Re: [Qemu PATCH v2 7/9] hw/cxl/cxl-mailbox-utils: Add mailbox commands to support add/release dynamic capacity response

[Fan Ni <fan.ni@gmx.us>]

On Fri, Sep 08, 2023 at 01:00:16PM +0000, J?rgen Hansen wrote:
> On 7/25/23 20:39, Fan Ni wrote:
> > From: Fan Ni <nifan@outlook.com>
> >
> > Per CXL spec 3.0, two mailbox commands are implemented:
> > Add Dynamic Capacity Response (Opcode 4802h) 8.2.9.8.9.3, and
> > Release Dynamic Capacity (Opcode 4803h) 8.2.9.8.9.4.
> >
> > Signed-off-by: Fan Ni <fan.ni@samsung.com>
> > ---
> >   hw/cxl/cxl-mailbox-utils.c  | 253 ++++++++++++++++++++++++++++++++++++
> >   include/hw/cxl/cxl_device.h |   3 +-
> >   2 files changed, 255 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> > index 3d25a9697e..1e4944da95 100644
> > --- a/hw/cxl/cxl-mailbox-utils.c
> > +++ b/hw/cxl/cxl-mailbox-utils.c
> > @@ -84,6 +84,8 @@ enum {
> >       DCD_CONFIG  = 0x48, /*r3.0: 8.2.9.8.9*/
> >           #define GET_DC_CONFIG          0x0
> >           #define GET_DYN_CAP_EXT_LIST   0x1
> > +        #define ADD_DYN_CAP_RSP        0x2
> > +        #define RELEASE_DYN_CAP        0x3
> >       PHYSICAL_SWITCH = 0x51
> >           #define IDENTIFY_SWITCH_DEVICE      0x0
> >   };
> > @@ -1086,6 +1088,251 @@ static CXLRetCode cmd_dcd_get_dyn_cap_ext_list(struct cxl_cmd *cmd,
> >       return CXL_MBOX_SUCCESS;
> >   }
> >
> > +/*
> > + * Check whether the bits at addr between [nr, nr+size) are all set,
> > + * return 1 if all 1s, else return 0
> > + */
> > +static inline int test_bits(const unsigned long *addr, int nr, int size)
> > +{
> > +    unsigned long res = find_next_zero_bit(addr, size + nr, nr);
> > +
> > +    return (res >= nr + size) ? 1 : 0;
> > +}
> > +
> > +/*
> > + * Find dynamic capacity region id based on dpa range [dpa, dpa+len)
> > + */
> > +static uint8_t find_region_id(struct CXLType3Dev *dev, uint64_t dpa,
> > +        uint64_t len)
> > +{
> > +    int8_t i = dev->dc.num_regions - 1;
> > +
> > +    while (i > 0 && dpa < dev->dc.regions[i].base) {
> > +        i--;
> > +    }
> > +
> > +    if (dpa < dev->dc.regions[i].base
> > +            || dpa + len > dev->dc.regions[i].base + dev->dc.regions[i].len) {
> > +        return dev->dc.num_regions;
> > +    }
> > +
> > +    return i;
> > +}
> > +
> > +static void insert_extent_to_extent_list(CXLDCDExtentList *list, uint64_t dpa,
> > +        uint64_t len, uint8_t *tag, uint16_t shared_seq)
> > +{
> > +    CXLDCD_Extent *extent;
> > +    extent = g_new0(CXLDCD_Extent, 1);
> > +    extent->start_dpa = dpa;
> > +    extent->len = len;
> > +    if (tag) {
> > +        memcpy(extent->tag, tag, 0x10);
> > +    } else {
> > +        memset(extent->tag, 0, 0x10);
> > +    }
> > +    extent->shared_seq = shared_seq;
> > +
> > +    QTAILQ_INSERT_TAIL(list, extent, node);
> > +}
> > +
> > +typedef struct updated_dc_extent_list_in_pl {
> > +    uint32_t num_entries_updated;
> > +    uint8_t rsvd[4];
> > +    struct { /* r3.0: Table 8-130 */
> > +        uint64_t start_dpa;
> > +        uint64_t len;
> > +        uint8_t rsvd[8];
> > +    } QEMU_PACKED updated_entries[];
> > +} QEMU_PACKED updated_dc_extent_list_in_pl;
> > +
> > +/*
> > + * The function only check the input extent list against itself.
> > + */
> > +static CXLRetCode detect_malformed_extent_list(CXLType3Dev *dev,
> > +        const updated_dc_extent_list_in_pl *in)
> > +{
> > +    unsigned long *blk_bitmap;
> > +    uint64_t min_block_size = dev->dc.regions[0].block_size;
> > +    struct CXLDCD_Region *region = &dev->dc.regions[0];
> > +    uint32_t i;
> > +    uint64_t dpa, len;
> > +    uint8_t rid;
> > +    CXLRetCode ret;
> > +
> > +    for (i = 1; i < dev->dc.num_regions; i++) {
> > +        region = &dev->dc.regions[i];
> > +        if (min_block_size > region->block_size) {
> > +            min_block_size = region->block_size;
> > +        }
> > +    }
> > +
> > +    blk_bitmap = bitmap_new((region->len + region->base
> > +                - dev->dc.regions[0].base) / min_block_size);
> > +
> > +    for (i = 0; i < in->num_entries_updated; i++) {
> > +        dpa = in->updated_entries[i].start_dpa;
> > +        len = in->updated_entries[i].len;
> > +
> > +        rid = find_region_id(dev, dpa, len);
> > +        if (rid == dev->dc.num_regions) {
> > +            ret = CXL_MBOX_INVALID_PA;
> > +            goto out;
> > +        }
> > +
> > +        region = &dev->dc.regions[rid];
> > +        if (dpa % region->block_size || len % region->block_size) {
> > +            ret = CXL_MBOX_INVALID_EXTENT_LIST;
> > +            goto out;
> > +        }
>
> Hi,
>
> The bitmap uses the dc region 0 base address as the baseline, so when
> checking the dpa against the bitmap it needs to be adjusted for that
> before the bitmap checks, e.g.,
>
> +        dpa -= dev->dc.regions[0].base;
>
> Thanks,
> Jorgen

Make sense. Will fix. Thanks.

Fan
>
> > +        /* the dpa range already covered by some other extents in the list */
> > +        if (test_bits(blk_bitmap, dpa / min_block_size, len / min_block_size)) {
> > +            ret = CXL_MBOX_INVALID_EXTENT_LIST;
> > +            goto out;
> > +        }
> > +        bitmap_set(blk_bitmap, dpa / min_block_size, len / min_block_size);
> > +   }
> > +
> > +    ret = CXL_MBOX_SUCCESS;
> > +
> > +out:
> > +    g_free(blk_bitmap);
> > +    return ret;
> > +}
> > +
> > +/*
> > + * cxl spec 3.0: 8.2.9.8.9.3
> > + * Add Dynamic Capacity Response (opcode 4802h)
> > + * Assume an extent is added only after the response is processed successfully
> > + * TODO: for better extent list validation, a better solution would be
> > + * maintaining a pending extent list and use it to verify the extent list in
> > + * the response.
> > + */
> > +static CXLRetCode cmd_dcd_add_dyn_cap_rsp(struct cxl_cmd *cmd,
> > +        CXLDeviceState *cxl_dstate, uint16_t *len_unused)
> > +{
> > +    updated_dc_extent_list_in_pl *in = (void *)cmd->payload;
> > +    struct CXLType3Dev *ct3d = container_of(cxl_dstate, CXLType3Dev,
> > +            cxl_dstate);
> > +    CXLDCDExtentList *extent_list = &ct3d->dc.extents;
> > +    CXLDCD_Extent *ent;
> > +    uint32_t i;
> > +    uint64_t dpa, len;
> > +    CXLRetCode ret;
> > +
> > +    if (in->num_entries_updated == 0) {
> > +        ret = CXL_MBOX_SUCCESS;
> > +        goto out;
> > +    }
> > +
> > +    ret = detect_malformed_extent_list(ct3d, in);
> > +    if (ret != CXL_MBOX_SUCCESS) {
> > +        goto out;
> > +    }
> > +
> > +    for (i = 0; i < in->num_entries_updated; i++) {
> > +        dpa = in->updated_entries[i].start_dpa;
> > +        len = in->updated_entries[i].len;
> > +
> > +        /*
> > +         * Check if the DPA range of the to-be-added extent overlaps with
> > +         * existing extent list maintained by the device.
> > +         */
> > +        QTAILQ_FOREACH(ent, extent_list, node) {
> > +            if (ent->start_dpa == dpa && ent->len == len) {
> > +                ret = CXL_MBOX_INVALID_PA;
> > +                goto out;
> > +            } else if (ent->start_dpa <= dpa
> > +                    && dpa + len <= ent->start_dpa + ent->len) {
> > +                ret = CXL_MBOX_INVALID_PA;
> > +                goto out;
> > +            } else if ((dpa < ent->start_dpa + ent->len
> > +                        && dpa + len > ent->start_dpa + ent->len)
> > +                    || (dpa < ent->start_dpa && dpa + len > ent->start_dpa)) {
> > +                ret = CXL_MBOX_INVALID_PA;
> > +                goto out;
> > +            }
> > +        }
> > +
> > +        /*
> > +         * TODO: add a pending extent list based on event log record and verify
> > +         * the input response
> > +         */
> > +
> > +        insert_extent_to_extent_list(extent_list, dpa, len, NULL, 0);
> > +    }
> > +    ret = CXL_MBOX_SUCCESS;
> > +
> > +out:
> > +    return ret;
> > +}
> > +
> > +/*
> > + * Spec 3.0: 8.2.9.8.9.4
> > + * Release Dynamic Capacity (opcode 4803h)
> > + **/
> > +static CXLRetCode cmd_dcd_release_dyn_cap(struct cxl_cmd *cmd,
> > +        CXLDeviceState *cxl_dstate,
> > +        uint16_t *len_unused)
> > +{
> > +    updated_dc_extent_list_in_pl *in = (void *)cmd->payload;
> > +    struct CXLType3Dev *ct3d = container_of(cxl_dstate, CXLType3Dev,
> > +            cxl_dstate);
> > +    CXLDCDExtentList *extent_list = &ct3d->dc.extents;
> > +    CXLDCD_Extent *ent;
> > +    uint32_t i;
> > +    uint64_t dpa, len;
> > +    CXLRetCode ret;
> > +
> > +    if (in->num_entries_updated == 0) {
> > +        return CXL_MBOX_INVALID_INPUT;
> > +    }
> > +
> > +    ret = detect_malformed_extent_list(ct3d, in);
> > +    if (ret != CXL_MBOX_SUCCESS) {
> > +        return ret;
> > +    }
> > +
> > +    for (i = 0; i < in->num_entries_updated; i++) {
> > +        dpa = in->updated_entries[i].start_dpa;
> > +        len = in->updated_entries[i].len;
> > +
> > +        QTAILQ_FOREACH(ent, extent_list, node) {
> > +            if (ent->start_dpa == dpa && ent->len == len) {
> > +                break;
> > +            } else if (ent->start_dpa < dpa
> > +                    && dpa + len <= ent->start_dpa + ent->len) {
> > +                /* remove partial extent */
> > +                uint64_t len1 = dpa - ent->start_dpa;
> > +                uint64_t len2 = ent->start_dpa + ent->len - dpa - len;
> > +
> > +                if (len1) {
> > +                    insert_extent_to_extent_list(extent_list, ent->start_dpa,
> > +                            len1, NULL, 0);
> > +                }
> > +                if (len2) {
> > +                    insert_extent_to_extent_list(extent_list, dpa + len, len2,
> > +                            NULL, 0);
> > +                }
> > +                break;
> > +            } else if ((dpa < ent->start_dpa + ent->len
> > +                        && dpa + len > ent->start_dpa + ent->len)
> > +                    || (dpa < ent->start_dpa && dpa + len > ent->start_dpa))
> > +                return CXL_MBOX_INVALID_EXTENT_LIST;
> > +        }
> > +
> > +        if (ent) {
> > +            QTAILQ_REMOVE(extent_list, ent, node);
> > +            g_free(ent);
> > +        } else {
> > +            /* Try to remove a non-existing extent */
> > +            return CXL_MBOX_INVALID_PA;
> > +        }
> > +    }
> > +
> > +    return CXL_MBOX_SUCCESS;
> > +}
> > +
> >   #define IMMEDIATE_CONFIG_CHANGE (1 << 1)
> >   #define IMMEDIATE_DATA_CHANGE (1 << 2)
> >   #define IMMEDIATE_POLICY_CHANGE (1 << 3)
> > @@ -1129,6 +1376,12 @@ static struct cxl_cmd cxl_cmd_set[256][256] = {
> >       [DCD_CONFIG][GET_DYN_CAP_EXT_LIST] = {
> >           "DCD_GET_DYNAMIC_CAPACITY_EXTENT_LIST", cmd_dcd_get_dyn_cap_ext_list,
> >           8, 0 },
> > +    [DCD_CONFIG][ADD_DYN_CAP_RSP] = {
> > +        "ADD_DCD_DYNAMIC_CAPACITY_RESPONSE", cmd_dcd_add_dyn_cap_rsp,
> > +        ~0, IMMEDIATE_DATA_CHANGE },
> > +    [DCD_CONFIG][RELEASE_DYN_CAP] = {
> > +        "RELEASE_DCD_DYNAMIC_CAPACITY", cmd_dcd_release_dyn_cap,
> > +        ~0, IMMEDIATE_DATA_CHANGE },
> >   };
> >
> >   static struct cxl_cmd cxl_cmd_set_sw[256][256] = {
> > diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
> > index 3a338b3b37..01a5eaca48 100644
> > --- a/include/hw/cxl/cxl_device.h
> > +++ b/include/hw/cxl/cxl_device.h
> > @@ -130,7 +130,8 @@ typedef enum {
> >       CXL_MBOX_INCORRECT_PASSPHRASE = 0x14,
> >       CXL_MBOX_UNSUPPORTED_MAILBOX = 0x15,
> >       CXL_MBOX_INVALID_PAYLOAD_LENGTH = 0x16,
> > -    CXL_MBOX_MAX = 0x17
> > +    CXL_MBOX_INVALID_EXTENT_LIST = 0x1E, /* cxl r3.0: Table 8-34*/
> > +    CXL_MBOX_MAX = 0x1F
> >   } CXLRetCode;
> >
> >   struct cxl_cmd;
> > --
> > 2.25.1