>-----Original Message-----
>From: Christian König <[email protected]>
>Sent: Thursday, August 16, 2018 9:24 PM
>To: Deng, Emily <[email protected]>; [email protected]
>Subject: Re: [PATCH 2/2] drm/amdgpu: use kiq to do invalidate tlb
>
>Am 16.08.2018 um 15:05 schrieb Emily Deng:
>> To avoid the tlb flush not interrupted by world switch, use kiq and
>> one command to do tlb invalidate.
>>
>> Signed-off-by: Emily Deng <[email protected]>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 4 +++
>> drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c | 3 --
>> drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 60
>++++++++++++++++++++++++++++++++
>> 3 files changed, 64 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> index 6265b88..19ef7711 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -212,6 +212,10 @@ enum amdgpu_kiq_irq {
>> AMDGPU_CP_KIQ_IRQ_LAST
>> };
>>
>> +#define MAX_KIQ_REG_WAIT 5000 /* in usecs, 5ms */
>> +#define MAX_KIQ_REG_BAILOUT_INTERVAL 5 /* in msecs, 5ms */
>> +#define MAX_KIQ_REG_TRY 20
>> +
>> int amdgpu_device_ip_set_clockgating_state(void *dev,
>> enum amd_ip_block_type block_type,
>> enum amd_clockgating_state state);
>diff --git
>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
>> index 21adb1b6..3885636 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
>> @@ -22,9 +22,6 @@
>> */
>>
>> #include "amdgpu.h"
>> -#define MAX_KIQ_REG_WAIT 5000 /* in usecs, 5ms */
>> -#define MAX_KIQ_REG_BAILOUT_INTERVAL 5 /* in msecs, 5ms */
>> -#define MAX_KIQ_REG_TRY 20
>>
>> uint64_t amdgpu_csa_vaddr(struct amdgpu_device *adev)
>> {
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> index ed467de..6c164bd 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> @@ -311,6 +311,58 @@ static uint32_t
>gmc_v9_0_get_invalidate_req(unsigned int vmid)
>> return req;
>> }
>>
>> +signed long amdgpu_kiq_reg_write_reg_wait(struct amdgpu_device *adev,
>> + uint32_t reg0, uint32_t reg1,
>> + uint32_t ref, uint32_t mask)
>> +{
>> + signed long r, cnt = 0;
>> + unsigned long flags;
>> + uint32_t seq;
>> + struct amdgpu_kiq *kiq = &adev->gfx.kiq;
>> + struct amdgpu_ring *ring = &kiq->ring;
>> +
>> + if (!ring->ready)
>> + return -EINVAL;
>> +
>> + spin_lock_irqsave(&kiq->ring_lock, flags);
>> +
>> + amdgpu_ring_alloc(ring, 32);
>> + amdgpu_ring_emit_reg_write_reg_wait(ring, reg0, reg1,
>> + ref, mask);
>> + amdgpu_fence_emit_polling(ring, &seq);
>> + amdgpu_ring_commit(ring);
>> + spin_unlock_irqrestore(&kiq->ring_lock, flags);
>> +
>> + r = amdgpu_fence_wait_polling(ring, seq, MAX_KIQ_REG_WAIT);
>> +
>> + /* don't wait anymore for gpu reset case because this way may
>> + * block gpu_recover() routine forever, e.g. this virt_kiq_rreg
>> + * is triggered in TTM and ttm_bo_lock_delayed_workqueue() will
>> + * never return if we keep waiting in virt_kiq_rreg, which cause
>> + * gpu_recover() hang there.
>> + *
>> + * also don't wait anymore for IRQ context
>> + * */
>> + if (r < 1 && (adev->in_gpu_reset || in_interrupt()))
>> + goto failed_kiq;
>> +
>> + might_sleep();
>> +
>> + while (r < 1 && cnt++ < MAX_KIQ_REG_TRY) {
>> + msleep(MAX_KIQ_REG_BAILOUT_INTERVAL);
>> + r = amdgpu_fence_wait_polling(ring, seq,
>MAX_KIQ_REG_WAIT);
>> + }
>> +
>> + if (cnt > MAX_KIQ_REG_TRY)
>> + goto failed_kiq;
>> +
>> + return 0;
>> +
>> +failed_kiq:
>> + pr_err("failed to invalidate tlb with kiq\n");
>> + return r;
>> +}
>> +
>> /*
>> * GART
>> * VMID 0 is the physical GPU addresses as used by the kernel.
>> @@ -332,6 +384,7 @@ static void gmc_v9_0_flush_gpu_tlb(struct
>amdgpu_device *adev,
>> /* Use register 17 for GART */
>> const unsigned eng = 17;
>> unsigned i, j;
>> + int r;
>>
>> spin_lock(&adev->gmc.invalidate_lock);
>>
>> @@ -339,6 +392,13 @@ static void gmc_v9_0_flush_gpu_tlb(struct
>amdgpu_device *adev,
>> struct amdgpu_vmhub *hub = &adev->vmhub[i];
>> u32 tmp = gmc_v9_0_get_invalidate_req(vmid);
>>
>> + spin_unlock(&adev->gmc.invalidate_lock);
>
>Well just remove the lock altogether. Taking it and dropping it again
>immediately doesn't do anything useful.
>
>> + r = amdgpu_kiq_reg_write_reg_wait(adev, hub-
>>vm_inv_eng0_req + eng,
>> + hub->vm_inv_eng0_ack + eng, tmp, 1 << vmid);
>> + spin_lock(&adev->gmc.invalidate_lock);
>> + if (!r)
>> + continue;
>> +
>> WREG32_NO_KIQ(hub->vm_inv_eng0_req + eng, tmp);
>>
>> /* Busy wait for ACK.*/
>Since you now use the KIQ to wait for the TLB flush I think we can now remove
>the MMIO implementation.
Ok. If remove the MMIO implementation, then we don't need
adev->gmc.invalidate_lock.
>
>Regards,
>Christian.
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