[PATCH 5.10 130/145] drm/i915: clear the shadow batch

Greg Kroah-Hartman
2021-01-11T13:21:40Z

From: Matthew Auld <matthew.auld@intel.com>

commit 75353bcd2184010f08a3ed2f0da019bd9d604e1e upstream.

The shadow batch is an internal object, which doesn't have any page
clearing, and since the batch_len can be smaller than the object, we
should take care to clear it.

Testcase: igt/gen9_exec_parse/shadow-peek
Fixes: 4f7af1948abc ("drm/i915: Support ro ppgtt mapped cmdparser shadow buffers")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201224151358.401345-1-matthew.auld@intel.com
Cc: stable@vger.kernel.org
(cherry picked from commit eeb52ee6c4a429ec301faf1dc48988744960786e)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/i915/i915_cmd_parser.c | 27 +++++++++------------------
1 file changed, 9 insertions(+), 18 deletions(-)

--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -1166,7 +1166,7 @@ static u32 *copy_batch(struct drm_i915_g
}
}
if (IS_ERR(src)) {
- unsigned long x, n;
+ unsigned long x, n, remain;
void *ptr;

/*
@@ -1177,14 +1177,15 @@ static u32 *copy_batch(struct drm_i915_g
* We don't care about copying too much here as we only
* validate up to the end of the batch.
*/
+ remain = length;
if (!(dst_obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ))
- length = round_up(length,
+ remain = round_up(remain,
boot_cpu_data.x86_clflush_size);

ptr = dst;
x = offset_in_page(offset);
- for (n = offset >> PAGE_SHIFT; length; n++) {
- int len = min(length, PAGE_SIZE - x);
+ for (n = offset >> PAGE_SHIFT; remain; n++) {
+ int len = min(remain, PAGE_SIZE - x);

src = kmap_atomic(i915_gem_object_get_page(src_obj, n));
if (needs_clflush)
@@ -1193,13 +1194,15 @@ static u32 *copy_batch(struct drm_i915_g
kunmap_atomic(src);

ptr += len;
- length -= len;
+ remain -= len;
x = 0;
}
}

i915_gem_object_unpin_pages(src_obj);

+ memset32(dst + length, 0, (dst_obj->base.size - length) / sizeof(u32));
+
/* dst_obj is returned with vmap pinned */
return dst;
}
@@ -1392,11 +1395,6 @@ static unsigned long *alloc_whitelist(u3

#define LENGTH_BIAS 2

-static bool shadow_needs_clflush(struct drm_i915_gem_object *obj)
-{
- return !(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE);
-}
-
/**
* intel_engine_cmd_parser() - parse a batch buffer for privilege violations
* @engine: the engine on which the batch is to execute
@@ -1539,16 +1537,9 @@ int intel_engine_cmd_parser(struct intel
ret = 0; /* allow execution */
}
}
-
- if (shadow_needs_clflush(shadow->obj))
- drm_clflush_virt_range(batch_end, 8);
}

- if (shadow_needs_clflush(shadow->obj)) {
- void *ptr = page_mask_bits(shadow->obj->mm.mapping);
-
- drm_clflush_virt_range(ptr, (void *)(cmd + 1) - ptr);
- }
+ i915_gem_object_flush_map(shadow->obj);

if (!IS_ERR_OR_NULL(jump_whitelist))
kfree(jump_whitelist);