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

["Yu, Xiangliang" <Xiangliang.Yu-5C7GfCeVMHo@public.gmane.org>]

> -----Original Message-----
> From: Christian König [mailto:deathsimple@vodafone.de]
> Sent: Tuesday, January 10, 2017 9:09 PM
> To: Yu, Xiangliang <Xiangliang.Yu@amd.com>; amd-
> gfx@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@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.

> 
> > +	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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