Re: [Qemu-devel] [PATCH v3 2/3] xen/pt: Pass the whole msi addr/data to Xen

[Anthony PERARD <anthony.perard@citrix.com>]

On Fri, Nov 17, 2017 at 02:24:24PM +0800, Chao Gao wrote:
> Previously, some fields (reserved or unalterable) are filtered by
> Qemu. This fields are useless for the legacy interrupt format.
> However, these fields are may meaningful (for intel platform)
> for the interrupt of remapping format. It is better to pass the whole
> msi addr/data to Xen without any filtering.
> 
> The main reason why we want this is QEMU doesn't have the knowledge
> to decide the interrupt format after we introduce vIOMMU inside Xen.
> Passing the whole msi message down and let arch-specific vIOMMU to
> decide the interrupt format.
> 
> Signed-off-by: Chao Gao <chao.gao@intel.com>
> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
> ---
> v3:
>  - new
> ---
>  hw/xen/xen_pt_msi.c | 47 ++++++++++++-----------------------------------
>  1 file changed, 12 insertions(+), 35 deletions(-)
> 
> diff --git a/hw/xen/xen_pt_msi.c b/hw/xen/xen_pt_msi.c
> index 6d1e3bd..f7d6e76 100644
> --- a/hw/xen/xen_pt_msi.c
> +++ b/hw/xen/xen_pt_msi.c
> @@ -47,25 +47,6 @@ static inline uint32_t msi_ext_dest_id(uint32_t addr_hi)
>      return addr_hi & 0xffffff00;
>  }
>  
> -static uint32_t msi_gflags(uint32_t data, uint64_t addr)
> -{
> -    uint32_t result = 0;
> -    int rh, dm, dest_id, deliv_mode, trig_mode;
> -
> -    rh = (addr >> MSI_ADDR_REDIRECTION_SHIFT) & 0x1;
> -    dm = (addr >> MSI_ADDR_DEST_MODE_SHIFT) & 0x1;
> -    dest_id = msi_dest_id(addr);
> -    deliv_mode = (data >> MSI_DATA_DELIVERY_MODE_SHIFT) & 0x7;
> -    trig_mode = (data >> MSI_DATA_TRIGGER_SHIFT) & 0x1;
> -
> -    result = dest_id | (rh << XEN_PT_GFLAGS_SHIFT_RH)
> -        | (dm << XEN_PT_GFLAGS_SHIFT_DM)
> -        | (deliv_mode << XEN_PT_GFLAGSSHIFT_DELIV_MODE)
> -        | (trig_mode << XEN_PT_GFLAGSSHIFT_TRG_MODE);
> -
> -    return result;
> -}
> -
>  static inline uint64_t msi_addr64(XenPTMSI *msi)
>  {
>      return (uint64_t)msi->addr_hi << 32 | msi->addr_lo;
> @@ -160,23 +141,20 @@ static int msi_msix_update(XenPCIPassthroughState *s,
>                             bool masked)
>  {
>      PCIDevice *d = &s->dev;
> -    uint8_t gvec = msi_vector(data);
> -    uint32_t gflags = msi_gflags(data, addr);
> +    uint32_t gflags = masked ? 0 : (1u << XEN_PT_GFLAGSSHIFT_UNMASKED);
>      int rc = 0;
>      uint64_t table_addr = 0;
>  
> -    XEN_PT_LOG(d, "Updating MSI%s with pirq %d gvec %#x gflags %#x"
> -               " (entry: %#x)\n",
> -               is_msix ? "-X" : "", pirq, gvec, gflags, msix_entry);
> +    XEN_PT_LOG(d, "Updating MSI%s with pirq %d gvec %#x addr %"PRIx64
> +               " data %#x gflags %#x (entry: %#x)\n",
> +               is_msix ? "-X" : "", pirq, addr, data, gflags, msix_entry);
>  
>      if (is_msix) {
>          table_addr = s->msix->mmio_base_addr;
>      }
>  
> -    gflags |= masked ? 0 : (1u << XEN_PT_GFLAGSSHIFT_UNMASKED);
> -
> -    rc = xc_domain_update_msi_irq(xen_xc, xen_domid, gvec,
> -                                  pirq, gflags, table_addr);
> +    rc = xc_domain_update_msi_irq(xen_xc, xen_domid, pirq, addr,
> +                                  data, gflags, table_addr);

Are you trying to modifie an existing API? That is not going to work. We
want to be able to build QEMU against older version of Xen, and it
should work as well.

>  
>      if (rc) {
>          XEN_PT_ERR(d, "Updating of MSI%s failed. (err: %d)\n",
> @@ -199,8 +177,6 @@ static int msi_msix_disable(XenPCIPassthroughState *s,
>                              bool is_binded)
>  {
>      PCIDevice *d = &s->dev;
> -    uint8_t gvec = msi_vector(data);
> -    uint32_t gflags = msi_gflags(data, addr);
>      int rc = 0;
>  
>      if (pirq == XEN_PT_UNASSIGNED_PIRQ) {
> @@ -208,12 +184,13 @@ static int msi_msix_disable(XenPCIPassthroughState *s,
>      }
>  
>      if (is_binded) {
> -        XEN_PT_LOG(d, "Unbind MSI%s with pirq %d, gvec %#x\n",
> -                   is_msix ? "-X" : "", pirq, gvec);
> -        rc = xc_domain_unbind_msi_irq(xen_xc, xen_domid, gvec, pirq, gflags);
> +        XEN_PT_LOG(d, "Unbind MSI%s with pirq %d, addr %"PRIx64", data %#x\n",
> +                   is_msix ? "-X" : "", pirq, addr, data);
> +        rc = xc_domain_unbind_msi_irq(xen_xc, xen_domid, pirq, addr, data);

Same here, this build against older version of Xen, but I don't think an
older libxc (like from Xen 4.10) is going to correctly with this new
arguments.

>          if (rc) {
> -            XEN_PT_ERR(d, "Unbinding of MSI%s failed. (err: %d, pirq: %d, gvec: %#x)\n",
> -                       is_msix ? "-X" : "", errno, pirq, gvec);
> +            XEN_PT_ERR(d, "Unbinding of MSI%s failed. (err: %d, pirq: %d, "
> +                       "addr: %"PRIx64", data: %#x)\n",
> +                       is_msix ? "-X" : "", errno, pirq, addr, data);
>              return rc;
>          }
>      }

Thanks,

-- 
Anthony PERARD