Re: [PATCH v4 1/2] drm/i915/gvt: Save/restore HW status for GVT during suspend/resume

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On 2020.10.16 14:20:29 +0800, Colin Xu wrote:
> 
> On 2020-10-16 13:54, Zhenyu Wang wrote:
> > On 2020.10.16 13:59:59 +0800, Colin Xu wrote:
> > > This patch save/restore necessary GVT info during i915 suspend/resume so
> > > that GVT enabled QEMU VM can continue running.
> > > 
> > > Only GGTT and fence regs are saved/restored now. GVT will save GGTT
> > > entries into GVT in suspend routine, and restore the saved entries
> > > and re-init fence regs in resume routine.
> > > 
> > > V2:
> > > - Change kzalloc/kfree to vzalloc/vfree since the space allocated
> > > from kmalloc may not enough for all saved GGTT entries.
> > > - Keep gvt suspend/resume wrapper in intel_gvt.h/intel_gvt.c and
> > > move the actual implementation to gvt.h/gvt.c. (zhenyu)
> > > - Check gvt config on and active with intel_gvt_active(). (zhenyu)
> > > 
> > > V3: (zhenyu)
> > > - Incorrect copy length. Should be num entries * entry size.
> > > - Use memcpy_toio()/memcpy_fromio() instead of memcpy for iomem.
> > > - Add F_PM_SAVE flags to indicate which MMIOs to save/restore for PM.
> > > 
> > > V4:
> > > Rebase.
> > > 
> > > Signed-off-by: Hang Yuan <hang.yuan@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Colin Xu <colin.xu@xxxxxxxxx>
> > > ---
> > >   drivers/gpu/drm/i915/gvt/gtt.c      | 75 +++++++++++++++++++++++++++++
> > >   drivers/gpu/drm/i915/gvt/gtt.h      |  2 +
> > >   drivers/gpu/drm/i915/gvt/gvt.c      | 15 ++++++
> > >   drivers/gpu/drm/i915/gvt/gvt.h      |  8 +++
> > >   drivers/gpu/drm/i915/gvt/handlers.c | 39 +++++++++++++--
> > >   drivers/gpu/drm/i915/gvt/mmio.h     |  3 ++
> > >   drivers/gpu/drm/i915/gvt/vgpu.c     |  1 +
> > >   drivers/gpu/drm/i915/intel_gvt.c    | 29 +++++++++++
> > >   drivers/gpu/drm/i915/intel_gvt.h    | 10 ++++
> > >   9 files changed, 179 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> > > index a3a4305eda01..534bb2e08538 100644
> > > --- a/drivers/gpu/drm/i915/gvt/gtt.c
> > > +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> > > @@ -2533,6 +2533,11 @@ static void intel_vgpu_destroy_ggtt_mm(struct intel_vgpu *vgpu)
> > >   	}
> > >   	intel_vgpu_destroy_mm(vgpu->gtt.ggtt_mm);
> > >   	vgpu->gtt.ggtt_mm = NULL;
> > > +
> > > +	if (vgpu->ggtt_entries) {
> > > +		vfree(vgpu->ggtt_entries);
> > > +		vgpu->ggtt_entries = NULL;
> > > +	}
> > >   }
> > >   /**
> > > @@ -2852,3 +2857,73 @@ void intel_vgpu_reset_gtt(struct intel_vgpu *vgpu)
> > >   	intel_vgpu_destroy_all_ppgtt_mm(vgpu);
> > >   	intel_vgpu_reset_ggtt(vgpu, true);
> > >   }
> > > +
> > > +/**
> > > + * intel_gvt_save_ggtt - save all vGPU's ggtt entries
> > > + * @gvt: intel gvt device
> > > + *
> > > + * This function is called at driver suspend stage to save
> > > + * GGTT entries of every active vGPU.
> > > + *
> > > + */
> > > +void intel_gvt_save_ggtt(struct intel_gvt *gvt)
> > > +{
> > > +	struct intel_vgpu *vgpu;
> > > +	int id;
> > > +	u32 index, num_low, num_hi;
> > > +	void __iomem *addr;
> > > +
> > > +	for_each_active_vgpu(gvt, vgpu, id) {
> > > +		num_low = vgpu_aperture_sz(vgpu) >> PAGE_SHIFT;
> > > +		num_hi = vgpu_hidden_sz(vgpu) >> PAGE_SHIFT;
> > > +		vgpu->ggtt_entries = vzalloc((num_low + num_hi) * sizeof(u64));
> > > +		if (!vgpu->ggtt_entries)
> > > +			continue;
> > I think doing allocation in suspend is not good, that should prealloc
> > at vgpu create time and free at destroy.
>  Yes Hang and I discussed about the two approaches. This buffer is only
> useful during system suspend time for status backing store, but useless when
> system in S0. If we move it to vgpu creation time, large piece of memory
> could be wasted.

But looks error handling is problematic that just bypass possible failed vgpu,
which is not good...As gvt traps all vgpu ggtt access, could we just save/restore
trapped ones?

> > 
> > > +
> > > +		index = vgpu_aperture_gmadr_base(vgpu) >> PAGE_SHIFT;
> > > +		addr = (gen8_pte_t __iomem *)gvt->gt->i915->ggtt.gsm + index;
> > > +		memcpy_fromio(vgpu->ggtt_entries, addr, num_low * sizeof(u64));
> > > +
> > > +		index = vgpu_hidden_gmadr_base(vgpu) >> PAGE_SHIFT;
> > > +		addr = (gen8_pte_t __iomem *)gvt->gt->i915->ggtt.gsm + index;
> > > +		memcpy_fromio(vgpu->ggtt_entries + num_low,
> > > +			      addr, num_hi * sizeof(u64));
> > > +	}
> > > +}
> > > +
> > > +/**
> > > + * intel_gvt_restore_ggtt - restore all vGPU's ggtt entries
> > > + * @gvt: intel gvt device
> > > + *
> > > + * This function is called at driver resume stage to restore
> > > + * GGTT entries of every active vGPU.
> > > + *
> > > + */
> > > +void intel_gvt_restore_ggtt(struct intel_gvt *gvt)
> > > +{
> > > +	struct intel_vgpu *vgpu;
> > > +	int id;
> > > +	u32 index, num_low, num_hi;
> > > +	void __iomem *addr;
> > > +
> > > +	for_each_active_vgpu(gvt, vgpu, id) {
> > > +		if (!vgpu->ggtt_entries) {
> > > +			gvt_vgpu_err("fail to get saved ggtt\n");
> > > +			continue;
> > > +		}
> > > +
> > > +		num_low = vgpu_aperture_sz(vgpu) >> PAGE_SHIFT;
> > > +		num_hi = vgpu_hidden_sz(vgpu) >> PAGE_SHIFT;
> > > +
> > > +		index = vgpu_aperture_gmadr_base(vgpu) >> PAGE_SHIFT;
> > > +		addr = (gen8_pte_t __iomem *)gvt->gt->i915->ggtt.gsm + index;
> > > +		memcpy_toio(addr, vgpu->ggtt_entries, num_low * sizeof(u64));
> > > +		index = vgpu_hidden_gmadr_base(vgpu) >> PAGE_SHIFT;
> > > +		addr = (gen8_pte_t __iomem *)gvt->gt->i915->ggtt.gsm + index;
> > > +		memcpy_toio(addr, vgpu->ggtt_entries + num_low,
> > > +			    num_hi * sizeof(u64));
> > > +
> > > +		vfree(vgpu->ggtt_entries);
> > > +		vgpu->ggtt_entries = NULL;
> > > +	}
> > > +}
> > > diff --git a/drivers/gpu/drm/i915/gvt/gtt.h b/drivers/gpu/drm/i915/gvt/gtt.h
> > > index 52d0d88abd86..141e0a41cd50 100644
> > > --- a/drivers/gpu/drm/i915/gvt/gtt.h
> > > +++ b/drivers/gpu/drm/i915/gvt/gtt.h
> > > @@ -280,5 +280,7 @@ int intel_vgpu_emulate_ggtt_mmio_write(struct intel_vgpu *vgpu,
> > >   	unsigned int off, void *p_data, unsigned int bytes);
> > >   void intel_vgpu_destroy_all_ppgtt_mm(struct intel_vgpu *vgpu);
> > > +void intel_gvt_save_ggtt(struct intel_gvt *gvt);
> > > +void intel_gvt_restore_ggtt(struct intel_gvt *gvt);
> > >   #endif /* _GVT_GTT_H_ */
> > > diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
> > > index c7c561237883..3de740fa0911 100644
> > > --- a/drivers/gpu/drm/i915/gvt/gvt.c
> > > +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> > > @@ -405,6 +405,21 @@ int intel_gvt_init_device(struct drm_i915_private *i915)
> > >   	return ret;
> > >   }
> > > +int
> > > +intel_gvt_pm_suspend(struct intel_gvt *gvt)
> > > +{
> > > +	intel_gvt_save_ggtt(gvt);
> > > +	return 0;
> > > +}
> > > +
> > > +int
> > > +intel_gvt_pm_resume(struct intel_gvt *gvt)
> > > +{
> > > +	intel_gvt_restore_regs(gvt);
> > > +	intel_gvt_restore_ggtt(gvt);
> > > +	return 0;
> > > +}
> > > +
> > >   int
> > >   intel_gvt_register_hypervisor(struct intel_gvt_mpt *m)
> > >   {
> > > diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> > > index a81cf0f01e78..3459a0ea1d4d 100644
> > > --- a/drivers/gpu/drm/i915/gvt/gvt.h
> > > +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> > > @@ -199,9 +199,13 @@ struct intel_vgpu {
> > >   	struct intel_vgpu_submission submission;
> > >   	struct radix_tree_root page_track_tree;
> > >   	u32 hws_pga[I915_NUM_ENGINES];
> > > +
> > >   	/* Set on PCI_D3, reset on DMLR, not reflecting the actual PM state */
> > >   	bool d3_entered;
> > > +	/* Saved GGTT entries during host suspend state */
> > > +	u64 *ggtt_entries;
> > > +
> > >   	struct dentry *debugfs;
> > >   	/* Hypervisor-specific device state. */
> > > @@ -255,6 +259,8 @@ struct intel_gvt_mmio {
> > >   #define F_CMD_ACCESS	(1 << 3)
> > >   /* This reg has been accessed by a VM */
> > >   #define F_ACCESSED	(1 << 4)
> > > +/* This reg requires save & restore during host PM suspend/resume */
> > > +#define F_PM_SAVE	(1 << 5)
> > >   /* This reg could be accessed by unaligned address */
> > >   #define F_UNALIGN	(1 << 6)
> > >   /* This reg is in GVT's mmio save-restor list and in hardware
> > > @@ -685,6 +691,8 @@ void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu);
> > >   void intel_gvt_debugfs_init(struct intel_gvt *gvt);
> > >   void intel_gvt_debugfs_clean(struct intel_gvt *gvt);
> > > +int intel_gvt_pm_suspend(struct intel_gvt *gvt);
> > > +int intel_gvt_pm_resume(struct intel_gvt *gvt);
> > >   #include "trace.h"
> > >   #include "mpt.h"
> > > diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
> > > index 0031e7c43ea8..ea1d040916d9 100644
> > > --- a/drivers/gpu/drm/i915/gvt/handlers.c
> > > +++ b/drivers/gpu/drm/i915/gvt/handlers.c
> > > @@ -3092,9 +3092,10 @@ static int init_skl_mmio_info(struct intel_gvt *gvt)
> > >   	MMIO_DFH(TRVATTL3PTRDW(2), D_SKL_PLUS, F_CMD_ACCESS, NULL, NULL);
> > >   	MMIO_DFH(TRVATTL3PTRDW(3), D_SKL_PLUS, F_CMD_ACCESS, NULL, NULL);
> > >   	MMIO_DFH(TRVADR, D_SKL_PLUS, F_CMD_ACCESS, NULL, NULL);
> > > -	MMIO_DFH(TRTTE, D_SKL_PLUS, F_CMD_ACCESS,
> > > -		NULL, gen9_trtte_write);
> > > -	MMIO_DH(_MMIO(0x4dfc), D_SKL_PLUS, NULL, gen9_trtt_chicken_write);
> > > +	MMIO_DFH(TRTTE, D_SKL_PLUS, F_CMD_ACCESS | F_PM_SAVE,
> > > +		 NULL, gen9_trtte_write);
> > > +	MMIO_DFH(_MMIO(0x4dfc), D_SKL_PLUS, F_PM_SAVE,
> > > +		 NULL, gen9_trtt_chicken_write);
> > >   	MMIO_D(_MMIO(0x46430), D_SKL_PLUS);
> > > @@ -3631,3 +3632,35 @@ int intel_vgpu_mmio_reg_rw(struct intel_vgpu *vgpu, unsigned int offset,
> > >   		intel_vgpu_default_mmio_read(vgpu, offset, pdata, bytes) :
> > >   		intel_vgpu_default_mmio_write(vgpu, offset, pdata, bytes);
> > >   }
> > > +
> > > +static inline int mmio_pm_restore_handler(struct intel_gvt *gvt,
> > > +					  u32 offset, void *data)
> > > +{
> > > +	struct intel_vgpu *vgpu = data;
> > > +	struct drm_i915_private *dev_priv = gvt->gt->i915;
> > > +
> > > +	if (gvt->mmio.mmio_attribute[offset >> 2] & F_PM_SAVE)
> > > +		I915_WRITE(_MMIO(offset), vgpu_vreg(vgpu, offset));
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +void intel_gvt_restore_regs(struct intel_gvt *gvt)
> > > +{
> > > +	struct intel_vgpu *vgpu;
> > > +	int i, id;
> > > +	u64 val;
> > > +
> > > +	for_each_active_vgpu(gvt, vgpu, id) {
> > > +		mmio_hw_access_pre(gvt->gt);
> > > +		for (i = 0; i < vgpu_fence_sz(vgpu); i++) {
> > > +			val = vgpu_vreg64(vgpu, fence_num_to_offset(i));
> > > +			intel_vgpu_write_fence(vgpu, i, val);
> > > +		}
> > > +
> > > +		intel_gvt_for_each_tracked_mmio(gvt,
> > > +						mmio_pm_restore_handler, vgpu);
> > > +
> > > +		mmio_hw_access_post(gvt->gt);
> > > +	}
> > > +}
> > > diff --git a/drivers/gpu/drm/i915/gvt/mmio.h b/drivers/gpu/drm/i915/gvt/mmio.h
> > > index cc4812648bf4..999d9dda0614 100644
> > > --- a/drivers/gpu/drm/i915/gvt/mmio.h
> > > +++ b/drivers/gpu/drm/i915/gvt/mmio.h
> > > @@ -104,4 +104,7 @@ int intel_vgpu_mmio_reg_rw(struct intel_vgpu *vgpu, unsigned int offset,
> > >   int intel_vgpu_mask_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
> > >   				  void *p_data, unsigned int bytes);
> > > +
> > > +void intel_gvt_restore_regs(struct intel_gvt *gvt);
> > > +
> > >   #endif
> > > diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
> > > index f6d7e33c7099..bfe2fb5fcc30 100644
> > > --- a/drivers/gpu/drm/i915/gvt/vgpu.c
> > > +++ b/drivers/gpu/drm/i915/gvt/vgpu.c
> > > @@ -396,6 +396,7 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
> > >   	idr_init(&vgpu->object_idr);
> > >   	intel_vgpu_init_cfg_space(vgpu, param->primary);
> > >   	vgpu->d3_entered = false;
> > > +	vgpu->ggtt_entries = NULL;
> > >   	ret = intel_vgpu_init_mmio(vgpu);
> > >   	if (ret)
> > > diff --git a/drivers/gpu/drm/i915/intel_gvt.c b/drivers/gpu/drm/i915/intel_gvt.c
> > > index 99fe8aef1c67..33650daef567 100644
> > > --- a/drivers/gpu/drm/i915/intel_gvt.c
> > > +++ b/drivers/gpu/drm/i915/intel_gvt.c
> > > @@ -24,6 +24,7 @@
> > >   #include "i915_drv.h"
> > >   #include "i915_vgpu.h"
> > >   #include "intel_gvt.h"
> > > +#include "gvt/gvt.h"
> > >   /**
> > >    * DOC: Intel GVT-g host support
> > > @@ -147,3 +148,31 @@ void intel_gvt_driver_remove(struct drm_i915_private *dev_priv)
> > >   	intel_gvt_clean_device(dev_priv);
> > >   }
> > > +
> > > +/**
> > > + * intel_gvt_suspend - GVT suspend routine wapper
> > > + *
> > > + * @dev_priv: drm i915 private *
> > > + *
> > > + * This function is called at the i915 driver suspend stage to save necessary
> > > + * HW status for GVT so that vGPU can continue running after resume.
> > > + */
> > > +void intel_gvt_suspend(struct drm_i915_private *dev_priv)
> > > +{
> > > +	if (intel_gvt_active(dev_priv))
> > > +		intel_gvt_pm_suspend(dev_priv->gvt);
> > > +}
> > > +
> > > +/**
> > > + * intel_gvt_suspend - GVT resume routine wapper
> > > + *
> > > + * @dev_priv: drm i915 private *
> > > + *
> > > + * This function is called at the i915 driver resume stage to restore required
> > > + * HW status for GVT so that vGPU can continue running after resumed.
> > > + */
> > > +void intel_gvt_resume(struct drm_i915_private *dev_priv)
> > > +{
> > > +	if (intel_gvt_active(dev_priv))
> > > +		intel_gvt_pm_resume(dev_priv->gvt);
> > > +}
> > > diff --git a/drivers/gpu/drm/i915/intel_gvt.h b/drivers/gpu/drm/i915/intel_gvt.h
> > > index 502fad8a8652..5732c7b10ab2 100644
> > > --- a/drivers/gpu/drm/i915/intel_gvt.h
> > > +++ b/drivers/gpu/drm/i915/intel_gvt.h
> > > @@ -33,6 +33,8 @@ int intel_gvt_init_device(struct drm_i915_private *dev_priv);
> > >   void intel_gvt_clean_device(struct drm_i915_private *dev_priv);
> > >   int intel_gvt_init_host(void);
> > >   void intel_gvt_sanitize_options(struct drm_i915_private *dev_priv);
> > > +void intel_gvt_suspend(struct drm_i915_private *dev_priv);
> > > +void intel_gvt_resume(struct drm_i915_private *dev_priv);
> > >   #else
> > >   static inline int intel_gvt_init(struct drm_i915_private *dev_priv)
> > >   {
> > > @@ -46,6 +48,14 @@ static inline void intel_gvt_driver_remove(struct drm_i915_private *dev_priv)
> > >   static inline void intel_gvt_sanitize_options(struct drm_i915_private *dev_priv)
> > >   {
> > >   }
> > > +
> > > +static inline void intel_gvt_suspend(struct drm_i915_private *dev_priv)
> > > +{
> > > +}
> > > +
> > > +static inline void intel_gvt_resume(struct drm_i915_private *dev_priv)
> > > +{
> > > +}
> > >   #endif
> > >   #endif /* _INTEL_GVT_H_ */
> > > -- 
> > > 2.28.0
> > > 
> -- 
> Best Regards,
> Colin Xu
> 

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