Re: [PATCH v1 14/22] intel_iommu: bind/unbind guest page table to host

[Peter Xu <peterx@redhat.com>]

On Sun, Mar 22, 2020 at 05:36:11AM -0700, Liu Yi L wrote:
> This patch captures the guest PASID table entry modifications and
> propagates the changes to host to setup dual stage DMA translation.
> The guest page table is configured as 1st level page table (GVA->GPA)
> whose translation result would further go through host VT-d 2nd
> level page table(GPA->HPA) under nested translation mode. This is the
> key part of vSVA support, and also a key to support IOVA over 1st-
> level page table for Intel VT-d in virtualization environment.
> 
> Cc: Kevin Tian <kevin.tian@intel.com>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Yi Sun <yi.y.sun@linux.intel.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> ---
>  hw/i386/intel_iommu.c          | 98 +++++++++++++++++++++++++++++++++++++++---
>  hw/i386/intel_iommu_internal.h | 25 +++++++++++
>  2 files changed, 118 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index c985cae..0423c83 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -41,6 +41,7 @@
>  #include "migration/vmstate.h"
>  #include "trace.h"
>  #include "qemu/jhash.h"
> +#include <linux/iommu.h>
>  
>  /* context entry operations */
>  #define VTD_CE_GET_RID2PASID(ce) \
> @@ -695,6 +696,16 @@ static inline uint16_t vtd_pe_get_domain_id(VTDPASIDEntry *pe)
>      return VTD_SM_PASID_ENTRY_DID((pe)->val[1]);
>  }
>  
> +static inline uint32_t vtd_pe_get_fl_aw(VTDPASIDEntry *pe)
> +{
> +    return 48 + ((pe->val[2] >> 2) & VTD_SM_PASID_ENTRY_FLPM) * 9;
> +}
> +
> +static inline dma_addr_t vtd_pe_get_flpt_base(VTDPASIDEntry *pe)
> +{
> +    return pe->val[2] & VTD_SM_PASID_ENTRY_FLPTPTR;
> +}
> +
>  static inline bool vtd_pdire_present(VTDPASIDDirEntry *pdire)
>  {
>      return pdire->val & 1;
> @@ -1856,6 +1867,81 @@ static void vtd_context_global_invalidate(IntelIOMMUState *s)
>      vtd_iommu_replay_all(s);
>  }
>  
> +/**
> + * Caller should hold iommu_lock.
> + */
> +static int vtd_bind_guest_pasid(IntelIOMMUState *s, VTDBus *vtd_bus,
> +                                int devfn, int pasid, VTDPASIDEntry *pe,
> +                                VTDPASIDOp op)
> +{
> +    VTDHostIOMMUContext *vtd_dev_icx;
> +    HostIOMMUContext *host_icx;
> +    DualIOMMUStage1BindData *bind_data;
> +    struct iommu_gpasid_bind_data *g_bind_data;
> +    int ret = -1;
> +
> +    vtd_dev_icx = vtd_bus->dev_icx[devfn];
> +    if (!vtd_dev_icx) {
> +        return -EINVAL;
> +    }
> +
> +    host_icx = vtd_dev_icx->host_icx;
> +    if (!host_icx) {
> +        return -EINVAL;
> +    }
> +
> +    if (!(host_icx->stage1_formats
> +             & IOMMU_PASID_FORMAT_INTEL_VTD)) {
> +        error_report_once("IOMMU Stage 1 format is not compatible!\n");

Shouldn't we fail with this?

> +    }
> +
> +    bind_data = g_malloc0(sizeof(*bind_data));
> +    bind_data->pasid = pasid;
> +    g_bind_data = &bind_data->bind_data.gpasid_bind;
> +
> +    g_bind_data->flags = 0;
> +    g_bind_data->vtd.flags = 0;
> +    switch (op) {
> +    case VTD_PASID_BIND:
> +    case VTD_PASID_UPDATE:

Is VTD_PASID_UPDATE used anywhere?

But since it's called "UPDATE"... I really want to confirm with you
that the bind() to the kernel will handle the UPDATE case, right?  I
mean, we need to unbind first if there is an existing pgtable pointer.

If the answer is yes, then I think we're good, but we really need to
comment it somewhere about the fact.

> +        g_bind_data->version = IOMMU_UAPI_VERSION;
> +        g_bind_data->format = IOMMU_PASID_FORMAT_INTEL_VTD;
> +        g_bind_data->gpgd = vtd_pe_get_flpt_base(pe);
> +        g_bind_data->addr_width = vtd_pe_get_fl_aw(pe);
> +        g_bind_data->hpasid = pasid;
> +        g_bind_data->gpasid = pasid;
> +        g_bind_data->flags |= IOMMU_SVA_GPASID_VAL;
> +        g_bind_data->vtd.flags =
> +                             (VTD_SM_PASID_ENTRY_SRE_BIT(pe->val[2]) ? 1 : 0)
> +                           | (VTD_SM_PASID_ENTRY_EAFE_BIT(pe->val[2]) ? 1 : 0)
> +                           | (VTD_SM_PASID_ENTRY_PCD_BIT(pe->val[1]) ? 1 : 0)
> +                           | (VTD_SM_PASID_ENTRY_PWT_BIT(pe->val[1]) ? 1 : 0)
> +                           | (VTD_SM_PASID_ENTRY_EMTE_BIT(pe->val[1]) ? 1 : 0)
> +                           | (VTD_SM_PASID_ENTRY_CD_BIT(pe->val[1]) ? 1 : 0);
> +        g_bind_data->vtd.pat = VTD_SM_PASID_ENTRY_PAT(pe->val[1]);
> +        g_bind_data->vtd.emt = VTD_SM_PASID_ENTRY_EMT(pe->val[1]);
> +        ret = host_iommu_ctx_bind_stage1_pgtbl(host_icx, bind_data);
> +        break;
> +    case VTD_PASID_UNBIND:
> +        g_bind_data->version = IOMMU_UAPI_VERSION;
> +        g_bind_data->format = IOMMU_PASID_FORMAT_INTEL_VTD;
> +        g_bind_data->gpgd = 0;
> +        g_bind_data->addr_width = 0;
> +        g_bind_data->hpasid = pasid;
> +        g_bind_data->gpasid = pasid;
> +        g_bind_data->flags |= IOMMU_SVA_GPASID_VAL;
> +        ret = host_iommu_ctx_unbind_stage1_pgtbl(host_icx, bind_data);
> +        break;
> +    default:
> +        error_report_once("Unknown VTDPASIDOp!!!\n");
> +        break;
> +    }
> +
> +    g_free(bind_data);
> +
> +    return ret;
> +}
> +
>  /* Do a context-cache device-selective invalidation.
>   * @func_mask: FM field after shifting
>   */
> @@ -2481,10 +2567,10 @@ static inline void vtd_fill_in_pe_in_cache(IntelIOMMUState *s,
>  
>      pc_entry->pasid_entry = *pe;
>      pc_entry->pasid_cache_gen = s->pasid_cache_gen;
> -    /*
> -     * TODO:
> -     * - send pasid bind to host for passthru devices
> -     */
> +    vtd_bind_guest_pasid(s, vtd_pasid_as->vtd_bus,
> +                         vtd_pasid_as->devfn,
> +                         vtd_pasid_as->pasid,
> +                         pe, VTD_PASID_BIND);
>  }
>  
>  /**
> @@ -2574,11 +2660,13 @@ static gboolean vtd_flush_pasid(gpointer key, gpointer value,
>       * - when pasid-base-iotlb(piotlb) infrastructure is ready,
>       *   should invalidate QEMU piotlb togehter with this change.
>       */
> +
>      return false;
>  remove:
> +    vtd_bind_guest_pasid(s, vtd_bus, devfn,
> +                         pasid, NULL, VTD_PASID_UNBIND);
>      /*
>       * TODO:
> -     * - send pasid bind to host for passthru devices
>       * - when pasid-base-iotlb(piotlb) infrastructure is ready,
>       *   should invalidate QEMU piotlb togehter with this change.
>       */
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index 01fd95c..4451acf 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -516,6 +516,20 @@ typedef struct VTDRootEntry VTDRootEntry;
>  #define VTD_SM_CONTEXT_ENTRY_RSVD_VAL0(aw)  (0x1e0ULL | ~VTD_HAW_MASK(aw))
>  #define VTD_SM_CONTEXT_ENTRY_RSVD_VAL1      0xffffffffffe00000ULL
>  
> +enum VTD_DUAL_STAGE_UAPI {
> +    UAPI_BIND_GPASID,
> +    UAPI_NUM
> +};
> +typedef enum VTD_DUAL_STAGE_UAPI VTD_DUAL_STAGE_UAPI;
> +
> +enum VTDPASIDOp {
> +    VTD_PASID_BIND,
> +    VTD_PASID_UNBIND,
> +    VTD_PASID_UPDATE,

Same here (whether to drop?).

> +    VTD_OP_NUM
> +};
> +typedef enum VTDPASIDOp VTDPASIDOp;
> +
>  struct VTDPASIDCacheInfo {
>  #define VTD_PASID_CACHE_GLOBAL   (1ULL << 0)
>  #define VTD_PASID_CACHE_DOMSI    (1ULL << 1)
> @@ -552,6 +566,17 @@ typedef struct VTDPASIDCacheInfo VTDPASIDCacheInfo;
>  #define VTD_SM_PASID_ENTRY_AW          7ULL /* Adjusted guest-address-width */
>  #define VTD_SM_PASID_ENTRY_DID(val)    ((val) & VTD_DOMAIN_ID_MASK)
>  
> +#define VTD_SM_PASID_ENTRY_FLPM          3ULL
> +#define VTD_SM_PASID_ENTRY_FLPTPTR       (~0xfffULL)
> +#define VTD_SM_PASID_ENTRY_SRE_BIT(val)  (!!((val) & 1ULL))
> +#define VTD_SM_PASID_ENTRY_EAFE_BIT(val) (!!(((val) >> 7) & 1ULL))
> +#define VTD_SM_PASID_ENTRY_PCD_BIT(val)  (!!(((val) >> 31) & 1ULL))
> +#define VTD_SM_PASID_ENTRY_PWT_BIT(val)  (!!(((val) >> 30) & 1ULL))
> +#define VTD_SM_PASID_ENTRY_EMTE_BIT(val) (!!(((val) >> 26) & 1ULL))
> +#define VTD_SM_PASID_ENTRY_CD_BIT(val)   (!!(((val) >> 25) & 1ULL))
> +#define VTD_SM_PASID_ENTRY_PAT(val)      (((val) >> 32) & 0xFFFFFFFFULL)
> +#define VTD_SM_PASID_ENTRY_EMT(val)      (((val) >> 27) & 0x7ULL)
> +
>  /* Second Level Page Translation Pointer*/
>  #define VTD_SM_PASID_ENTRY_SLPTPTR     (~0xfffULL)
>  
> -- 
> 2.7.4
> 

-- 
Peter Xu