From cfe65f4037cedb911a840ebcf6dafc5b69e535b4 Mon Sep 17 00:00:00 2001 From: Changbin Du Date: Fri, 13 Jan 2017 11:16:02 +0800 Subject: [PATCH] drm/i915/gvt: fix vGPU instance reuse issues by vGPU reset function Our function tests found several issues related to reusing vGPU instance. They are qemu reboot failure, guest tdr after reboot, host hang when reboot guest. All these issues are caused by dirty status inherited from last VM. This patch fix all these issues by resetting a virtual GPU before VM use it. The reset logical is put into a low level function _intel_gvt_reset_vgpu(), which supports Device Model Level Reset, Full GT Reset and Per-Engine Reset. vGPU Device Model Level Reset (DMLR) simulates the PCI reset to reset the whole vGPU to default state as when it is created, including GTT, execlist, scratch pages, cfg space, mmio space, pvinfo page, scheduler and fence registers. The ultimate goal of vGPU DMLR is that reuse a vGPU instance by different virtual machines. When we reassign a vGPU to a virtual machine we must issue such reset first. Full GT Reset and Per-Engine GT Reset are soft reset flow for GPU engines (Render, Blitter, Video, Video Enhancement). It is defined by GPU Spec. Unlike the FLR, GT reset only reset particular resource of a vGPU per the reset request. Guest driver can issue a GT reset by programming the virtual GDRST register to reset specific virtual GPU engine or all engines. Since vGPU DMLR and GT reset can share some code so we implement both these two into one single function intel_gvt_reset_vgpu_locked(). The parameter dmlr is to identify if we will do FLR or GT reset. The parameter engine_mask is to specific the engines that need to be resetted. If value ALL_ENGINES is given for engine_mask, it means the caller requests a full gt reset that we will reset all virtual GPU engines. Signed-off-by: Changbin Du Reviewed-by: Jike Song Reviewed-by: Kevin Tian Signed-off-by: Zhenyu Wang --- drivers/gpu/drm/i915/gvt/gvt.h | 2 + drivers/gpu/drm/i915/gvt/vgpu.c | 73 ++++++++++++++++++++++++++++++++- 2 files changed, 74 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h index 9832e7f2a662..e227caf5859e 100644 --- a/drivers/gpu/drm/i915/gvt/gvt.h +++ b/drivers/gpu/drm/i915/gvt/gvt.h @@ -376,6 +376,8 @@ void intel_gvt_clean_vgpu_types(struct intel_gvt *gvt); struct intel_vgpu *intel_gvt_create_vgpu(struct intel_gvt *gvt, struct intel_vgpu_type *type); void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu); +void intel_gvt_reset_vgpu_locked(struct intel_vgpu *vgpu, bool dmlr, + unsigned int engine_mask); void intel_gvt_reset_vgpu(struct intel_vgpu *vgpu); diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c index 958c3ed1c6c6..7295bc8e12fb 100644 --- a/drivers/gpu/drm/i915/gvt/vgpu.c +++ b/drivers/gpu/drm/i915/gvt/vgpu.c @@ -327,7 +327,75 @@ struct intel_vgpu *intel_gvt_create_vgpu(struct intel_gvt *gvt, } /** - * intel_gvt_reset_vgpu - reset a virtual GPU + * intel_gvt_reset_vgpu_locked - reset a virtual GPU by DMLR or GT reset + * @vgpu: virtual GPU + * @dmlr: vGPU Device Model Level Reset or GT Reset + * @engine_mask: engines to reset for GT reset + * + * This function is called when user wants to reset a virtual GPU through + * device model reset or GT reset. The caller should hold the gvt lock. + * + * vGPU Device Model Level Reset (DMLR) simulates the PCI level reset to reset + * the whole vGPU to default state as when it is created. This vGPU function + * is required both for functionary and security concerns.The ultimate goal + * of vGPU FLR is that reuse a vGPU instance by virtual machines. When we + * assign a vGPU to a virtual machine we must isse such reset first. + * + * Full GT Reset and Per-Engine GT Reset are soft reset flow for GPU engines + * (Render, Blitter, Video, Video Enhancement). It is defined by GPU Spec. + * Unlike the FLR, GT reset only reset particular resource of a vGPU per + * the reset request. Guest driver can issue a GT reset by programming the + * virtual GDRST register to reset specific virtual GPU engine or all + * engines. + * + * The parameter dev_level is to identify if we will do DMLR or GT reset. + * The parameter engine_mask is to specific the engines that need to be + * resetted. If value ALL_ENGINES is given for engine_mask, it means + * the caller requests a full GT reset that we will reset all virtual + * GPU engines. For FLR, engine_mask is ignored. + */ +void intel_gvt_reset_vgpu_locked(struct intel_vgpu *vgpu, bool dmlr, + unsigned int engine_mask) +{ + struct intel_gvt *gvt = vgpu->gvt; + struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler; + + gvt_dbg_core("------------------------------------------\n"); + gvt_dbg_core("resseting vgpu%d, dmlr %d, engine_mask %08x\n", + vgpu->id, dmlr, engine_mask); + vgpu->resetting = true; + + intel_vgpu_stop_schedule(vgpu); + /* + * The current_vgpu will set to NULL after stopping the + * scheduler when the reset is triggered by current vgpu. + */ + if (scheduler->current_vgpu == NULL) { + mutex_unlock(&gvt->lock); + intel_gvt_wait_vgpu_idle(vgpu); + mutex_lock(&gvt->lock); + } + + intel_vgpu_reset_execlist(vgpu, dmlr ? ALL_ENGINES : engine_mask); + + /* full GPU reset or device model level reset */ + if (engine_mask == ALL_ENGINES || dmlr) { + intel_vgpu_reset_gtt(vgpu, dmlr); + intel_vgpu_reset_resource(vgpu); + intel_vgpu_reset_mmio(vgpu); + populate_pvinfo_page(vgpu); + + if (dmlr) + intel_vgpu_reset_cfg_space(vgpu); + } + + vgpu->resetting = false; + gvt_dbg_core("reset vgpu%d done\n", vgpu->id); + gvt_dbg_core("------------------------------------------\n"); +} + +/** + * intel_gvt_reset_vgpu - reset a virtual GPU (Function Level) * @vgpu: virtual GPU * * This function is called when user wants to reset a virtual GPU. @@ -335,4 +403,7 @@ struct intel_vgpu *intel_gvt_create_vgpu(struct intel_gvt *gvt, */ void intel_gvt_reset_vgpu(struct intel_vgpu *vgpu) { + mutex_lock(&vgpu->gvt->lock); + intel_gvt_reset_vgpu_locked(vgpu, true, 0); + mutex_unlock(&vgpu->gvt->lock); } -- 2.39.5