diff options
| author | Jason Wang <jasowang@redhat.com> | 2022-02-14 14:03:46 +0800 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2022-03-06 05:08:23 -0500 |
| commit | b8ffd7d6713fb2703f4b09cea3e62d1c61767107 (patch) | |
| tree | c4d35897c53f09c81366f67f682be60be2b5d13c /hw/i386 | |
| parent | b1f030a0a2e281193b09350c0281c0084e84bcf4 (diff) | |
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 <jasowang@redhat.com>
Message-Id: <20220214060346.72455-1-jasowang@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/i386')
| -rw-r--r-- | hw/i386/intel_iommu.c | 14 | ||||
| -rw-r--r-- | hw/i386/intel_iommu_internal.h | 1 |
2 files changed, 14 insertions, 1 deletions
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) |