> From: Peter Xu [mailto:[email protected]]
> Sent: Friday, January 13, 2017 11:06 AM
>
> From: Aviv Ben-David <[email protected]>
>
> This capability asks the guest to invalidate cache before each map operation.
> We can use this invalidation to trap map operations in the hypervisor.
>
> Signed-off-by: Aviv Ben-David <[email protected]>
> Signed-off-by: Peter Xu <[email protected]>
> ---
> hw/i386/intel_iommu.c | 5 +++++
> hw/i386/intel_iommu_internal.h | 1 +
> include/hw/i386/intel_iommu.h | 2 ++
> 3 files changed, 8 insertions(+)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index ec62239..2868e37 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -2107,6 +2107,7 @@ static Property vtd_properties[] = {
> DEFINE_PROP_ON_OFF_AUTO("eim", IntelIOMMUState, intr_eim,
> ON_OFF_AUTO_AUTO),
> DEFINE_PROP_BOOL("x-buggy-eim", IntelIOMMUState, buggy_eim, false),
> + DEFINE_PROP_BOOL("cache-mode", IntelIOMMUState, cache_mode_enabled,
> FALSE),
> DEFINE_PROP_END_OF_LIST(),
> };
>
> @@ -2488,6 +2489,10 @@ static void vtd_init(IntelIOMMUState *s)
> s->ecap |= VTD_ECAP_DT;
> }
>
> + if (s->cache_mode_enabled) {
> + s->cap |= VTD_CAP_CM;
> + }
> +
I think some of my old comments are not answered:
1) Better to use caching_mode to follow spec
2) Does it make sense to automatically set this flag if any VFIO device
has been statically assigned when starting Qemu? Also for hot-add
device path, some check of caching mode is required. If not set,
should we fail hot-add operation? I don't think we have such physical
platform with some devices behind IOMMU while others not.
> vtd_reset_context_cache(s);
> vtd_reset_iotlb(s);
>
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index 356f188..4104121 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -202,6 +202,7 @@
> #define VTD_CAP_MAMV (VTD_MAMV << 48)
> #define VTD_CAP_PSI (1ULL << 39)
> #define VTD_CAP_SLLPS ((1ULL << 34) | (1ULL << 35))
> +#define VTD_CAP_CM (1ULL << 7)
>
> /* Supported Adjusted Guest Address Widths */
> #define VTD_CAP_SAGAW_SHIFT 8
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index 405c9d1..749eef9 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -257,6 +257,8 @@ struct IntelIOMMUState {
> uint8_t womask[DMAR_REG_SIZE]; /* WO (write only - read returns 0) */
> uint32_t version;
>
> + bool cache_mode_enabled; /* RO - is cap CM enabled? */
> +
> dma_addr_t root; /* Current root table pointer */
> bool root_extended; /* Type of root table (extended or not)
> */
> bool dmar_enabled; /* Set if DMA remapping is enabled */
> --
> 2.7.4
