think above need to block merging.

Sorry for the delay of this series.

Looks like we still need to wait until we got explicit acks for vfio
patch 2-3 from Alex/Paolo/David since that'll be required by the
following series. (I'll address all Jason's new comments as well in
next post)

Do you like to merge the iommu cleanups first? Or you can also wait
for above to be confirmed, and I'll repost for a final version then
(if we don't have further comments).

Thanks,

-- peterx

Re: [Qemu-devel] [PATCH v5 00/18] VT-d: vfio enablement and misc enhances

[Michael S. Tsirkin]

On Wed, Jan 25, 2017 at 12:48:37PM +0800, Peter Xu wrote:
> On Tue, Jan 24, 2017 at 04:48:49PM +0200, Michael S. Tsirkin wrote:
> > On Tue, Jan 24, 2017 at 07:49:10PM +0800, Peter Xu wrote:
> > > On Tue, Jan 24, 2017 at 06:25:53PM +0800, Peter Xu wrote:
> > > > This is v5 of vt-d vfio enablement series.
> > > > 
> > > > Most of the changes in v5 is not functionally, but related to
> > > > comments, error_report()s, debugging, squashing patches, etc. (which
> > > > are confirmed changes in v4), besides a tiny tweak when unmapping a
> > > > whole address space (please see below changelog). There are still
> > > > discussions in v4 thread, we can just continue there (or here), and
> > > > from this version I'll remove RFC tag.
> > > > 
> > > > I didn't rebase to master since current master failed to build on my
> > > > laptop (with a "vl.c/hax..." error), however this series should be
> > > > okay to be applied cleanly upon it.
> > > 
> > > Sorry I forgot to append the todo list (please help adding in in case
> > > I missed anything):
> > > 
> > > - don't need to notify IOTLB (psi/gsi/global) invalidations to devices
> > >   that with ATS enabled
> > > - investigate when guest map page while mask contains existing mapped
> > >   pages (e.g. map 12k-16k first, then map 0-12k)
> > > - coalesce unmap during page walk (currently, we send it once per
> > >   page)
> > > - when do PSI for unmap, whether we can send one notify directly
> > >   instead of walking over the page table?
> > > 
> > > Above does not contain those that are still during discussion. And,
> > > some of the entries still need tests to further prove it's
> > > feasibility.
> > > 
> > > Thanks,
> > > 
> > > -- peterx
> > 
> > While valid I don't think above need to block merging.
> 
> Sorry for the delay of this series.
> 
> Looks like we still need to wait until we got explicit acks for vfio
> patch 2-3 from Alex/Paolo/David since that'll be required by the
> following series. (I'll address all Jason's new comments as well in
> next post)
> 
> Do you like to merge the iommu cleanups first? Or you can also wait
> for above to be confirmed, and I'll repost for a final version then
> (if we don't have further comments).
> 
> Thanks,
> 
> -- peterx

I can do that. If you want me to, pls post just the patches
that are ready separately.

-- 
MST

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Alex Williamson]

On Wed, 25 Jan 2017 12:32:21 +0800
Peter Xu <peterx@redhat.com> wrote:

> On Tue, Jan 24, 2017 at 09:29:05AM -0700, Alex Williamson wrote:
> > On Tue, 24 Jan 2017 18:25:55 +0800
> > Peter Xu <peterx@redhat.com> wrote:
> >   
> > > A cleanup for vfio_iommu_map_notify(). Should have no functional change,
> > > just to make the function shorter and easier to understand.
> > > 
> > > Signed-off-by: Peter Xu <peterx@redhat.com>
> > > ---
> > >  hw/vfio/common.c | 58 +++++++++++++++++++++++++++++++++++++-------------------
> > >  1 file changed, 38 insertions(+), 20 deletions(-)
> > > 
> > > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > > index 174f351..ce55dff 100644
> > > --- a/hw/vfio/common.c
> > > +++ b/hw/vfio/common.c
> > > @@ -294,25 +294,14 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> > >             section->offset_within_address_space & (1ULL << 63);
> > >  }
> > >  
> > > -static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> > > +static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
> > > +                           bool *read_only)
> > >  {
> > > -    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
> > > -    VFIOContainer *container = giommu->container;
> > > -    hwaddr iova = iotlb->iova + giommu->iommu_offset;
> > >      MemoryRegion *mr;
> > >      hwaddr xlat;
> > >      hwaddr len = iotlb->addr_mask + 1;
> > > -    void *vaddr;
> > > -    int ret;
> > > -
> > > -    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> > > -                                iova, iova + iotlb->addr_mask);
> > > -
> > > -    if (iotlb->target_as != &address_space_memory) {
> > > -        error_report("Wrong target AS \"%s\", only system memory is allowed",
> > > -                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> > > -        return;
> > > -    }
> > > +    bool ret = false;
> > > +    bool writable = iotlb->perm & IOMMU_WO;
> > >  
> > >      /*
> > >       * The IOMMU TLB entry we have just covers translation through
> > > @@ -322,12 +311,13 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> > >      rcu_read_lock();
> > >      mr = address_space_translate(&address_space_memory,
> > >                                   iotlb->translated_addr,
> > > -                                 &xlat, &len, iotlb->perm & IOMMU_WO);
> > > +                                 &xlat, &len, writable);
> > >      if (!memory_region_is_ram(mr)) {
> > >          error_report("iommu map to non memory area %"HWADDR_PRIx"",
> > >                       xlat);
> > >          goto out;
> > >      }
> > > +
> > >      /*
> > >       * Translation truncates length to the IOMMU page size,
> > >       * check that it did not truncate too much.
> > > @@ -337,11 +327,41 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> > >          goto out;
> > >      }
> > >  
> > > +    *vaddr = memory_region_get_ram_ptr(mr) + xlat;
> > > +    *read_only = !writable || mr->readonly;
> > > +    ret = true;
> > > +
> > > +out:
> > > +    rcu_read_unlock();
> > > +    return ret;
> > > +}
> > > +
> > > +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;
> > > +
> > > +    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> > > +                                iova, iova + iotlb->addr_mask);
> > > +
> > > +    if (iotlb->target_as != &address_space_memory) {
> > > +        error_report("Wrong target AS \"%s\", only system memory is allowed",
> > > +                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> > > +        return;
> > > +    }
> > > +
> > > +    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> > > +        return;
> > > +    }
> > > +
> > >      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> > > -        vaddr = memory_region_get_ram_ptr(mr) + xlat;
> > >          ret = vfio_dma_map(container, iova,
> > >                             iotlb->addr_mask + 1, vaddr,
> > > -                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
> > > +                           read_only);
> > >          if (ret) {
> > >              error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
> > >                           "0x%"HWADDR_PRIx", %p) = %d (%m)",
> > > @@ -357,8 +377,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> > >                           iotlb->addr_mask + 1, ret);
> > >          }
> > >      }
> > > -out:
> > > -    rcu_read_unlock();  
> > 
> > The comment from v4 still needs input from Paolo, is it valid to make
> > use of vaddr (based on address_space_translate ->
> > memory_region_get_ram_ptr) outside of the rcu read lock or could future
> > BQL reduction efforts allow this to race?  
> 
> Yes we should continue the discussion. Sorry for the inconvenient and
> misunderstanding (I was only trying to provide a non-rfc version of
> the series, in case Michael would like to pick up some cleanup any of
> the patches).
> 
> I have similar question as well above - IIUC the RCU read lock
> protects us from not losing the references of memory objects, however
> in our case even after we release the lock, we are still using the
> backend ram (vaddr) since we have set it up inside kernel to build up
> the IO page table. After that, the kernel/device should be able to
> write to addresses of that backend ram any time. Is there possibly a
> window that kernel/device may write to that backend ram even after
> guest destroyed the memory objects (e.g., by memory unplug?) and its
> backend ram?

If the memory object is destroyed, we better get an unmap, but my
question is whether releasing the rcu read lock before the map ioctl
means that the object could be destroyed between the release and ioctl
and now we have map an unmap code paths racing each other.  I suspect
that QEMU is not nearly this asynchronous and we're all gated on the
BQL, but if the intent of previous commits was to standardize around
the rcu lock so that we can work to get rid of the BQL, I don't want to
make a change explicitly counter to that.  Thanks,

Alex

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Paolo Bonzini]

On 24/01/2017 17:29, Alex Williamson wrote:
> On Tue, 24 Jan 2017 18:25:55 +0800
> Peter Xu <peterx@redhat.com> wrote:
> 
>> A cleanup for vfio_iommu_map_notify(). Should have no functional change,
>> just to make the function shorter and easier to understand.
>>
>> Signed-off-by: Peter Xu <peterx@redhat.com>
>> ---
>>  hw/vfio/common.c | 58 +++++++++++++++++++++++++++++++++++++-------------------
>>  1 file changed, 38 insertions(+), 20 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 174f351..ce55dff 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -294,25 +294,14 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
>>             section->offset_within_address_space & (1ULL << 63);
>>  }
>>  
>> -static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>> +static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
>> +                           bool *read_only)
>>  {
>> -    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
>> -    VFIOContainer *container = giommu->container;
>> -    hwaddr iova = iotlb->iova + giommu->iommu_offset;
>>      MemoryRegion *mr;
>>      hwaddr xlat;
>>      hwaddr len = iotlb->addr_mask + 1;
>> -    void *vaddr;
>> -    int ret;
>> -
>> -    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
>> -                                iova, iova + iotlb->addr_mask);
>> -
>> -    if (iotlb->target_as != &address_space_memory) {
>> -        error_report("Wrong target AS \"%s\", only system memory is allowed",
>> -                     iotlb->target_as->name ? iotlb->target_as->name : "none");
>> -        return;
>> -    }
>> +    bool ret = false;
>> +    bool writable = iotlb->perm & IOMMU_WO;
>>  
>>      /*
>>       * The IOMMU TLB entry we have just covers translation through
>> @@ -322,12 +311,13 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>>      rcu_read_lock();
>>      mr = address_space_translate(&address_space_memory,
>>                                   iotlb->translated_addr,
>> -                                 &xlat, &len, iotlb->perm & IOMMU_WO);
>> +                                 &xlat, &len, writable);
>>      if (!memory_region_is_ram(mr)) {
>>          error_report("iommu map to non memory area %"HWADDR_PRIx"",
>>                       xlat);
>>          goto out;
>>      }
>> +
>>      /*
>>       * Translation truncates length to the IOMMU page size,
>>       * check that it did not truncate too much.
>> @@ -337,11 +327,41 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>>          goto out;
>>      }
>>  
>> +    *vaddr = memory_region_get_ram_ptr(mr) + xlat;
>> +    *read_only = !writable || mr->readonly;
>> +    ret = true;
>> +
>> +out:
>> +    rcu_read_unlock();
>> +    return ret;
>> +}
>> +
>> +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;
>> +
>> +    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
>> +                                iova, iova + iotlb->addr_mask);
>> +
>> +    if (iotlb->target_as != &address_space_memory) {
>> +        error_report("Wrong target AS \"%s\", only system memory is allowed",
>> +                     iotlb->target_as->name ? iotlb->target_as->name : "none");
>> +        return;
>> +    }
>> +
>> +    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
>> +        return;
>> +    }
>> +
>>      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
>> -        vaddr = memory_region_get_ram_ptr(mr) + xlat;
>>          ret = vfio_dma_map(container, iova,
>>                             iotlb->addr_mask + 1, vaddr,
>> -                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
>> +                           read_only);
>>          if (ret) {
>>              error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
>>                           "0x%"HWADDR_PRIx", %p) = %d (%m)",
>> @@ -357,8 +377,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>>                           iotlb->addr_mask + 1, ret);
>>          }
>>      }
>> -out:
>> -    rcu_read_unlock();
> 
> The comment from v4 still needs input from Paolo, is it valid to make
> use of vaddr (based on address_space_translate ->
> memory_region_get_ram_ptr) outside of the rcu read lock or could future
> BQL reduction efforts allow this to race?

You need to keep a reference to the MemoryRegion if you do
rcu_read_unlock.  But it's simpler to call vfio_get_vaddr within
rcu_read_lock, and keep the lock/unlock in vfio_iommu_map_notify.

You probably should also put a comment about why VFIO does *not* need to
keep a reference between vfio_dma_map and vfio_dma_unmap (which doesn't
sound easy to do either).  Would any well-behaved guest invalidate the
IOMMU page tables before a memory hot-unplug?

Paolo

>>  }
>>  
>>  static void vfio_listener_region_add(MemoryListener *listener,
> 
> 
> 

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Paolo Bonzini]

On 25/01/2017 17:43, Alex Williamson wrote:
> On Wed, 25 Jan 2017 12:32:21 +0800
> Peter Xu <peterx@redhat.com> wrote:
>> I have similar question as well above - IIUC the RCU read lock
>> protects us from not losing the references of memory objects, however
>> in our case even after we release the lock, we are still using the
>> backend ram (vaddr) since we have set it up inside kernel to build up
>> the IO page table. After that, the kernel/device should be able to
>> write to addresses of that backend ram any time.

I don't think that's what happens.  As far as I understand, VFIO pins
the pages corresponding to vaddr, not vaddr itself.  The memory backend
is mmap-ed memory; when you hot-unplug it the munmap releases the VMA
and loses the connection between QEMU's virtual address space and the
pages.  However, the pages stay pinned and stay mapped into VFIO's own
IOMMU page tables.

So if a guest does a memory hot-unplug without IOMMU unmap, it would
keep on seeing the content of the hot-unplugged memory, and the host
could not release the pages, but the guest cannot overwrite QEMU data
structures.

Paolo

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Alex Williamson]

On Wed, 25 Jan 2017 18:11:37 +0100
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 24/01/2017 17:29, Alex Williamson wrote:
> > On Tue, 24 Jan 2017 18:25:55 +0800
> > Peter Xu <peterx@redhat.com> wrote:
> >   
> >> A cleanup for vfio_iommu_map_notify(). Should have no functional change,
> >> just to make the function shorter and easier to understand.
> >>
> >> Signed-off-by: Peter Xu <peterx@redhat.com>
> >> ---
> >>  hw/vfio/common.c | 58 +++++++++++++++++++++++++++++++++++++-------------------
> >>  1 file changed, 38 insertions(+), 20 deletions(-)
> >>
> >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> >> index 174f351..ce55dff 100644
> >> --- a/hw/vfio/common.c
> >> +++ b/hw/vfio/common.c
> >> @@ -294,25 +294,14 @@ static bool vfio_listener_skipped_section(MemoryRegionSection *section)
> >>             section->offset_within_address_space & (1ULL << 63);
> >>  }
> >>  
> >> -static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >> +static bool vfio_get_vaddr(IOMMUTLBEntry *iotlb, void **vaddr,
> >> +                           bool *read_only)
> >>  {
> >> -    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
> >> -    VFIOContainer *container = giommu->container;
> >> -    hwaddr iova = iotlb->iova + giommu->iommu_offset;
> >>      MemoryRegion *mr;
> >>      hwaddr xlat;
> >>      hwaddr len = iotlb->addr_mask + 1;
> >> -    void *vaddr;
> >> -    int ret;
> >> -
> >> -    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> >> -                                iova, iova + iotlb->addr_mask);
> >> -
> >> -    if (iotlb->target_as != &address_space_memory) {
> >> -        error_report("Wrong target AS \"%s\", only system memory is allowed",
> >> -                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> >> -        return;
> >> -    }
> >> +    bool ret = false;
> >> +    bool writable = iotlb->perm & IOMMU_WO;
> >>  
> >>      /*
> >>       * The IOMMU TLB entry we have just covers translation through
> >> @@ -322,12 +311,13 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >>      rcu_read_lock();
> >>      mr = address_space_translate(&address_space_memory,
> >>                                   iotlb->translated_addr,
> >> -                                 &xlat, &len, iotlb->perm & IOMMU_WO);
> >> +                                 &xlat, &len, writable);
> >>      if (!memory_region_is_ram(mr)) {
> >>          error_report("iommu map to non memory area %"HWADDR_PRIx"",
> >>                       xlat);
> >>          goto out;
> >>      }
> >> +
> >>      /*
> >>       * Translation truncates length to the IOMMU page size,
> >>       * check that it did not truncate too much.
> >> @@ -337,11 +327,41 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >>          goto out;
> >>      }
> >>  
> >> +    *vaddr = memory_region_get_ram_ptr(mr) + xlat;
> >> +    *read_only = !writable || mr->readonly;
> >> +    ret = true;
> >> +
> >> +out:
> >> +    rcu_read_unlock();
> >> +    return ret;
> >> +}
> >> +
> >> +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;
> >> +
> >> +    trace_vfio_iommu_map_notify(iotlb->perm == IOMMU_NONE ? "UNMAP" : "MAP",
> >> +                                iova, iova + iotlb->addr_mask);
> >> +
> >> +    if (iotlb->target_as != &address_space_memory) {
> >> +        error_report("Wrong target AS \"%s\", only system memory is allowed",
> >> +                     iotlb->target_as->name ? iotlb->target_as->name : "none");
> >> +        return;
> >> +    }
> >> +
> >> +    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> >> +        return;
> >> +    }
> >> +
> >>      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> >> -        vaddr = memory_region_get_ram_ptr(mr) + xlat;
> >>          ret = vfio_dma_map(container, iova,
> >>                             iotlb->addr_mask + 1, vaddr,
> >> -                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
> >> +                           read_only);
> >>          if (ret) {
> >>              error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
> >>                           "0x%"HWADDR_PRIx", %p) = %d (%m)",
> >> @@ -357,8 +377,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >>                           iotlb->addr_mask + 1, ret);
> >>          }
> >>      }
> >> -out:
> >> -    rcu_read_unlock();  
> > 
> > The comment from v4 still needs input from Paolo, is it valid to make
> > use of vaddr (based on address_space_translate ->
> > memory_region_get_ram_ptr) outside of the rcu read lock or could future
> > BQL reduction efforts allow this to race?  
> 
> You need to keep a reference to the MemoryRegion if you do
> rcu_read_unlock.  But it's simpler to call vfio_get_vaddr within
> rcu_read_lock, and keep the lock/unlock in vfio_iommu_map_notify.

Right, a memory_region_{un}ref() would be another option.
 
> You probably should also put a comment about why VFIO does *not* need to
> keep a reference between vfio_dma_map and vfio_dma_unmap (which doesn't
> sound easy to do either).  Would any well-behaved guest invalidate the
> IOMMU page tables before a memory hot-unplug?

Hmm, we do take a reference in vfio_listener_region_add(), but this is
of course to the iommu region not to the RAM region we're translating.
In the non-vIOMMU case we would be holding a reference to the memory
region backing a DMA mapping.  I would expect a well behaved guest to
evacuate DMA mappings targeting a hotplug memory region before it gets
ejected, but how much do we want to rely on well behaved guests.
Perhaps we should be taking a reference for each mapping entry, though
this makes Peter's plans to invalidate the entire address space much
more difficult.  Thanks,

Alex

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Paolo Bonzini]

On 25/01/2017 18:36, Alex Williamson wrote:
>> You probably should also put a comment about why VFIO does *not* need to
>> keep a reference between vfio_dma_map and vfio_dma_unmap (which doesn't
>> sound easy to do either).  Would any well-behaved guest invalidate the
>> IOMMU page tables before a memory hot-unplug?
>
> Hmm, we do take a reference in vfio_listener_region_add(), but this is
> of course to the iommu region not to the RAM region we're translating.
> In the non-vIOMMU case we would be holding a reference to the memory
> region backing a DMA mapping.  I would expect a well behaved guest to
> evacuate DMA mappings targeting a hotplug memory region before it gets
> ejected, but how much do we want to rely on well behaved guests.

It depends of what happens if they aren't.  I think it's fine (see other
message), but taking a reference for each mapping entry isn't so easy
because the unmap case doesn't know the old memory region.

Paolo


> Perhaps we should be taking a reference for each mapping entry, though
> this makes Peter's plans to invalidate the entire address space much
> more difficult.  Thanks,

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Alex Williamson]

On Wed, 25 Jan 2017 18:40:56 +0100
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 25/01/2017 18:36, Alex Williamson wrote:
> >> You probably should also put a comment about why VFIO does *not* need to
> >> keep a reference between vfio_dma_map and vfio_dma_unmap (which doesn't
> >> sound easy to do either).  Would any well-behaved guest invalidate the
> >> IOMMU page tables before a memory hot-unplug?  
> >
> > Hmm, we do take a reference in vfio_listener_region_add(), but this is
> > of course to the iommu region not to the RAM region we're translating.
> > In the non-vIOMMU case we would be holding a reference to the memory
> > region backing a DMA mapping.  I would expect a well behaved guest to
> > evacuate DMA mappings targeting a hotplug memory region before it gets
> > ejected, but how much do we want to rely on well behaved guests.  
> 
> It depends of what happens if they aren't.  I think it's fine (see other
> message), but taking a reference for each mapping entry isn't so easy
> because the unmap case doesn't know the old memory region.

If we held a reference to the memory region from the mapping path and
walk the IOMMU page table to generate the unmap, then we really should
get to the same original memory region, right?  The vfio iommu notifier
should only be mapping native page sizes of the IOMMU, 4k/2M/1G.  The
problem is that it's a lot of overhead to flush the entire address
space that way vs the single invalidation Peter is trying to enable
here.  It's actually similar to how the type1 iommu works in the kernel
though, we can unmap by iova because we ask the iommu for the iova->pfn
translation in order to unpin the page.

I do agree with your description in the other message about how things
would work for a memory hot-unplug w/o unmap though, which does seem to
imply that we don't need that reference.  Thanks,

Alex

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Paolo Bonzini]

On 25/01/2017 19:36, Alex Williamson wrote:
>> It depends of what happens if they aren't.  I think it's fine (see other
>> message), but taking a reference for each mapping entry isn't so easy
>> because the unmap case doesn't know the old memory region.
> If we held a reference to the memory region from the mapping path and
> walk the IOMMU page table to generate the unmap, then we really should
> get to the same original memory region, right?  The vfio iommu notifier
> should only be mapping native page sizes of the IOMMU, 4k/2M/1G.  The
> problem is that it's a lot of overhead to flush the entire address
> space that way vs the single invalidation Peter is trying to enable
> here.  It's actually similar to how the type1 iommu works in the kernel
> though, we can unmap by iova because we ask the iommu for the iova->pfn
> translation in order to unpin the page.

But in the kernel you can trust the IOMMU page tables because you build
them, here instead it's the guest's page tables that you'd walk, right?
You cannot trust the guest.

Paolo

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Alex Williamson]

On Wed, 25 Jan 2017 20:42:19 +0100
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 25/01/2017 19:36, Alex Williamson wrote:
> >> It depends of what happens if they aren't.  I think it's fine (see other
> >> message), but taking a reference for each mapping entry isn't so easy
> >> because the unmap case doesn't know the old memory region.  
> > If we held a reference to the memory region from the mapping path and
> > walk the IOMMU page table to generate the unmap, then we really should
> > get to the same original memory region, right?  The vfio iommu notifier
> > should only be mapping native page sizes of the IOMMU, 4k/2M/1G.  The
> > problem is that it's a lot of overhead to flush the entire address
> > space that way vs the single invalidation Peter is trying to enable
> > here.  It's actually similar to how the type1 iommu works in the kernel
> > though, we can unmap by iova because we ask the iommu for the iova->pfn
> > translation in order to unpin the page.  
> 
> But in the kernel you can trust the IOMMU page tables because you build
> them, here instead it's the guest's page tables that you'd walk, right?
> You cannot trust the guest.

Yes, you're right, we're not shadowing the vt-d page tables, we're
working on the explicit invalidation model.  So there could be
anything, or nothing in the page tables when we go to try to lookup the
unref.  So clearly taking that reference without a shadow page table
would be the wrong approach.  Thanks,

Alex

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Peter Xu]

On Wed, Jan 25, 2017 at 06:16:44PM +0100, Paolo Bonzini wrote:
> 
> 
> On 25/01/2017 17:43, Alex Williamson wrote:
> > On Wed, 25 Jan 2017 12:32:21 +0800
> > Peter Xu <peterx@redhat.com> wrote:
> >> I have similar question as well above - IIUC the RCU read lock
> >> protects us from not losing the references of memory objects, however
> >> in our case even after we release the lock, we are still using the
> >> backend ram (vaddr) since we have set it up inside kernel to build up
> >> the IO page table. After that, the kernel/device should be able to
> >> write to addresses of that backend ram any time.
> 
> I don't think that's what happens.  As far as I understand, VFIO pins
> the pages corresponding to vaddr, not vaddr itself.  The memory backend
> is mmap-ed memory; when you hot-unplug it the munmap releases the VMA
> and loses the connection between QEMU's virtual address space and the
> pages.  However, the pages stay pinned and stay mapped into VFIO's own
> IOMMU page tables.
> 
> So if a guest does a memory hot-unplug without IOMMU unmap, it would
> keep on seeing the content of the hot-unplugged memory, and the host
> could not release the pages, but the guest cannot overwrite QEMU data
> structures.

Sounds reasonable. I forgot that these pages are pinned if without an
explicit unmap.

Thanks Paolo. :)

-- peterx

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Peter Xu]

On Wed, Jan 25, 2017 at 01:09:47PM -0700, Alex Williamson wrote:
> On Wed, 25 Jan 2017 20:42:19 +0100
> Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
> > On 25/01/2017 19:36, Alex Williamson wrote:
> > >> It depends of what happens if they aren't.  I think it's fine (see other
> > >> message), but taking a reference for each mapping entry isn't so easy
> > >> because the unmap case doesn't know the old memory region.  
> > > If we held a reference to the memory region from the mapping path and
> > > walk the IOMMU page table to generate the unmap, then we really should
> > > get to the same original memory region, right?  The vfio iommu notifier
> > > should only be mapping native page sizes of the IOMMU, 4k/2M/1G.  The
> > > problem is that it's a lot of overhead to flush the entire address
> > > space that way vs the single invalidation Peter is trying to enable
> > > here.  It's actually similar to how the type1 iommu works in the kernel
> > > though, we can unmap by iova because we ask the iommu for the iova->pfn
> > > translation in order to unpin the page.  
> > 
> > But in the kernel you can trust the IOMMU page tables because you build
> > them, here instead it's the guest's page tables that you'd walk, right?
> > You cannot trust the guest.
> 
> Yes, you're right, we're not shadowing the vt-d page tables, we're
> working on the explicit invalidation model.  So there could be
> anything, or nothing in the page tables when we go to try to lookup the
> unref.  So clearly taking that reference without a shadow page table
> would be the wrong approach.  Thanks,

IIUC of above discussion, moving rcu read lock/unlock out of
vfio_get_vaddr() would be the nicest approach here.

Thanks to you both on helping verify and confirm the problem!

-- peterx

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Peter Xu]

On Wed, Jan 25, 2017 at 06:11:37PM +0100, Paolo Bonzini wrote:

[...]

> > The comment from v4 still needs input from Paolo, is it valid to make
> > use of vaddr (based on address_space_translate ->
> > memory_region_get_ram_ptr) outside of the rcu read lock or could future
> > BQL reduction efforts allow this to race?
> 
> You need to keep a reference to the MemoryRegion if you do
> rcu_read_unlock.  But it's simpler to call vfio_get_vaddr within
> rcu_read_lock, and keep the lock/unlock in vfio_iommu_map_notify.
> 
> You probably should also put a comment about why VFIO does *not* need to
> keep a reference between vfio_dma_map and vfio_dma_unmap (which doesn't
> sound easy to do either).

How about this one?

    /*
     * Here, we need to have the lock not only for vfio_get_vaddr(),
     * but also needs to make sure that the vaddr will be valid for
     * further operations.
     *
     * When we map new pages, we need the lock to make sure that vaddr
     * is valid along the way we build up the IO page table (via
     * vfio_dma_map()). Then, as long as the mapping is set up, we can
     * unlock since those pages will be pinned in kernel (which makes
     * sure that the RAM backend of vaddr will always be there, even
     * if the memory object is destroyed and RAM released).
     *
     * For unmapping case, we don't really need the protection since
     * the pages are in all cases locked in kernel, so we'll probably
     * be safe even without the lock. However, it won't hurt we have
     * the lock as well here.
     */

Thanks,

-- peterx

Re: [Qemu-devel] [PATCH v5 00/18] VT-d: vfio enablement and misc enhances

[Peter Xu]

On Wed, Jan 25, 2017 at 04:26:59PM +0200, Michael S. Tsirkin wrote:
> On Wed, Jan 25, 2017 at 12:48:37PM +0800, Peter Xu wrote:
> > On Tue, Jan 24, 2017 at 04:48:49PM +0200, Michael S. Tsirkin wrote:
> > > On Tue, Jan 24, 2017 at 07:49:10PM +0800, Peter Xu wrote:
> > > > On Tue, Jan 24, 2017 at 06:25:53PM +0800, Peter Xu wrote:
> > > > > This is v5 of vt-d vfio enablement series.
> > > > > 
> > > > > Most of the changes in v5 is not functionally, but related to
> > > > > comments, error_report()s, debugging, squashing patches, etc. (which
> > > > > are confirmed changes in v4), besides a tiny tweak when unmapping a
> > > > > whole address space (please see below changelog). There are still
> > > > > discussions in v4 thread, we can just continue there (or here), and
> > > > > from this version I'll remove RFC tag.
> > > > > 
> > > > > I didn't rebase to master since current master failed to build on my
> > > > > laptop (with a "vl.c/hax..." error), however this series should be
> > > > > okay to be applied cleanly upon it.
> > > > 
> > > > Sorry I forgot to append the todo list (please help adding in in case
> > > > I missed anything):
> > > > 
> > > > - don't need to notify IOTLB (psi/gsi/global) invalidations to devices
> > > >   that with ATS enabled
> > > > - investigate when guest map page while mask contains existing mapped
> > > >   pages (e.g. map 12k-16k first, then map 0-12k)
> > > > - coalesce unmap during page walk (currently, we send it once per
> > > >   page)
> > > > - when do PSI for unmap, whether we can send one notify directly
> > > >   instead of walking over the page table?
> > > > 
> > > > Above does not contain those that are still during discussion. And,
> > > > some of the entries still need tests to further prove it's
> > > > feasibility.
> > > > 
> > > > Thanks,
> > > > 
> > > > -- peterx
> > > 
> > > While valid I don't think above need to block merging.
> > 
> > Sorry for the delay of this series.
> > 
> > Looks like we still need to wait until we got explicit acks for vfio
> > patch 2-3 from Alex/Paolo/David since that'll be required by the
> > following series. (I'll address all Jason's new comments as well in
> > next post)
> > 
> > Do you like to merge the iommu cleanups first? Or you can also wait
> > for above to be confirmed, and I'll repost for a final version then
> > (if we don't have further comments).
> > 
> > Thanks,
> > 
> > -- peterx
> 
> I can do that. If you want me to, pls post just the patches
> that are ready separately.

Thanks for the offer!

Since I see that currently the only uncertainty of this series would
be the impact that patch 3 might bring to Power, I'll prefer we wait
for several more days until David's back (I suppose it's next Monday
or so), to see whether I can send a complete final version.

Thanks,

-- peterx

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Paolo Bonzini]

On 26/01/2017 08:12, Peter Xu wrote:
> 
>     /*
>      * Here, we need to have the lock not only for vfio_get_vaddr(),
>      * but also needs to make sure that the vaddr will be valid for
>      * further operations.
>      *
>      * When we map new pages, we need the lock to make sure that vaddr
>      * is valid along the way we build up the IO page table (via
>      * vfio_dma_map()). Then, as long as the mapping is set up, we can
>      * unlock since those pages will be pinned in kernel (which makes
>      * sure that the RAM backend of vaddr will always be there, even
>      * if the memory object is destroyed and RAM released).
>      *
>      * For unmapping case, we don't really need the protection since
>      * the pages are in all cases locked in kernel, so we'll probably
>      * be safe even without the lock. However, it won't hurt we have
>      * the lock as well here.
>      */

Even simpler, just before the definition of vfio_get_vaddr:

/* Called with rcu_read_lock held.  */

and just before the vfio_dma_map call:

    /* vaddr is only valid until rcu_read_unlock().  But after
     * vfio_dma_map has set up the mapping the pages will be pinned
     * by the kernel.  This makes sure that the RAM backend of vaddr
     * will always be there, even if the memory object is destroyed
     * and its backing memory munmap-ed.
     */

I'm not sure that you can get rid of the lock for the unmapping case.
Better remove that part of the comment.

Thanks,

Paolo

Re: [Qemu-devel] [PATCH v5 02/18] vfio: introduce vfio_get_vaddr()

[Peter Xu]

On Thu, Jan 26, 2017 at 11:55:22AM +0100, Paolo Bonzini wrote:
> 
> 
> On 26/01/2017 08:12, Peter Xu wrote:
> > 
> >     /*
> >      * Here, we need to have the lock not only for vfio_get_vaddr(),
> >      * but also needs to make sure that the vaddr will be valid for
> >      * further operations.
> >      *
> >      * When we map new pages, we need the lock to make sure that vaddr
> >      * is valid along the way we build up the IO page table (via
> >      * vfio_dma_map()). Then, as long as the mapping is set up, we can
> >      * unlock since those pages will be pinned in kernel (which makes
> >      * sure that the RAM backend of vaddr will always be there, even
> >      * if the memory object is destroyed and RAM released).
> >      *
> >      * For unmapping case, we don't really need the protection since
> >      * the pages are in all cases locked in kernel, so we'll probably
> >      * be safe even without the lock. However, it won't hurt we have
> >      * the lock as well here.
> >      */
> 
> Even simpler, just before the definition of vfio_get_vaddr:
> 
> /* Called with rcu_read_lock held.  */
> 
> and just before the vfio_dma_map call:
> 
>     /* vaddr is only valid until rcu_read_unlock().  But after
>      * vfio_dma_map has set up the mapping the pages will be pinned
>      * by the kernel.  This makes sure that the RAM backend of vaddr
>      * will always be there, even if the memory object is destroyed
>      * and its backing memory munmap-ed.
>      */
> 
> I'm not sure that you can get rid of the lock for the unmapping case.
> Better remove that part of the comment.

Sure. Let me take yours. Thanks!

-- peterx

Re: [Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very large region

[David Gibson]

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On Tue, Jan 24, 2017 at 09:32:07AM -0700, Alex Williamson wrote:
> On Tue, 24 Jan 2017 18:25:56 +0800
> Peter Xu <peterx@redhat.com> wrote:
> 
> > Linux vfio driver supports to do VFIO_IOMMU_UNMAP_DMA for a very big
> > region. This can be leveraged by QEMU IOMMU implementation to cleanup
> > existing page mappings for an entire iova address space (by notifying
> > with an IOTLB with extremely huge addr_mask). However current
> > vfio_iommu_map_notify() does not allow that. It make sure that all the
> > translated address in IOTLB is falling into RAM range.
> > 
> > The check makes sense, but it should only be a sensible checker for
> > mapping operations, and mean little for unmap operations.
> > 
> > This patch moves this check into map logic only, so that we'll get
> > faster unmap handling (no need to translate again), and also we can then
> > better support unmapping a very big region when it covers non-ram ranges
> > or even not-existing ranges.
> > 
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  hw/vfio/common.c | 7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> > 
> > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > index ce55dff..4d90844 100644
> > --- a/hw/vfio/common.c
> > +++ b/hw/vfio/common.c
> > @@ -354,11 +354,10 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> >          return;
> >      }
> >  
> > -    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> > -        return;
> > -    }
> > -
> >      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> > +        if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> > +            return;
> > +        }
> 
> 
> David, is SPAPR going to freak out if it sees unmaps to ranges that
> extend beyond individual mappings, or perhaps include no mappings?
> This effectively allows unmapping the entire address space of the iommu
> in one pass, without validating or translating the backing.

Extending beyond an individual mapping will be fine.  However, if the
unmap extends beyond the extent of IOVAs mapped by a single TCE table,
then the unmap will fail (with ENXIO or EINVAL depending on whether
there's a problem with origin or only size).

With holidays I've lost the context of this thread, so I can't easily
find the whole patch series this relates to.  From your brief
description above it sounds likes it should be ok - a range covering
just the IOVA space (as long as that's actually correct for spapr tce)
should be ok.

> 
> >          ret = vfio_dma_map(container, iova,
> >                             iotlb->addr_mask + 1, vaddr,
> >                             read_only);
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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Re: [Qemu-devel] [PATCH v5 03/18] vfio: allow to notify unmap for very large region

[Peter Xu]

On Tue, Jan 31, 2017 at 02:35:00PM +1100, David Gibson wrote:
> On Tue, Jan 24, 2017 at 09:32:07AM -0700, Alex Williamson wrote:
> > On Tue, 24 Jan 2017 18:25:56 +0800
> > Peter Xu <peterx@redhat.com> wrote:
> > 
> > > Linux vfio driver supports to do VFIO_IOMMU_UNMAP_DMA for a very big
> > > region. This can be leveraged by QEMU IOMMU implementation to cleanup
> > > existing page mappings for an entire iova address space (by notifying
> > > with an IOTLB with extremely huge addr_mask). However current
> > > vfio_iommu_map_notify() does not allow that. It make sure that all the
> > > translated address in IOTLB is falling into RAM range.
> > > 
> > > The check makes sense, but it should only be a sensible checker for
> > > mapping operations, and mean little for unmap operations.
> > > 
> > > This patch moves this check into map logic only, so that we'll get
> > > faster unmap handling (no need to translate again), and also we can then
> > > better support unmapping a very big region when it covers non-ram ranges
> > > or even not-existing ranges.
> > > 
> > > Signed-off-by: Peter Xu <peterx@redhat.com>
> > > ---
> > >  hw/vfio/common.c | 7 +++----
> > >  1 file changed, 3 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > > index ce55dff..4d90844 100644
> > > --- a/hw/vfio/common.c
> > > +++ b/hw/vfio/common.c
> > > @@ -354,11 +354,10 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
> > >          return;
> > >      }
> > >  
> > > -    if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> > > -        return;
> > > -    }
> > > -
> > >      if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
> > > +        if (!vfio_get_vaddr(iotlb, &vaddr, &read_only)) {
> > > +            return;
> > > +        }
> > 
> > 
> > David, is SPAPR going to freak out if it sees unmaps to ranges that
> > extend beyond individual mappings, or perhaps include no mappings?
> > This effectively allows unmapping the entire address space of the iommu
> > in one pass, without validating or translating the backing.
> 
> Extending beyond an individual mapping will be fine.  However, if the
> unmap extends beyond the extent of IOVAs mapped by a single TCE table,
> then the unmap will fail (with ENXIO or EINVAL depending on whether
> there's a problem with origin or only size).
> 
> With holidays I've lost the context of this thread, so I can't easily
> find the whole patch series this relates to.  From your brief
> description above it sounds likes it should be ok - a range covering
> just the IOVA space (as long as that's actually correct for spapr tce)
> should be ok.

Thanks for the confirmation! Then I'll move ahead for the next spin.

Thanks,

-- peterx