| Message ID | 20230530175937.24202-9-joao.m.martins@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfio: VFIO migration support with vIOMMU | expand |
On 30/5/23 19:59, Joao Martins wrote: > Relax the vIOMMU migration blocker when the underlying IOMMU reports that > DMA translation disabled. When it is disabled there will be no DMA mappings > via the vIOMMU and the guest only uses it for Interrupt Remapping. > > The latter is done via the vfio_viommu_preset() return value whereby in > addition to validating that the address space is memory, we also check > whether the IOMMU MR has DMA translation on. > Assume it is enabled if > there's no IOMMU MR or if no dma-translation property is supported. This comment ^ ... > Signed-off-by: Joao Martins <joao.m.martins@oracle.com> > --- > hw/vfio/common.c | 22 +++++++++++++++++++++- > 1 file changed, 21 insertions(+), 1 deletion(-) > > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index fa8fd949b1cf..060acccb3443 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -414,12 +414,32 @@ void vfio_unblock_multiple_devices_migration(void) > multiple_devices_migration_blocker = NULL; > } > > +static bool vfio_viommu_dma_translation_enabled(VFIOAddressSpace *space) > +{ > + bool enabled = false; > + int ret; > + > + if (!space->iommu_mr) { > + return true; > + } > + > + ret = memory_region_iommu_get_attr(space->iommu_mr, > + IOMMU_ATTR_DMA_TRANSLATION, > + &enabled); > + if (ret || enabled) { ... could be helpful if duplicated here. > + return true; > + } > + > + return false; > +}
On 30/05/2023 22:39, Philippe Mathieu-Daudé wrote: > On 30/5/23 19:59, Joao Martins wrote: >> Relax the vIOMMU migration blocker when the underlying IOMMU reports that >> DMA translation disabled. When it is disabled there will be no DMA mappings >> via the vIOMMU and the guest only uses it for Interrupt Remapping. >> >> The latter is done via the vfio_viommu_preset() return value whereby in >> addition to validating that the address space is memory, we also check >> whether the IOMMU MR has DMA translation on. > >> Assume it is enabled if >> there's no IOMMU MR or if no dma-translation property is supported. > > This comment ^ ... > >> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> >> --- >> hw/vfio/common.c | 22 +++++++++++++++++++++- >> 1 file changed, 21 insertions(+), 1 deletion(-) >> >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >> index fa8fd949b1cf..060acccb3443 100644 >> --- a/hw/vfio/common.c >> +++ b/hw/vfio/common.c >> @@ -414,12 +414,32 @@ void vfio_unblock_multiple_devices_migration(void) >> multiple_devices_migration_blocker = NULL; >> } >> +static bool vfio_viommu_dma_translation_enabled(VFIOAddressSpace *space) >> +{ >> + bool enabled = false; >> + int ret; >> + >> + if (!space->iommu_mr) { >> + return true; >> + } >> + >> + ret = memory_region_iommu_get_attr(space->iommu_mr, >> + IOMMU_ATTR_DMA_TRANSLATION, >> + &enabled); >> + if (ret || enabled) { > > ... could be helpful if duplicated here. > I'll add it. >> + return true; >> + } >> + >> + return false; >> +} >
diff --git a/hw/vfio/common.c b/hw/vfio/common.c index fa8fd949b1cf..060acccb3443 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -414,12 +414,32 @@ void vfio_unblock_multiple_devices_migration(void) multiple_devices_migration_blocker = NULL; } +static bool vfio_viommu_dma_translation_enabled(VFIOAddressSpace *space) +{ + bool enabled = false; + int ret; + + if (!space->iommu_mr) { + return true; + } + + ret = memory_region_iommu_get_attr(space->iommu_mr, + IOMMU_ATTR_DMA_TRANSLATION, + &enabled); + if (ret || enabled) { + return true; + } + + return false; +} + static bool vfio_viommu_preset(void) { VFIOAddressSpace *space; QLIST_FOREACH(space, &vfio_address_spaces, list) { - if (space->as != &address_space_memory) { + if ((space->as != &address_space_memory) && + vfio_viommu_dma_translation_enabled(space)) { return true; } }
Relax the vIOMMU migration blocker when the underlying IOMMU reports that DMA translation disabled. When it is disabled there will be no DMA mappings via the vIOMMU and the guest only uses it for Interrupt Remapping. The latter is done via the vfio_viommu_preset() return value whereby in addition to validating that the address space is memory, we also check whether the IOMMU MR has DMA translation on. Assume it is enabled if there's no IOMMU MR or if no dma-translation property is supported. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> --- hw/vfio/common.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-)