-----Original Message-----
From: Kuehling, Felix <Felix.Kuehling@xxxxxxx>
Sent: Friday, July 28, 2023 4:00 PM
To: Francis, David <David.Francis@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx;
Yat Sin, David <David.YatSin@xxxxxxx>
Subject: Re: [PATCH v3] drm/amdgpu: Add EXT_COHERENT memory allocation
flags
On 2023-07-28 15:39, David Francis wrote:
These flags (for GEM and SVM allocations) allocate memory that allows
for system-scope atomic semantics.
On GFX943 these flags cause caches to be avoided on non-local memory.
On all other ASICs they are identical in functionality to the
equivalent COHERENT flags.
Corresponding Thunk patch is at
https://github.com/RadeonOpenCompute/ROCT-Thunk-Interface/pull/88
v3: changed name of flag
Signed-off-by: David Francis <David.Francis@xxxxxxx>
I made one comment on the user mode patch regarding the explicit handling
of invalid combinations of Uncached, Coherent, ExtCoherent flags. I'm not
sure what we agreed on any more. But I don't think we want to just leave it up
to chance. Other than that, this patch looks good to me.
Regards,
Felix
---
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 ++
drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 1 +
drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c | 1 +
drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c | 1 +
drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 5 ++++-
drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 10 +++++++++-
include/uapi/drm/amdgpu_drm.h | 10 +++++++++-
include/uapi/linux/kfd_ioctl.h | 3 +++
8 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index d34c3ef8f3ed..a1ce261f2d06 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1738,6 +1738,8 @@ int
amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
if (flags & KFD_IOC_ALLOC_MEM_FLAGS_COHERENT)
alloc_flags |= AMDGPU_GEM_CREATE_COHERENT;
+ if (flags & KFD_IOC_ALLOC_MEM_FLAGS_EXT_COHERENT)
+ alloc_flags |= AMDGPU_GEM_CREATE_EXT_COHERENT;
if (flags & KFD_IOC_ALLOC_MEM_FLAGS_UNCACHED)
alloc_flags |= AMDGPU_GEM_CREATE_UNCACHED;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
index 12210598e5b8..76b618735dc0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
@@ -331,6 +331,7 @@ amdgpu_dma_buf_create_obj(struct drm_device
*dev,
struct dma_buf *dma_buf)
flags |= other->flags &
(AMDGPU_GEM_CREATE_CPU_GTT_USWC |
AMDGPU_GEM_CREATE_COHERENT
|
+
AMDGPU_GEM_CREATE_EXT_COHERENT |
AMDGPU_GEM_CREATE_UNCACHED);
}
diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
index 6b430e10d38e..301ffe30824f 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
@@ -632,6 +632,7 @@ static void gmc_v10_0_get_vm_pte(struct
amdgpu_device *adev,
}
if (bo && bo->flags & (AMDGPU_GEM_CREATE_COHERENT |
+ AMDGPU_GEM_CREATE_EXT_COHERENT |
AMDGPU_GEM_CREATE_UNCACHED))
*flags = (*flags & ~AMDGPU_PTE_MTYPE_NV10_MASK) |
AMDGPU_PTE_MTYPE_NV10(MTYPE_UC); diff --git
a/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
b/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
index a6ee0220db56..846894e212e7 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
@@ -540,6 +540,7 @@ static void gmc_v11_0_get_vm_pte(struct
amdgpu_device *adev,
}
if (bo && bo->flags & (AMDGPU_GEM_CREATE_COHERENT |
+ AMDGPU_GEM_CREATE_EXT_COHERENT |
AMDGPU_GEM_CREATE_UNCACHED))
*flags = (*flags & ~AMDGPU_PTE_MTYPE_NV10_MASK) |
AMDGPU_PTE_MTYPE_NV10(MTYPE_UC); diff --git
a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index 880460cd3239..92a623e130d9 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -1183,7 +1183,8 @@ static void gmc_v9_0_get_coherence_flags(struct
amdgpu_device *adev,
{
struct amdgpu_device *bo_adev = amdgpu_ttm_adev(bo->tbo.bdev);
bool is_vram = bo->tbo.resource->mem_type == TTM_PL_VRAM;
- bool coherent = bo->flags & AMDGPU_GEM_CREATE_COHERENT;
+ bool coherent = bo->flags & (AMDGPU_GEM_CREATE_COHERENT |
AMDGPU_GEM_CREATE_EXT_COHERENT);
+ bool ext_coherent = bo->flags &
AMDGPU_GEM_CREATE_EXT_COHERENT;
bool uncached = bo->flags & AMDGPU_GEM_CREATE_UNCACHED;
struct amdgpu_vm *vm = mapping->bo_va->base.vm;
unsigned int mtype_local, mtype;
@@ -1251,6 +1252,8 @@ static void gmc_v9_0_get_coherence_flags(struct
amdgpu_device *adev,
snoop = true;
if (uncached) {
mtype = MTYPE_UC;
+ } else if (ext_coherent) {
+ mtype = is_local ? MTYPE_CC : MTYPE_UC;
} else if (adev->flags & AMD_IS_APU) {
mtype = is_local ? mtype_local : MTYPE_NC;
} else {
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 1b50eae051a4..e9ffcfc5dedc 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1155,7 +1155,8 @@ svm_range_get_pte_flags(struct kfd_node
*node,
uint32_t mapping_flags = 0;
uint64_t pte_flags;
bool snoop = (domain != SVM_RANGE_VRAM_DOMAIN);
- bool coherent = flags & KFD_IOCTL_SVM_FLAG_COHERENT;
+ bool coherent = flags & (KFD_IOCTL_SVM_FLAG_COHERENT |
KFD_IOCTL_SVM_FLAG_EXT_COHERENT);
+ bool ext_coherent = flags & KFD_IOCTL_SVM_FLAG_EXT_COHERENT;
bool uncached = false; /*flags &
KFD_IOCTL_SVM_FLAG_UNCACHED;*/
unsigned int mtype_local;
@@ -1203,6 +1204,13 @@ svm_range_get_pte_flags(struct kfd_node
*node,
snoop = true;
if (uncached) {
mapping_flags |= AMDGPU_VM_MTYPE_UC;
+ } else if (ext_coherent) {
+ /* local HBM region close to partition */
+ if (bo_node->adev == node->adev &&
+ (!bo_node->xcp || !node->xcp || bo_node->xcp-
mem_id == node->xcp->mem_id))
+ mapping_flags |= AMDGPU_VM_MTYPE_CC;
+ else
+ mapping_flags |= AMDGPU_VM_MTYPE_UC;
} else if (domain == SVM_RANGE_VRAM_DOMAIN) {
/* local HBM region close to partition */
if (bo_node->adev == node->adev && diff --git
a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index
79b14828d542..629860dbc9ec 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -145,7 +145,7 @@ extern "C" {
*/
#define AMDGPU_GEM_CREATE_DISCARDABLE (1 << 12)
/* Flag that BO is shared coherently between multiple devices or CPU
threads.
- * May depend on GPU instructions to flush caches explicitly
+ * May depend on GPU instructions to flush caches to system scope
explicitly.
*
* This influences the choice of MTYPE in the PTEs on GFXv9 and later GPUs
and
* may override the MTYPE selected in AMDGPU_VA_OP_MAP.
@@ -158,6 +158,14 @@ extern "C" {
* may override the MTYPE selected in AMDGPU_VA_OP_MAP.
*/
#define AMDGPU_GEM_CREATE_UNCACHED (1 << 14)
+/* Flag that BO should be coherent across devices when using
+device-level
+ * atomics. May depend on GPU instructions to flush caches to device
+scope
+ * explicitly, promoting them to system scope automatically.
+ *
+ * This influences the choice of MTYPE in the PTEs on GFXv9 and later
+GPUs and
+ * may override the MTYPE selected in AMDGPU_VA_OP_MAP.
+ */
+#define AMDGPU_GEM_CREATE_EXT_COHERENT (1 << 15)
struct drm_amdgpu_gem_create_in {
/** the requested memory size */
diff --git a/include/uapi/linux/kfd_ioctl.h
b/include/uapi/linux/kfd_ioctl.h index eeb2fdcbdcb7..f0ed68974c54
100644
--- a/include/uapi/linux/kfd_ioctl.h
+++ b/include/uapi/linux/kfd_ioctl.h
@@ -405,6 +405,7 @@ struct kfd_ioctl_acquire_vm_args {
#define KFD_IOC_ALLOC_MEM_FLAGS_AQL_QUEUE_MEM (1 << 27)
#define KFD_IOC_ALLOC_MEM_FLAGS_COHERENT (1 << 26)
#define KFD_IOC_ALLOC_MEM_FLAGS_UNCACHED (1 << 25)
+#define KFD_IOC_ALLOC_MEM_FLAGS_EXT_COHERENT (1 << 24)
/* Allocate memory for later SVM (shared virtual memory) mapping.
*
@@ -659,6 +660,8 @@ enum kfd_mmio_remap {
#define KFD_IOCTL_SVM_FLAG_GPU_READ_MOSTLY 0x00000020
/* Keep GPU memory mapping always valid as if XNACK is disable */
#define KFD_IOCTL_SVM_FLAG_GPU_ALWAYS_MAPPED 0x00000040
+/* Fine grained coherency between all devices using device-scope atomics
*/
+#define KFD_IOCTL_SVM_FLAG_EXT_COHERENT 0x00000080
/**
* kfd_ioctl_svm_op - SVM ioctl operations
