Re: [Qemu-devel] [PATCH v2 22/23] q35: implement TSEG

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 03, 2015 at 07:08:47PM +0200, Paolo Bonzini wrote:
> From: Gerd Hoffmann <kraxel@redhat.com>
> 
> TSEG provides larger amounts of SMRAM than the 128 KB available with
> legacy SMRAM and high SMRAM.
> 
> Route access to tseg into nowhere when enabled, for both cpus and
> busmaster dma, and add tseg window to smram region, so cpus can access
> it in smm mode.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  hw/pci-host/q35.c         | 72 ++++++++++++++++++++++++++++++++++++++++++++++-
>  include/hw/pci-host/q35.h |  1 +
>  2 files changed, 72 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
> index 2f37c29..9fb1b20 100644
> --- a/hw/pci-host/q35.c
> +++ b/hw/pci-host/q35.c
> @@ -198,6 +198,28 @@ static const TypeInfo q35_host_info = {
>   * MCH D0:F0
>   */
>  
> +static uint64_t tseg_blackhole_read(void *ptr, hwaddr reg, unsigned size)
> +{
> +    return 0xffffffff;
> +}
> +
> +static void tseg_blackhole_write(void *opaque, hwaddr addr, uint64_t val,
> +                                 unsigned width)
> +{
> +    /* nothing */
> +}
> +
> +static const MemoryRegionOps tseg_blackhole_ops = {
> +    .read = tseg_blackhole_read,
> +    .write = tseg_blackhole_write,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +    .valid.min_access_size = 1,
> +    .valid.max_access_size = 4,
> +    .impl.min_access_size = 4,
> +    .impl.max_access_size = 4,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +};
> +
>  /* PCIe MMCFG */
>  static void mch_update_pciexbar(MCHPCIState *mch)
>  {
> @@ -267,6 +289,7 @@ static void mch_update_smram(MCHPCIState *mch)
>  {
>      PCIDevice *pd = PCI_DEVICE(mch);
>      bool h_smrame = (pd->config[MCH_HOST_BRIDGE_ESMRAMC] & MCH_HOST_BRIDGE_ESMRAMC_H_SMRAME);
> +    uint32_t tseg_size;
>  
>      /* implement SMRAM.D_LCK */
>      if (pd->config[MCH_HOST_BRIDGE_SMRAM] & MCH_HOST_BRIDGE_SMRAM_D_LCK) {
> @@ -296,6 +319,39 @@ static void mch_update_smram(MCHPCIState *mch)
>          memory_region_set_enabled(&mch->high_smram, false);
>      }
>  
> +    if (pd->config[MCH_HOST_BRIDGE_ESMRAMC] & MCH_HOST_BRIDGE_ESMRAMC_T_EN) {
> +        switch (pd->config[MCH_HOST_BRIDGE_ESMRAMC] &
> +                MCH_HOST_BRIDGE_ESMRAMC_TSEG_SZ_MASK) {
> +        case MCH_HOST_BRIDGE_ESMRAMC_TSEG_SZ_1MB:
> +            tseg_size = 1024 * 1024;
> +            break;
> +        case MCH_HOST_BRIDGE_ESMRAMC_TSEG_SZ_2MB:
> +            tseg_size = 1024 * 1024 * 2;
> +            break;
> +        case MCH_HOST_BRIDGE_ESMRAMC_TSEG_SZ_8MB:
> +            tseg_size = 1024 * 1024 * 8;
> +            break;
> +        default:
> +            tseg_size = 0;
> +            break;
> +        }
> +    } else {
> +        tseg_size = 0;
> +    }
> +    memory_region_del_subregion(mch->system_memory, &mch->tseg_blackhole);
> +    memory_region_set_enabled(&mch->tseg_blackhole, tseg_size);
> +    memory_region_set_size(&mch->tseg_blackhole, tseg_size);
> +    memory_region_add_subregion_overlap(mch->system_memory,
> +                                        mch->below_4g_mem_size - tseg_size,
> +                                        &mch->tseg_blackhole, 1);
> +
> +    memory_region_set_enabled(&mch->tseg_window, tseg_size);
> +    memory_region_set_size(&mch->tseg_window, tseg_size);
> +    memory_region_set_address(&mch->tseg_window,
> +                              mch->below_4g_mem_size - tseg_size);
> +    memory_region_set_alias_offset(&mch->tseg_window,
> +                                   mch->below_4g_mem_size - tseg_size);
> +
>      memory_region_transaction_commit();
>  }
>  
> @@ -443,9 +499,23 @@ static void mch_realize(PCIDevice *d, Error **errp)
>                               mch->ram_memory, 0xa0000, 0x20000);
>      memory_region_set_enabled(&mch->high_smram, true);
>      memory_region_add_subregion(&mch->smram, 0xfeda0000, &mch->high_smram);
> +
> +    memory_region_init_io(&mch->tseg_blackhole, OBJECT(mch),
> +                          &tseg_blackhole_ops, NULL,
> +                          "tseg-blackhole", 0);
> +    memory_region_set_enabled(&mch->tseg_blackhole, false);
> +    memory_region_add_subregion_overlap(mch->system_memory,
> +                                        mch->below_4g_mem_size,
> +                                        &mch->tseg_blackhole, 1);
> +
> +    memory_region_init_alias(&mch->tseg_window, OBJECT(mch), "tseg-window",
> +                             mch->ram_memory, mch->below_4g_mem_size, 0);
> +    memory_region_set_enabled(&mch->tseg_window, false);
> +    memory_region_add_subregion(&mch->smram, mch->below_4g_mem_size,
> +                                &mch->tseg_window);
> +
>      object_property_add_const_link(qdev_get_machine(), "smram",
>  				   OBJECT(&mch->smram), &error_abort);
> -
>      init_pam(DEVICE(mch), mch->ram_memory, mch->system_memory,
>               mch->pci_address_space, &mch->pam_regions[0],
>               PAM_BIOS_BASE, PAM_BIOS_SIZE);
> diff --git a/include/hw/pci-host/q35.h b/include/hw/pci-host/q35.h
> index 113cbe8..dbe6dc0 100644
> --- a/include/hw/pci-host/q35.h
> +++ b/include/hw/pci-host/q35.h
> @@ -54,6 +54,7 @@ typedef struct MCHPCIState {
>      PAMMemoryRegion pam_regions[13];
>      MemoryRegion smram_region, open_high_smram;
>      MemoryRegion smram, low_smram, high_smram;
> +    MemoryRegion tseg_blackhole, tseg_window;
>      PcPciInfo pci_info;
>      ram_addr_t below_4g_mem_size;
>      ram_addr_t above_4g_mem_size;
> -- 
> 2.4.1
>