[Intel-gfx] [PATCH v1 02/12] drm/i915: vgpu shared memory setup for pv support
Jani Nikula
jani.nikula at linux.intel.com
Thu Sep 10 13:16:09 UTC 2020
On Sat, 05 Sep 2020, Xiaolin Zhang <xiaolin.zhang at intel.com> wrote:
> To support vgpu pv features, a common shared memory is setup used for
> communication and data exchange between guest and host GVTg to reduce
> data access overhead and trap cost.
>
> guest i915 will allocate this common memory (1 page size) and then pass
> it's physical address to host GVTg through PVINFO register so that host
> GVTg can access this shared guest page meory without trap cost with
> hyperviser's facility.
>
> guest i915 will send VGT_G2V_SHARED_PAGE_SETUP notification to host GVTg
> once shared memory setup succcessfully finished.
>
> the layout of the shared_page also defined as well, the first part is the
> PV vervsion information used for compabilty support.
>
> Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.c | 2 +
> drivers/gpu/drm/i915/i915_drv.h | 4 +-
> drivers/gpu/drm/i915/i915_pvinfo.h | 5 +-
> drivers/gpu/drm/i915/i915_vgpu.c | 94 ++++++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/i915_vgpu.h | 14 ++++++
> 5 files changed, 117 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 00292a8..5fbb4ab 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1071,6 +1071,8 @@ static void i915_driver_release(struct drm_device *dev)
>
> disable_rpm_wakeref_asserts(rpm);
>
> + intel_vgpu_destroy(dev_priv);
> +
> i915_gem_driver_release(dev_priv);
>
> intel_memory_regions_driver_release(dev_priv);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 16d1b51..3cde2c5f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -809,7 +809,9 @@ struct i915_virtual_gpu {
> bool active;
> u32 caps;
> u32 pv_caps;
> -};
> +
> + struct i915_virtual_gpu_pv *pv;
> +} __packed;
I'm unsure why this struct should be packed.
>
> struct intel_cdclk_config {
> unsigned int cdclk, vco, ref, bypass;
> diff --git a/drivers/gpu/drm/i915/i915_pvinfo.h b/drivers/gpu/drm/i915/i915_pvinfo.h
> index 8b0dc25..1d44876 100644
> --- a/drivers/gpu/drm/i915/i915_pvinfo.h
> +++ b/drivers/gpu/drm/i915/i915_pvinfo.h
> @@ -48,6 +48,7 @@ enum vgt_g2v_type {
> VGT_G2V_PPGTT_L4_PAGE_TABLE_DESTROY,
> VGT_G2V_EXECLIST_CONTEXT_CREATE,
> VGT_G2V_EXECLIST_CONTEXT_DESTROY,
> + VGT_G2V_SHARED_PAGE_REGISTER,
> VGT_G2V_MAX,
> };
>
> @@ -112,7 +113,9 @@ struct vgt_if {
>
> u32 pv_caps;
>
> - u32 rsv7[0x200 - 25]; /* pad to one page */
> + u64 shared_page_gpa;
> +
> + u32 rsv7[0x200 - 27]; /* pad to one page */
> } __packed;
>
> #define vgtif_offset(x) (offsetof(struct vgt_if, x))
> diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
> index 10960125..8b2b451 100644
> --- a/drivers/gpu/drm/i915/i915_vgpu.c
> +++ b/drivers/gpu/drm/i915/i915_vgpu.c
> @@ -110,6 +110,17 @@ void intel_vgpu_detect(struct drm_i915_private *dev_priv)
> pci_iounmap(pdev, shared_area);
> }
>
> +void intel_vgpu_destroy(struct drm_i915_private *i915)
> +{
> + struct i915_virtual_gpu_pv *pv = i915->vgpu.pv;
> +
> + if (!intel_vgpu_active(i915) || !pv)
> + return;
> +
> + __free_page(virt_to_page(pv->shared_page));
> + kfree(pv);
> +}
> +
> void intel_vgpu_register(struct drm_i915_private *i915)
> {
> /*
> @@ -360,6 +371,83 @@ int intel_vgt_balloon(struct i915_ggtt *ggtt)
> */
>
> /*
> + * shared_page setup for VGPU PV features
> + */
> +static int intel_vgpu_setup_shared_page(struct drm_i915_private *i915,
> + void __iomem *shared_area)
> +{
> + void __iomem *addr;
> + struct i915_virtual_gpu_pv *pv;
> + struct gvt_shared_page *base;
> + u64 gpa;
> + u16 ver_maj, ver_min;
> + int ret = 0;
> +
> + /* We allocate 1 page shared between guest and GVT for data exchange.
> + * _______________________________
> + * |version |
> + * |_______________________________PAGE/8
> + * | |
> + * |_______________________________PAGE/4
> + * | |
> + * | |
> + * | |
> + * |_______________________________PAGE/2
> + * | |
> + * | |
> + * | |
> + * | |
> + * | |
> + * | |
> + * | |
> + * |_______________________________|
> + *
> + * 0 offset: PV version area
> + */
> +
> + base = (struct gvt_shared_page *)get_zeroed_page(GFP_KERNEL);
> + if (!base) {
> + dev_info(i915->drm.dev, "out of memory for shared memory\n");
> + return -ENOMEM;
> + }
> +
> + /* pass guest memory pa address to GVT and then read back to verify */
> + gpa = __pa(base);
> + addr = shared_area + vgtif_offset(shared_page_gpa);
> + writeq(gpa, addr);
> + if (gpa != readq(addr)) {
> + dev_info(i915->drm.dev, "passed shared_page_gpa failed\n");
> + ret = -EIO;
> + goto err;
> + }
> +
> + addr = shared_area + vgtif_offset(g2v_notify);
> + writel(VGT_G2V_SHARED_PAGE_REGISTER, addr);
> +
> + ver_maj = base->ver_major;
> + ver_min = base->ver_minor;
> + if (ver_maj != PV_MAJOR || ver_min != PV_MINOR) {
> + dev_info(i915->drm.dev, "VGPU PV version incompatible\n");
> + ret = -EIO;
> + goto err;
> + }
> +
> + pv = kzalloc(sizeof(struct i915_virtual_gpu_pv), GFP_KERNEL);
> + if (!pv) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + DRM_INFO("vgpu PV ver major %d and minor %d\n", ver_maj, ver_min);
Please use drm_info(), and please polish the message for info
level. This looks like debug to me.
> + i915->vgpu.pv = pv;
> + pv->shared_page = base;
> + return ret;
> +err:
> + __free_page(virt_to_page(base));
> + return ret;
> +}
> +
> +/*
> * Config vgpu PV ops for different PV capabilities
> */
> void intel_vgpu_config_pv_caps(struct drm_i915_private *i915,
> @@ -395,5 +483,11 @@ bool intel_vgpu_detect_pv_caps(struct drm_i915_private *i915,
> if (!pvcaps)
> return false;
>
> + if (intel_vgpu_setup_shared_page(i915, shared_area)) {
> + i915->vgpu.pv_caps = 0;
> + writel(0, shared_area + vgtif_offset(pv_caps));
> + return false;
> + }
> +
> return true;
> }
> diff --git a/drivers/gpu/drm/i915/i915_vgpu.h b/drivers/gpu/drm/i915/i915_vgpu.h
> index 1b10175..aeef20f 100644
> --- a/drivers/gpu/drm/i915/i915_vgpu.h
> +++ b/drivers/gpu/drm/i915/i915_vgpu.h
> @@ -29,12 +29,26 @@
> struct drm_i915_private;
> struct i915_ggtt;
>
> +#define PV_MAJOR 0
> +#define PV_MINOR 1
> +
> /* define different PV capabilities */
> enum pv_caps {
> PV_NONE = 0,
> };
>
> +/* A common shared page(4KB) between GVTg and vgpu allocated by guest */
> +struct gvt_shared_page {
Prefix with intel_?
> + u16 ver_major;
> + u16 ver_minor;
> +};
> +
> +struct i915_virtual_gpu_pv {
Why i915_virtual_gpu instead of intel_vgpu like everywhere else?
> + struct gvt_shared_page *shared_page;
> +};
> +
> void intel_vgpu_detect(struct drm_i915_private *i915);
> +void intel_vgpu_destroy(struct drm_i915_private *i915);
> bool intel_vgpu_active(struct drm_i915_private *i915);
> void intel_vgpu_register(struct drm_i915_private *i915);
> bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *i915);
--
Jani Nikula, Intel Open Source Graphics Center
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