linux-kernel - [PATCH v4 07/29] drm/i915/gvt: Error out on an attempt to shadowing an unknown GTT entry type

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Message-ID: <20230729013535.1070024-8-seanjc@google.com>
Date:   Fri, 28 Jul 2023 18:35:13 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>,
        Zhi Wang <zhi.a.wang@...el.com>
Cc:     kvm@...r.kernel.org, intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Yan Zhao <yan.y.zhao@...el.com>,
        Yongwei Ma <yongwei.ma@...el.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: [PATCH v4 07/29] drm/i915/gvt: Error out on an attempt to shadowing
 an unknown GTT entry type

Bail from ppgtt_populate_shadow_entry() if an unexpected GTT entry type
is encountered instead of subtly falling through to the common "direct
shadow" path.  Eliminating the default/error path's reliance on the common
handling will allow hoisting intel_gvt_dma_map_guest_page() into the case
statements so that the 2MiB case can try intel_gvt_dma_map_guest_page()
and fallback to splitting the entry on failure.

Reviewed-by: Zhi Wang <zhi.a.wang@...el.com>
Tested-by: Yongwei Ma <yongwei.ma@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 drivers/gpu/drm/i915/gvt/gtt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 2aed31b497c9..61e38acee2d5 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -1306,6 +1306,7 @@ static int ppgtt_populate_shadow_entry(struct intel_vgpu *vgpu,
 		return -EINVAL;
 	default:
 		GEM_BUG_ON(1);
+		return -EINVAL;
 	}
 
 	/* direct shadow */
-- 
2.41.0.487.g6d72f3e995-goog