Hi Jean, On 2/5/24 11:13, Jean-Philippe Brucker wrote: > Hi Eric, > > On Thu, Feb 01, 2024 at 05:32:22PM +0100, Eric Auger wrote: >> aw-bits is a new option that allows to set the bit width of >> the input address range. This value will be used as a default for >> the device config input_range.end. By default it is set to 64 bits >> which is the current value. >> >> Signed-off-by: Eric Auger <eric.au...@redhat.com> >> >> --- >> >> v1 -> v2: >> - Check the aw-bits value is within [32,64] >> --- >> include/hw/virtio/virtio-iommu.h | 1 + >> hw/virtio/virtio-iommu.c | 7 ++++++- >> 2 files changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/include/hw/virtio/virtio-iommu.h >> b/include/hw/virtio/virtio-iommu.h >> index 781ebaea8f..5fbe4677c2 100644 >> --- a/include/hw/virtio/virtio-iommu.h >> +++ b/include/hw/virtio/virtio-iommu.h >> @@ -66,6 +66,7 @@ struct VirtIOIOMMU { >> bool boot_bypass; >> Notifier machine_done; >> bool granule_frozen; >> + uint8_t aw_bits; >> }; >> >> #endif >> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c >> index ec2ba11d1d..7870bdbeee 100644 >> --- a/hw/virtio/virtio-iommu.c >> +++ b/hw/virtio/virtio-iommu.c >> @@ -1314,7 +1314,11 @@ static void virtio_iommu_device_realize(DeviceState >> *dev, Error **errp) >> */ >> s->config.bypass = s->boot_bypass; >> s->config.page_size_mask = qemu_real_host_page_mask(); >> - s->config.input_range.end = UINT64_MAX; >> + if (s->aw_bits < 32 || s->aw_bits > 64) { > I'm wondering if we should lower this to 16 bits, just to support all > possible host SMMU configurations (the smallest address space configurable > with T0SZ is 25-bit, or 16-bit with the STT extension). I have no objection relaxing that check. Alex suggested this 32b low limit with his knowledge of x86. I am a bit reluctant to add extra machine specific checks though. Anyway I assume that some [low] aw-bits will fail with some guests and this will be difficult to understand from bug reports.
Thanks Eric > > Thanks, > Jean > >> + error_setg(errp, "aw-bits must be within [32,64]"); >> + } >> + s->config.input_range.end = >> + s->aw_bits == 64 ? UINT64_MAX : BIT_ULL(s->aw_bits) - 1; >> s->config.domain_range.end = UINT32_MAX; >> s->config.probe_size = VIOMMU_PROBE_SIZE; >> >> @@ -1525,6 +1529,7 @@ static Property virtio_iommu_properties[] = { >> DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus, >> TYPE_PCI_BUS, PCIBus *), >> DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true), >> + DEFINE_PROP_UINT8("aw-bits", VirtIOIOMMU, aw_bits, 64), >> DEFINE_PROP_END_OF_LIST(), >> }; >> >> -- >> 2.41.0 >>