Re: [Qemu-devel] [PATCH v11 14/28] intel_iommu: Add support for PCI MSI remap

[David Kiarie]

On Tue, Jul 5, 2016 at 11:19 AM, Peter Xu <address@hidden> wrote:
> This patch enables interrupt remapping for PCI devices.
>
> To play the trick, one memory region "iommu_ir" is added as child region
> of the original iommu memory region, covering range 0xfeeXXXXX (which is
> the address range for APIC). All the writes to this range will be taken
> as MSI, and translation is carried out only when IR is enabled.
>
> Idea suggested by Paolo Bonzini.
>
> Signed-off-by: Peter Xu <address@hidden>
> ---
>  hw/i386/intel_iommu.c          | 251 
> +++++++++++++++++++++++++++++++++++++++++
>  hw/i386/intel_iommu_internal.h |   2 +
>  include/hw/i386/intel_iommu.h  |  66 +++++++++++
>  3 files changed, 319 insertions(+)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index a12091e..90bf9e9 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -1982,6 +1982,252 @@ static Property vtd_properties[] = {
>      DEFINE_PROP_END_OF_LIST(),
>  };
>
> +/* Read IRTE entry with specific index */
> +static int vtd_irte_get(IntelIOMMUState *iommu, uint16_t index,
> +                        VTD_IRTE *entry)
> +{
> +    dma_addr_t addr = 0x00;
> +
> +    addr = iommu->intr_root + index * sizeof(*entry);
> +    if (dma_memory_read(&address_space_memory, addr, entry,
> +                        sizeof(*entry))) {
> +        VTD_DPRINTF(GENERAL, "error: fail to access IR root at 0x%"PRIx64
> +                    " + %"PRIu16, iommu->intr_root, index);
> +        return -VTD_FR_IR_ROOT_INVAL;
> +    }
> +
> +    if (!entry->present) {
> +        VTD_DPRINTF(GENERAL, "error: present flag not set in IRTE"
> +                    " entry index %u value 0x%"PRIx64 " 0x%"PRIx64,
> +                    index, le64_to_cpu(entry->data[1]),
> +                    le64_to_cpu(entry->data[0]));
> +        return -VTD_FR_IR_ENTRY_P;
> +    }
> +
> +    if (entry->__reserved_0 || entry->__reserved_1 || \
> +        entry->__reserved_2) {
> +        VTD_DPRINTF(GENERAL, "error: IRTE entry index %"PRIu16
> +                    " reserved fields non-zero: 0x%"PRIx64 " 0x%"PRIx64,
> +                    index, le64_to_cpu(entry->data[1]),
> +                    le64_to_cpu(entry->data[0]));
> +        return -VTD_FR_IR_IRTE_RSVD;
> +    }
> +
> +    /*
> +     * TODO: Check Source-ID corresponds to SVT (Source Validation
> +     * Type) bits
> +     */
> +
> +    return 0;
> +}
> +
> +/* Fetch IRQ information of specific IR index */
> +static int vtd_remap_irq_get(IntelIOMMUState *iommu, uint16_t index, VTDIrq 
> *irq)
> +{
> +    VTD_IRTE irte;
> +    int ret = 0;
> +
> +    bzero(&irte, sizeof(irte));
> +
> +    ret = vtd_irte_get(iommu, index, &irte);
> +    if (ret) {
> +        return ret;
> +    }
> +
> +    irq->trigger_mode = irte.trigger_mode;
> +    irq->vector = irte.vector;
> +    irq->delivery_mode = irte.delivery_mode;
> +    /* Not support EIM yet: please refer to vt-d 9.10 DST bits */
> +#define  VTD_IR_APIC_DEST_MASK         (0xff00ULL)
> +#define  VTD_IR_APIC_DEST_SHIFT        (8)
> +    irq->dest = (le32_to_cpu(irte.dest_id) & VTD_IR_APIC_DEST_MASK) >> \
> +        VTD_IR_APIC_DEST_SHIFT;
> +    irq->dest_mode = irte.dest_mode;
> +    irq->redir_hint = irte.redir_hint;
> +
> +    VTD_DPRINTF(IR, "remapping interrupt index %d: trig:%u,vec:%u,"
> +                "deliver:%u,dest:%u,dest_mode:%u", index,
> +                irq->trigger_mode, irq->vector, irq->delivery_mode,
> +                irq->dest, irq->dest_mode);
> +
> +    return 0;
> +}
> +
> +/* Generate one MSI message from VTDIrq info */
> +static void vtd_generate_msi_message(VTDIrq *irq, MSIMessage *msg_out)
> +{
> +    VTD_MSIMessage msg = {};
> +
> +    /* Generate address bits */
> +    msg.dest_mode = irq->dest_mode;
> +    msg.redir_hint = irq->redir_hint;
> +    msg.dest = irq->dest;
> +    msg.__addr_head = cpu_to_le32(0xfee);
> +    /* Keep this from original MSI address bits */
> +    msg.__not_used = irq->msi_addr_last_bits;
> +
> +    /* Generate data bits */
> +    msg.vector = irq->vector;
> +    msg.delivery_mode = irq->delivery_mode;
> +    msg.level = 1;
> +    msg.trigger_mode = irq->trigger_mode;
> +
> +    msg_out->address = msg.msi_addr;
> +    msg_out->data = msg.msi_data;
> +}
> +
> +/* Interrupt remapping for MSI/MSI-X entry */
> +static int vtd_interrupt_remap_msi(IntelIOMMUState *iommu,
> +                                   MSIMessage *origin,
> +                                   MSIMessage *translated)
> +{
> +    int ret = 0;
> +    VTD_IR_MSIAddress addr;
> +    uint16_t index;
> +    VTDIrq irq = {0};
> +
> +    assert(origin && translated);
> +
> +    if (!iommu || !iommu->intr_enabled) {
> +        goto do_not_translate;
> +    }
> +
> +    if (origin->address & VTD_MSI_ADDR_HI_MASK) {
> +        VTD_DPRINTF(GENERAL, "error: MSI addr high 32 bits nonzero"
> +                    " during interrupt remapping: 0x%"PRIx32,
> +                    (uint32_t)((origin->address & VTD_MSI_ADDR_HI_MASK) >> \
> +                    VTD_MSI_ADDR_HI_SHIFT));
> +        return -VTD_FR_IR_REQ_RSVD;
> +    }
> +
> +    addr.data = origin->address & VTD_MSI_ADDR_LO_MASK;
> +    if (le16_to_cpu(addr.__head) != 0xfee) {
> +        VTD_DPRINTF(GENERAL, "error: MSI addr low 32 bits invalid: "
> +                    "0x%"PRIx32, addr.data);
> +        return -VTD_FR_IR_REQ_RSVD;
> +    }
> +
> +    /* This is compatible mode. */
> +    if (addr.int_mode != VTD_IR_INT_FORMAT_REMAP) {
> +        goto do_not_translate;
> +    }
> +
> +    index = addr.index_h << 15 | le16_to_cpu(addr.index_l);
> +
> +#define  VTD_IR_MSI_DATA_SUBHANDLE       (0x0000ffff)
> +#define  VTD_IR_MSI_DATA_RESERVED        (0xffff0000)
> +
> +    if (addr.sub_valid) {
> +        /* See VT-d spec 5.1.2.2 and 5.1.3 on subhandle */
> +        index += origin->data & VTD_IR_MSI_DATA_SUBHANDLE;
> +    }
> +
> +    ret = vtd_remap_irq_get(iommu, index, &irq);
> +    if (ret) {
> +        return ret;
> +    }
> +
> +    if (addr.sub_valid) {
> +        VTD_DPRINTF(IR, "received MSI interrupt");
> +        if (origin->data & VTD_IR_MSI_DATA_RESERVED) {
> +            VTD_DPRINTF(GENERAL, "error: MSI data bits non-zero for "
> +                        "interrupt remappable entry: 0x%"PRIx32,
> +                        origin->data);
> +            return -VTD_FR_IR_REQ_RSVD;
> +        }
> +    } else {
> +        uint8_t vector = origin->data & 0xff;
> +        VTD_DPRINTF(IR, "received IOAPIC interrupt");
> +        /* IOAPIC entry vector should be aligned with IRTE vector
> +         * (see vt-d spec 5.1.5.1). */
> +        if (vector != irq.vector) {
> +            VTD_DPRINTF(GENERAL, "IOAPIC vector inconsistent: "
> +                        "entry: %d, IRTE: %d, index: %d",
> +                        vector, irq.vector, index);
> +        }
> +    }
> +
> +    /*
> +     * We'd better keep the last two bits, assuming that guest OS
> +     * might modify it. Keep it does not hurt after all.
> +     */
> +    irq.msi_addr_last_bits = addr.__not_care;
> +
> +    /* Translate VTDIrq to MSI message */
> +    vtd_generate_msi_message(&irq, translated);
> +
> +    VTD_DPRINTF(IR, "mapping MSI 0x%"PRIx64":0x%"PRIx32 " -> "
> +                "0x%"PRIx64":0x%"PRIx32, origin->address, origin->data,
> +                translated->address, translated->data);
> +    return 0;
> +
> +do_not_translate:
> +    memcpy(translated, origin, sizeof(*origin));
> +    return 0;
> +}
> +
> +static MemTxResult vtd_mem_ir_read(void *opaque, hwaddr addr,
> +                                   uint64_t *data, unsigned size,
> +                                   MemTxAttrs attrs)
> +{
> +    addr += VTD_INTERRUPT_ADDR_FIRST;
> +
> +    VTD_DPRINTF(IR, "read mem_ir addr 0x%"PRIx64 " size %u",
> +                addr, size);
> +
> +    if (dma_memory_read(&address_space_memory, addr, &data, size)) {
> +        VTD_DPRINTF(GENERAL, "error: fail to access 0x%"PRIx64, addr);
> +        return MEMTX_ERROR;
> +    }
> +
> +    return MEMTX_OK;
> +}

I'm looking at this and wondering whether dma_memory_read expected a
double pointer as the third argument. (??)

> +
> +static MemTxResult vtd_mem_ir_write(void *opaque, hwaddr addr,
> +                                    uint64_t value, unsigned size,
> +                                    MemTxAttrs attrs)
> +{
> +    int ret = 0;
> +    MSIMessage from = {0}, to = {0};
> +
> +    from.address = (uint64_t) addr + VTD_INTERRUPT_ADDR_FIRST;
> +    from.data = (uint32_t) value;
> +
> +    ret = vtd_interrupt_remap_msi(opaque, &from, &to);
> +    if (ret) {
> +        /* TODO: report error */
> +        VTD_DPRINTF(GENERAL, "int remap fail for addr 0x%"PRIx64
> +                    " data 0x%"PRIx32, from.address, from.data);
> +        /* Drop this interrupt */
> +        return MEMTX_ERROR;
> +    }
> +
> +    VTD_DPRINTF(IR, "delivering MSI 0x%"PRIx64":0x%"PRIx32
> +                " for device sid 0x%04x",
> +                to.address, to.data, sid);
> +
> +    if (dma_memory_write(&address_space_memory, to.address,
> +                         &to.data, size)) {
> +        VTD_DPRINTF(GENERAL, "error: fail to write 0x%"PRIx64
> +                    " value 0x%"PRIx32, to.address, to.data);
> +    }
> +
> +    return MEMTX_OK;
> +}
> +
> +static const MemoryRegionOps vtd_mem_ir_ops = {
> +    .read_with_attrs = vtd_mem_ir_read,
> +    .write_with_attrs = vtd_mem_ir_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .impl = {
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +    },
> +    .valid = {
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +    },
> +};
>
>  static AddressSpace *vtd_find_add_as(X86IOMMUState *x86_iommu, PCIBus *bus,
>                                       int devfn)
> @@ -2011,6 +2257,11 @@ static AddressSpace *vtd_find_add_as(X86IOMMUState 
> *x86_iommu, PCIBus *bus,
>          vtd_dev_as->context_cache_entry.context_cache_gen = 0;
>          memory_region_init_iommu(&vtd_dev_as->iommu, OBJECT(s),
>                                   &s->iommu_ops, "intel_iommu", UINT64_MAX);
> +        memory_region_init_io(&vtd_dev_as->iommu_ir, OBJECT(s),
> +                              &vtd_mem_ir_ops, s, "intel_iommu_ir",
> +                              VTD_INTERRUPT_ADDR_SIZE);
> +        memory_region_add_subregion(&vtd_dev_as->iommu, 
> VTD_INTERRUPT_ADDR_FIRST,
> +                                    &vtd_dev_as->iommu_ir);
>          address_space_init(&vtd_dev_as->as,
>                             &vtd_dev_as->iommu, "intel_iommu");
>      }
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index 2a9987f..e1a08cb 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -110,6 +110,8 @@
>  /* Interrupt Address Range */
>  #define VTD_INTERRUPT_ADDR_FIRST    0xfee00000ULL
>  #define VTD_INTERRUPT_ADDR_LAST     0xfeefffffULL
> +#define VTD_INTERRUPT_ADDR_SIZE     (VTD_INTERRUPT_ADDR_LAST - \
> +                                     VTD_INTERRUPT_ADDR_FIRST + 1)
>
>  /* The shift of source_id in the key of IOTLB hash table */
>  #define VTD_IOTLB_SID_SHIFT         36
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index 9a898c1..b3f17d7 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -24,6 +24,8 @@
>  #include "hw/qdev.h"
>  #include "sysemu/dma.h"
>  #include "hw/i386/x86-iommu.h"
> +#include "hw/i386/ioapic.h"
> +#include "hw/pci/msi.h"
>
>  #define TYPE_INTEL_IOMMU_DEVICE "intel-iommu"
>  #define INTEL_IOMMU_DEVICE(obj) \
> @@ -46,6 +48,10 @@
>
>  #define DMAR_REPORT_F_INTR          (1)
>
> +#define  VTD_MSI_ADDR_HI_MASK        (0xffffffff00000000ULL)
> +#define  VTD_MSI_ADDR_HI_SHIFT       (32)
> +#define  VTD_MSI_ADDR_LO_MASK        (0x00000000ffffffffULL)
> +
>  typedef struct VTDContextEntry VTDContextEntry;
>  typedef struct VTDContextCacheEntry VTDContextCacheEntry;
>  typedef struct IntelIOMMUState IntelIOMMUState;
> @@ -54,6 +60,8 @@ typedef struct VTDIOTLBEntry VTDIOTLBEntry;
>  typedef struct VTDBus VTDBus;
>  typedef union VTD_IRTE VTD_IRTE;
>  typedef union VTD_IR_MSIAddress VTD_IR_MSIAddress;
> +typedef struct VTDIrq VTDIrq;
> +typedef struct VTD_MSIMessage VTD_MSIMessage;
>
>  /* Context-Entry */
>  struct VTDContextEntry {
> @@ -74,6 +82,7 @@ struct VTDAddressSpace {
>      uint8_t devfn;
>      AddressSpace as;
>      MemoryRegion iommu;
> +    MemoryRegion iommu_ir;      /* Interrupt region: 0xfeeXXXXX */
>      IntelIOMMUState *iommu_state;
>      VTDContextCacheEntry context_cache_entry;
>  };
> @@ -161,6 +170,63 @@ union VTD_IR_MSIAddress {
>      uint32_t data;
>  };
>
> +/* Generic IRQ entry information */
> +struct VTDIrq {
> +    /* Used by both IOAPIC/MSI interrupt remapping */
> +    uint8_t trigger_mode;
> +    uint8_t vector;
> +    uint8_t delivery_mode;
> +    uint32_t dest;
> +    uint8_t dest_mode;
> +
> +    /* only used by MSI interrupt remapping */
> +    uint8_t redir_hint;
> +    uint8_t msi_addr_last_bits;
> +};
> +
> +struct VTD_MSIMessage {
> +    union {
> +        struct {
> +#ifdef HOST_WORDS_BIGENDIAN
> +            uint32_t __addr_head:12; /* 0xfee */
> +            uint32_t dest:8;
> +            uint32_t __reserved:8;
> +            uint32_t redir_hint:1;
> +            uint32_t dest_mode:1;
> +            uint32_t __not_used:2;
> +#else
> +            uint32_t __not_used:2;
> +            uint32_t dest_mode:1;
> +            uint32_t redir_hint:1;
> +            uint32_t __reserved:8;
> +            uint32_t dest:8;
> +            uint32_t __addr_head:12; /* 0xfee */
> +#endif
> +            uint32_t __addr_hi:32;
> +        } QEMU_PACKED;
> +        uint64_t msi_addr;
> +    };
> +    union {
> +        struct {
> +#ifdef HOST_WORDS_BIGENDIAN
> +            uint16_t trigger_mode:1;
> +            uint16_t level:1;
> +            uint16_t __resved:3;
> +            uint16_t delivery_mode:3;
> +            uint16_t vector:8;
> +#else
> +            uint16_t vector:8;
> +            uint16_t delivery_mode:3;
> +            uint16_t __resved:3;
> +            uint16_t level:1;
> +            uint16_t trigger_mode:1;
> +#endif
> +            uint16_t __resved1:16;
> +        } QEMU_PACKED;
> +        uint32_t msi_data;
> +    };
> +};
> +
>  /* When IR is enabled, all MSI/MSI-X data bits should be zero */
>  #define VTD_IR_MSI_DATA          (0)
>
> --
> 2.4.11
>