Lionel pointed out that INSTPM was context saved, at least from gen6,
not from gen9. The only caveat is that INSTPM is a masked register (the
upper 16bits are a write-enable mask, the lower 16bits the value to
change) and also contains a read-only counter bit (which counts flushes,
and so flip flops between batches). Being a non-privileged register that
userspace wants to manipulate, it is writable and readable from a
userspace batch, so we can test whether or not a write from one context
is visible from a second.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
tests/gem_ctx_isolation.c | 51 ++++++++++++++++++++++++++++++++-------
1 file changed, 42 insertions(+), 9 deletions(-)
diff --git a/tests/gem_ctx_isolation.c b/tests/gem_ctx_isolation.c
index 4968e3678..fe7d3490c 100644
--- a/tests/gem_ctx_isolation.c
+++ b/tests/gem_ctx_isolation.c
@@ -63,10 +63,12 @@ static const struct named_register {
unsigned int engine_mask;
uint32_t offset;
uint32_t count;
+ uint32_t ignore_bits;
+ bool masked;
} nonpriv_registers[] = {
{ "NOPID", NOCTX, RCS0, 0x2094 },
{ "MI_PREDICATE_RESULT_2", NOCTX, RCS0, 0x23bc },
- { "INSTPM", GEN9, RCS0, 0x20c0 },
+ { "INSTPM", GEN6, RCS0, 0x20c0, 1, BIT(8) /* ro counter */, true },
{ "IA_VERTICES_COUNT", GEN4, RCS0, 0x2310, 2 },
{ "IA_PRIMITIVES_COUNT", GEN4, RCS0, 0x2318, 2 },
{ "VS_INVOCATION_COUNT", GEN4, RCS0, 0x2320, 2 },
@@ -167,6 +169,17 @@ static const char *register_name(uint32_t offset, char *buf, size_t len)
return "unknown";
}
+static const struct named_register *lookup_register(uint32_t offset)
+{
+ for (const struct named_register *r = nonpriv_registers; r->name; r++) {
+ unsigned int width = r->count ? 4*r->count : 4;
+ if (offset >= r->offset && offset < r->offset + width)
+ return r;
+ }
+
+ return NULL;
+}
+
static bool ignore_register(uint32_t offset)
{
for (const struct named_register *r = ignore_registers; r->name; r++) {
@@ -283,7 +296,10 @@ static void write_regs(int fd,
count--; offset += 4) {
*b++ = 0x22 << 23 | 1; /* LRI */
*b++ = offset;
- *b++ = value;
+ if (r->masked)
+ *b++ = value | 0xffffu << 16;
+ else
+ *b++ = value;
}
}
*b++ = MI_BATCH_BUFFER_END;
@@ -424,14 +440,31 @@ static void compare_regs(int fd, uint32_t A, uint32_t B, const char *who)
num_errors = 0;
for (unsigned int n = 0; n < NUM_REGS; n++) {
+ const struct named_register *r;
uint32_t offset = n * sizeof(uint32_t);
- if (a[n] != b[n] && !ignore_register(offset)) {
- igt_warn("Register 0x%04x (%s): A=%08x B=%08x\n",
- offset,
- register_name(offset, buf, sizeof(buf)),
- a[n], b[n]);
- num_errors++;
- }
+ uint32_t mask;
+
+ if (a[n] == b[n])
+ continue;
+
+ if (ignore_register(offset))
+ continue;
+
+ mask = ~0u;
+ r = lookup_register(offset);
+ if (r && r->masked)
+ mask >>= 16;
+ if (r && r->ignore_bits)
+ mask &= ~r->ignore_bits;
+
+ if ((a[n] & mask) == (b[n] & mask))
+ continue;
+
+ igt_warn("Register 0x%04x (%s): A=%08x B=%08x\n",
+ offset,
+ register_name(offset, buf, sizeof(buf)),
+ a[n] & mask, b[n] & mask);
+ num_errors++;
}
munmap(b, regs_size);
munmap(a, regs_size);
--
2.17.0
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