Re: [RFC v2 15/22] intel_iommu: bind/unbind guest page table to host

[Peter Xu]

On Thu, Oct 24, 2019 at 08:34:36AM -0400, Liu Yi L wrote:
> This patch captures the guest PASID table entry modifications and
> propagates the changes to host to setup nested 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
> a key part of vSVA support.
> 
> Cc: Kevin Tian <address@hidden>
> Cc: Jacob Pan <address@hidden>
> Cc: Peter Xu <address@hidden>
> Cc: Yi Sun <address@hidden>
> Signed-off-by: Liu Yi L <address@hidden>
> ---
>  hw/i386/intel_iommu.c          | 81 
> ++++++++++++++++++++++++++++++++++++++++++
>  hw/i386/intel_iommu_internal.h | 20 +++++++++++
>  2 files changed, 101 insertions(+)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index d8827c9..793b0de 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;
> @@ -1850,6 +1861,67 @@ static void 
> vtd_context_global_invalidate(IntelIOMMUState *s)
>      vtd_iommu_replay_all(s);
>  }
>  
> +static void vtd_bind_guest_pasid(IntelIOMMUState *s, VTDBus *vtd_bus,
> +            int devfn, int pasid, VTDPASIDEntry *pe, VTDPASIDOp op)
> +{
> +#ifdef __linux__
> +    VTDIOMMUContext *vtd_ic;
> +    IOMMUCTXEventData event_data;
> +    IOMMUCTXPASIDBindData bind;
> +    struct iommu_gpasid_bind_data *g_bind_data;
> +
> +    vtd_ic = vtd_bus->dev_ic[devfn];
> +    if (!vtd_ic) {
> +        return;
> +    }
> +
> +    g_bind_data = g_malloc0(sizeof(*g_bind_data));
> +    bind.flag = 0;
> +    g_bind_data->flags = 0;
> +    g_bind_data->vtd.flags = 0;
> +    switch (op) {
> +    case VTD_PASID_BIND:
> +    case VTD_PASID_UPDATE:
> +        g_bind_data->version = IOMMU_GPASID_BIND_VERSION_1;
> +        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]);
> +        bind.flag |= IOMMU_CTX_BIND_PASID;
> +        break;
> +
> +    case VTD_PASID_UNBIND:
> +        g_bind_data->gpgd = 0;
> +        g_bind_data->addr_width = 0;
> +        g_bind_data->hpasid = pasid;
> +        bind.flag |= IOMMU_CTX_UNBIND_PASID;
> +        break;
> +
> +    default:
> +        printf("Unknown VTDPASIDOp!!\n");

Please don't use printf()..  Here assert() suits.

> +        break;
> +    }
> +    if (bind.flag) {

Will this be untrue?  If not, assert() works too.

> +        event_data.event = IOMMU_CTX_EVENT_PASID_BIND;
> +        bind.data = g_bind_data;
> +        event_data.data = &bind;
> +        iommu_ctx_event_notify(&vtd_ic->iommu_context, &event_data);
> +    }
> +    g_free(g_bind_data);
> +#endif
> +}
> +
>  /* Do a context-cache device-selective invalidation.
>   * @func_mask: FM field after shifting
>   */
> @@ -2528,12 +2600,17 @@ static gboolean vtd_flush_pasid(gpointer key, 
> gpointer value,
>                  pc_entry->pasid_cache_gen = s->pasid_cache_gen;
>                  if (!vtd_pasid_entry_compare(&pe, &pc_entry->pasid_entry)) {
>                      pc_entry->pasid_entry = pe;
> +                    vtd_bind_guest_pasid(s, vtd_bus, devfn,
> +                                     pasid, &pe, VTD_PASID_UPDATE);
>                      /*
>                       * TODO: when pasid-base-iotlb(piotlb) infrastructure is
>                       * ready, should invalidate QEMU piotlb togehter with 
> this
>                       * change.
>                       */
>                  }
> +            } else {
> +                vtd_bind_guest_pasid(s, vtd_bus, devfn,
> +                                  pasid, NULL, VTD_PASID_UNBIND);

Please see the reply in the other thread on vtd_flush_pasid().  I've
filled in where I feel like this UNBIND should exist, I feel like your
current code could miss some places where you should unbind but didn't.

>              }
>          }
>      }
> @@ -2623,6 +2700,10 @@ static inline void vtd_fill_in_pe_cache(
>  
>      pc_entry->pasid_entry = *pe;
>      pc_entry->pasid_cache_gen = s->pasid_cache_gen;
> +    vtd_bind_guest_pasid(s, vtd_pasid_as->vtd_bus,
> +                         vtd_pasid_as->devfn,
> +                         vtd_pasid_as->pasid,
> +                         pe, VTD_PASID_UPDATE);
>  }
>  
>  static int vtd_pasid_cache_psi(IntelIOMMUState *s,
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index 12873e1..13e02e8 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -483,6 +483,14 @@ struct VTDRootEntry {
>  };
>  typedef struct VTDRootEntry VTDRootEntry;
>  
> +enum VTDPASIDOp {
> +    VTD_PASID_BIND,
> +    VTD_PASID_UNBIND,
> +    VTD_PASID_UPDATE,
> +    VTD_OP_NUM
> +};
> +typedef enum VTDPASIDOp VTDPASIDOp;
> +
>  struct VTDPASIDCacheInfo {
>  #define VTD_PASID_CACHE_DOMSI   (1ULL << 0);
>  #define VTD_PASID_CACHE_PASIDSI (1ULL << 1);
> @@ -549,6 +557,18 @@ 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)
>  
> +/* Adjusted guest-address-width */
> +#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