From 9dd5e808fc17ac92180965178a6e867c1e96ac57 Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Thu, 7 Mar 2024 14:43:04 +0100 Subject: virtio-iommu: Change the default granule to the host page size MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We used to set the default granule to 4KB but with VFIO assignment it makes more sense to use the actual host page size. Indeed when hotplugging a VFIO device protected by a virtio-iommu on a 64kB/64kB host/guest config, we current get a qemu crash: "vfio: DMA mapping failed, unable to continue" This is due to the hot-attached VFIO device calling memory_region_iommu_set_page_size_mask() with 64kB granule whereas the virtio-iommu granule was already frozen to 4KB on machine init done. Set the granule property to "host" and introduce a new compat. The page size mask used before 9.0 was qemu_target_page_mask(). Since the virtio-iommu currently only supports x86_64 and aarch64, this matched a 4KB granule. Note that the new default will prevent 4kB guest on 64kB host because the granule will be set to 64kB which would be larger than the guest page size. In that situation, the virtio-iommu driver fails on viommu_domain_finalise() with "granule 0x10000 larger than system page size 0x1000". In that case the workaround is to request 4K granule. The current limitation of global granule in the virtio-iommu should be removed and turned into per domain granule. But until we get this upgraded, this new default is probably better because I don't think anyone is currently interested in running a 4KB page size guest with virtio-iommu on a 64KB host. However supporting 64kB guest on 64kB host with virtio-iommu and VFIO looks a more important feature. Signed-off-by: Eric Auger Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Zhenzhong Duan Message-Id: <20240307134445.92296-4-eric.auger@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/core/machine.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'hw/core/machine.c') diff --git a/hw/core/machine.c b/hw/core/machine.c index 9ac5d5389a..6bd09d4592 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -30,9 +30,12 @@ #include "exec/confidential-guest-support.h" #include "hw/virtio/virtio-pci.h" #include "hw/virtio/virtio-net.h" +#include "hw/virtio/virtio-iommu.h" #include "audio/audio.h" -GlobalProperty hw_compat_8_2[] = {}; +GlobalProperty hw_compat_8_2[] = { + { TYPE_VIRTIO_IOMMU_PCI, "granule", "4k" }, +}; const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2); GlobalProperty hw_compat_8_1[] = { -- cgit 1.4.1 From 9b588be373ad01e7ce09e25f69f66b811af0b799 Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Thu, 7 Mar 2024 14:43:08 +0100 Subject: hw/i386/q35: Set virtio-iommu aw-bits default value to 39 Currently the default input range can extend to 64 bits. On x86, when the virtio-iommu protects vfio devices, the physical iommu may support only 39 bits. Let's set the default to 39, as done for the intel-iommu. We use hw_compat_8_2 to handle the compatibility for machines before 9.0 which used to have a virtio-iommu default input range of 64 bits. Of course if aw-bits is set from the command line, the default is overriden. Signed-off-by: Eric Auger Message-Id: <20240307134445.92296-8-eric.auger@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Zhenzhong Duan --- hw/core/machine.c | 1 + hw/i386/pc_q35.c | 9 +++++++++ tests/qtest/virtio-iommu-test.c | 2 +- 3 files changed, 11 insertions(+), 1 deletion(-) (limited to 'hw/core/machine.c') diff --git a/hw/core/machine.c b/hw/core/machine.c index 6bd09d4592..4b89172d1c 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -35,6 +35,7 @@ GlobalProperty hw_compat_8_2[] = { { TYPE_VIRTIO_IOMMU_PCI, "granule", "4k" }, + { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" }, }; const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2); diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index 1356c5d107..8a427c4647 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -45,6 +45,7 @@ #include "hw/i386/pc.h" #include "hw/i386/amd_iommu.h" #include "hw/i386/intel_iommu.h" +#include "hw/virtio/virtio-iommu.h" #include "hw/display/ramfb.h" #include "hw/ide/pci.h" #include "hw/ide/ahci-pci.h" @@ -63,6 +64,12 @@ /* ICH9 AHCI has 6 ports */ #define MAX_SATA_PORTS 6 +static GlobalProperty pc_q35_compat_defaults[] = { + { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "39" }, +}; +static const size_t pc_q35_compat_defaults_len = + G_N_ELEMENTS(pc_q35_compat_defaults); + struct ehci_companions { const char *name; int func; @@ -354,6 +361,8 @@ static void pc_q35_machine_options(MachineClass *m) machine_class_allow_dynamic_sysbus_dev(m, TYPE_INTEL_IOMMU_DEVICE); machine_class_allow_dynamic_sysbus_dev(m, TYPE_RAMFB_DEVICE); machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE); + compat_props_add(m->compat_props, + pc_q35_compat_defaults, pc_q35_compat_defaults_len); } static void pc_q35_9_0_machine_options(MachineClass *m) diff --git a/tests/qtest/virtio-iommu-test.c b/tests/qtest/virtio-iommu-test.c index 068e7a9e6c..afb225971d 100644 --- a/tests/qtest/virtio-iommu-test.c +++ b/tests/qtest/virtio-iommu-test.c @@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc) uint8_t bypass = qvirtio_config_readb(dev, 36); g_assert_cmpint(input_range_start, ==, 0); - g_assert_cmphex(input_range_end, ==, UINT64_MAX); + g_assert_cmphex(input_range_end, >=, UINT32_MAX); g_assert_cmpint(domain_range_start, ==, 0); g_assert_cmpint(domain_range_end, ==, UINT32_MAX); g_assert_cmpint(bypass, ==, 1); -- cgit 1.4.1