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[MOS] Fix SIGBUS crash on xe small BAR systems during vaInitialize #1990

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[MOS] Fix SIGBUS crash on xe small BAR systems during vaInitialize #1990

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48 changes: 48 additions & 0 deletions media_softlet/linux/common/os/xe/mos_bufmgr_xe.c
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Original file line number Diff line number Diff line change
Expand Up @@ -233,6 +233,7 @@ typedef struct mos_xe_bufmgr_gem {

//Note: DON't put these fields in xe_device
bool has_vram;
bool has_small_bar;
uint8_t va_bits;
/** bitmask of all memory regions */
uint64_t mem_regions_mask;
Expand Down Expand Up @@ -722,6 +723,39 @@ bool __mos_has_vram_xe(struct mos_bufmgr *bufmgr)
return has_vram;
}

static bool __mos_has_small_bar_xe(struct mos_bufmgr *bufmgr)
{
MOS_DRM_CHK_NULL_RETURN_VALUE(bufmgr, false)
struct mos_xe_bufmgr_gem *bufmgr_gem = (struct mos_xe_bufmgr_gem *)bufmgr;
struct mos_xe_device *dev = &bufmgr_gem->xe_device;
int fd = bufmgr_gem->fd;

if (!bufmgr_gem->has_vram)
{
bufmgr_gem->has_small_bar = false;
return false;
}

MOS_DRM_CHK_XE_DEV(dev, mem_regions, __mos_query_mem_regions_xe, false)

struct drm_xe_query_mem_regions *mem_regions = dev->mem_regions;
for (int i = 0; i < mem_regions->num_mem_regions; i++)
{
if (mem_regions->mem_regions[i].mem_class == DRM_XE_MEM_REGION_CLASS_VRAM &&
mem_regions->mem_regions[i].cpu_visible_size < mem_regions->mem_regions[i].total_size)
{
bufmgr_gem->has_small_bar = true;
MOS_DRM_NORMALMESSAGE("Small BAR detected: VRAM total %llu, CPU visible %llu",
(unsigned long long)mem_regions->mem_regions[i].total_size,
(unsigned long long)mem_regions->mem_regions[i].cpu_visible_size);
return true;
}
}

bufmgr_gem->has_small_bar = false;
return false;
}

uint8_t __mos_query_va_bits_xe(struct mos_bufmgr *bufmgr)
{
uint8_t va_bits = 48;
Expand Down Expand Up @@ -1337,6 +1371,19 @@ mos_bo_alloc_xe(struct mos_bufmgr *bufmgr,
{
//Note: memory_region is related to gt_id for multi-tiles gpu, take gt_id into consideration in case of multi-tiles
create.placement = bufmgr_gem->mem_regions_mask & (~0x1);

if (bufmgr_gem->has_small_bar)
{
/**
* On small BAR systems, only a portion of VRAM is CPU accessible.
* Set NEEDS_VISIBLE_VRAM to ensure the allocation lands in the
* CPU visible part of VRAM. Also add system memory as a fallback
* placement so the kernel can spill if CPU visible VRAM is full.
* On full BAR systems this flag is a noop.
*/
create.flags |= DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM;
create.placement |= bufmgr_gem->mem_regions_mask & 0x1;
}
}
else
{
Expand Down Expand Up @@ -3677,6 +3724,7 @@ mos_bufmgr_gem_init_xe(int fd, int batch_size)
bufmgr_gem->vm_id = __mos_vm_create_xe(&bufmgr_gem->bufmgr);
__mos_query_mem_regions_instance_mask_xe(&bufmgr_gem->bufmgr);
__mos_has_vram_xe(&bufmgr_gem->bufmgr);
__mos_has_small_bar_xe(&bufmgr_gem->bufmgr);
__mos_get_default_alignment_xe(&bufmgr_gem->bufmgr);

DRMLISTADD(&bufmgr_gem->managers, &bufmgr_list);
Expand Down