From b8ffd7d6713fb2703f4b09cea3e62d1c61767107 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Mon, 14 Feb 2022 14:03:46 +0800 Subject: [PATCH] intel_iommu: support snoop control SC is required for some kernel features like vhost-vDPA. So this patch implements basic SC feature. The idea is pretty simple, for software emulated DMA it would be always coherent. In this case we can simple advertise ECAP_SC bit. For VFIO and vhost, thing will be more much complicated, so this patch simply fail the IOMMU notifier registration. In the future, we may want to have a dedicated notifiers flag or similar mechanism to demonstrate the coherency so VFIO could advertise that if it has VFIO_DMA_CC_IOMMU, for vhost kernel backend we don't need that since it's a software backend. Signed-off-by: Jason Wang Message-Id: <20220214060346.72455-1-jasowang@redhat.com> Reviewed-by: Peter Xu Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/intel_iommu.c | 14 +++++++++++++- hw/i386/intel_iommu_internal.h | 1 + include/hw/i386/intel_iommu.h | 1 + 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 4c6c016388..32471a44cb 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -3030,6 +3030,13 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu, VTDAddressSpace *vtd_as = container_of(iommu, VTDAddressSpace, iommu); IntelIOMMUState *s = vtd_as->iommu_state; + /* TODO: add support for VFIO and vhost users */ + if (s->snoop_control) { + error_setg_errno(errp, -ENOTSUP, + "Snoop Control with vhost or VFIO is not supported"); + return -ENOTSUP; + } + /* Update per-address-space notifier flags */ vtd_as->notifier_flags = new; @@ -3113,6 +3120,7 @@ static Property vtd_properties[] = { VTD_HOST_ADDRESS_WIDTH), DEFINE_PROP_BOOL("caching-mode", IntelIOMMUState, caching_mode, FALSE), DEFINE_PROP_BOOL("x-scalable-mode", IntelIOMMUState, scalable_mode, FALSE), + DEFINE_PROP_BOOL("snoop-control", IntelIOMMUState, snoop_control, false), DEFINE_PROP_BOOL("dma-drain", IntelIOMMUState, dma_drain, true), DEFINE_PROP_END_OF_LIST(), }; @@ -3643,7 +3651,7 @@ static void vtd_init(IntelIOMMUState *s) vtd_spte_rsvd_large[3] = VTD_SPTE_LPAGE_L3_RSVD_MASK(s->aw_bits, x86_iommu->dt_supported); - if (s->scalable_mode) { + if (s->scalable_mode || s->snoop_control) { vtd_spte_rsvd[1] &= ~VTD_SPTE_SNP; vtd_spte_rsvd_large[2] &= ~VTD_SPTE_SNP; vtd_spte_rsvd_large[3] &= ~VTD_SPTE_SNP; @@ -3674,6 +3682,10 @@ static void vtd_init(IntelIOMMUState *s) s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS; } + if (s->snoop_control) { + s->ecap |= VTD_ECAP_SC; + } + vtd_reset_caches(s); /* Define registers with default values and bit semantics */ diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h index a6c788049b..1ff13b40f9 100644 --- a/hw/i386/intel_iommu_internal.h +++ b/hw/i386/intel_iommu_internal.h @@ -188,6 +188,7 @@ #define VTD_ECAP_IR (1ULL << 3) #define VTD_ECAP_EIM (1ULL << 4) #define VTD_ECAP_PT (1ULL << 6) +#define VTD_ECAP_SC (1ULL << 7) #define VTD_ECAP_MHMV (15ULL << 20) #define VTD_ECAP_SRS (1ULL << 31) #define VTD_ECAP_SMTS (1ULL << 43) diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h index 41783ee46d..3b5ac869db 100644 --- a/include/hw/i386/intel_iommu.h +++ b/include/hw/i386/intel_iommu.h @@ -228,6 +228,7 @@ struct IntelIOMMUState { bool caching_mode; /* RO - is cap CM enabled? */ bool scalable_mode; /* RO - is Scalable Mode supported? */ + bool snoop_control; /* RO - is SNP filed supported? */ dma_addr_t root; /* Current root table pointer */ bool root_scalable; /* Type of root table (scalable or not) */ -- 2.42.0