[PATCH] drm/amdgpu: resize VRAM BAR for CPU access v5

Ding, Pixel Pixel.Ding at amd.com
Mon Nov 6 07:21:05 UTC 2017


Hi Christian,

The latest driver fails to load on SRIOV VF with xen hypervisor driver.

+int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
+{
+     u64 space_needed = roundup_pow_of_two(adev->mc.real_vram_size);
+     u32 rbar_size = order_base_2(((space_needed >> 20) | 1)) - 1;
+     u16 cmd;
+     int r;
+
+     /* Disable memory decoding while we change the BAR addresses and size */
+     pci_read_config_word(adev->pdev, PCI_COMMAND, &cmd);
+     pci_write_config_word(adev->pdev, PCI_COMMAND,

The function above introduces 900ms latency during init in exclusive accessing.


+     cmd & ~PCI_COMMAND_MEMORY);
+


Can we bypass disablement of response in memory space here? Any concern or suggestion?


— 
Sincerely Yours,
Pixel







On 02/11/2017, 9:13 PM, "amd-gfx on behalf of Alex Deucher" <amd-gfx-bounces at lists.freedesktop.org on behalf of alexdeucher at gmail.com> wrote:

>On Thu, Nov 2, 2017 at 9:02 AM, Christian König <deathsimple at vodafone.de> wrote:
>> From: Christian König <christian.koenig at amd.com>
>>
>> Try to resize BAR0 to let CPU access all of VRAM.
>>
>> v2: rebased, style cleanups, disable mem decode before resize,
>>     handle gmc_v9 as well, round size up to power of two.
>> v3: handle gmc_v6 as well, release and reassign all BARs in the driver.
>> v4: rename new function to amdgpu_device_resize_fb_bar,
>>     reenable mem decoding only if all resources are assigned.
>> v5: reorder resource release, return -ENODEV instead of BUG_ON().
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>
>Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  1 +
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 48 ++++++++++++++++++++++++++++++
>>  drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c      | 12 ++++++--
>>  drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c      | 13 ++++++--
>>  drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c      | 13 ++++++--
>>  drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c      | 14 ++++++---
>>  6 files changed, 88 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> index 2730a75..4f919d3 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -1854,6 +1854,7 @@ void amdgpu_ttm_placement_from_domain(struct amdgpu_bo *abo, u32 domain);
>>  bool amdgpu_ttm_bo_is_amdgpu_bo(struct ttm_buffer_object *bo);
>>  void amdgpu_vram_location(struct amdgpu_device *adev, struct amdgpu_mc *mc, u64 base);
>>  void amdgpu_gart_location(struct amdgpu_device *adev, struct amdgpu_mc *mc);
>> +int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev);
>>  void amdgpu_ttm_set_active_vram_size(struct amdgpu_device *adev, u64 size);
>>  int amdgpu_ttm_init(struct amdgpu_device *adev);
>>  void amdgpu_ttm_fini(struct amdgpu_device *adev);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index 8b33adf..cb3a0ac 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -410,6 +410,9 @@ static int amdgpu_doorbell_init(struct amdgpu_device *adev)
>>                 return 0;
>>         }
>>
>> +       if (pci_resource_flags(adev->pdev, 2) & IORESOURCE_UNSET)
>> +               return -EINVAL;
>> +
>>         /* doorbell bar mapping */
>>         adev->doorbell.base = pci_resource_start(adev->pdev, 2);
>>         adev->doorbell.size = pci_resource_len(adev->pdev, 2);
>> @@ -749,6 +752,51 @@ int amdgpu_fw_reserve_vram_init(struct amdgpu_device *adev)
>>         return r;
>>  }
>>
>> +/**
>> + * amdgpu_device_resize_fb_bar - try to resize FB BAR
>> + *
>> + * @adev: amdgpu_device pointer
>> + *
>> + * Try to resize FB BAR to make all VRAM CPU accessible. We try very hard not
>> + * to fail, but if any of the BARs is not accessible after the size we abort
>> + * driver loading by returning -ENODEV.
>> + */
>> +int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
>> +{
>> +       u64 space_needed = roundup_pow_of_two(adev->mc.real_vram_size);
>> +       u32 rbar_size = order_base_2(((space_needed >> 20) | 1)) - 1;
>> +       u16 cmd;
>> +       int r;
>> +
>> +       /* Disable memory decoding while we change the BAR addresses and size */
>> +       pci_read_config_word(adev->pdev, PCI_COMMAND, &cmd);
>> +       pci_write_config_word(adev->pdev, PCI_COMMAND,
>> +                             cmd & ~PCI_COMMAND_MEMORY);
>> +
>> +       /* Free the VRAM and doorbell BAR, we most likely need to move both. */
>> +       amdgpu_doorbell_fini(adev);
>> +       if (adev->asic_type >= CHIP_BONAIRE)
>> +               pci_release_resource(adev->pdev, 2);
>> +
>> +       pci_release_resource(adev->pdev, 0);
>> +
>> +       r = pci_resize_resource(adev->pdev, 0, rbar_size);
>> +       if (r == -ENOSPC)
>> +               DRM_INFO("Not enough PCI address space for a large BAR.");
>> +       else if (r && r != -ENOTSUPP)
>> +               DRM_ERROR("Problem resizing BAR0 (%d).", r);
>> +
>> +       pci_assign_unassigned_bus_resources(adev->pdev->bus);
>> +
>> +       /* When the doorbell or fb BAR isn't available we have no chance of
>> +        * using the device.
>> +        */
>> +       r = amdgpu_doorbell_init(adev);
>> +       if (r || (pci_resource_flags(adev->pdev, 0) & IORESOURCE_UNSET))
>> +               return -ENODEV;
>> +
>> +       pci_write_config_word(adev->pdev, PCI_COMMAND, cmd);
>> +}
>>
>>  /*
>>   * GPU helpers function.
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
>> index f4603a7..d2a43db 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
>> @@ -283,6 +283,7 @@ static int gmc_v6_0_mc_init(struct amdgpu_device *adev)
>>
>>         u32 tmp;
>>         int chansize, numchan;
>> +       int r;
>>
>>         tmp = RREG32(mmMC_ARB_RAMCFG);
>>         if (tmp & (1 << 11)) {
>> @@ -324,12 +325,17 @@ static int gmc_v6_0_mc_init(struct amdgpu_device *adev)
>>                 break;
>>         }
>>         adev->mc.vram_width = numchan * chansize;
>> -       /* Could aper size report 0 ? */
>> -       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> -       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>>         /* size in MB on si */
>>         adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>>         adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>> +
>> +       if (!(adev->flags & AMD_IS_APU)) {
>> +               r = amdgpu_device_resize_fb_bar(adev);
>> +               if (r)
>> +                       return r;
>> +       }
>> +       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> +       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>>         adev->mc.visible_vram_size = adev->mc.aper_size;
>>
>>         /* set the gart size */
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>> index b0528ca..583d877 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>> @@ -322,6 +322,8 @@ static void gmc_v7_0_mc_program(struct amdgpu_device *adev)
>>   */
>>  static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
>>  {
>> +       int r;
>> +
>>         adev->mc.vram_width = amdgpu_atombios_get_vram_width(adev);
>>         if (!adev->mc.vram_width) {
>>                 u32 tmp;
>> @@ -367,13 +369,18 @@ static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
>>                 }
>>                 adev->mc.vram_width = numchan * chansize;
>>         }
>> -       /* Could aper size report 0 ? */
>> -       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> -       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>>         /* size in MB on si */
>>         adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>>         adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>>
>> +       if (!(adev->flags & AMD_IS_APU)) {
>> +               r = amdgpu_device_resize_fb_bar(adev);
>> +               if (r)
>> +                       return r;
>> +       }
>> +       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> +       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>> +
>>  #ifdef CONFIG_X86_64
>>         if (adev->flags & AMD_IS_APU) {
>>                 adev->mc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>> index f368cfe..9ca5fea 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>> @@ -498,6 +498,8 @@ static void gmc_v8_0_mc_program(struct amdgpu_device *adev)
>>   */
>>  static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
>>  {
>> +       int r;
>> +
>>         adev->mc.vram_width = amdgpu_atombios_get_vram_width(adev);
>>         if (!adev->mc.vram_width) {
>>                 u32 tmp;
>> @@ -543,13 +545,18 @@ static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
>>                 }
>>                 adev->mc.vram_width = numchan * chansize;
>>         }
>> -       /* Could aper size report 0 ? */
>> -       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> -       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>>         /* size in MB on si */
>>         adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>>         adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
>>
>> +       if (!(adev->flags & AMD_IS_APU)) {
>> +               r = amdgpu_device_resize_fb_bar(adev);
>> +               if (r)
>> +                       return r;
>> +       }
>> +       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> +       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>> +
>>  #ifdef CONFIG_X86_64
>>         if (adev->flags & AMD_IS_APU) {
>>                 adev->mc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> index 6216993..0de4dc0 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> @@ -440,6 +440,7 @@ static int gmc_v9_0_mc_init(struct amdgpu_device *adev)
>>  {
>>         u32 tmp;
>>         int chansize, numchan;
>> +       int r;
>>
>>         adev->mc.vram_width = amdgpu_atomfirmware_get_vram_width(adev);
>>         if (!adev->mc.vram_width) {
>> @@ -482,17 +483,22 @@ static int gmc_v9_0_mc_init(struct amdgpu_device *adev)
>>                 adev->mc.vram_width = numchan * chansize;
>>         }
>>
>> -       /* Could aper size report 0 ? */
>> -       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> -       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>>         /* size in MB on si */
>>         adev->mc.mc_vram_size =
>>                 ((adev->flags & AMD_IS_APU) ? nbio_v7_0_get_memsize(adev) :
>>                  nbio_v6_1_get_memsize(adev)) * 1024ULL * 1024ULL;
>>         adev->mc.real_vram_size = adev->mc.mc_vram_size;
>> -       adev->mc.visible_vram_size = adev->mc.aper_size;
>> +
>> +       if (!(adev->flags & AMD_IS_APU)) {
>> +               r = amdgpu_device_resize_fb_bar(adev);
>> +               if (r)
>> +                       return r;
>> +       }
>> +       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
>> +       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
>>
>>         /* In case the PCI BAR is larger than the actual amount of vram */
>> +       adev->mc.visible_vram_size = adev->mc.aper_size;
>>         if (adev->mc.visible_vram_size > adev->mc.real_vram_size)
>>                 adev->mc.visible_vram_size = adev->mc.real_vram_size;
>>
>> --
>> 2.7.4
>>
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