[Qemu-devel] [PULL 0/2] VFIO updates 2015-11-10

[Qemu-devel] [PULL 0/2] VFIO updates 2015-11-10

[Alex Williamson]

The following changes since commit a1a88589dc982f9f8b6c717c2ac98dd71dd4353d:

  Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20151110' into staging (2015-11-10 13:55:07 +0000)

are available in the git repository at:


  git://github.com/awilliam/qemu-vfio.git tags/vfio-update-20151110.0

for you to fetch changes up to bdd81addf4033ce26e6cd180b060f63095f3ded9:

  vfio: Use g_new() & friends where that makes obvious sense (2015-11-10 12:11:08 -0700)

----------------------------------------------------------------
VFIO updates 2015-11-10

 - Make Windows happy with vfio-pci devices exposed on conventional
   PCI buses on q35 by hiding PCIe capability (Alex Williamson)
 - Convert to g_new() where appropriate (Markus Armbruster)

----------------------------------------------------------------
Alex Williamson (1):
      vfio/pci: Hide device PCIe capability on non-express buses for PCIe VMs

Markus Armbruster (1):
      vfio: Use g_new() & friends where that makes obvious sense

 hw/vfio/pci-quirks.c | 16 ++++++++--------
 hw/vfio/pci.c        | 40 +++++++++++++++++++++++++++++++++-------
 hw/vfio/platform.c   |  2 +-
 3 files changed, 42 insertions(+), 16 deletions(-)

[Qemu-devel] [PULL 1/2] vfio/pci: Hide device PCIe capability on non-express buses for PCIe VMs

[Alex Williamson]

When we have a PCIe VM, such as Q35, guests start to care more about
valid configurations of devices relative to the VM view of the PCI
topology.  Windows will error with a Code 10 for an assigned device if
a PCIe capability is found for a device on a conventional bus.  We
also have the possibility of IOMMUs, like VT-d, where the where the
guest may be acutely aware of valid express capabilities on physical
hardware.

Some devices, like tg3 are adversely affected by this due to driver
dependencies on the PCIe capability.  The only solution for such
devices is to attach them to an express capable bus in the VM.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/pci.c |   36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 8fadbcf..035007f 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -28,6 +28,7 @@
 #include "config.h"
 #include "hw/pci/msi.h"
 #include "hw/pci/msix.h"
+#include "hw/pci/pci_bridge.h"
 #include "qemu/error-report.h"
 #include "qemu/range.h"
 #include "sysemu/kvm.h"
@@ -1524,13 +1525,38 @@ static int vfio_setup_pcie_cap(VFIOPCIDevice *vdev, int pos, uint8_t size)
     }
 
     if (!pci_bus_is_express(vdev->pdev.bus)) {
+        PCIBus *bus = vdev->pdev.bus;
+        PCIDevice *bridge;
+
         /*
-         * Use express capability as-is on PCI bus.  It doesn't make much
-         * sense to even expose, but some drivers (ex. tg3) depend on it
-         * and guests don't seem to be particular about it.  We'll need
-         * to revist this or force express devices to express buses if we
-         * ever expose an IOMMU to the guest.
+         * Traditionally PCI device assignment exposes the PCIe capability
+         * as-is on non-express buses.  The reason being that some drivers
+         * simply assume that it's there, for example tg3.  However when
+         * we're running on a native PCIe machine type, like Q35, we need
+         * to hide the PCIe capability.  The reason for this is twofold;
+         * first Windows guests get a Code 10 error when the PCIe capability
+         * is exposed in this configuration.  Therefore express devices won't
+         * work at all unless they're attached to express buses in the VM.
+         * Second, a native PCIe machine introduces the possibility of fine
+         * granularity IOMMUs supporting both translation and isolation.
+         * Guest code to discover the IOMMU visibility of a device, such as
+         * IOMMU grouping code on Linux, is very aware of device types and
+         * valid transitions between bus types.  An express device on a non-
+         * express bus is not a valid combination on bare metal systems.
+         *
+         * Drivers that require a PCIe capability to make the device
+         * functional are simply going to need to have their devices placed
+         * on a PCIe bus in the VM.
          */
+        while (!pci_bus_is_root(bus)) {
+            bridge = pci_bridge_get_device(bus);
+            bus = bridge->bus;
+        }
+
+        if (pci_bus_is_express(bus)) {
+            return 0;
+        }
+
     } else if (pci_bus_is_root(vdev->pdev.bus)) {
         /*
          * On a Root Complex bus Endpoints become Root Complex Integrated

[Qemu-devel] [PULL 2/2] vfio: Use g_new() & friends where that makes obvious sense

[Alex Williamson]

From: Markus Armbruster <armbru@redhat.com>

g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

This commit only touches allocations with size arguments of the form
sizeof(T).  Same Coccinelle semantic patch as in commit b45c03f.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/pci-quirks.c |   16 ++++++++--------
 hw/vfio/pci.c        |    4 ++--
 hw/vfio/platform.c   |    2 +-
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index c675d1b..30c68a1 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -284,7 +284,7 @@ static void vfio_vga_probe_ati_3c3_quirk(VFIOPCIDevice *vdev)
     }
 
     quirk = g_malloc0(sizeof(*quirk));
-    quirk->mem = g_malloc0(sizeof(MemoryRegion));
+    quirk->mem = g_new0(MemoryRegion, 1);
     quirk->nr_mem = 1;
 
     memory_region_init_io(quirk->mem, OBJECT(vdev), &vfio_ati_3c3_quirk, vdev,
@@ -319,7 +319,7 @@ static void vfio_probe_ati_bar4_quirk(VFIOPCIDevice *vdev, int nr)
     }
 
     quirk = g_malloc0(sizeof(*quirk));
-    quirk->mem = g_malloc0(sizeof(MemoryRegion) * 2);
+    quirk->mem = g_new0(MemoryRegion, 2);
     quirk->nr_mem = 2;
     window = quirk->data = g_malloc0(sizeof(*window) +
                                      sizeof(VFIOConfigWindowMatch));
@@ -368,7 +368,7 @@ static void vfio_probe_ati_bar2_quirk(VFIOPCIDevice *vdev, int nr)
 
     quirk = g_malloc0(sizeof(*quirk));
     mirror = quirk->data = g_malloc0(sizeof(*mirror));
-    mirror->mem = quirk->mem = g_malloc0(sizeof(MemoryRegion));
+    mirror->mem = quirk->mem = g_new0(MemoryRegion, 1);
     quirk->nr_mem = 1;
     mirror->vdev = vdev;
     mirror->offset = 0x4000;
@@ -544,7 +544,7 @@ static void vfio_vga_probe_nvidia_3d0_quirk(VFIOPCIDevice *vdev)
 
     quirk = g_malloc0(sizeof(*quirk));
     quirk->data = data = g_malloc0(sizeof(*data));
-    quirk->mem = g_malloc0(sizeof(MemoryRegion) * 2);
+    quirk->mem = g_new0(MemoryRegion, 2);
     quirk->nr_mem = 2;
     data->vdev = vdev;
 
@@ -661,7 +661,7 @@ static void vfio_probe_nvidia_bar5_quirk(VFIOPCIDevice *vdev, int nr)
     }
 
     quirk = g_malloc0(sizeof(*quirk));
-    quirk->mem = g_malloc0(sizeof(MemoryRegion) * 4);
+    quirk->mem = g_new0(MemoryRegion, 4);
     quirk->nr_mem = 4;
     bar5 = quirk->data = g_malloc0(sizeof(*bar5) +
                                    (sizeof(VFIOConfigWindowMatch) * 2));
@@ -756,7 +756,7 @@ static void vfio_probe_nvidia_bar0_quirk(VFIOPCIDevice *vdev, int nr)
 
     quirk = g_malloc0(sizeof(*quirk));
     mirror = quirk->data = g_malloc0(sizeof(*mirror));
-    mirror->mem = quirk->mem = g_malloc0(sizeof(MemoryRegion));
+    mirror->mem = quirk->mem = g_new0(MemoryRegion, 1);
     quirk->nr_mem = 1;
     mirror->vdev = vdev;
     mirror->offset = 0x88000;
@@ -775,7 +775,7 @@ static void vfio_probe_nvidia_bar0_quirk(VFIOPCIDevice *vdev, int nr)
     if (vdev->has_vga) {
         quirk = g_malloc0(sizeof(*quirk));
         mirror = quirk->data = g_malloc0(sizeof(*mirror));
-        mirror->mem = quirk->mem = g_malloc0(sizeof(MemoryRegion));
+        mirror->mem = quirk->mem = g_new0(MemoryRegion, 1);
         quirk->nr_mem = 1;
         mirror->vdev = vdev;
         mirror->offset = 0x1800;
@@ -938,7 +938,7 @@ static void vfio_probe_rtl8168_bar2_quirk(VFIOPCIDevice *vdev, int nr)
     }
 
     quirk = g_malloc0(sizeof(*quirk));
-    quirk->mem = g_malloc0(sizeof(MemoryRegion) * 2);
+    quirk->mem = g_new0(MemoryRegion, 2);
     quirk->nr_mem = 2;
     quirk->data = rtl = g_malloc0(sizeof(*rtl));
     rtl->vdev = vdev;
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 035007f..1fb868c 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -587,7 +587,7 @@ static void vfio_msix_enable(VFIOPCIDevice *vdev)
 {
     vfio_disable_interrupts(vdev);
 
-    vdev->msi_vectors = g_malloc0(vdev->msix->entries * sizeof(VFIOMSIVector));
+    vdev->msi_vectors = g_new0(VFIOMSIVector, vdev->msix->entries);
 
     vdev->interrupt = VFIO_INT_MSIX;
 
@@ -623,7 +623,7 @@ static void vfio_msi_enable(VFIOPCIDevice *vdev)
 
     vdev->nr_vectors = msi_nr_vectors_allocated(&vdev->pdev);
 retry:
-    vdev->msi_vectors = g_malloc0(vdev->nr_vectors * sizeof(VFIOMSIVector));
+    vdev->msi_vectors = g_new0(VFIOMSIVector, vdev->nr_vectors);
 
     for (i = 0; i < vdev->nr_vectors; i++) {
         VFIOMSIVector *vector = &vdev->msi_vectors[i];
diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index 5c1156c..289b498 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -478,7 +478,7 @@ static int vfio_populate_device(VFIODevice *vbasedev)
         struct vfio_region_info reg_info = { .argsz = sizeof(reg_info) };
         VFIORegion *ptr;
 
-        vdev->regions[i] = g_malloc0(sizeof(VFIORegion));
+        vdev->regions[i] = g_new0(VFIORegion, 1);
         ptr = vdev->regions[i];
         reg_info.index = i;
         ret = ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, &reg_info);

Re: [Qemu-devel] [PULL 0/2] VFIO updates 2015-11-10

[Peter Maydell]

On 10 November 2015 at 20:08, Alex Williamson
<alex.williamson@redhat.com> wrote:
> The following changes since commit a1a88589dc982f9f8b6c717c2ac98dd71dd4353d:
>
>   Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20151110' into staging (2015-11-10 13:55:07 +0000)
>
> are available in the git repository at:
>
>
>   git://github.com/awilliam/qemu-vfio.git tags/vfio-update-20151110.0
>
> for you to fetch changes up to bdd81addf4033ce26e6cd180b060f63095f3ded9:
>
>   vfio: Use g_new() & friends where that makes obvious sense (2015-11-10 12:11:08 -0700)
>
> ----------------------------------------------------------------
> VFIO updates 2015-11-10
>
>  - Make Windows happy with vfio-pci devices exposed on conventional
>    PCI buses on q35 by hiding PCIe capability (Alex Williamson)
>  - Convert to g_new() where appropriate (Markus Armbruster)
>
> ----------------------------------------------------------------
> Alex Williamson (1):
>       vfio/pci: Hide device PCIe capability on non-express buses for PCIe VMs
>
> Markus Armbruster (1):
>       vfio: Use g_new() & friends where that makes obvious sense

Applied, thanks.

-- PMM