[V2 04/11] drm/amdgpu/virt: use kiq to access registers

Yu, Xiangliang Xiangliang.Yu at amd.com
Tue Jan 10 14:14:54 UTC 2017


> -----Original Message-----
> From: Christian König [mailto:deathsimple at vodafone.de]
> Sent: Tuesday, January 10, 2017 10:08 PM
> To: Yu, Xiangliang <Xiangliang.Yu at amd.com>; amd-
> gfx at lists.freedesktop.org
> Subject: Re: [V2 04/11] drm/amdgpu/virt: use kiq to access registers
> 
> Am 10.01.2017 um 15:01 schrieb Yu, Xiangliang:
> >> -----Original Message-----
> >> From: Christian König [mailto:deathsimple at vodafone.de]
> >> Sent: Tuesday, January 10, 2017 9:09 PM
> >> To: Yu, Xiangliang <Xiangliang.Yu at amd.com>; amd-
> >> gfx at lists.freedesktop.org
> >> Subject: Re: [V2 04/11] drm/amdgpu/virt: use kiq to access registers
> >>
> >> Am 10.01.2017 um 11:00 schrieb Xiangliang Yu:
> >>> For virtualization, it is must for driver to use KIQ to access
> >>> registers when it is out of GPU full access mode.
> >>>
> >>> Signed-off-by: Xiangliang Yu <Xiangliang.Yu at amd.com>
> >>> ---
> >>>    drivers/gpu/drm/amd/amdgpu/Makefile        |  2 +-
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  6 +++
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c   | 86
> >> ++++++++++++++++++++++++++++++
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h   |  5 ++
> >>>    drivers/gpu/drm/amd/amdgpu/vi.c            |  3 ++
> >>>    5 files changed, 101 insertions(+), 1 deletion(-)
> >>>    create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> >>>
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile
> >>> b/drivers/gpu/drm/amd/amdgpu/Makefile
> >>> index 4185b03..0b8e470 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/Makefile
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/Makefile
> >>> @@ -30,7 +30,7 @@ amdgpu-y += amdgpu_device.o amdgpu_kms.o \
> >>>    	atombios_encoders.o amdgpu_sa.o atombios_i2c.o \
> >>>    	amdgpu_prime.o amdgpu_vm.o amdgpu_ib.o amdgpu_pll.o \
> >>>    	amdgpu_ucode.o amdgpu_bo_list.o amdgpu_ctx.o amdgpu_sync.o \
> >>> -	amdgpu_gtt_mgr.o amdgpu_vram_mgr.o
> >>> +	amdgpu_gtt_mgr.o amdgpu_vram_mgr.o amdgpu_virt.o
> >>>
> >>>    # add asic specific block
> >>>    amdgpu-$(CONFIG_DRM_AMDGPU_CIK)+= cik.o cik_ih.o kv_smc.o
> >> kv_dpm.o \
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>> index f82919d..9a2fd3e 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >>> @@ -95,6 +95,9 @@ uint32_t amdgpu_mm_rreg(struct amdgpu_device
> >> *adev, uint32_t reg,
> >>>    {
> >>>    	uint32_t ret;
> >>>
> >>> +	if (amdgpu_sriov_runtime(adev) && !in_interrupt())
> >>> +		return amdgpu_virt_kiq_rreg(adev, reg);
> >>> +
> >>>    	if ((reg * 4) < adev->rmmio_size && !always_indirect)
> >>>    		ret = readl(((void __iomem *)adev->rmmio) + (reg * 4));
> >>>    	else {
> >>> @@ -114,6 +117,9 @@ void amdgpu_mm_wreg(struct amdgpu_device
> >> *adev, uint32_t reg, uint32_t v,
> >>>    {
> >>>    	trace_amdgpu_mm_wreg(adev->pdev->device, reg, v);
> >>>
> >>> +	if (amdgpu_sriov_runtime(adev))
> >>> +		return amdgpu_virt_kiq_wreg(adev, reg, v);
> >>> +
> >>>    	if ((reg * 4) < adev->rmmio_size && !always_indirect)
> >>>    		writel(v, ((void __iomem *)adev->rmmio) + (reg * 4));
> >>>    	else {
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> >>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> >>> new file mode 100644
> >>> index 0000000..6520a4e
> >>> --- /dev/null
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> >>> @@ -0,0 +1,86 @@
> >>> +/*
> >>> + * Copyright 2017 Advanced Micro Devices, Inc.
> >>> + *
> >>> + * Permission is hereby granted, free of charge, to any person
> >>> +obtaining a
> >>> + * copy of this software and associated documentation files (the
> >>> +"Software"),
> >>> + * to deal in the Software without restriction, including without
> >>> +limitation
> >>> + * the rights to use, copy, modify, merge, publish, distribute,
> >>> +sublicense,
> >>> + * and/or sell copies of the Software, and to permit persons to
> >>> +whom the
> >>> + * Software is furnished to do so, subject to the following conditions:
> >>> + *
> >>> + * The above copyright notice and this permission notice shall be
> >>> +included in
> >>> + * all copies or substantial portions of the Software.
> >>> + *
> >>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
> >> KIND,
> >>> +EXPRESS OR
> >>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> >>> +MERCHANTABILITY,
> >>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN
> >> NO EVENT
> >>> +SHALL
> >>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM,
> >>> +DAMAGES OR
> >>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
> >>> +OTHERWISE,
> >>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
> OR
> >> THE USE
> >>> +OR
> >>> + * OTHER DEALINGS IN THE SOFTWARE.
> >>> + */
> >>> +
> >>> +#include "amdgpu.h"
> >>> +#include "amdgpu_virt.h"
> >>> +
> >>> +void amdgpu_virt_init_setting(struct amdgpu_device *adev) {
> >>> +	mutex_init(&adev->virt.lock);
> >>> +}
> >>> +
> >>> +uint32_t amdgpu_virt_kiq_rreg(struct amdgpu_device *adev, uint32_t
> >>> +reg) {
> >>> +	signed long r;
> >>> +	uint32_t val;
> >>> +	struct fence *f;
> >>> +	struct amdgpu_kiq *kiq = &adev->gfx.kiq;
> >>> +	struct amdgpu_ring *ring = &kiq->ring;
> >>> +
> >>> +	BUG_ON(!ring->funcs->emit_rreg);
> >>> +
> >>> +	mutex_lock(&adev->virt.lock);
> >>> +	amdgpu_ring_alloc(ring, 32);
> >>> +	amdgpu_ring_emit_hdp_flush(ring);
> >>> +	amdgpu_ring_emit_rreg(ring, reg);
> >>> +	amdgpu_ring_emit_hdp_invalidate(ring);
> >>> +	amdgpu_fence_emit(ring, &f);
> >>> +	fence_get(f);
> >>> +	amdgpu_ring_commit(ring);
> >>> +	mutex_unlock(&adev->virt.lock);
> >>> +
> >>> +	r = fence_wait(f, false);
> >>> +	fence_put(f);
> >> Why do you grab and release an extra fence reference here?
> > KIQ ring has no scheduler, I think we need to take care fence.
> 
> No, that is nonsense. Fence reference counting is completely separate to the
> scheduler.
> 
> Please just drop the extra fence_get()/fence_put() dance here.
> 
> amdgpu_fence_emit() returns the fence with one reference held which you
> need to drop before "f" leaves scope here. No need for anything else.

Let me check with Monk.

> 
> >
> >>> +	if (r)
> >>> +		DRM_ERROR("wait for kiq fence error: %ld.\n", r);
> >>> +	fence_put(f);
> >>> +
> >>> +	val = adev->wb.wb[adev->virt.val_offs];
> >>> +
> >>> +	return val;
> >>> +}
> >>> +
> >>> +void amdgpu_virt_kiq_wreg(struct amdgpu_device *adev, uint32_t reg,
> >>> +uint32_t v) {
> >>> +	signed long r;
> >>> +	struct fence *f;
> >>> +	struct amdgpu_kiq *kiq = &adev->gfx.kiq;
> >>> +	struct amdgpu_ring *ring = &kiq->ring;
> >>> +
> >>> +	BUG_ON(!ring->funcs->emit_wreg);
> >>> +
> >>> +	mutex_lock(&adev->virt.lock);
> >>> +	amdgpu_ring_alloc(ring, 32);
> >>> +	amdgpu_ring_emit_hdp_flush(ring);
> >>> +	amdgpu_ring_emit_wreg(ring, reg, v);
> >>> +	amdgpu_ring_emit_hdp_invalidate(ring);
> >>> +	amdgpu_fence_emit(ring, &f);
> >>> +	fence_get(f);
> >>> +	amdgpu_ring_commit(ring);
> >>> +	mutex_unlock(&adev->virt.lock);
> >>> +
> >>> +	r = fence_wait(f, false);
> >>> +	fence_put(f);
> >>> +	if (r)
> >>> +		DRM_ERROR("wait for kiq fence error: %ld.\n", r);
> >>> +	fence_put(f);
> >>> +}
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> >>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> >>> index 79619b6..24f0590 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> >>> @@ -33,6 +33,7 @@
> >>>    struct amdgpu_virt {
> >>>    	uint32_t		caps;
> >>>    	uint32_t		val_offs;
> >>> +	struct mutex		lock;
> >>>    };
> >>>
> >>>    #define amdgpu_sriov_enabled(adev) \ @@ -59,4 +60,8 @@ static
> >>> inline bool is_virtual_machine(void)
> >>>    #endif
> >>>    }
> >>>
> >>> +void amdgpu_virt_init_setting(struct amdgpu_device *adev); uint32_t
> >>> +amdgpu_virt_kiq_rreg(struct amdgpu_device *adev, uint32_t reg);
> >>> +void amdgpu_virt_kiq_wreg(struct amdgpu_device *adev, uint32_t reg,
> >>> +uint32_t v);
> >>> +
> >>>    #endif
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/vi.c
> >>> b/drivers/gpu/drm/amd/amdgpu/vi.c index 7350a8f..dc0d4fa 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/vi.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/vi.c
> >>> @@ -892,6 +892,9 @@ static int vi_common_early_init(void *handle)
> >>>    		(amdgpu_ip_block_mask & (1 <<
> >> AMD_IP_BLOCK_TYPE_SMC)))
> >>>    		smc_enabled = true;
> >>>
> >>> +	if (amdgpu_sriov_vf(adev))
> >>> +		amdgpu_virt_init_setting(adev);
> >>> +
> >>>    	adev->rev_id = vi_get_rev_id(adev);
> >>>    	adev->external_rev_id = 0xFF;
> >>>    	switch (adev->asic_type) {
> 



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