Am 05.11.21 um 20:25 schrieb Alex Sierra:
The low 16MB of virtual address space are currently reserved for kernel mode allocations mapped into user virtual address space. This causes conflicts with HMM/SVM mappings at low virtual addresses. We tried to move those kernel mode allocations to the upper half of the 64-bit virtual address space for GFX9, which is naturally reserved for kernel use. However, TBA (trap handler code) has problems to access addresses in the high virtual space. We have decided to set this to 8KB of the lower address space as a temporary fix, while investigate TBA address problem. It is very unlikely for user space to map memory at this low region.
Unfortunately that is not correct. IIRC every program run inside wine maps something at the 16-64KiB addresses.
Don't ask me what that stuff is good for, but we already ran into problems because of exactly that.
Regards, Christian.
Signed-off-by: Alex Sierra <alex.sierra@xxxxxxx> --- drivers/gpu/drm/amd/amdkfd/kfd_flat_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_flat_memory.c b/drivers/gpu/drm/amd/amdkfd/kfd_flat_memory.c index 2e86692def19..d1388896f9c1 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_flat_memory.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_flat_memory.c @@ -308,7 +308,7 @@ * 16MB are reserved for kernel use (CWSR trap handler and kernel IB * for now). */ -#define SVM_USER_BASE 0x1000000ull +#define SVM_USER_BASE (u64)(KFD_CWSR_TBA_TMA_SIZE + 2*PAGE_SIZE) #define SVM_CWSR_BASE (SVM_USER_BASE - KFD_CWSR_TBA_TMA_SIZE) #define SVM_IB_BASE (SVM_CWSR_BASE - PAGE_SIZE)
